classyharlan
Active Member
I found a YEDS-35 for $5. Are all the YEDS series suitable for CD player testing purposes or only the one/ones titled "Test CD"?
Troubleshooting CD Players
- Thread starter dr*audio
- Start date
I found a YEDS-35 for $5. Are all the YEDS series suitable for CD player testing purposes or only the one/ones titled "Test CD"?
If you want the test signals, then you need the YEDS-18. The others I think are only demonstration CD's. Dr. Audio can confirm.
I am working on yet another Technics SL-P8 and wanted to get some input from @dr*audio, if he will be so kind.
This unit as it sits will load and spin up a disc and read the TOC almost instantly, showing track and time totals in the display. But, there is a periodic rubbing/scraping noise while the disc spins, and once playback is attempted (from any track number) it will never start playback and will eventually time out and spin down.
I have suspected an issue with the height of the disc hub, but am reluctant to adjust it until I get an expert opinion. As a quick and dirty test, I cut some masking tape (two layers worth) and placed it on the hub to increase the height of the disc relative to the table. This significantly reduced - pretty well eliminated - the mechanical rubbing/scraping noise while spinning, and also had the effect of causing some tracks (10 and up) on the disc being used to actually play with about 80-90% reliability.
It does still skip around a little and has very infrequent but audible wavering of the playback speed, without the pitch control engaged. Fast back and forward search do not work reliably, they skip around generally in only a forward direction, even when pressing fast back search. In have cleaned and lubed the sled rails and upper bearing, as well as installed new belts.
So, the question is this: based on present symptoms, should I loosen the set screw and move the hub slightly up the shaft? That is my working theory (and I do have the factory service manual for this unit to refer to) or is my theory junk? The hub does have the factory anti-slip fiber ring present, and the clamp appears to be entirely nominal in it's operation. Clearly the laser is still good as when it works, it works well, but something is mechanically out of spec. Input much appreciated.
This unit as it sits will load and spin up a disc and read the TOC almost instantly, showing track and time totals in the display. But, there is a periodic rubbing/scraping noise while the disc spins, and once playback is attempted (from any track number) it will never start playback and will eventually time out and spin down.
I have suspected an issue with the height of the disc hub, but am reluctant to adjust it until I get an expert opinion. As a quick and dirty test, I cut some masking tape (two layers worth) and placed it on the hub to increase the height of the disc relative to the table. This significantly reduced - pretty well eliminated - the mechanical rubbing/scraping noise while spinning, and also had the effect of causing some tracks (10 and up) on the disc being used to actually play with about 80-90% reliability.
It does still skip around a little and has very infrequent but audible wavering of the playback speed, without the pitch control engaged. Fast back and forward search do not work reliably, they skip around generally in only a forward direction, even when pressing fast back search. In have cleaned and lubed the sled rails and upper bearing, as well as installed new belts.
So, the question is this: based on present symptoms, should I loosen the set screw and move the hub slightly up the shaft? That is my working theory (and I do have the factory service manual for this unit to refer to) or is my theory junk? The hub does have the factory anti-slip fiber ring present, and the clamp appears to be entirely nominal in it's operation. Clearly the laser is still good as when it works, it works well, but something is mechanically out of spec. Input much appreciated.
classyharlan
Active Member
Maybe you've checked this already but instead of the table it might be a cracked or loose part around the mecha chassis. I've had 2 cases like yours, one was a cracked chassis frame and after I secured the frame the problem disappeared, the other was a loose clip on the left of the chuck arm and tightening that solved that player's issues. I found both of those causes after a lot of poking around with a pen during playback.
dr*audio
Fish fingers and custard!
The height of the disc table affects the focus. Since it reads TOC and attempts to play, the table height is probably ok. I think the suspension is sagging. This is especially common on units that use silicone bellows instead of springs. The check should float in the chucking arm such that there is equal play above and below the arm with the disc loaded.
If your player uses silicone bellows, you will have to put washers under them to correct the height. If it uses springs, stretch the springs by the distance of the space between 2 turns. The springs are not identical so do one at a time and keep them in the same position.
If your player uses silicone bellows, you will have to put washers under them to correct the height. If it uses springs, stretch the springs by the distance of the space between 2 turns. The springs are not identical so do one at a time and keep them in the same position.
Thank you both for the input. To clarify in case it makes any difference, this unit would read TOC solidly before placing the masking tape shims, even when the disc rotation made rubbing noises, but would never successfully play any track. Addition of the masking tape shims has nearly eliminated the rubbing noises and has allowed playback of tracks closer to the outside edge of the disc, but still not any closer in. This runs counter to most of my experience with tracking issues on CD players, usually the tracking gets unreliable the further towards the outside edge the optics have to track.
