Ampex MM-1000 Story...

[briank]

What the hey, I'm game

 

[evm1024]

Don't let that distorted waveform bother you. What counts is the DC smoothness at the PS output. I assume that you are looking at a low voltage here and this represents the interaction of the ability of the transformer to supply current, C1s point of charge, the demand of the regulator and the actual load. In effect it is a servo loop and is fully describable using lots and lots of complex math....

For sake of clarity to use a scope to measure floating voltages in differential mode you set both vert channels to the same voltage, add the channels together and invert channel 2. This then gives a positive and negative input probe in a differential mode (for us audio folks make that balanced mode).

Regards, Ethan

PS thanks for the kind words

 

[sweetbeats]

This place is so great...

Ethan, thanks again...the "INVERT" setting is the one in which I was remiss...that makes perfect sense. Now I gotta try it.

ALSO: I measured the voltage differential of the series-pass transistors with the supply powering the capstan motor at 7.5ips, no other load...I don't recall what the voltage was (when measuring between the supply + output and the emitter of each transistor), but it was very small and the measurement was identical on both emitters.

Ready to rock.

The intermittent PLAY problem is still there (i.e. Matilda decides when she is ready to engage PLAY mode...I hit the PLAY button and sometimes it engages right away and other times I have to wait up to 15~20 seconds), though I've picked up on a couple more clues and I still have yet to study the schematics, but I've noticed that if the STOP button is not lit, the problem is present. The lamp in the STOP button doesn't tell you that you have pressed STOP, it tells you that the transport is actually static...the STOP lamp is linked to the motion sensor and if the transport is moving at all the relay logic considers the machine is not stopped..."STOP" truly means stopped. So identifying this clue will help because it gives my another pickup point to reference in the schematics.

The 1" headblock should be back from JRF this week.

OHHHHHHHKayyyyyyy...Brian, this is for you...

Last week I received a long-awaited package containing a complete 16-track wiring harness from a working 2" 16-track MM-1000 as well as some metalwork. This absolutely completes what is needed to convert my MM-1000 to 2" 16-track.

Here is what was inside...

Head cabling harnesses (LOTS of military spec connectors):

That second one is the one I'm REALLY interested in as that is the one that goes to channels 9~16...

The I/O panel for channels 9~16, and I'm totally jazzed because this one doesn't need to be rebuilt...I'm pretty sure now, after seeing this one, that my original panel for channels 1~8 was not a factory solder job as it was bad/sloppy, and this one I got for 9~16 is, in Ampex tradition, VERY nicely done. It'll need a little TLC but overall it is straight and relatively clean (cleaner than I expected) and 90% ready to mount up and plug in...and this one has the matching connectors...Ampex outfitted the MM-1000's with either Cannon or Switchcraft connectors and mine has the Cannon parts like this here panel assembly:

Annnnnd here's the big ol' freaky mass...this is all the power and mode control harnessing...the main part of the system harnessing...I've looked it over and it is all there and in pretty fine shape...a little cleaning and some minor attention and it'll be ready to go...the BONUS here is that I wasn't expecting to get the power switch panel (the one with the big "2" on it). This is nice because the early MM-1000's had a power switch panel that had nothing on it except the power switch...then Ampex added a separate 110V outlet and a connector to plug in a brake release foot switch. This is nice because the MM-1000 does not have an EDIT mode, so when you need to scrub or thread it is difficult to relase the brakes with one of the brake release arms (the "tension arms"), but with the foot switch you can release the brakes with your foot and have your hands free to manipulate the tape...cutting-edge technology, folks:

This is the backside of the power/remote connector panel that is a part of the above mass...the large mil-spec circular connector in the middle is a bit of a puzzle to me...The wiring presents it as a later custom add-on but the hole that it sits in looks factory. At any rate I believe this is an alternate remote interface:

These need a little TLC but they are Ampex-issue 2U blank panels...heavy-guage stuff. I just wanted 'em because the paint will match. These go at the bottom of the two rack bays in front, below the electronics for channels 9~16. They'll clean up pretty well though they will always exhibit some battle scars and I'm okay with that:

I'm very excited to have these...these are 6U rack ears to inset the power, remote and I/O panels so that the connectors can't get creamed against the wall when you carelessly get 700lbs moving in the wrong direction (which is why some of my panels needed straightening as they had been crunched...the early MM-1000's did not have these ears...) I wish I could describe how overbuilt these things are for what they do:

Even some vintage racking hardware...SWEET!

