The Sad Fate of Direct Drive Turntables...
- Thread starter Arkay
- Start date
Azimuth
Well-Known Member
I'm confused about what he's saying about the huge number of Technics consumer-level DD tables out there. I have an SL 5200, SL D2, and SL 1700. There are millions of this type of DD unit around the world. Are they all living on borrowed time? Or just the high-end complicated ones?
Tripod
Well-Known Member
Heck, Arkay
This makes for depressing reading:tears: All work I put in here fer nuthin:tears: Perfect pitch since '72. Where will it all end? Talking about those dying chips. Since these are encapsulated and relatively immune to corrosion caused by humid climes, could the problem not be with the circuit corrosion or oxidation which surrounds and connects to those chips?
I once had a Pioneer integrated which also 'died' unexpectedly. It had a large multipin chip inside for which I ordered and got a replacement.
Desoldering the chip to remove it looked a bit daunting and I decided to 'reflow' all the soldered pins and got things to work again. The replacement chip was never needed and it is still here somewhere.
tripod
This makes for depressing reading:tears: All work I put in here fer nuthin:tears: Perfect pitch since '72. Where will it all end? Talking about those dying chips. Since these are encapsulated and relatively immune to corrosion caused by humid climes, could the problem not be with the circuit corrosion or oxidation which surrounds and connects to those chips?
I once had a Pioneer integrated which also 'died' unexpectedly. It had a large multipin chip inside for which I ordered and got a replacement.
Desoldering the chip to remove it looked a bit daunting and I decided to 'reflow' all the soldered pins and got things to work again. The replacement chip was never needed and it is still here somewhere.
tripod
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Arkay
Lunatic Member
You raise an interesting point, which was also touched on in the conversation that inspired this thread. Tommy did say that in some cases, even if you could find the right replacement chip, you couldn't always replace it, because some of those factory-soldered chips (that were NOT mounted in sockets) required "factory" gear to desolder and resolder; you couldn't do it with normal soldering gear, even the kind used for some smaller chips. I don't have the firsthand knowledge to contradict him, and from what I have seen of chips over the years, perhaps it is true(?).
Arkay
Lunatic Member
They wouldn't all use the same circuits, any more than two different motors would necessarily use the same voltages, or the same start-up capacitors, etc... The circuits are designed for the specific motors/TTs, and won't always transfer to others. Motors don't all have the same number of coils, for example, so the timing of the circuits in "smoothing out" the "cogs" (I'm over-simplifying here) would be different. Otherwise, there would be no worries, as anyone could just start making standard chips or circuits and all DD TTs could be easily kept going that way.
Tripod
Well-Known Member
Hi Arkay
OT but perhaps last weekend's experience could have a bearing on the problem why dd chips (or circuits?) fail. I use SUT's for mc cartridges. My favourite is rare and dates from the late 70's. The one I'm referring to failed last weekend, with loss of signal on both channels.
This sparked a frenzy of checking every single connection from the cartridge to the pre amp. The last thing I suspected was that the SUT could be at fault and I opened it as a last resort when I found nothing wrong with all the other cabling and equipment.
To my amazement, I found the wires from the pair of transformers which is silver-wound, still dangling in position at the phono jacks but they were completely without solder.
I re-soldered them, using solder with silver content and all is well again.
A clever gent on another forum suggested that the problem was caused by lead solder 'leaching' away the silver of the trannie wires. I'm not sure if lead has the same adverse reaction on a circuit board which could have goldplated tracks. So maybe the chips are OK but the circuit tracks to them could be affected by the lead used to solder them.
I understand my speculation will not help much after the fact, due to the special tools required to do repairs.
tripod
OT but perhaps last weekend's experience could have a bearing on the problem why dd chips (or circuits?) fail. I use SUT's for mc cartridges. My favourite is rare and dates from the late 70's. The one I'm referring to failed last weekend, with loss of signal on both channels.
This sparked a frenzy of checking every single connection from the cartridge to the pre amp. The last thing I suspected was that the SUT could be at fault and I opened it as a last resort when I found nothing wrong with all the other cabling and equipment.
To my amazement, I found the wires from the pair of transformers which is silver-wound, still dangling in position at the phono jacks but they were completely without solder.
