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Post by Polymoog Lover on Sept 10, 2010 19:11:59 GMT
Okay, So I'm out to figure it out, once and for all and I believe that this thread will be a great source of information on what to expect for potential Polymoog buyers. Anyone who could contribute the following information would be greatly appreciated.
TOPIC AT HAND "Just how reliable/unreliable are Polymoogs?"
1: How long can a pristine Polymoog be used (this includes powering on and off between usage) before one should expect reliability issues?
2: When these issues come to be, how serious are they? Also, what would usually be the first component to go?
3: As far as parts commonality goes, would the cost of a pristine (or atleast good condition) Polymoog quickly become overshadowed by the price of repairs?
Finally,
4: For those who own a Polymoog Synthesizer (203a), or Polymoog Keyboard (280a) how would you rate the Polymoog's overall stability/reliability on a scale from 1 - 10 with one being that it's a time vampire and is barely ever working?
Also, quite a few members of this thriving community are qualified to service/maintain Polymoogs. As such, if those people are okay with it, please, tell us your name, and location.
Let the games begin......
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Post by martymoog on Sept 12, 2010 13:00:12 GMT
An interesting thread, can I begin?
1) Never seen a 'pristine' condition Polymoog unless you count those splendid beasts I saw at a distance on stage with GN way back in 1979 (which I obviously didn't get to play with). My own 280a was at least 2nd hand, I don't know its history before the last owner (I could email and ask him I suppose!)
2) Of the three 280a's and one 203a I've had dealings with its been the PSU thats gone, often taking something else along with it. Fairly easy to repair (in my opinion having done four!)
3) Parts ? The IC's are usually obtainable. I wouldn't put a price on repairing own 280a, imo it HAD to be done but then I repaired it myself. I have heard some horror stories of people being quoted horrendous prices for repair shops just to look at one, which may be fair enough if you're in the repair business, (complete circuit boards are almost impossible to obtain until a machine is parted out, so its time consuming trying to locate a duff component or two!)
4) I'd rate mine at 7 maybe 8 on the reliability scale. If you've seen my previous posts I had her all working after my PSU incineration and then she melted an IC on the CL board for no apparent reason, other than maybe age? Not a good sign for the future !!!
Martymoog
Oh and I'm in Misserableborough, bottom of the economic resiliance league if the BBC is to be believed!
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Post by Polymoog Lover on Sept 12, 2010 15:32:41 GMT
Thanks for your contribution, Martymoog! The goal of this thread is to provide a wealth of information for the potential buyer and to get rid of some nasty rumors going around. At the end of the thread, I will average up the reliability ratings based on as many responses I can get, and then I guess we'll just play it by ear from there.
So far we learned that one of the most common culprits of failure on the Polymoog is the PSU (Power Supply Unit) and that many of the more common parts are readily available; IC's and such. HOWEVER, more proprietary components to the overall design such as complete circuit boards, are quite difficult to obtain unless you can savage them from another Polymoog.
Thanks Martymoog!
Let's keep this one alive, guys; it will be very helpful to the community!
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Post by nervejam on Sept 13, 2010 11:44:46 GMT
Oh and I'm in Misserableborough, bottom of the economic resiliance league if the BBC is to be believed! I work in Miserableborough..