50lbs of old-smellin' electronical stuff!

 

[sweetbeats]

Some other updates...

With me edumacated on the finer (or not so finer) points of using my scope I got the 24VDC supply all put back together and mounted back in the machine...check that one off the list...here it is before it went back into its hidey-hole in the back of the machine:

And I got those 6U rack ears cleaned up and installed:

 

[sweetbeats]

Just a silly nonsensical post to iterate that this thread is far from dead...just been busy on oodles of other things, namely getting my mixer back together.

I must admit, sometimes I just open the headcover and flip down the gate just because...

 

[cjacek]

I must admit, sometimes I just open the headcover and flip down the gate just because...

I must admit I do that sometimes too. No different than a classic car restorer popping the hood, just because... Guys like us understand.

 

[briank]

I must admit, sometimes I just open the headcover and flip down the gate just because...

Heard. I like to play with the head shield on our MCI. It makes a cool "casshhhunk" sound and I like the weight of the little lever, I like that you can FEEL its connection to the thing it controls. We're not entirely different creatures, are we?

 

[sweetbeats]

Ahhhhh my compadres!!

 

[JasonG]

Dude, that is a beautiful site! I'm jealous! You got one of my dream machines there! Nice!

 

[sweetbeats]

The wonders never cease. I'm picking up something pertinent to my MM-1000...don't want to count my chickens before they hatch so I'll hold off on the details for the moment...its nothing exciting like a set of heads or anything but just one of those things I never expected would come to fruition.

 

[sweetbeats]

One man's junk...

Yeah...so that's a bin of stuff that followed me home. I get to keep it.

So here's the deal...pretty unbelievable, really...the lady that originally sold me the MM-1000 along with the whole $300 haul had said all along that she was sure there was a spare wiring harness of some sort around somewhere...she looked and looked...I contacted her a couple times over the last couple years to check but no go...nothing turned up. Well, she recently moved and you know how that goes...stuff turns up. She was kind enough in all the chaos to set it aside for me and look me up.

Wasn't sure what all was found until I could pick it up and go through it, which I will now do for you. I'll exclude the chunks of insulation, wood, and collection of sawdust.

MM-1100 16-track remote carcass. Clearly attacked by electronics buzzards but partially intact...I'll see if I can sell for parts for a little $$$.

MM-1000 8-track remote. I'll be honest...since there were a number of parts that came with the MM-1000 that hinted at some effort being made to convert it to 2" I was hopeful that when the lady said she had found a "shell of a remote" it was a 16-track shell. Nope. That's okay. This has bulbs and switches in it, and the wiring and other guts are actually in much better shape than the one that came with the MM-1000 which have some significant moisture damage. This one is pretty clean inside so it'll help.

Hm...THERE'S the power cord!!! Some of you may recall that was challenge #1 when brought the MM-1000 home was fashioning a power cord for it. Yeah...think I'll continue using the one I made. This one's a little scary.

Another 440/MM-1000 electronics power cable...always handy...

And a plug-in input balancing transformer for an electronics module...this is a nice addition to the lot.

Here's where it get's fun...sort of. You may recall that a few months back I took delivery on a complete 16-track wiring harness for a chunk of $$$...necessary to convert my MM-1000 to 2" 16-track. Well, looks like I've got doubles of some of that now. Haven't totally sorted out what I've got, but for sure one harness is the "Supplemental Signal Harness" p/n 4952286...the one you got that goes between the heads, sync module and 8 additional electronics modules when converting from 8 to 16 tracks. The other I'm not sure exactly what it is...It is similar to the other one but also includes all the harnessing to 8 electronics modules including power, mode control and even the additional pins for the remote connector. Unfortunately this one has some damage from a busy puppy...not extensive and repairable. So, not sure what I'm going to do with these since, AFAIK, I don't need them, but get this...they are NOS! So I'll hang on to them until I'm certain of what all I need or feel I should hang on to for spares and sell the rest, but needless to say I'm swimming in mil-spec connectors...

