Tascam 58-OB Story...

  • Thread starter Thread starter sweetbeats
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sweetbeats said:
Danny, I know... :o

Totally no offense taken. Can't imagine getting offended anyway after all the support and help you've given me. ;)

I might consider it if the ES-50 is the tach pulse culprit (i.e. if the tach pulses are getting to the ES-50 but once inside they are getting lost).

What type of connector does the microlynx have on the back for the sync cable connection?
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Cory,

You have to make sure you locate one with the cable. You can change the machine end to a Elco connector. The connector to the Microlynx is a 40 pin something or other. Here's the library drawings for MICROLYNX. Forget the older LYNX. Scroll down a bit and you see the library. http://www.sessioncontrol.com/TL_archives.htm

Danny
 
Danny,

Thanks for putting those up. I will study them. Unfortunately it looks as though the problem (i.e. the tach issue) may lie within my 58 and is not something I will be able to resolve. Without the tach pulses leaving the 58 it won't matter if I'm using an ES-50, MicroLynx or a pop tart to sync. :(
 
sweetbeats said:
Danny,

Thanks for putting those up. I will study them. Unfortunately it looks as though the problem (i.e. the tach issue) may lie within my 58 and is not something I will be able to resolve. Without the tach pulses leaving the 58 it won't matter if I'm using an ES-50, MicroLynx or a pop tart to sync. :(
Click to expand...


Uh oh.That's too bad.
 
Cory, I have all the faith in the world in you but you really have to step back, and take a breather 'cause you're gonna burn yourself out. Perfectionism is great but it can drain the life outta you and the next thing you know, you're making all the wrong decisions, including possibly selling off your machines. Ya gotta back off a bit and take it slow and one thing at a time.

----
 
Yeah, I know Daniel, but the problem is that the client is waiting.

I can let the sync stuff go for now. I had already decided that but then when I was on the phone with Tascam yesterday I thought I'd bring it up since I was talking to them.

The tension issue is another story because it may or may not (can't really determine yet) be causing head-contact issues, plus I worry about it being hard on the tape (the way the tension arms are interacting with the braking mechanisms now is getting wierd) and/or the tape path. Its gone from being a perfectionism issue to just trying to get the thing to behave relatively normal before I recal the deck. The tape packs or looking ugly now and I can't figure out why. There are suddenly multiple issues going on.

I appreciate what you are saying very much. It is good advice for all and frankly I need the reminder because I do get a bit consumed even when there isn't external pressure (i.e. client). Its a hard thing to accept because the rest of the deck has come into spec just fine, and it is such a clean machine but I know that's no gaurantee...its just trying to accept reality that the deck may have issues after all. What do I expect for $150 huh?

:(
 
Some marginal headway...

Synchronization/tach pulse issue: Okay...my tach is indeed transmitting pulses. What is still unanswered is that I can't figure out what pin on the ACCESSORY connector satisfies the other end of the circuit. The ACCESSORY connector has two pins that transmit open collector signal. Pin J transmits 12Hz signal at 15ips, and pin L transmits 60Hz signal at 15ips. The schematic for the ES-50 sync cable doesn't use J, but it does use L. If I connect one end of the frequency counter to L and the other to TP-4 or TP-5 on the Control PCB I get about 60Hz in PLAY, which is proper. I also get consistent frequency counts in SPOOL and fast-wind in either direction. I also confirmed that there is appropriate voltage information for the transport direction (- for REW modes, + for forward modes). Again, what I'm struggling to confirm is whether or not the above signals are actually getting to the synchronizer because I can't figure out what the equivalent point to TP-4 or TP-5 is on the ACCESSORY terminal. Anyway, at least I know the tach is working right, at least for the time being. :o

Tape tension issue: well, first of all part of what was causing my tape pack problems and tape path adjustment issues last night is that it is the first time I've put the test tape on in a bit, and its that old 12.5mm vs. 12.7mm. The MRL tape is 12.5mm, and my roll of SM911 is 12.7mm issue. Man...that .2mm is small but mighty. Plus there must be something funky with the MRL tape reel, or something funny about how it is sitting on the reel table, because the tape pack looked much better tonight when I had the SM911 back on the deck.

I got some springs at the hardware store. I temporarily rigged one up on the supply side arm (the one that's been running low). Well, it did bring the tension up. A lot of adjustment was needed to keep the deck from running away in EDIT mode, and I wasn't able to get the right tension arm positions setup in EDIT, but this was a test. Anyway, those initial tweaks brought playback tensions of supply: 100g, takeup: 120g. I messed with it awhile longer to try and get the tension arm positions right and get the right tensions. Wierd...even with the different spring, once I get the arms properly positioned in EDIT, my tensions are back to supply: 60g, takeup: 80g. Even the fast-wind tensions are as they were last night...! So there must be something else going on here because changes I'm making to the hardware are being automatically compensated by the tension system. There must be something else I'm missing...gonna have to get back into the manual on this.