I re-soldered them, using solder with silver content and all is well again.
A clever gent on another forum suggested that the problem was caused by lead solder 'leaching' away the silver of the trannie wires. I'm not sure if lead has the same adverse reaction on a circuit board which could have goldplated tracks. So maybe the chips are OK but the circuit tracks to them could be affected by the lead used to solder them.
I understand my speculation will not help much after the fact, due to the special tools required to do repairs.
tripod
steerpike2
Super Member
That is a very vaild point. My personal experience has been that service departments tend to replace components in a sequence until things start to work again, without ever bothering to understand or test how the circuit works, or doesn't work.
So in many cases, chips are replaced while they are without fault.
Apart from some known bad chips, or known bad designs (the servo amp in Sony's CDP101 comes to mind), ICs are very, very reliable when operated within design limits - the CDP101 ran that chip with no heatsink, what did they expect? Conversely, it is possible that a faulty capacitor or other unreliable component fails, and damages the chip.
In reference to my earlier link to re-doing the Technics SP10 electronics, it will always be possible to re-engineer the electronics of DD turntables; As mentioned, each design is specific, but the general theory is the same throughout. The only major catastrophe is a burned out motor armature - but that can also be re-wound if you are dedicated.
I'm biased in this matter though: I hate the idea of discarding anything well made that can be restored, so I never let anyone get away with the argument that "it can't be repaired". You just have to put in a bit more effort.
I'm a bit perplexed by the reference to factory soldered chips that you can't swap. I have not encountered such a thing. The only thing I can think of that fits this description are the VLSI chips that are bonded directly to the circuit board, such as in calculators, and LCD displays. But you wont find that type of throwaway construction in turntables.
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Hmm. I'd bet there are any number of gear-modders who would look at that as a challenge or obstacle to be overcome.
Again, I'd be willing to bet that with the proper application of money and time, those TT's that wound up in the trash copuld have been rescued or even improved.
If you have a schematic, it's not magic. You could probably replicate the whole darn thing. Again, it's a crime that the dumpster was the destination. The Tuners forum has a number of posts where there are people making new circuit boards for unobtanium-tuner repair. A TT can't be any harder.
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Arkay
Lunatic Member
Personally, I'm inclined to be of the mindset that if something can be built once, it can be re-created. It's only a matter of cost and resources. If it is a circuit that isn't hugely large or complicated, it can be reproduced. If it is complicated, it can be re-manufactured, but that is way beyond the resources of a DIYer.
Short of that, I suggested to Tommy during the conversation that even large, multi-prong chips could probably be removed by freeing one small section of the chip's connectors at a time, with a suitable tool and cooling time between, but having spoken with two factory-owner/engineers since then, they both agreed that some chip connections cannot be done manually, without the right gear. I'm not sure whether such chips are found in these TTs. Tommy seemed to think that some were, at least in some of the later models, and I believe that he --and especially his repair expert(s) here and in Japan-- know these rare, Japan-market-only tables better than any of us. When even the former factory techs in Japan say they cannot, or will not, repair them because they cannot get parts, there must be SOME level of truth in it.
Perhaps in part he was thinking with a commercial mind. A DIYer might not mind putting in, say, 200 hours to rebuild a circuit that could replace the function(s) of a chip, as a "labor of love". But commercially, this would be uneconomical. And, as we both agreed, there might still be some parts hidden away somewhere, unknown and un-findable without great persistence and some luck. A dedicated searcher might seek those out, and with some luck, find them, but the search would cost far more than it would be worth in a purely monetary calculation, so again this would not be a commercially viable option.
In any event, I wouldn't throw away any truly fine TT just because someone else said it was unrepairable. I would keep looking, seeking, trying to find a way to make it come back to life. USUALLY, where there is a will, there is a way. But the practical impediments to "repairing" something that relies on a chip that is no longer in production and no longer in stock, are formidable, to put it mildly.
