"dead" marantz cd 4000

[johncass]

Hello

I have a marantz cd4000 cd player which has been in storage (dry, safe) for several years and was working when went in...now I am wanting to use it, its not responding at all when plugged in - nothing on screen, no response to keypresses, I can hear a slight hum so internal transformers may be active...
I have downloaded schematics and will try to test power distribution - just wondered if anyone had seen anything like this and maybe there's a common cause (e.g. a fuse or weak connector) - also any tips on where you would start looking for the problem would be welcome!

Cheers
John

 

[cherik]

Transformers hum, some more than others, and usually more so under excessive load. The hum could be normal or could be because of a heavily loaded or shorted rail. So, check power rails and take it from there.

 

[johncass]

Thanks cherik -
I'll open it up and test how the power is flowing to the various boards...Im sure I'll be back with more specific questions!
Cheers
John

 

[johncass]

Just an update in case anyone interested, having opened up and checked power - all power circuitry seems fine, the only thing I could think of - was the power switch working (its a standby switch so a microswitch, not actual power)? I found the point where its wired into the circuit board and shorted it, and lo and behold the cd player powered up! Then tried to eject the tray - again no response, found the point on the circuit, shorted it and tray opened...
So it would appear that the switches are the weak link, perhaps they have corroded internally over time...I wonder if they can be cleaned or need replacing - I have to extract the front control board to expose them and check further..

 

[Puffin]

Try some spray contact cleaner (not WD40) if it is possible to get to where the contacts are for it to to be effective.

 

[johncass]

Thanks Puffin - I'll look into that, though I guess they may be sealed switches...will update once ive got further

 

[cherik]

Spraying contact cleaner into momentary switches isn't worth the trouble IMHO. It may work but chances are that they'd still be intermittent and it won't last either. Replace them, you might as well since you already have to take the board out. They cost pennies too. If one or a few are bad, all will most likely go bad.

Do it right the first time, otherwise you'll likely have to take it apart sometime in the near future when something like skip, play or whatever starts to act up.

 

[johncass]

Oops - posted this in the wrong thread earlier

Ok - thanks for the help so far, and maybe you can help again...

Before finding and replacing all those switches, Ive been checking to see if everything else works - I cleaned the lens with a cotton bud and alcohol but I am getting 2 problems:

1) sometimes it does not recognise a CD (commercial, not CDR) - syas "Disc not finalised" (YouTube)

2) sometimes it looks like its playing but playtime is not changing and no audio (YouTube)

I linked to a couple of short videos I took to clarify what's going on...any ideas? I dont want to go and replace all the switches if there is something more fundamental wrong!

Thanks
John

 

[johncass]

Sorry those links didnt come through cut and paste, here are the videos:

YouTube

and

YouTube

Thanks for helping
John