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Post by brassteacher on Sept 15, 2010 2:35:03 GMT
I think I'll add my few thoughts in now: 1. Marty is correct, the PSU is the #1 cause of trouble. If you've just picked one up, even if the PSU appears fine, and the Polymoog powers up correctly, let the machine sit for a few minutes (assuming there is no smoke ) then check the voltages on the power supply. I would be willing to bet it needs attention unless the seller calibrated the PSU before delivery. 2. Again, if you have just acquired a Polymoog, or if you were insane enough to move it from one location to another, even within the same building, save yourself some time by removing the top, tilt up the three main boards (They are hinged on one end, guess why... ), and unplug EVERY one of the 71 Polycom cards, and the three balance cards, and then reseat them FIRMLY. 3. If after completing #2 above, if you still have one dead note repeat step #2 for that card. If still no joy, switch it with another card and see if the same note is dead or if the dead note follows the card. If the dead note follows the card, it is time to track down another card. 4. Divider chips: These are what finally did in my Polymoog. If you have a dead note, and the same notes in all the lower octaves are dead, you have a dead divider chip. The reason I didn't complete repairs on my Polymoog after a near total rebuild was that I had FOURTEEN dead divider chips #yikes# . At the time, I couldn't even afford the nice new reproductions. There is a link to the reproduction chips in the "Announcements" section of the board. If you intend to keep and actively play your Polymoog, I strongly suggest picking a few up for spares, even if all your chips are currently fine. 5. If you don't have one, pick up a Polypedal. Don't ask why, just do it, you will thank me later. 6. Reliability tip: On the model 203A, there are 37 LEDs on the left and right control panel circuit boards. If you ever need to take these out, consider swapping ALL those LEDs for modern low-current ones. Why? at any given moment, roughly half, sometimes more, of those LEDs are lit. Assuming the originals draw 40mA each (I never could get a good reading on one of my LEDs, it could possibly be more) and you replace them with LEDs that only draw 10mA each, you've just taken 570mA or more load off your PSU. If that doesn't sound like a lot to you, just ask that poor, overworked transformer and PSU board how it feels with that much less of a load #bow#. BTW, I've found that the 3mm type fit just fine, even the lead spacing was the same on the ones I used. Oh, this thread was about reliability. Well, put it this way: Marty KNOWS how to keep his in good shape, plus he has plenty of spare parts lying about, and he gives his a 7 or 8 out of 10. If you already have one, you probably already know how to do at least some maintenance/repair work already, or you have a really good friend who does (On occasion, even a really GOOD friend will need to be bribed , #pintslugger# , #boozer01# , #beerchug# , #ganja# , #rasta# , #mazin# , #birthday02# (if that last smilie makes you go: #wtf# , realize that there is a lot of blowing involved there)). If you are thinking about getting a Polymoog, make sure you have a bribable friend who knows how to work on it, or find a PROPER repair shop and make sure that at least one tech has worked on one (successfully) before. HINT: Ask to see their Polymoog Service Manual. If they can't show you one, even if it only resides on a computer, leave that shop and find another. HINT #2: Once the correct repair establishment has been found, start putting money aside for the eventuality. If you happen to pick up a Polymoog that is in great shape and needs no repairs initially, don't tell any of us here, because we will either: 1- Come beat on your door to make sure you are not lying, 2- Come beat on your door and then beat your ass you lucky bastard, or 3- Both 1 and 2. If for some reason one of us does not do any of the former, it is because: 1- We are absolutely paralyzed in shock, 2- We plan on stealing spare parts when you are not looking, or 3- Both 1. and 2. Overall reliability rating varies. If you know how to work on it: 7. If you can afford to keep it well maintained and never move it: 6. If it is not well maintained, or it you move it around a lot: 4. Marty, as a service to people here and in future, perhaps we should put together a "Polymoog Buyer's Guide" of some sort...
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Post by Minimoog on Sept 15, 2010 11:54:57 GMT
Oh and I'm in Misserableborough, bottom of the economic resiliance league if the BBC is to be believed! You mean I'm sat here in Newcastle, with a broken 280a PSU all boxed up and ready for repair, and I happen to be in Boro this weekend to visit my mum? Can you guess what I'm thinking...?!
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Post by spoonz on Sept 15, 2010 12:06:37 GMT
Ohhh Polymoog reliability.
Having done quite a few of various conditions and versions i can give you my insights for what they are worth.
Generally they are not anywhere near as bad as people would have you beleive.
The Psu's are very reliable generally. Most of you are doing the first or second psu rebuild in 30 odd years. I call that a reliable psu. The Faratron psu's are shite full stop, but anything from Moog is very good. They fail as do many related components because the psu's are not recapped early enough. The caps are to reduce ripple on the outputs mainly. Ripple if bad enough is going to do some damage as well as making your calibration pointless and unstable. If you repair without recapping expect a re visit sometime soon. Caps need to be High temp (105 deg at least)
All Ic's and caps in the Moog psu are available without issue for the most part. Faratron used CAN style Ic's which you now won't get so will need an dip conversion.
