T
The Ghost of FM
Banned
Nice restoration job, Cory! 
Those last few pics clearly show that you are superior to Photoshop!
Cheers!
Those last few pics clearly show that you are superior to Photoshop!
Cheers!
sweetbeats
Reel deep thoughts...
"sweetbeats --- superior to Photoshop" THAT'S a new one...heheh.
Thanks, Ghost.
So I spent quite awhile last night somewhat exhaustively going through the wiring from the control box to everything else, and then between different sections of the machine to try and chase down the problem with the channels that aren't going into record. Once again I am stumped.
I DID find a number of details that, though not the cause of the problem, weren't good and are now rectified. I'll go into those below with pics of course.
What I know so far:
And it is still intermittent on some. Usually I only get channels 1, 6 and 8 to kick into record, and sometimes channel 2. Last night there was another one that popped up but only when I had channels 4 and 6 disconnected.
OH! And its not just bad lamps because I've checked that and the lamps are good.
I had wondered if it was related to a problem in one of the two audio power supplies (one provides power and logic pass-through for channels 1, 3, 5 and 7, and the other does channels 2, 4, 6 and 8), but there is no pattern that coincides with the assignment of each supply...IOW if the problem was with just channels 1, 3, 5, and 7 then, well, you know what would be at the top of the suspect list...something with that power supply.
So, I'm just stumped right now. At least all my work on the control box and cabling last night has rectified the issue with the record button killing the transport power supply...all transport logic functions are working great.
Here is some of what I found in my point-to-point sleuthing:
This is the 24-pin Cinch Jones plug exposed that plugs into J2 on the control box which, again, handles all logic I/O:
There are pins that go through the connector block and hood to fix the hood to the block. Sometimes there is 1, sometimes 2 pins. On a plug this size there are 2...you can see the small holes there along the top of the block. Well, problem #1 was that only 1 of the 2 pins was present, and the 1 pin that was there was not the right length...too short. See here...I've got the pin that was installed on the right in my hand and a proper length pin on the left.
I pulled the pins out of the J3 plug for now since I'm not using that one anyway at this time...I'll dig through spares later and replace those. Anyway, the way it was it could appear that the plug is all the way seated since the hood would be bottomed to the back of the control box, but the connector block was able to shift inside the hood and I wasn't getting reliable contact.
I also cleaned all the pins and did the repairs on those 3 sockets on the female connector mounted to the control box as I mentioned previously. Here's what those sockets look like when they are removed from the block:
The male pins fit into the "U" of the socket. The sockets should look more like this:
So that's what I did for EVERY FAMALE CINCH JONES CONNECTOR ON THE MACHINE LAST NIGHT...inspected each female contact and any sockets that were opened up I pulled the hood on that plug, removed the socket from the connector block, tweaked the contacts and reinstalled.
Kind of hard to see but this is the plug that connects to J1 on the control box. This provides AC and DC input to the control box. Pretty important. The 2 left-most sockets are the +24V and 24V common. Again, kind of hard to see but down in there the contacts are more that "U" shape instead of a nice "V" shape.
Before:
After:
The is what I found in 1 of the 10-pin input cables to channel 2 electronics...this is the contact that is supposed to provide holding voltage to the record relay; the one at the top...it was all messed up...I hadn't yet removed it. That's what it looked like when I removed the connector hood. Didn't make any difference with improving my problem, but I'm sure this would have caused me headaches at *some* point.
So anyway, I have NO idea where to go from here. It was all working fine, then several months ago that cap blew in one of the audio power supplies and the next time I tried out the transport functions after getting the supply recapped and cleaned up I have this problem with record arming. Not convinced they are related, but also not convinced they AREN'T.
Word to the wise: if you haven't figured it out yet, refurbishing old "big iron" can take a lot of time and patience. I mostly enjoy the process. Its part of the fun, and I really liked this machine from the get-go...at no point in all this have I ever felt like letting it go or like I made a mistake. I've been discouraged sure...but never to the point of thinking "maybe I should just deep-six this thing." My point is that these simple old electronics and mechanicals are VERY hearty and can function EXTREMELY reliably when brought back to proper condition, but that's the rub...after 40+ years, some neglect, and a lot of miles there is work to do and it is important to do it right and take the time or you just end up chasing your tail. It'll be a great reward at the end and I'll know the machine inside and out and, literally, it'll be ready for another 40+ years. It just takes...time, and patience.
Thanks, Ghost.
So I spent quite awhile last night somewhat exhaustively going through the wiring from the control box to everything else, and then between different sections of the machine to try and chase down the problem with the channels that aren't going into record. Once again I am stumped.
I DID find a number of details that, though not the cause of the problem, weren't good and are now rectified. I'll go into those below with pics of course.