I did a primitive test to make sure that both reel motors had roughly the same torque and they seem to be good. Both very strong.

So anyway, some headway beyond last night...at least I'm kind of back where I was...:D

Gonna call Jim Finch again...
 
Answers at last...

Well, I recently got off the phone with Jimmy (not Jim Finch) at Tascam. Both those guys are just wonderful.

The news isn't really all that good regarding my tach/sync and tension issues, but it is definitive news and for that reason it is, at this point, music to my ears.

Tach/sync issue:

In summary, the ES-50 synchronizer has to have both slave and master atr's connected for it to recognize and setup the tachometer pulse signal stream. I'll have to refurb my 48 and build the master interface sync cable before I can resolve my runaway slave issue.

Because I can see reliable tach activity between TP-4 and TP-5 on the Control PCB, or between either TP-4 or TP-5 and terminal L on the ACCESSORY connector, it can be assumed that the deck is okay and it is doing what it is supposed to do with regard to transmitting tach information. I still can't confirm for sure if the tach signal is getting to the ES-50 because you can't simply measure it with a DMM...the +5V terminal SS on the ACCESSORY connector completes the circuit with the tach signal at terminal L, but you won't see the pulses when measuring across SS and L "because of the logic [circuits] in those machines" sez Jimmy. But that is really a secondary issue at this point because the ES-50 won't read/setup the tach info until it is getting it from both the master and slave machines. Since my setup is a "code-only master" setup (there is no master machine, just the slave 58 and the timecode streaming from the DAW as the master reference), it won't be getting tach info from the non-existent master machine and therefore it ignores the tach info from the 58 as well. So I'll need to refurb the 48 and build the master interface sync cable before the 58 can be properly setup with the ES-50. Once I do those things, then I'll know for sure if the slave interface cable I built is doing everything it should, and I'll find out if the ES-50 is working right. So I'm totally ready to bump that all down on the priority list for now and handle my pending project by tracking straight to the 58 and dumping to the DAW for editing. I may still stripe SMPTE on the 58 though in case I do decide to layer synchronized track dumps to the DAW, sinch the 58 is syncing just fine to the DAW, I just have to work around the runaway slave issue until I can get the ES-50 to recognize the tach pulses from the 58.

Tension issue:

In summary, Jimmy diagnosed that my 58 tension sensors are magnetized and sending the wrong positional information to the logic circuitry. I'll have to try to demag them if I can find a pro-power bulk demag unit.

Apparently there is a known problem that can arise with the 50 series decks where the tension sensors, specifically the Hall sensors become magnetized. The only way to possibly fix it, and it doesn't always work, is to put the sensors in a pro bulk demag unit. I guess this also happened with some X2000 decks. Anybody have a bulk demag unit and would be willing to demag my tension sensors if I shipped them to you and provided return postage?
 
sweetbeats said:
Anybody have a bulk demag unit and would be willing to demag my tension sensors if I shipped them to you and provided return postage?
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Yep, just send 'em and I'll take care of it.

Cory, do you have any sort of bulk eraser at all... like for tape?

:)
 
Tim,

Thanks man.

I have no bulk eraser, just the Han-D-Mag.
 
Now I've really got some demag questions...

So I'm wondering if I may have contributed in a small or big way to me alleged magnetized tension sensor issue...

I've only demag'ed the 58 once since I bought it, and that was before I bought the Han-D-Mag (i.e. I demag'ed it with the lame-o cheapy wand I got off of eBay a couple years ago to demag the 424). When I did it I think the dress panel, which is steel, was off of the 58, and I demag'ed the tension arm rollers too. This would mean that a weak demag wand got close to the sensors, but not closer than 1-2" away, no steel shield (dress panel) in place. I need to know:

1. Is it a better idea to remove the tension arm rollers and demag them away from the deck?

2. Am I right that I ought to demag only with the dress panel in place?

Changing the subject now...

I ended up purchasing a bulk eraser. I am nervous about subjecting my tension sensors to the demag treatment, though Jimmy at Tascam seemed very certain of the issue, and didn't mention any caution about demag'ing the sensors and I would definitely consider him a reliable source. ;)

Another thought I had though was, couldn't I just reposition the sensors to fool the deck? I'm not sure if the magnetization of the sensors causes a linear error or if it is non-linear. If it is linear I would think repositioning the sensor would work. Even if the error is non-linear, it might still get me closer to the right performance. I might try it...any opinions? Does my idea make any sense?
 