The next biggest issue on is op amp failures. Mostly 3080's which although available are becoming harder to find. 5823's can also fail. Your biggest worry is the Motorola Ic's in the phase lock loop to the HFO cards failing. They are rocking horse poo to find and if they fail your in trouble generally. Luckilly they don't go often.
On the 203a the Keyboard and Synth versions are more or less equally reliable if they both have the moog psu (about serial 1750). The Factory updates for the Synth version were largely not reliability based and many factory updates were in use on the keyboard version long before it became a synth anyway. They focused mainly on sound stability and removing noise from the output signal. The presets had a tweak to the sound settings as did the S & H. Don't be put off either if they are Moog powered.
The 4007 Ic's are a common issue on the front boards of the 203a. They are in effect electronic switches (latches) and very prone to sticking on or off when they fail. There are bucket loads on the 203a but only a few on the 280a.
Leds are 5mm low profile and still available (in low current also) High profile will break the panel legend and 3mm versions are a dead giveaway for a repaired unit as they are easily spottable over the 5mm versions although they work fine. I use 5mm low profile diffused. (anyone who had my repair kit a while back should have one) Even availbe in tacky colours should the need grab you.
Keyboard triggering and bushing is also likely an issue. The bus bars tarnish sometime very badly. If the tarnish is left long enough it won't remove and you will have endless triggering issues. The spring contacts of the Poly/mini is much better than the j wire versions of the Oddy and later moogs in that it at least doesn't wear through the plating. Springs are replaceable as is the bus bar if you can get them. Goog cleaning requires the Buss bar be removed though.
Bushes are easy enough to replace but easy to lose the springs etc when removing them. Time comsuming also.
Divider chips. Everyone qoutes them as a biggy problem but they are not that bad generally. They suffer largely beacuse they have no overcurrent protection built in like many Ic's so when they fail to a short they often then daisy chain the fault down the line to the other dividers. (in banks of 3). The good news is they usually go open circuit and what appears to be maybe a row of dead dividers is in fact only 1. If the first in a chain fails the signal is lost to the dividers down the chain so they all appear dead when in fact they are not. Replace the duff Ic and the chain is restored. The most i ever had to replace is in Andy Bouchers Poly (5) and in 10 years i have put 1 in mine. I've fitted far more op amps in that time than dividers. It comes back to that psu ripple. If the psu is suspect then the problem can manifest itself in other IC's and the Divider is not well protected.
As is well documented the older Ic's have a very thin substrate (insulation between internal transistors) and the subrate deteriorates with time so it's fully possible for an Ic to fail even when not in use. It's just one of those things that happens with Ic's of that era. Hence why many Poly's come out of storage with issues.
Voice cards/ balance cards etc are repaireable provided you have a source of Polycom Ic's. Sources are closely guarded these days as the stock gets snapped up if it's made public. Made that mistake before.
In Conclusion i would say don't be put off any of the versions but you do want a Moog psu if at all possible. If it's been stored outside or a loft and looks rusty walk away. They corrode quite badly inside on the keyboard chassis if in a damp environment. Slider pots get pretty stiff and need stripping after a while also.
Go for the best condition model. Buy a good Keyboard version 203a over a bad synth version as you can do all of the mods yourself in a day should you need too. 90% of the Ic's are available and when working they are more or less as reliable as most vintage stuff.
The Pro 5, Cs80's some Juno's etc have much more frequent issues than a Poly and the Pro 5 has a psu 500% worse than any Poly.
Reliability wise for my own unit = 8. Higher than i would give the Jupiter 4 or Oddy i have owned to put it in perspective.
It is a limited animal in terms of what it can do but what it does do is unique. It still looks superb even not doing anything. Every one sounds a little different in some respect as does a mini and for that reason digital will never be quite the same.
ps. Don;t be tempted to replace every chip with new versions or conversions in search of reliability. It may work but there is a sound difference. They sound too clean.