The first three pics are of first harness and the rest are of the second.

NO puppy NO!

Moral of the story...you never know what might turn up if you just keep waiting. I'm not feeling regretful about getting the 16-track harness...it is complete and in good condition and came with a LOT of wiring and parts not included with this recent lot...the channel 9~16 I/O panel and harnessing, the brackets for offsetting the I/O and power/remote panels, the power/remote panel with the right remote connector...the power switch panel with the 110V outlet and brake release connector...all that stuff. And honestly I think it was pretty reasonable for me to assume that this stuff I just got wasn;t going to turn up. She'd tried, and literally years had passed. But it is true what a good friend told me recently: "When we get anxious, stuff gets expensive." Lesson learned, no regrets. I'm set for wiring.

Still on the lookout for that 16-track remote.

Wasn't this fun?

 

[purerad]

awesome! will be cool when you get it all going! It's amazing what turns up sometimes isn't it!

 

[cjacek]

Yes, that was indeed fun, Cory! Thanks for taking the time and sharing. The moral of the story is also that one needs to be unyielding and many times it pays off. Pretty cool about that NOS find. I hope that puppy didn't damage too much.

 

[sweetbeats]

Thanks, Daniel!

So I got the 39V electronics supply repaired (the one that had one of the caps blow as detailed here in post #75)...disassembled the supply, thoroughly cleaned it, reassembled, new cap, repaired wiring to the pass transistor, and triple-checked the cap orientation , and then pulled the other 39V supply and replaced that same cap because it was also in backwards and I'm sure has taken a beating even though it hadn't blown yet. Got both supplies back in.

That feels good.

What doesn't feel good is that there are only about 3 channels that consistently will enter record mode, a couple that are intermittent, and 3 that just won't...my intermittent PLAY problem is getting worse too. *sigh*

I'm pretty sure I'm gonna have to pull the relay box and tear into that.

 

[briank]

What doesn't feel good is that there are only about 3 channels that consistently will enter record mode, a couple that are intermittent, and 3 that just won't...my intermittent PLAY problem is getting worse too. *sigh*

I'm pretty sure I'm gonna have to pull the relay box and tear into that.

Ah, but you're getting on towards the audio electronics, that's a good milestone.

When getting our JH-110 8-track back into service, I had spent so much time and frustration (and learning curve) on the transport that when that was finally sorted out, even though by then I was expecting the audio to need a bunch of work, at least I was comfortable enough with the machine and already knew what my plan of attack would be. When I finally got that transport sorted out, it was like "well the audio is going to be another adventure but...what the hell, I'm just glad I'm moving on!" ...opened up the audio drawers, heated up the soldering iron and got through it. Not such a bad feeling after all!

Anyway, it's kind of like with the 416 project...with this part, you have the motivation of "I get to hear it soon and it's going to be sweeeet!"

Sweet beats as it were

 

[sweetbeats]

Heheh...

Yeah...

Though it FEELS like I'm stepping backwards because I can't HEAR it until the transport is working right and until I can get each channel to enter record mode reliably.

BUT...

I just pulled the trigger on purchasing all new relays.

A fellow MM-1000 owner sent me a link to a product page at Apex Electronics...they actually have the big "truck" relays in stock. The MM-1000 relay box has eight of them. Four ar 3PDT, and four are 5PDT. Apex only has the 5PDT versions, BUT...I believe there is enough room on the control box chassis to just mount the 5PDT versions for all eight of the relays and just not use the terminals that are unneeded for the 5PDT relays that are replacing the 3PDT versions...and I thought the new relays didn't come with the copper braided strapping that ties the appropriate terminals together...they're there on the new ones and that means a LOT less soldering for me...this would actually make the replacement process enjoyable to just have to transfer input/output wires from the old relays to the new!

And the great news? The relays are only $3 EACH!!!

So I went ahead and bought ten to replace all eight of the relays in the box and have two spares.

