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Old 09-28-2018, 01:07 PM   #1
Chungalin
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Default Sony CD player CDP-397 repair, No Disc, fixed

This nice and simple CD player based on KSS-240A doesnít read discs. Disc spins with apparent normality but after a few seconds it throws NO DISC message. Disc stops spinning but it doesnít actively brake.

25 years old and itís clean as new, incredible. This even rules out dirtiness. I suspect of badly bend 12 track FFC, but replacing it doesnít improve anything.

CD Servo PCB doesnít have any electrolytic cap to check. Thatís a source of problems in Sony CD PCBs with a few caps (either through-hole or SMD). Iím running out of ideas but I resist to replace optical pickup. Then I check front PCB, since in this minimalistic model all circuitry but Servo is there. Check ESR for all small electrolytic caps and I find two with disturbing >10Ω ESR due to aging. Both 10ĶF/10V, around IC291 special 5V regulator. I replace them and itís fixed!
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Old 09-30-2018, 09:35 PM   #2
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Default Re: Sony CD player CDP-397 repair, No Disc, fixed

Nice work! So two small caps was the issue here? I guess I better bookmark this for future reference. My uncle has an old Sony CD player that doesn't work and he wants to get it fixed. Most shops he went to already said they can't do it. I guess next time I see him, I just have to remember to bring my cheap cap tester with me.
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Old 10-01-2018, 04:29 AM   #3
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Default Re: Sony CD player CDP-397 repair, No Disc, fixed

I’ve repaired more than 150 Sony CD players from the 90’s and they’re always repairable. KSS-240A insides can be cleaned with care, never require replacement. Main failures are: dirtiness, loading belt, broken FFC, broken sled gears, and capacitors.
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Old 10-02-2018, 07:25 AM   #4
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Default Re: Sony CD player CDP-397 repair, No Disc, fixed

So the lasers don't wear out on these older Sony CD players? Basically, my uncle had the same problem with his (I forgot what the model number is, but it's from the 90's I'm pretty sure): CD spins up and sometimes plays for 1-5 seconds, then CD player gives NOCD error. Pretty much every service shop he went to told him he had a worn laser and nothing that could be fixed (or maybe they just couldn't be bothered to fix it?). Not sure if dirtiness is an issue - the player looks pretty clean inside. He already tried cleaning the laser lens with alcohol. Perhaps it's dirty on the bottom (under) side or the pickup itself? From what I saw, the sled gears were okay too - clean and easy spinning. So perhaps that leaves only the capacitors as you suggest.

Also, sorry for the silly question, but what's an FFC? Is that the flat ribbon cable between the laser sled and the main board?

Thanks!

Last edited by momaka; 10-02-2018 at 07:27 AM..
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Old 10-02-2018, 08:10 AM   #5
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Default Re: Sony CD player CDP-397 repair, No Disc, fixed

In this context, FFC is Flexible Flat Cable, but it can also mean Flexible Foil Circuit (a thin transparent foil where a circuit is printed and SMD components can be soldered).

These KSS-240A players use a 12 track 1mm pitch FFC. When the two layers of material split at certain point (due to repeated bending) then air begins to corrode tracks and they eventualy break. You can use a more common 16 track 1mm pitch FFC from KSS-213B, C, E, F, etc. (and many other CD pickups) and cut extra 4 tracks.

KSS-240A can be cleaned internally with a thin cotton stick. You must NOT remove lens assembly because itís callibrated and glued. Other CD pickups allow lens assembly to be removed and this makes inner cleaning easier. This one not. I donít recommend IPA alone to clean lenses. I donít clean my eyeglasses with alcohol, but with a special liquid from eyeglasses shop. So the same for laser lenses. Itís not magic, it contains alcohol, of course, but thereís something else that makes it slightly soapy.

Iíve replaced very few KSS-240A, most of the times they can be cleaned or the problem is somewhere else.
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Old 10-02-2018, 11:07 AM   #6
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Default Re: Sony CD player CDP-397 repair, No Disc, fixed

FFC means Flat Flexible Cable. There is nothing like FFC meaning Flexible Foil Circuit in any of the books I've read so far. I think you mean FPC which means Flexible Printed Circuit.
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Old 10-05-2018, 05:13 PM   #7
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Default Re: Sony CD player CDP-397 repair, No Disc, fixed

Thanks for the info again fellas and sorry for hijacking the thread with questions. I just don't want to create a new thread as I don't have the unit in front of me and if someone asks for more info or pictures, it would be silly as I wouldn't be able to post any of that.

That said, I think my uncle's unit used a KSS-271a laser - or at least based on some bookmarks I've made.
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Old 10-17-2018, 05:57 AM   #8
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Default Re: Sony CD player CDP-397 repair, No Disc, fixed

Quote:
Originally Posted by momaka View Post
That said, I think my uncle's unit used a KSS-271A laser - or at least based on some bookmarks I've made.
KSS-271A ? Looks like you are talking about a ES series from Sony ("flagship" series). Never repaired one of these. ES series means quality but also more complexity, sometimes unnecessary except for price inflation.
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Old 10-21-2018, 11:15 PM   #9
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Default Re: Sony CD player CDP-397 repair, No Disc, fixed

^ Yeah, it's a high-end model, which is why my uncle is trying to get it working (for himself).
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Old 10-23-2018, 10:21 AM   #10
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Default Re: Sony CD player CDP-397 repair, No Disc, fixed

Addendum to original CDP-397 repair: it wasn’t so easy, like almost all repairs. That’s why this, as a job, sucks.

The CD returned two weeks later with even weirder/crazy behavior. When it was able to play a disc I noticed some audio artifacts similar to bad reading or massive jitter. Touching the front board close to IC302 seemed to improve or fix the problem. Upon closer inspection I saw that IC291 had many broken solder joints, because of repeated heating/cooling effect over years of use. It has some sense, because replaced caps were related to this regulator, and working close to that IC worsened solder joints state.
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