What I know so far:
- The record relays are getting good grounding, good energizing voltage and good holding voltage. I've confirmed this in theory with an ohmmeter all the way from the control box through allllll the guts all the way up to each electronics module, and in operation with a voltmeter. I say "good" voltage assuming about +22.5VDC is adequate to trip the relays. One question I have is whether or not that is the proper output for that power supply under load. The trick is that there are no instructions for setting the output voltage. I can see schematically where the trimmer is for the output adjustment on the supply and I know physically where it is, but what I don't know is the procedure or parameters for adjusting. Is it done under load, isolated, etc. There are instructions in the manual for adjusting the audio supplies but not the transport power supply. The transport power supply is not made by Ampex and I guess they chose not to include maintenance instructions in the manual even though they included everything else about it. As I said the output of this +24VDC supply is about +22.5VDC under load (capstan and reel motors spinning away, etc.). I'm sure it can be adjusted to +24VDC under load but I don't know if that is proper or not and whether or not that would make any difference. I'm assuming the 24V "ice-cube" relays used for the record relays will operate at 22.5V...I'd be surprised if they didn't, but I still have to wonder.
- I've tried swapping record relays to see if I've got a bunch of bum relays but the problem doesn't move with the relays.
- I've tried swapping record cards to see if I've got a bunch of bum cards but the problem doesn't move with the cards.
- I've tried swapping cabling but (IIRC because its been a bit since I did that) the problem doesn't follow the cabling.
And it is still intermittent on some. Usually I only get channels 1, 6 and 8 to kick into record, and sometimes channel 2. Last night there was another one that popped up but only when I had channels 4 and 6 disconnected.
OH! And its not just bad lamps because I've checked that and the lamps are good.
I had wondered if it was related to a problem in one of the two audio power supplies (one provides power and logic pass-through for channels 1, 3, 5 and 7, and the other does channels 2, 4, 6 and 8), but there is no pattern that coincides with the assignment of each supply...IOW if the problem was with just channels 1, 3, 5, and 7 then, well, you know what would be at the top of the suspect list...something with that power supply.
So, I'm just stumped right now. At least all my work on the control box and cabling last night has rectified the issue with the record button killing the transport power supply...all transport logic functions are working great.
Here is some of what I found in my point-to-point sleuthing:
This is the 24-pin Cinch Jones plug exposed that plugs into J2 on the control box which, again, handles all logic I/O:
There are pins that go through the connector block and hood to fix the hood to the block. Sometimes there is 1, sometimes 2 pins. On a plug this size there are 2...you can see the small holes there along the top of the block. Well, problem #1 was that only 1 of the 2 pins was present, and the 1 pin that was there was not the right length...too short. See here...I've got the pin that was installed on the right in my hand and a proper length pin on the left.
I pulled the pins out of the J3 plug for now since I'm not using that one anyway at this time...I'll dig through spares later and replace those. Anyway, the way it was it could appear that the plug is all the way seated since the hood would be bottomed to the back of the control box, but the connector block was able to shift inside the hood and I wasn't getting reliable contact.
I also cleaned all the pins and did the repairs on those 3 sockets on the female connector mounted to the control box as I mentioned previously. Here's what those sockets look like when they are removed from the block:
The male pins fit into the "U" of the socket. The sockets should look more like this:
So that's what I did for EVERY FAMALE CINCH JONES CONNECTOR ON THE MACHINE LAST NIGHT...inspected each female contact and any sockets that were opened up I pulled the hood on that plug, removed the socket from the connector block, tweaked the contacts and reinstalled.
Kind of hard to see but this is the plug that connects to J1 on the control box. This provides AC and DC input to the control box. Pretty important. The 2 left-most sockets are the +24V and 24V common. Again, kind of hard to see but down in there the contacts are more that "U" shape instead of a nice "V" shape.
Before:
After:
The is what I found in 1 of the 10-pin input cables to channel 2 electronics...this is the contact that is supposed to provide holding voltage to the record relay; the one at the top...it was all messed up...I hadn't yet removed it. That's what it looked like when I removed the connector hood. Didn't make any difference with improving my problem, but I'm sure this would have caused me headaches at *some* point.
So anyway, I have NO idea where to go from here. It was all working fine, then several months ago that cap blew in one of the audio power supplies and the next time I tried out the transport functions after getting the supply recapped and cleaned up I have this problem with record arming. Not convinced they are related, but also not convinced they AREN'T.
Word to the wise: if you haven't figured it out yet, refurbishing old "big iron" can take a lot of time and patience. I mostly enjoy the process. Its part of the fun, and I really liked this machine from the get-go...at no point in all this have I ever felt like letting it go or like I made a mistake. I've been discouraged sure...but never to the point of thinking "maybe I should just deep-six this thing." My point is that these simple old electronics and mechanicals are VERY hearty and can function EXTREMELY reliably when brought back to proper condition, but that's the rub...after 40+ years, some neglect, and a lot of miles there is work to do and it is important to do it right and take the time or you just end up chasing your tail. It'll be a great reward at the end and I'll know the machine inside and out and, literally, it'll be ready for another 40+ years. It just takes...time, and patience.