Short of that, I suggested to Tommy during the conversation that even large, multi-prong chips could probably be removed by freeing one small section of the chip's connectors at a time, with a suitable tool and cooling time between, but having spoken with two factory-owner/engineers since then, they both agreed that some chip connections cannot be done manually, without the right gear. I'm not sure whether such chips are found in these TTs. Tommy seemed to think that some were, at least in some of the later models, and I believe that he --and especially his repair expert(s) here and in Japan-- know these rare, Japan-market-only tables better than any of us. When even the former factory techs in Japan say they cannot, or will not, repair them because they cannot get parts, there must be SOME level of truth in it.
Perhaps in part he was thinking with a commercial mind. A DIYer might not mind putting in, say, 200 hours to rebuild a circuit that could replace the function(s) of a chip, as a "labor of love". But commercially, this would be uneconomical. And, as we both agreed, there might still be some parts hidden away somewhere, unknown and un-findable without great persistence and some luck. A dedicated searcher might seek those out, and with some luck, find them, but the search would cost far more than it would be worth in a purely monetary calculation, so again this would not be a commercially viable option.
In any event, I wouldn't throw away any truly fine TT just because someone else said it was unrepairable. I would keep looking, seeking, trying to find a way to make it come back to life. USUALLY, where there is a will, there is a way. But the practical impediments to "repairing" something that relies on a chip that is no longer in production and no longer in stock, are formidable, to put it mildly.
Arkay
Lunatic Member
No, early DD TTs without chips are not affected.
DD TTs with chips that are still available, or for which there are common/easy substitutes or work-arounds available, are not affected.
AFAIK, Only a FEW of the later-era (1980s) (and mostly Japanese-market-only) models are really affected by this problem.
Of course, in theory ANYTHING with chips in it is at risk of ultimately meeting this kind of fate. It's only a question of when/how long... but that said, the end for any given DD TT could still be many years (decades) ahead, if they are taken care of and kept in a good (for them) climate. And you can always try to stockpile spares, if this is a concern for a particular model TT.
:scratch2: Wonder where I can find parts for a PL-L1 to start stockpiling....
:sigh:
Balifly
Listening
:scratch2: Wonder where I can find parts for a PL-L1 to start stockpiling....
There are Japanese audio groups that specialise in rare/extreme high end turntables. They should be able to shed some light on the possible fixes.
dnewma04
The Healer
An adventuresome individual with some skills with electronics and motors could always recreate the obselete chips with discrete circuits or use modern chips that are made to perform similar tasks. Directly drive motors are still used often, not just in turntables and the science on how to control them obviously still exists. The only worry would be cost of getting it back up and running, but if you are spending 8-10k on an SP-10MkIII, somehow I don't think cost would be a huge hurdle.
interalian
Super Member
Posting in this thread killed my Hitachi HT-860! :tears:
Out of the blue the other day it didn't auto-return at the end of a side. Next side it cued up a couple of minutes into the first track. Now the platter won't stop and the arm clutch is stuck engaged. I think I let the smoke out of something*.
Troubleshooting to begin when I have a spare hour or 20...
*You know that electronic components run on smoke - let it out and the part stops working. (Trying to put on a brave face.)
Out of the blue the other day it didn't auto-return at the end of a side. Next side it cued up a couple of minutes into the first track. Now the platter won't stop and the arm clutch is stuck engaged. I think I let the smoke out of something*.
Troubleshooting to begin when I have a spare hour or 20...
*You know that electronic components run on smoke - let it out and the part stops working. (Trying to put on a brave face.)
mhardy6647
Lunatic Member
These are quantum mechanical effects, and defy logic.
;-)
;-)
It's all rather odd. Not that I doubt the veracity of what Arkay is espousing, but an IC is very robust. A failure of one is so rare in my ken that I've forgotten that it actually can happen. Usually, when they fail, it occurs immediately upon initial powerup due to inadequate quality control during the assembly stage. Are these failures inevitable? My suspicion is that in the grander scheme of things everything else will fail first before the IC's go. 
ara:
I wouldn't have any worries about purchasing and enjoying a TT with IC's at all. If it burns out so be it. In the meantime some thought to the environment that is friendly to these electronic devices could be considered: Humidity and temperature control perhaps.
ara: I wouldn't have any worries about purchasing and enjoying a TT with IC's at all. If it burns out so be it. In the meantime some thought to the environment that is friendly to these electronic devices could be considered: Humidity and temperature control perhaps.