I'm guessing this has minor focus/tracking issues as well, but wanted to establish how best to proceed with mechanical remediation before doing any electronic alignments. I'll check the suspension and frame, and do have two other identical good working units here I can make visual comparison and measurements on.
I did previously do a minor repair to the clamp, there is a small round plastic bushing on one metal ear at the hinged end of the clamp that was broken, causing it to sit slightly cocked. I scavenged the identical part from a donor unit, which corrected the symmetry of the clamp.
Really want to save this one, it is the silver version and is exceptionally clean. Besides, as vintage CDPs go, these were surprisingly good in both function and sound.
I'm guessing this has minor focus/tracking issues as well, but wanted to establish how best to proceed with mechanical remediation before doing any electronic alignments. I'll check the suspension and frame, and do have two other identical good working units here I can make visual comparison and measurements on.
I did previously do a minor repair to the clamp, there is a small round plastic bushing on one metal ear at the hinged end of the clamp that was broken, causing it to sit slightly cocked. I scavenged the identical part from a donor unit, which corrected the symmetry of the clamp.
Really want to save this one, it is the silver version and is exceptionally clean. Besides, as vintage CDPs go, these were surprisingly good in both function and sound.
classyharlan
Active Member
The laser resistor only turned 1/8 of a turn either direction, going all the way clockwise got it up to 1.2V. That seemed to get rid of the returning home on failure / trying to go past home errors.
Of the previously failing long discs that I newly tried today: Disc 1 was ok. Discs 2 and 3 would jump back before being able to reach the end, e.g. get 10 seconds to finish, jump back a minute, repeat. A previously ok long disc also now had this behavior. Disc 2 was iffy on searching the last track--sled would move out and then sit there thinking.
I don't know if this is relevant but the eye pattern is not clear at all, it's very blurry.
dr*audio
Fish fingers and custard!
The pot should turn close to 270 degrees. There may be paint on it. Pick the paint off gently with a dental pick.
classyharlan
Active Member
I figured out the pot rotation issue.
With the pot maxed out the rf height is only 1.2V, or less on bad discs. Previously failing discs still fail.
With the pot maxed out the rf height is only 1.2V, or less on bad discs. Previously failing discs still fail.
dr*audio
Fish fingers and custard!
Probably bad laser, then. What is the number on the laser? There should be a label on it with a part number. If this is the Denon DCD-910, the laser is a Sony KSS150A. Replacement is KSS210A. Liberty Electronics has good ones.
https://www.ebay.com/itm/3607241842...j4Mouf5QK3eeicfw|clp:2334524|tkp:BFBMrPnE4tRf
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classyharlan
Active Member
I'm not in the US so I'm going to try someone local, I just found a few. Is there any way to differentiate between a good KSS210A from a lemon before buying, just from the product listings?
dr*audio
Fish fingers and custard!
1. Look at the other auctions from the seller. Only choose a seller that sells ONLY electronic parts, not a bunch of miscellaneous stuff like handbags and toys.
2. Look at the seller's feedback, especially for lasers they have sold. You want close to 100%.
There are a lot of sellers selling junk lasers. All of the lasers now are sourced from China, but Liberty Electronics found a reliable supplier.
Bradbrews
Super Member
Sony XA777ES plays redbook CD’s fine but won’t recognize a hybrid SACD. It will only play it as a standard CD.
Tried cleaning the laser and as it was fairly dirty thought I might get lucky but it didn’t work.
The owner is listening to mostly multi channel and unless it plays SACD again it’s not as useful.
Tried cleaning the laser and as it was fairly dirty thought I might get lucky but it didn’t work.
The owner is listening to mostly multi channel and unless it plays SACD again it’s not as useful.
classyharlan
Active Member
Even after changing the pickup there isn't much improvement. The rf on the new pickup was only .4V.
There is noise/static on later tracks of certain discs. One disc won't advance the final minute.
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dr*audio
Fish fingers and custard!
Can't be .4V, it wouldn't play the disc at all. Check your measurements.
classyharlan
Active Member
Yes I misread it. The new pickup is about .8V.
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dr*audio
Fish fingers and custard!
Try adjusting it, but I think you got one of the crappy ones.
classyharlan
Active Member
It just became completely unresponsive so I guess you're right.
dr*audio
Fish fingers and custard!
So far the only reliable source I have is Liberty Electronics. Would you care to share the name of the vendor you got that from so people are warned?