Okay...so I finally got up the courage/found the time to pull the tension sensors from the deck to demag them with my new-to-me Inmac bulk eraser (thanks Beck! ;)).

Yikes tha thing packs a punch!! Hang on tight to them sensors! Mind you, there is very little metal to each sensor, and yet the sensor would start humming in my hand 8 inches out from the demag unit...WOW!

Anyway, I did them both, reinstalled them in my deck...haven't done a full test yet, but I know I didn't kill anything. :)

So far the preliminary tension performance doesn't seem to be improved :(, but visually the tension arms seem to be smoother and more reliable in their performance. I'll be able to do a full tension adjustment series in the next several days. Plus, to be sure, the tension springs are still available from Tascam so I ordered a couple...couple bucks each...cheap insurance to rule out a worn spring.

Also ordered a replacement set of guides and lifter arms for some year down the road when they're needed.

I'll keep y'all posted.
 
So I got the replacement tension springs, mounted them and re-checked the tension sensor positions and readjusted the trimmers.

In the end the tension measurement results are still off, but they are better, and the deck seems to perform more like it should according to the descriptors in the manual. Plus I did a FWD SPOOL onto the takeup reel and it...is...nice. ;) I'll double-check the wrap once I step back into the calibration (i.e. make sure there is no meter deviation when slight back pressure is applied to the supply reel in repro-mode). I expect all will be well with it though, and anticipate I'll be relatively gliding through the calibration.
 
Cory, my friend, is it still at all possible and worth revisiting the likelihood of perhaps the tools and ways that tape tension was measured that may be at fault, rather than the machine? Just putting it out there..

---
 
Hey, Daniel...how are ya?

Hey, I'm always open to tools and/or user being at fault y'know? :o

I'm getting such consistent variances side to side tho'...did you check out the last video I posted up in my "Tentelometer...Am I doin' it right???" thread? Maybe you can pick up something I am doing wrong if you didn't see it...dunno. I've been really careful...I'd be hard-pressed to think I'm still doing something wrong, but I'd love it if I was! :D
 
Cory, I'm sure you're waaay ahead of me but I guess I'm looking for that certain something, a simple answer that may have been overlooked.... I took a look at the video and your tests seems correct and if you had calibrated the tentelometer and followed the 58 manual then I continue to be stumped at what the cause of the measurements being 'off' are......

Say, have you tried, real quick, to adjust the tension on your 48? If they're dead on or you can adjust them as that then at least we can rule out the possibility of the tentelometer being the issue. I don't know... maybe I'm a blind man, in a dark room, trying to find a match...:(

Man, I really wish we could find a solution.

-------
 
Daniel,

I wish I could too, but I'm trying to live by the good advice of a friend:

Cory, I have all the faith in the world in you but you really have to step back, and take a breather 'cause you're gonna burn yourself out. Perfectionism is great but it can drain the life outta you and the next thing you know, you're making all the wrong decisions...
Click to expand...

Remember that one? :D:D:p:)

Y'know, I'm not sure what more to do at this point. The left spring is maxed out, the right is almost totally the opposite. I've demagged the tension sensors with the mighty Inmac, I've got new springs in there...I've dickered and dickered. The only thing I haven't done that might be good at some point would be to swap the reel motors...Early on I replaced one of the original motors with one of the same p/n due to a bent shaft...When I put that motor in I also put a quick disconnect inline with the motor cable for easy removal in the future without desoldering. The folks at Tascam said that that shouldn't make any difference (the disconnect or the different motor...but I've often wondered.)

Your idea of checking tensions on the 48 is a fantastic idea...the only hitch is that neither of my 48's are in any way setup yet. The parts 48 is still pulling tape poorly...haven't tackled that yet, and my "good" 48 hasn't even received step one of the refurbishing treatment which is to get those gooey solenoid cushions replaced.

Maybe, unless you or anybody has any additional ideas to try, I'm going to get the pending recording project behind me and then try some of the above ideas. Time is pressing now.
 
The dress panel is on...

I haven't had all the panels installed on my 58 in I don't know how long...I am done messing with tensions for now and am stepping back through the entire calibration process.

I've demagged it now with the Han-D-Mag...can't tell you how much I like that demag unit after the cheapey one off of eBay.

Re-checked the wrap and it looks great at 1kHz and 10kHz.