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Post by Minimoog on Sept 15, 2010 12:22:04 GMT
#wavey#
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Post by Polymoog Lover on Sept 15, 2010 15:02:19 GMT
So far we've got some great information here! I'm amazed to find that the Polymoog isn't as unreliable as I thought it was. A point I would like to emphasize (which actually shocked me!) was made by "Spoonz" just above:
"Buy a good Keyboard version 203a over a bad synth version as you can do all of the mods yourself in a day should you need too."
So in other words, don't judge the Poly by what badge it has plated over it's Mode selector!
I would like to drag this thread on for as long as possible, as to provide the most info for newcomers and PolyLovers; this brings me to my next question:
"What about the chasis? Everyone seems to say the same thing about the chasis flexing and wobbling, thus knocking cards and chips out of place and just generally screwing things up!"
Is the above statement true?
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Post by Polymoog Lover on Sept 15, 2010 15:06:53 GMT
Ooops! Forgot to mentions a great tip from "brassteacher" (a Polymoog Tech) who said:
" Reliability tip: On the model 203A, there are 37 LEDs on the left and right control panel circuit boards. If you ever need to take these out, consider swapping ALL those LEDs for modern low-current ones. Why? at any given moment, roughly half, sometimes more, of those LEDs are lit. Assuming the originals draw 40mA each (I never could get a good reading on one of my LEDs, it could possibly be more) and you replace them with LEDs that only draw 10mA each, you've just taken 570mA or more load off your PSU. If that doesn't sound like a lot to you, just ask that poor, overworked transformer and PSU board how it feels with that much less of a load . BTW, I've found that the 3mm type fit just fine, even the lead spacing was the same on the ones I used."
In short, the original stock LEDs are quite power-hungry and put a lot of unnecessary strain on the PSU, so replace them with newer ones! Also, according to the rest of his post, one should learn some good Fellatio techniques if they would like a professionally serviced Polymoog!!!
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Post by Minimoog on Sept 15, 2010 15:36:31 GMT
Also, according to the rest of his post, one should learn some good Fellatio techniques if they would like a professionally serviced Polymoog!!! That's why mine's still broken. Yes they flex like buggery, being heavy but with low torsional rigidity because it's just a thin placcy shell attached to a frame. Bit like cars where a separate chassis with the bodywork bolted on is much less stiff than a monocoque body #geek# It doesn't take much effort to imagine the movement this lot (pictured on Mr Spoonz very own dining table ) may suffer when being lugged about:
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Post by martymoog on Sept 15, 2010 18:40:22 GMT
Sorry just read this, wasn't online yesterday as I was at a wedding in Guisborough Hall Pop it my way Minimoog and I'll sort it for you Martymoog
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Post by martymoog on Sept 15, 2010 19:15:18 GMT
Mr. Spoonz post is spot on with his Synopses and advice.
I should clarify my point on the PSU issue. The Moog PSU's are extremely reliable and stable in themselves. Time is the enemy (having just clocked another year on my own life clock I'm all to aware!!). Capacitors were never designed to last 30 years but once replaced a PSU should last well into the future with no reliability issues.
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Post by brassteacher on Sept 16, 2010 9:19:30 GMT
Caps need to be High temp (105 deg at least) Absolutely! That, or find a way to ventilate the PSU. Most people won't want to cut or drill holes in the top and bottom of their case above and below the PSU, but I've heard of it being done, and a friend is considering having me do this to his 203A. All Ic's and caps in the Moog psu are available without issue for the most part. Faratron used CAN style Ic's which you now won't get so will need an dip conversion. 14-pin wire-wrap IC sockets are IDEAL for this task! Leds are 5mm low profile and still available (in low current also) High profile will break the panel legend and 3mm versions are a dead giveaway for a repaired unit as they are easily spottable over the 5mm versions although they work fine. As an aside, in the case of the Polymoog, perhaps having a dead giveaway for a repaired unit isn't such a bad thing. Goog cleaning requires the Buss bar be removed though. Good suggestion. I would go as far as to say if you plan on cleaning the bus bar AT ALL, remove the thing. If you accidently bend it while trying to clean it in place, good luck trying to adjust the contacts for accurate triggering. If the spacing of the contacts is not consistent from key to