Last edited:
L
lukpac
New member
More good stuff.
Not really related to your recent work, but while searching some old Ampex digests I came across some Les Paul 300-8/Octopus posts, which made some comparisons to the MM-1000. Wondering if you could offer some input:
- It was mentioned the Octopus would have been a bear to punch in on, as there would have been 3 separate changes to be made (safe to record ready, output from sync to line, and...there was one more). I thought the person indicated the MM-1000 made the whole process much easier, but I seem to recall reading somewhere above that it was a similar process, and only using the remote made it *slightly* easier. Thoughts?
- Also mentioned was the poor sync response, and that again, that was far better (almost as good as repro?) on the MM-1000. Again, any thoughts?
I think I have the message saved at home if anybody is interested.
Not really related to your recent work, but while searching some old Ampex digests I came across some Les Paul 300-8/Octopus posts, which made some comparisons to the MM-1000. Wondering if you could offer some input:
- It was mentioned the Octopus would have been a bear to punch in on, as there would have been 3 separate changes to be made (safe to record ready, output from sync to line, and...there was one more). I thought the person indicated the MM-1000 made the whole process much easier, but I seem to recall reading somewhere above that it was a similar process, and only using the remote made it *slightly* easier. Thoughts?
- Also mentioned was the poor sync response, and that again, that was far better (almost as good as repro?) on the MM-1000. Again, any thoughts?
I think I have the message saved at home if anybody is interested.
sweetbeats
Reel deep thoughts...
Here's the deal...the "one more" task is to hold the record button and simultaneously hit PLAY to engage record mode. So yep, you've got to arm the track, switch the source and put the machine into record all at once.
That is the procedure with the "classic" MM-1000, the early version. The later versions (and somewhere I have serial number info as to when the change took place) have "auto-input switching". This is the same as the option available for the 440-8 (starting with the "B" versions) called the "Signal Monitoring Kit" which automatically switched the source when you did the other functions so only two hands were needed.
Any non-auto-input switching MM-1000 can be converted to auto-input switching but it ain't cheap unless you can find the auto-input switching electronics...which...ain't cheap. The schematics are available and at some point I will have pics of the applicable guts and scans of the original switcher PCB's which in the MM-1000 is the main part of the upgrade. The signal monitoring kit also provided a remote with the track-by-track reproduce mode and/or track arming, but that same hardware is already built into the control panel of the MM-1000 so the only REAL difference is some harnessing additions and the installation of the switcher cards and associated changes to the electronics module to accomodate them. Then the latest and best punch-in change is the bias PURC cards which provide for gapless punch-ins.
I may or may not try to convert mine to auto-input switching at some point, but maybe not. I don't really do punches.
So the short answer is that the MM-1000 DID make it a whole lot easier (if it was outfitted with auto-input switching) AND it was very similar to the Octopus (in classic non-auto-input switching trim).
Sync response...yes the MM-1000 has differing gaps between the record and playback heads which optimizes the record response and the reproduce response but doesn't help for sync response. Improvements in the head design would have accounted for better sync response from the Octopus to the MM-1000, and understand that the heads on the Octopus were a custom affair:
The MM-1000 production run ended before there were further improvements to the head construction which ultimately was the shift to identical gaps between the two heads which you will find on the MM-1100 and MM-1200 machines. There was an intermediate step on the 440-8 when the 440C-8 came out. The 440C heads had something like triple the number of laminations which accounted from some improvements in HF response on the playback head and most notably improved HF sync response off the record head. All of the factory heads fitted to the MM-1000 featured construction akin to the 440B heads.
I happen to have the near-new 440C-8 heads ready to go as setup by JFR...still sitting in the box on the transport. There are different reproduce cards to go along with the heads...different output transformer so if all you 8-track MM-1000 owners out there decide you're going to go getcherself a set of 440C heads for your machine don't forget to pick up a set of repro cards too.
The 440C type heads offer the best potential response range in terms of Ampex heads on the MM-1000, but naturally you are limited to 1" 8-track operation. At some point I'll be able to do a comparison because I also have a set of the original MM-1000 1" heads (the 440B type) as well as a set of IEM heads.
I don't know if I would say that the sync response with the 440C type heads is "almost as good as repro". AFAIK there is still a very audible difference between playback off the record head vs. the playback head, but it is far less of a distraction if you know what I mean.
Personally I think the comparison of the Octopus and the MM-1000 is a bit obtuse...I rather think a more appropriate comparison is the Octopus to the 440-8, but then the MM-1000 is just an overgrown 440-8 right? Or is it a quad VTR converted for audio-only use?
