damn, got a semi-minor problem with this sucker. if i go to play a disc directly after power-up, the player behaves as if it's having difficulty syncing to the disc, whether factory CD or CD-R, and sometimes starts to play, with a popping sound as the only output, and the time counter momentarily fritzes out at random, displaying letters instead of time count. (perhaps a fault code?) now, if i leave it sit for 5/10 mins. or so, it starts playing perfectly, as quick and sure-footedly as the PD-91. it continues to function flawlessly until power-off, and i go to test it out again some time later. does anybody have any ideas about this? it sounds like a flaky cap to me. like a faulty vital cap somewhere in the playback electronics that needs several minutes to charge up to it's proper values...

I concur with you. Since this is an old cdp i'll check all the caps.

i've never checked caps before. how does one go about it? i've never had a problem like this with either of my 1986 model CDPs, (PIONEER PD-M6, the very first cart. CDP ever made! and the DENON DCD-1500 TOTL single disc) they both perform flawlessly, as does my 1987 PD-91. this PD-M90X is a multi-voltage model. when i got it home, the selector was set to the japanese 110V setting rather than the U.S. 120V one. the guy i got it from was the original owner that claimed that he bought it direct from the factory in the late '80s when he was stationed in japan during his tenure in the armed forces. since i found it in the JPN voltage setting, it is likely that this CDP has been run on JPN voltage settings all of these years. is it possible that running a Hi-Fi component in the U.S. for two decades on JPN voltage settings has damaged one ore more of the power supply caps? it has been said in the past that many japanese home electronic components have worked just fine on on U.S. voltages without a step-down trannie. i guess this situation proves them wrong...

The visible physical indication of a cap problem is a shiny, oozing substance on the circuit board under the capacitor or above the capacitor. Sometimes you can see it, other times you can't (and you may need a magnifying glass or binocular magnifiers to see the leakage).

Here's a few photo examples:

okay, so the best thing is to have the PS caps tested, and if one or more measure below the values of the others, than those are faulty and need replacement? i remember looking at the caps, and not seeing any form of leakage. perhaps today i'll open her up again for the umpteenth time and take a very close scrutinizing look like you say. my mother's hubby has a volt/ohm meter; how would i go about testing the caps with it?

In most cases you simply CAN'T use a multimeter to test a capacitor.Most multi-meters are incapable of reading 'Farads' (capacitance) which is what capacitors are rated by.
At least, you can't measure the cap's value, but you can tell if the cap has a short.

A GOOD CAPACITOR will measure a very HIGH resistance on ALL ranges.

However, if the capacitor is SHORTED (a common problem) then the OHMETER function can be used to check it.

If the capacitor is SHORTED then the ohmeter will read 0 (zero) ohms.

It is also possible for a capacitor to have a HIGH RESISTANCE short. So check the capacitor using several different ohmeter ranges. A high resistance short will measure open ciruit on the low ohm ranges, and medium resistance on the high ohm ranges.


BTW: Watch the polarity on electrolytic caps. Always connect + to + and - to -

Other than the above, you need a special Capacitance Check Meter available through your local electronics supply store.

okay. just got to looking at it. as you can see, i've lubed the daylights out of the changer mecha with white lithium grease. as such, it operates beautifully, perhaps better than new. on to the PS caps:





i have failed to notice any visible anomalies. can anyone see anything that i may be missing? it would appear to me that the only course of action is to test them electrically...

You have other caps than those in power supply.....

where? on the trannie board there?

One question first.
Do you have some kind of electronic's knowledge? and also a little about solder and desolder electronic sutff? If so, it's well clear thta's a lot of caps everywhere on the pcb that you should clearly checked with a magnifying glass or binocular magnifiers to see any kind of leakage, descolorations or even smell. Bad caps smell. You need patience and a sharp eye.

U.S. voltage runs 110-120 thats why we use power cond. they keep it at a constant. Put it back on 110 maybe it likes it there. Then try it..

Also remember a cap will give you a nice jolt if it isn't discharged.

My own rule of thumb about caps: if they have more than 15 years old or older, replace it.
When it is in doubt, replace it.
If something strange is happening on a board, replace it.

New low ESR caps are much better than anything used in older gear that the reasons NOT to replace them pale in comparison to the benefits.

http://www.elna-america.com/tech_al_reliability.php

yeah, i can soulder/desoulder. i had to do just that when the ON/OFF switch broke. thankfully, i had a replacement out of my outmoded laserdisc player. i had to warm the two pins and pull both off their boards so i could put the replacement in place on the M90X's POW. SW. board. i have also done other jobs. still, i have no education in electrical, so i'll just sit tight a couple months until my S.S. comes through, and then haul it up to AT HOME ELECTRONICS in KENNEWICK, WASH. and have the fault professionally worked. at any rate, thanks for your help, clint. you've been a pal...

tell me about it!! i got a good fun-buzz a couple months back when i was diddling with the faulty power supply of my SONY SLV-R5UC S-VHS VCR...