key, the aftertouch will not be consistent from key to key. Bushes are easy enough to replace but easy to lose the springs etc when removing them. Time comsuming also. I guess someone should mention that if the keyboard still has the original bushings, it would be best to go ahead and replace them before trying to adjust the key contacts. Divider chips. Everyone qoutes them as a biggy problem but they are not that bad generally. They suffer largely beacuse they have no overcurrent protection built in like many Ic's so when they fail to a short they often then daisy chain the fault down the line to the other dividers. (in banks of 3). The good news is they usually go open circuit and what appears to be maybe a row of dead dividers is in fact only 1. If the first in a chain fails the signal is lost to the dividers down the chain so they all appear dead when in fact they are not. Replace the duff Ic and the chain is restored. The most i ever had to replace is in Andy Bouchers Poly (5) and in 10 years i have put 1 in mine. I've fitted far more op amps in that time than dividers. It comes back to that psu ripple. If the psu is suspect then the problem can manifest itself in other IC's and the Divider is not well protected. Ah yes, I forgot about mentioning that the lower divider(s) may still be alive if an upper octave divider dies. Thanks for reminding me, I still have to get some things on my friend's 203A sorted out. Voice cards/ balance cards etc are repaireable provided you have a source of Polycom Ic's. Sources are closely guarded these days as the stock gets snapped up if it's made public. Made that mistake before. Perhaps I should bribe you! #boozer02# That, or send you these two dead Mod cards I have. I was considering making them into a pair of those really cool Polycom card paperweights! If I remember correctly, the Polycom IC on the balance card is different from the one on the Mod/voice card? That may explain why I have seen many Mod/voice card failures, but why I have never even HEARD of a balance card failing. In fact, the balance card may be the most dependable part of the entire beast! I also made a similar source disclosure mistake once, except the item in question was a CHEAP, but very reliable source of CA3080H (Metal can) chips. I stocked up, but when I went back for more a day or two after I opened my big mouth they were all gone... #wall# I'm going to go out on a very thin limb here by doing something I don't do often, and that's make a generalization: A Polymoog of either type that has had a severe power supply failure, especially involving either the +15V or -15V rail is likely to have FAR more reliability issues than a Polymoog that has not. Spoonz is correct on looking for the Moog PSU vs. the Faratron. However, I have seen a Moog PSU fail spectacularly (As in there were four bits of charred wire in the space formerly occupied by two of the rectifier diodes on one of the 15V rails...). If you are able to inspect a Polymoog before purchase, take a DMM with you and check the PSU voltages. This can be easily done without opening the unit, simply take your measurements from the socket that the Polypedal plugs into. If any part of it deviates significantly from +5V and ±15V (or even if one rail is completely gone) consider shopping elsewhere. The aforementioned Moog PSU explosion is why Marty's 280A has nearly all brand new semiconductors on the TL board, and over half the semiconductors on the TC and TR board are new. One other thought just transversed my feeble mind: If you replace an IC put a good quality socket in place before fitting the new one. Despite the old saying, lightning actually can strike more than once in the same place! Oh, an addendum to the above thought: On the control panel boards, there will not be enough clearance to mount IC sockets on the selector board, and the very forward parts of the CL and CR boards.
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Post by spoonz on Sept 16, 2010 13:14:09 GMT
Same Polycom IC on balance card as mod card. Just later versions were branded the DM8670 and called the Polycom 2 and earlier versions were branded by the manufacturing number 949-040077 only. The same IC in function but just that the DM version was outsourced to reduce costs. (national semiconducter) and is probably better made.
Some Poly's have both, some have all of the old style.
Service manual just makes it seem like they are different in it's description.
I'm open to bribes but only big ones but i have lots and lots and lots of some of the Ic's and will let them go no problem.
My last balance card went in Martin's machine a few weeks back and i have yet to fix his. Yes they do fail but usually not outright. You will just loose brightness and a little volume across a 2 octave stretch when they play up.
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Post by Polymoog Lover on Sept 16, 2010 16:11:03 GMT
Keep it coming, guys, I like where this is going!