That is the procedure with the "classic" MM-1000, the early version. The later versions (and somewhere I have serial number info as to when the change took place) have "auto-input switching". This is the same as the option available for the 440-8 (starting with the "B" versions) called the "Signal Monitoring Kit" which automatically switched the source when you did the other functions so only two hands were needed.
Any non-auto-input switching MM-1000 can be converted to auto-input switching but it ain't cheap unless you can find the auto-input switching electronics...which...ain't cheap. The schematics are available and at some point I will have pics of the applicable guts and scans of the original switcher PCB's which in the MM-1000 is the main part of the upgrade. The signal monitoring kit also provided a remote with the track-by-track reproduce mode and/or track arming, but that same hardware is already built into the control panel of the MM-1000 so the only REAL difference is some harnessing additions and the installation of the switcher cards and associated changes to the electronics module to accomodate them. Then the latest and best punch-in change is the bias PURC cards which provide for gapless punch-ins.
I may or may not try to convert mine to auto-input switching at some point, but maybe not. I don't really do punches.
So the short answer is that the MM-1000 DID make it a whole lot easier (if it was outfitted with auto-input switching) AND it was very similar to the Octopus (in classic non-auto-input switching trim).
Sync response...yes the MM-1000 has differing gaps between the record and playback heads which optimizes the record response and the reproduce response but doesn't help for sync response. Improvements in the head design would have accounted for better sync response from the Octopus to the MM-1000, and understand that the heads on the Octopus were a custom affair:
The MM-1000 production run ended before there were further improvements to the head construction which ultimately was the shift to identical gaps between the two heads which you will find on the MM-1100 and MM-1200 machines. There was an intermediate step on the 440-8 when the 440C-8 came out. The 440C heads had something like triple the number of laminations which accounted from some improvements in HF response on the playback head and most notably improved HF sync response off the record head. All of the factory heads fitted to the MM-1000 featured construction akin to the 440B heads.
I happen to have the near-new 440C-8 heads ready to go as setup by JFR...still sitting in the box on the transport. There are different reproduce cards to go along with the heads...different output transformer so if all you 8-track MM-1000 owners out there decide you're going to go getcherself a set of 440C heads for your machine don't forget to pick up a set of repro cards too.
The 440C type heads offer the best potential response range in terms of Ampex heads on the MM-1000, but naturally you are limited to 1" 8-track operation. At some point I'll be able to do a comparison because I also have a set of the original MM-1000 1" heads (the 440B type) as well as a set of IEM heads.
I don't know if I would say that the sync response with the 440C type heads is "almost as good as repro". AFAIK there is still a very audible difference between playback off the record head vs. the playback head, but it is far less of a distraction if you know what I mean.
Personally I think the comparison of the Octopus and the MM-1000 is a bit obtuse...I rather think a more appropriate comparison is the Octopus to the 440-8, but then the MM-1000 is just an overgrown 440-8 right? Or is it a quad VTR converted for audio-only use?
L
lukpac
New member
Are you saying you have to hit record/play even after the transport is moving? Because you generally would start rolling a bit before the spot you wanted to punch in. I know on my Teac 2340 (same thing, right?!), you would press record when you started rolling, then switch the source and arm the track at the spot you wanted to punch in.
This was the post, FWIW:
sweetbeats
Reel deep thoughts...
Huh!
The problem DOES follow the cabling...!
Luke, No, you can ready a track but if you ready it after the transport is in record then you have to re-initiate record.
And in that quote comparing the Octopus and the MM-1000, if the person who said that doesn't think much of the 440 in sync mode, then they wouldn't think much of the MM-1000...head type are one and the same. I honestly think they were thinking of the MM-1100 or MM-1200. Could have had aftermarket heads on it with identical gaps but that would also mean mods to the record and repro cards because the amp circuitry is tailored to the gaps.
And yes the MM-1000 did deal with punch-in noise and making the punch-in more automated but that wasn't until LATE in the MM-1000 cycle with the auto-input switching and bias PURC cards.
Now back to my record arming problem...the problem follows the cabling, so its NOT in the electronics...but...WHERE????????
The problem DOES follow the cabling...!
Luke, No, you can ready a track but if you ready it after the transport is in record then you have to re-initiate record.
And in that quote comparing the Octopus and the MM-1000, if the person who said that doesn't think much of the 440 in sync mode, then they wouldn't think much of the MM-1000...head type are one and the same. I honestly think they were thinking of the MM-1100 or MM-1200. Could have had aftermarket heads on it with identical gaps but that would also mean mods to the record and repro cards because the amp circuitry is tailored to the gaps.
