very slow fire-up from cold start on two Nakamichi CD-Player4's

[j ferguson]

I inherited my Dad's state-of-the-art HI-FI setup vintage 1989.  I found the bad cap in the Nakamichi CR-3A Cassette deck - it was easy, one channel played, the other didn't but both wrote to tape.  I glued the broken gear in the cassette loader back together in the TASCAM deck and now it works.

At first the Nakamichi CD-Player 4 worked fine even though it hadn't run in maybe 6 or 8 years.  But now, it lights up and spins the disk on cold start (after a month of disuse) but won't lock on to disk - tracking numbers don't show.  So I bought another one on Ebay.  It worked when I got it, but then relapsed into same problem.

So I googled and googled and found a couple of other guys with same symptoms. One had discovered if he turned power on, did nothing else, and let it sit for about an hour with power on, it would then play FB.  So I tried it on each machine and VOILA!

I'm guessing that a voltage is either not comng up or is being pulled down by a component which gives up after an hour and lets it through.

This smacks of a capacitor problem where the shakey one needs an hour to get with the program.  I opened the boxes and looked at those involved in the power supply but no leaks on the electrolytics, no soot, nor other visible symptoms of distress.

My plan is, with the schematic (which I have) in hand, to measure the likely voltages when one of these things is running, then do the same thing on turn-on when it's sat for a month and doesn't play.  Maybe ESR meter readings at both stages.

my question then, is it possible that this might be other than a capacitor?

[Rasz]

This smacks of a capacitor problem where the shakey one needs an hour to get with the program.  I opened the boxes and looked at those involved in the power supply but no leaks on the electrolytics, no soot, nor other visible symptoms of distress.

capacitors dont always fail visibly, especially if they arent driven hard in switching circuit. Either buy $12 ESR meter from ebay, or start hunting for bad caps on power rails with scope/swapping them one by one.
might not be caps, but healing after warming up is a classic symptom.

[j ferguson]

Thanks Rasz, that was pretty much my plan.  the two decks are not identical even though both are labeled nakamichi cdplayer 4's.  I haven't checked to see if the boards are much different.
i have an ESR, which unfortunately cost more than $12, but should work just as well as the cheap ones.

[amyk]

They're 28-year-old electrolytic caps, replacing all of them would not be a bad idea.