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Post by brassteacher on Sept 16, 2010 18:07:28 GMT
Same Polycom IC on balance card as mod card. Just later versions were branded the DM8670 and called the Polycom 2 and earlier versions were branded by the manufacturing number 949-040077 only. The same IC in function but just that the DM version was outsourced to reduce costs. (national semiconducter) and is probably better made. Some Poly's have both, some have all of the old style. Service manual just makes it seem like they are different in it's description. I'm open to bribes but only big ones but i have lots and lots and lots of some of the Ic's and will let them go no problem. My last balance card went in Martin's machine a few weeks back and i have yet to fix his. Yes they do fail but usually not outright. You will just loose brightness and a little volume across a 2 octave stretch when they play up. AH, what added to my confusion was not only the service manual, but the odd coincidence that in my old 280A, EVERY Mod card's chip is/was labeled 949-040077, and all three balance cards have the DM8670 chip. The next time that set of three DM8670 chips pops up on eBay for $10 each, I may grab them... I still have two balance cards left. I wonder if it would be worth working up a small batch of clone circuit boards, since I can do the artwork and etching myself. That just triggered a random thought: if we're really going to try to keep a few of these beasts going, perhaps a small cottage industry of making reproduction/clone assemblies would be worthwhile, just as there are a few small firms here in the US making brand new body, trim, and interior parts for classic Ford Mustangs. In no way would it be profitable, other than saving a LOT of time for a repair by simply swapping a board out. Perhaps there could even be a discount for trading an old board in. The old board can then be refurbished/remanufactured. As another aside, the above may not be so far-fetched. I have already cloned a Concertmate MG-1 main board. I have yet to finish building it out, as I have as yet not been entirely successful in tin plating it. It's too big to fit all of it at once in my current tin plating "tank", and the results have been spotty at best so far (Pun intended ).
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gt
Prodigy
Posts: 5
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Post by gt on Nov 29, 2010 11:38:19 GMT
Hello. This was a very promising thread for a short while. I hope everyone hasn't abandoned it! I picked this thread up searching for polycom ICs for my polymoog keyboard. S/N 1414. I had this on the back burner for a while and have now spent a while to 1 - repair the PSU and associated VTS and tantalums which had gone s/c 2 - replace three faulty divider chips ( thanks to Chris Burrell and his FLATKEYS MM5823N clone ) 3 - reseated, resoldered etc
I am now left with a machine that is almost there. I have four failed polycom cards ( shifted to the two highest and lowest notes) and a failed balance card ( removed cos it sounds better than nothing!) The machine sounds pretty good now and I only wish I could find some spare polycom cards/ ICs.
As far as reliability is concerned, I've found that once fixed they seem reasonable. They are not very portable, one fault can propagate many more and they need TLC as befits their age. There are also some strange design elements e.g. 1% resistors in series with variables ! But we love 'em! Looking forward to hearing /reading about other folks' experience.
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Post by Polymoog Lover on Nov 29, 2010 14:40:13 GMT
Good to know that this thread started to help someone! Hehehe. Let's finish the job, guys. Can anyone help this fellow? Also, let's keep this thread alive!!!
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Post by brassteacher on Nov 29, 2010 18:54:19 GMT
Hello. This was a very promising thread for a short while. I hope everyone hasn't abandoned it! I picked this thread up searching for polycom ICs for my polymoog keyboard. S/N 1414. I had this on the back burner for a while and have now spent a while to 1 - repair the PSU and associated VTS and tantalums which had gone s/c 2 - replace three faulty divider chips ( thanks to Chris Burrell and his FLATKEYS MM5823N clone ) 3 - reseated, resoldered etc I am now left with a machine that is almost there. I have four failed polycom cards ( shifted to the two highest and lowest notes) and a failed balance card ( removed cos it sounds better than nothing!) The machine sounds pretty good now and I only wish I could find some spare polycom cards/ ICs. As far as reliability is concerned, I've found that once fixed they seem reasonable. They are not very portable, one fault can propagate many more and they need TLC as befits their age. There are also some strange design elements e.g. 1% resistors in series with variables ! But we love 'em! Looking forward to hearing /reading about other folks' experience. Unfortunately, someone snapped up my last ten Polycom cards a month ago. With your Balance card, someone, I can't remember who, had success in reviving their balance card by replacing both LM358 opamps. Have you gone through the calibration process?
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