And yes the MM-1000 did deal with punch-in noise and making the punch-in more automated but that wasn't until LATE in the MM-1000 cycle with the auto-input switching and bias PURC cards.
Now back to my record arming problem...the problem follows the cabling, so its NOT in the electronics...but...WHERE????????
L
lukpac
New member
Thanks for the punch-in info. I think I mostly understand...
Details? Are you swapping the cables on both ends, or just on the electronics side?
Details? Are you swapping the cables on both ends, or just on the electronics side?
sweetbeats
Reel deep thoughts...
Just on the electronics side.
I'm actually pretty excited because that's a pretty substantial clue...
I'm actually pretty excited because that's a pretty substantial clue...
L
lukpac
New member
You certainly know far more about that than I do, but I just mentioned it wondering if there could be an issue with something that the other ends of the cables connect to, rather than the actual cables. Of course, if you've already looked into that, feel free to ignore me...
sweetbeats
Reel deep thoughts...
Oh I pretty much try to ignore nothing. I spent 3 frustrating hours tearing off the top end of our tractor once because I couldn't get it started only to realize that I'd forgotten to switch the fuel valve on.
It does appear that it is indeed coming down to the cabling somehow though I can't conceive of how or why, but those traps have to be ignored. By moving the cable that carries the signal to the record relay from an electronics module that is working to one that is not, and then to have the one that wasn't working work with the cable from the working one tells me its not the module. As you had asked I had ALSO tried moving a working cable set from jack to jack on the power supply and it doesn't matter what jack its plugged into, it works. I then did a redundant check and took a cable set that WASN'T working and moved it from jack to jack and it never worked. So it is a problem with the harnessing I believe but there are other elements at play because there are other components in that relay circuit on other cable sets...have to have it all plugged in in order to test the function but then that becomes self-defeating if there is, say, a short in that additional circuit...have to have it plugged in to test, but having it plugged in kills it. So the trick is to try and deduce where the problem is and start doing some comparative measurements between a known working set and one that isn't working, hope to find some differences between the two where there shouldn't be, and then track down why they are different.
I have a hunch...
It does appear that it is indeed coming down to the cabling somehow though I can't conceive of how or why, but those traps have to be ignored. By moving the cable that carries the signal to the record relay from an electronics module that is working to one that is not, and then to have the one that wasn't working work with the cable from the working one tells me its not the module. As you had asked I had ALSO tried moving a working cable set from jack to jack on the power supply and it doesn't matter what jack its plugged into, it works. I then did a redundant check and took a cable set that WASN'T working and moved it from jack to jack and it never worked. So it is a problem with the harnessing I believe but there are other elements at play because there are other components in that relay circuit on other cable sets...have to have it all plugged in in order to test the function but then that becomes self-defeating if there is, say, a short in that additional circuit...have to have it plugged in to test, but having it plugged in kills it. So the trick is to try and deduce where the problem is and start doing some comparative measurements between a known working set and one that isn't working, hope to find some differences between the two where there shouldn't be, and then track down why they are different.
I have a hunch...
P
Peck
Guest
Congratulations. That must feel so good.
L
lukpac
New member
Well, what was it?!
Nice avatar...
Nice avatar...
staticmethods
New member
Awesome!!! The MM-1000 is looking great! I love that sound of all the channels switching and relays clicking...
Yeah, so, what turned out to be the culprit?!?
-Tom.
Yeah, so, what turned out to be the culprit?!?
-Tom.
sweetbeats
Reel deep thoughts...
Yeah, I decided it was time to upgrade the avatar. That one of the reel in motion was from years ago when I still had my Tascam 58. The 58 is long gone. I like my MM-1000. Avatar = ode to Matilda.
SO...
Thanks for the interest in what it was.
I chased down a couple other hunches to no avail, retraced my steps that led me to believe it was cabling but it wasn't totally adding up because the cabling tested good. I then remembered that I was going to bump the output of the +24V supply.
Remember that it was outputting about +22.5V under load.
I realize now that I refurbished that supply around in between the tracks all arming and then the onset of the track arming problem...recapped it, replaced the bridge rectifier as well as a zener on the regulator board...certainly that might change things. But it was still outputting +24V under no load and I see now that there's a note on the schematic that states that "All voltages listed are with no load on the output...", so I hesitated to increase it because it was outputting +24V with no load. Well, I decided to increase it just a little bit like to +23.5V under load and lo and behold all tracks armed except for 7 and 4. So I took it to +24V under load which was about +24.75V no-load and *BAM* all tracks arm no problem.
Peck, it does feel good. The machine has been pulled out from the wall and there's a mess in the room from, in part, the unsettled nature of its operation. Time to start straightening up.
I want to get a snake mae up before I push it up to the wall to plug it up to the mixer, and get the tensions reset since those are set at the back of the machine. Then I can tuck back up to the wall, clean up my mess, recheck the brakes and then adjust the pinch roller tension and position and then....I get to start calibrating.