Re-checked the azimuth adjustment, and this time I used a VST oscilloscope plugin instead of the No O'Scope method...I can really understand now why using some type of scope is preferred...it is easier. Less dickering and I feel more confident of the results...instead of trying to guesstimate the crest of a wavering VU needle the scope gives you a graphical representation of the phase relation. The VST plug worked good enough for me. It was free for the trial which is unlimited use, but only two instances running simultaneously (I only needed one anyway), and the scope temporarily bypasses every 35 seconds...no big deal. It has a pretty good refresh rate and worked without any hassles. Just connected outputs 2 and 7 on the 58 to inputs 1 and 2 on my Yamaha i88x, routed those inputs to Cubase using the graphical patchbays, created two tracks in Cubase, hit the monitor buttons and inserted the scope on the master buss. I checked coarse at 500Hz and 1kHz and fine at 10kHz...The repro head looks great at 1kHz and 10kHz, the sync head looks great at 10kHz but is about 20-30 degrees out at 1kHz. I'm assuming that is probably a head wear thingy...I'm not going to sweat it as it is still well within the 90 degree spec, and the manual only talks about testing it at 10kHz at it looks good there so...

Once I had re-checked the azimuth I looked in the manual for the next step and it is the electronic calibration (I have adjusted/tweaked the tape path a gazillion times due to the fact that I have to tweak when I have the test tape loaded as it is from Quantegy stock at 12.5mm and my BASF and RMGI tape is all 12.7mm...:mad:). I figured it was time to call it a night, but I looked at the trimmers and adjustments that were exposed and realized I won't be needing to get to those for the electronic calibration, so I "dressed it up" again. It felt really good to put everything back in place knowing I have done the best I can to get the deck back into spec thus far. It looks nice with its skin back on. :)

Looking back over the past 1 to 2 years I have learned a ton. Used to take me so long to do anything on the deck, and now its no big deal: from adjusting tension response to calibrating the brakes to adjusting the tape path to electronic calibration. I know where stuff is located on the deck and how to get to it. I am no longer intimidated by it all, at least the procedures I know...If I ever have IC's or SMC's go bad on the thing that will be a new adventure, but it is great to be able to open it up to test or tweak anything that is necessary to get it running right. Very satisfying, and the big deal is that I knew nothing when I got this deck. With some knack, know-how and gumption, and truly a lot of invaluable help from all of you, it is indeed possible for an amatuer to become his/her own atr technician. I will never need to take my 58 anywhere for adjustment/calibration physical or electronic, and that will mean saving $$$, downtime, and keeping it adjusted more frequently which will help it last longer and run better. I have probably spent $400-$450 for the tools and equipment to do this, but about half of that was the Tentelometer which is not essential. Even at what I've spent, there will surely be a return on the investment eventually considering what it would cost to pay others to do it, and I believe I will do a more thorough job. Plus I'll avoid the pitfalls of transporting it (even if I personally transport it there is still risk to the deck, and me considering it is 90lbs...and I will never forget some of the horror stories of people whose gear was ruined by an unqualified tech...)

Sorry for the speech, but I'm cresting.

Thanks for following/contributing to this thread and my adventure.
 
Hey Cory, thanks for sharing and updating your '58-OB Story'. It's been inspiring, to say the least.:)

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Input calibration complete...

Everything went very well in my estimation with the input calibration.

The only issue was that there was a 1-2VU variation on tracks 1 ~ 3 when playing back the 1kHz test tone and other tones in relatively close proximity...I think it is related to the tape path issue, that the test tape is 12.5mm and my tape path has been carefully set for 12.7mm. I'm trying to tweak the tape path as little as possible so I don't loose the setup for the 12.7mm tape. It looks fine; the tape going through the path, but when I REW the tape lifts slightly up in the left guide. It settles down just like it should when I press PLAY, but then the opposite is happening in the right guide...when I put it in REW the tape rides onto the guide base just for a bit...I don't want to damage my cal tape but I think that, ultimately, I'd have to tweak the reel table heights to get this to run right...the last time I did that, and it took forever, I had to redo the whole process when I put 12.7mm tape back on the deck.

So anyway, hopefully it is related to that. I will know more when I thread up the 12.7mm tape for the record level calibration and bias adjust. Might do some of that tonight.

But anyway, outside of all that, I think the repairs I did to the amp cards many moons ago worked well. No wacky meter issues, no intermittent signals when switching from sync to repro, everything responds really nice.

I'm going to follow Ethan's advice from some time ago and I'm calibrating the deck for 0VU at 250nWb/m, and though the manual states to set the peak LED's at +12, I'm setting mine to light at +9.

ONWARD!!!
 
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