Here's the link to the product page...about 2/3 the way down the page...item #33BQA5D7

Here is a partial shot of the relay box again (posted this pic many moons ago, but we've come full circle so here it is again...) I'm pointing to one of the 5PDT relays and to its right is one of the smaller 3PDT relays and you can see that it looks like there is enough room in between. The relays are identical except that the 5PDT relays have the additional "wings" on each side with the 2 additional sets of contacts.

This is pretty exciting. Putting all new relays should, at best, resolve my problems, and at worst eradicate the relay box as the cause of my issues and get me closer to getting things working right reliably. Some of you may recall that some of the wiring between the relay box and the tension resistors was bad (burned) due to bad connections...many of the contacts on many of the relays were pretty badly pitted and corroded as a result. I cleaned them up pretty nice but I ignored advice to replace the contacts if they were at all pitted and/or otherwise not shiny perfect.

$41 including shipping to rebuild the box and have spares. Good deal.

 

[cjacek]

Cory, really great to hear that you got the power supply sorted and that you scored those relays for a steal of a deal! I too feel the relays, once replaced, will solve many problems. I think overall very positive news.

 

[sweetbeats]

Cory, really great to hear that you got the power supply sorted and that you scored those relays for a steal of a deal! I too feel the relays, once replaced, will solve many problems. I think overall very positive news.

Yeah, thanks, Daniel! To be honest I had this feeling when I went through the relay box last year that I wasn't really doing it "right". I spent a lot of time filing the contacts down to fresh material, shaping and polishing them up. I was told (in a nice way) "good luck with that but you really need to just replace the contacts." Had I known the source of new relays at that point I'm sure I would have just shotgunned them. Here's to intuition because here I am back at square-one, but I should be steps-ahead once the relays are replaced with a truly "rebuilt" relay box. Its already recapped (YES the caps are in the right way!!! ), with the aforementioned wiring repairs as well. I am going to heed some additional recent advice to make the changes in steps to limit the troubleshooting if something doesn't go right. I'll start with replacing just the PLAY relay and test that, and then move on to the record relay and then the others one at a time. I actually think there's enough room in the console that I can pull the relay box out just once, remove the shield that covers the tension resistors (the ones that are the size of a Coney Island hot dog), and then be able to get to all the relay mount screws from the back so I don't have to pull the relay box in-between each relay. Not that it is a big deal, but if I don't HAVE to pull the connectors from the box and pull it out and put it back in 8 times I don't want to. The connectors are heavy-duty but why test their endurance if I don't have to? I WILL pull the output of the 24V power supply though...I figure with the transport connected the filter cap in the power supply drains fairly quickly, but I'm just a bit wary at this point...I can recall having a supply cap arc on me once when I thought there was no way it could be charged still (DUMB), and with my recent exploding cap saga I have to say I'm just a little bit more jumpy around my electronics these days, which, really, is a very good thing. We should all take GREAT care around this stuff. If the lid hadn't been fastened on the 39V supply that had the cap blow it could have caused SERIOUS injury, and that was the "small" cap. You shoulda seen me when I power tested the repaired supplies the other night...ear protectors on...safety glasses...double checking the covers tightly secured...shield barrier in place between me and the guts of the console...seriously, if I owned a flak jacket I'd have probably put it on. Again, it was a 500uF cap. Not small, but not huge either, and after it blew all the cymbals on my kit were going "ahhhhhhhhhhhhhhhhhhh". It go bang.

BUT ANYWAY...

I'm getting there, a little wiser each time and still alive.

 

[cjacek]

Cory, you're absolutely right that it's good to be extra cautious with these things. Only good can come of it. Stay alive!

 

[sweetbeats]

I just love NOS parts...got the relays today and check it out...I didn't know they were NOS but there's just something about getting parts for your old machine that come in old boxes:

I'm trying to determine if there is a reason to solder the wires from the old relays to the new since the terminals on the new relays are standard 0.205" male quick-disconnect terminals. I could use solderless crimp connectors...dunno what's better or if there is any benefit to either. What I like about the idea of using the crimp connectors is the ease of removal down the road if needed, and also I'm going to lose a little length when I remove the wires from the existing relays and clean up the ends and there isn't much wiggle room on a lot of those wires.

Anyway, just wanted to give a quick report that the relays got here and look great. Apex Electronics was good to work with.