SO...
Thanks for the interest in what it was.
I chased down a couple other hunches to no avail, retraced my steps that led me to believe it was cabling but it wasn't totally adding up because the cabling tested good. I then remembered that I was going to bump the output of the +24V supply.
Remember that it was outputting about +22.5V under load.
I realize now that I refurbished that supply around in between the tracks all arming and then the onset of the track arming problem...recapped it, replaced the bridge rectifier as well as a zener on the regulator board...certainly that might change things. But it was still outputting +24V under no load and I see now that there's a note on the schematic that states that "All voltages listed are with no load on the output...", so I hesitated to increase it because it was outputting +24V with no load. Well, I decided to increase it just a little bit like to +23.5V under load and lo and behold all tracks armed except for 7 and 4. So I took it to +24V under load which was about +24.75V no-load and *BAM* all tracks arm no problem.
Peck, it does feel good. The machine has been pulled out from the wall and there's a mess in the room from, in part, the unsettled nature of its operation. Time to start straightening up.
I want to get a snake mae up before I push it up to the wall to plug it up to the mixer, and get the tensions reset since those are set at the back of the machine. Then I can tuck back up to the wall, clean up my mess, recheck the brakes and then adjust the pinch roller tension and position and then....I get to start calibrating.
cjacek
Analogue Enthusiast
Best news I've heard! I'm really happy for you my friend. Love the new avatar, seems fitting too!!
Love the new avatar, seems fitting too!!
T
The Ghost of FM
Banned
Yeah, I decided it was time to upgrade the avatar. That one of the reel in motion was from years ago when I still had my Tascam 58. The 58 is long gone. I like my MM-1000. Avatar = ode to Matilda.
SO...
Thanks for the interest in what it was.
I chased down a couple other hunches to no avail, retraced my steps that led me to believe it was cabling but it wasn't totally adding up because the cabling tested good. I then remembered that I was going to bump the output of the +24V supply.
Remember that it was outputting about +22.5V under load.
I realize now that I refurbished that supply around in between the tracks all arming and then the onset of the track arming problem...recapped it, replaced the bridge rectifier as well as a zener on the regulator board...certainly that might change things. But it was still outputting +24V under no load and I see now that there's a note on the schematic that states that "All voltages listed are with no load on the output...", so I hesitated to increase it because it was outputting +24V with no load. Well, I decided to increase it just a little bit like to +23.5V under load and lo and behold all tracks armed except for 7 and 4. So I took it to +24V under load which was about +24.75V no-load and *BAM* all tracks arm no problem.
Peck, it does feel good. The machine has been pulled out from the wall and there's a mess in the room from, in part, the unsettled nature of its operation. Time to start straightening up.
Glad to hear you resolved the issue!
How exactly do you bump up those voltages to such precise levels? Is it not the transformer in the power supply that sets this initial voltage?
Cheers!
jpmorris
Tape Wolf
At a guess, he's doing that at the regulator level and the supply itself is outputting 30v or something.
What really has me curious is the peculiar order in which the arming lights come on...
sweetbeats
Reel deep thoughts...
Thanks, Daniel!
Yeah the avatar thing was kind of spontaneous...I'm not one to change it but that record arming thing was, like, the last hurdle before the transport was finally ready again to be dialed in and when I got it licked and was sitting there jest lookin' at thm purty laghts and in perticuler that one big red one that was it.jpmorris is right...that initial main step-down transformer in a power supply converts the mains AC to a lower voltage AC that can be tolerated by the rest of the supply that converts the AC to DC and regulates it. Sure those components could convert and regulate full mains voltage AC but it would be a bigger more expensive and hotter running supply, so we step down the AC first with that big transformer. Then the AC gets converted or "rectified" to unregulated DC through a diode "bridge" or a set of discrete diodes and then finally through the regulator circuitry we go. The power supplies in the MM-1000 all have discrete regulators (as opposed to an integrated circuit or chip) and the regulation is typically handled by a transistor loop and there's a variable resistor in the loop that regulates the speed of the loop and as a result the voltage...something like that. Anyway that trimmer ultimately controls the output voltage quite nicely. I can't recall for sure but I think the main transformer in the transport supply steps it down to 28 ~ 29VAC.
Yeah that IS a good question...I was wondering that myself...lessee...they kind of go from the outside in don't they? It could be a number of things, but I'm hedging on harnessing. Those record status lamps on the control panel get their power FROM the control panel alllll they way up to the electronics bridge and allll they way back down to the control panel. The mode control toggle switches enable power to the record relays on the back of the electronics module as well as the record lamps on the modules and then there's a connector to extend that lamp circuit back down to the control panel lamps. Why not just have the control panel lamps get their power straight from the switches? Dunno for sure but I'd bet it has something to do with the fact that we are using AG-440 electronics here right? And the record relays power the lamps, and the relays are plugged into the back of each electronics module. There's a lot less wiring this way and since that wiring passes through the power supplies for the electonics module there'd be a real mess if it was done a different way.
Thanks for the comments, fellas!
Now for more updates...
sweetbeats
Reel deep thoughts...
Here's a how-to for the MM-1000 with respect to accessing the tension resistors:
Step 1, locate the control relay box which has the tension resistors mounted on the back under a perforated aluminum screen...
Step 2, remove the 4 screws that anchor the control box to the console rack...not the 4 that fasten the hinges to the rack, but the actual box...remove them and swing the control box down...
Now remove the perforated cover and there they are like a bunch of Coney Island hot dogs!
No fer cryin' out loud don't EVER do this with the machine powered up...that is AC line voltage coursing through those gihugic resistors!
So I reset the tensions according to the manual, and this time I used my "real" spring scales that gcalo found as opposed to my home-made versions. Ampex specifiied using spring scales to set the holdback and takeup tensions as well as the initial play boost tension. To check the play boost tension you wedge the time delay relay K7 "closed" and the hit PLAY, or if you have my machine you wedge it closed and then just turn the machine on and your spring scale goes across the room. I seem to recall this happening last time. Maybe I'll make a note...at any rate, no sweat getting the proper tensions dialed in EXCEPT for the play boost tension...this is supposed to apply a 1.5sec takeup torque 3x the normal takeup tension. I believe this is mainly to aide in minimizing the time it takes for the transport to stabilize in PLAY or RECORD mode...this seems or seemed to be a big deal...how fast the transport could reach stable operation from stop to start. There is supposed to be 50~60oz. of boost takeup torque...mine is about 24oz. and you know what? I'm leaving it, and I *may* even decrease it. I could care less if my transport takes 2sec to stabilize versus a fraction of a second because that CAN'T be gentle on the tape. All I care about is that the capstan doesn't throw a loop or cause any slackness when putting the transport in PLAY so at some point I'm going to back it off until that starts to happen and then increase it back past that point. And also once I get to calibrating and running the MRL tape I will readjust the holdback and takeup tensions using my Tentelometer. Ampex gave no instructions for using such an animal but I got some practical advice to reproduce a 10k tone and watch the output level and when the reduction of the holdback tension allows the output level of that 10k tone to start drooping then that's the tension knee point and to increase it just above that knee with a little safety buffer, and then measure what THAT tension is on the Tentelometer and that's what you dial it into in the future and set the takeup tension to the same amount. Makes sense. Holdback tension on an open-loop transport like this is for the purpose of maintaining good tape-to-head contact and when you lose that good contact the high frequencies will suffer first.
Next task is to adjust the pinch roller. I've devised a method by which I can determine the pinch roller is axially parallel to the capstan shaft. So I'll get that set first and then set the pressure.
Then I'll see if the brakes are still adjusted within spec.
I can say that I no longer have that wierd variable noise from the tape when its going through the path. Sorry you newcomers, that goes WAYYYYY back to over a year ago. Wow! Its been that long since I've run tape on this thing...been a crazy year, folks. But that tape was 996 and now I'm certain it was starting to go sticky. Tonight it was some of my 499 and it ran really clean in the tape path, except for a little edge shed at my custom rolling guide just ahead of the erase head, but that may be slight over-thickness of the custom machined base for the guide, OR maladjusted pinch roller jockeying the tape in the path. Otherwise the tape looks really good in the path. STILL having issues with tape rubbing the reels when using precision reels. Bugs me. I DO NOT want to hear the "ship-ship-ship" of tape hitting a reel flange...and the other thing is that the tape tracks poorly onto the takeup reel in FFWD. I'll have to watch what the tape is doing...might be a tilted guide or brake-arm pin.
Anyway, John French did a wonderful job setting up the 1" block. OH! That's right! I've taken pics of the 1" block setup by John in the machine for the first time...this is the block with the near-new 440C-8 heads and the custom rolling guide...fresh-fresh-fresh headblock assembly ready for the long haul:
I just really like all the round things in there!
The other bugaboo is I've got some noisy bearings in the rotary guide I custom installed just ahead of the head cover. New bearings too. Here's a goofy video where you can see all the components of the tape path in motion and the transport get cycled through its modes while I was trying to figure out what was making the noise:
YouTube
And here are a couple pics I took of the MM-1000 in the dark...the first one I was just running the transport empty to warm everything up and I stepped out of the room and shut the lights off to let it run...left the work light on and when I came back after 15 minutes or so this is what I saw:
And then when I dimmed the lights to step out while I was play-spooling the tape I had to stop and take a picture...The MM-1000 is a curious looking thing to me...several elements look its age at 40+ (crawling up on 50 if you take into account its quad VTR heritage), and at the same time there is something modern about some of the lines with the headcover or something...the Ampex logo there...I don't know...
That's all for now! Coming along.
Step 1, locate the control relay box which has the tension resistors mounted on the back under a perforated aluminum screen...
Step 2, remove the 4 screws that anchor the control box to the console rack...not the 4 that fasten the hinges to the rack, but the actual box...remove them and swing the control box down...
Now remove the perforated cover and there they are like a bunch of Coney Island hot dogs!
No fer cryin' out loud don't EVER do this with the machine powered up...that is AC line voltage coursing through those gihugic resistors!
So I reset the tensions according to the manual, and this time I used my "real" spring scales that gcalo found as opposed to my home-made versions. Ampex specifiied using spring scales to set the holdback and takeup tensions as well as the initial play boost tension. To check the play boost tension you wedge the time delay relay K7 "closed" and the hit PLAY, or if you have my machine you wedge it closed and then just turn the machine on and your spring scale goes across the room. I seem to recall this happening last time. Maybe I'll make a note...at any rate, no sweat getting the proper tensions dialed in EXCEPT for the play boost tension...this is supposed to apply a 1.5sec takeup torque 3x the normal takeup tension. I believe this is mainly to aide in minimizing the time it takes for the transport to stabilize in PLAY or RECORD mode...this seems or seemed to be a big deal...how fast the transport could reach stable operation from stop to start. There is supposed to be 50~60oz. of boost takeup torque...mine is about 24oz. and you know what? I'm leaving it, and I *may* even decrease it. I could care less if my transport takes 2sec to stabilize versus a fraction of a second because that CAN'T be gentle on the tape. All I care about is that the capstan doesn't throw a loop or cause any slackness when putting the transport in PLAY so at some point I'm going to back it off until that starts to happen and then increase it back past that point. And also once I get to calibrating and running the MRL tape I will readjust the holdback and takeup tensions using my Tentelometer. Ampex gave no instructions for using such an animal but I got some practical advice to reproduce a 10k tone and watch the output level and when the reduction of the holdback tension allows the output level of that 10k tone to start drooping then that's the tension knee point and to increase it just above that knee with a little safety buffer, and then measure what THAT tension is on the Tentelometer and that's what you dial it into in the future and set the takeup tension to the same amount. Makes sense. Holdback tension on an open-loop transport like this is for the purpose of maintaining good tape-to-head contact and when you lose that good contact the high frequencies will suffer first.
Next task is to adjust the pinch roller. I've devised a method by which I can determine the pinch roller is axially parallel to the capstan shaft. So I'll get that set first and then set the pressure.
Then I'll see if the brakes are still adjusted within spec.
I can say that I no longer have that wierd variable noise from the tape when its going through the path. Sorry you newcomers, that goes WAYYYYY back to over a year ago. Wow! Its been that long since I've run tape on this thing...been a crazy year, folks. But that tape was 996 and now I'm certain it was starting to go sticky. Tonight it was some of my 499 and it ran really clean in the tape path, except for a little edge shed at my custom rolling guide just ahead of the erase head, but that may be slight over-thickness of the custom machined base for the guide, OR maladjusted pinch roller jockeying the tape in the path. Otherwise the tape looks really good in the path. STILL having issues with tape rubbing the reels when using precision reels. Bugs me. I DO NOT want to hear the "ship-ship-ship" of tape hitting a reel flange...and the other thing is that the tape tracks poorly onto the takeup reel in FFWD. I'll have to watch what the tape is doing...might be a tilted guide or brake-arm pin.
Anyway, John French did a wonderful job setting up the 1" block. OH! That's right! I've taken pics of the 1" block setup by John in the machine for the first time...this is the block with the near-new 440C-8 heads and the custom rolling guide...fresh-fresh-fresh headblock assembly ready for the long haul:
I just really like all the round things in there!
The other bugaboo is I've got some noisy bearings in the rotary guide I custom installed just ahead of the head cover. New bearings too. Here's a goofy video where you can see all the components of the tape path in motion and the transport get cycled through its modes while I was trying to figure out what was making the noise:
YouTube
And here are a couple pics I took of the MM-1000 in the dark...the first one I was just running the transport empty to warm everything up and I stepped out of the room and shut the lights off to let it run...left the work light on and when I came back after 15 minutes or so this is what I saw:
And then when I dimmed the lights to step out while I was play-spooling the tape I had to stop and take a picture...The MM-1000 is a curious looking thing to me...several elements look its age at 40+ (crawling up on 50 if you take into account its quad VTR heritage), and at the same time there is something modern about some of the lines with the headcover or something...the Ampex logo there...I don't know...
That's all for now! Coming along.
Last edited: