Yes, I know.  Two 4500 issues in one day.  I had wanted to resolve the beomaster one first though, which I did.  So here's my other problem.  When I play this CD4500 I just acquired all I get is a high pitched ringing sound coming through the speakers.  All the tracks on the CD are displayed, and I can skip through and play any track I want, but all I ever get is high pitched ringing.  It's faint when I have the receiver turned all the way down, and it just gets louder as I turn the volume up.  I have tried two different receivers, and different CD's, so I'm pretty sure the fault is in the CD player.  I didn't think this sounded like a standard issue cap problem, but when I get a chance tonight I'll replace that one cap (I think its number 2013) that often seems to go bad on this generation of cd players.  Unfortunately the CD4500 service manual isn't on the site, so I'll try to go by the CD6500 one.

Thanks!

Austin 

Thanks for the reply Peter, I'll give that a try.

Austin 

It's C2103... but only if the player has problems reading a CD. This defect does not sound like C2103, more like a broken cable, maybe ground is missing. Is the remote control still working?

Well I tried changing the c2103 cap just for the heck of it, and no it didn't make a difference.  As you said Bogener, the schematic looks like the cap is mainly for tracking and reading.  I used an ohm meter to make sure the pins in the cable are in contact with the 4 points on the circuit board where they connect, and I don't see any issues there.  Is the metal shield on the plug supposed to be connected to anything?  Because it didn't look like it was.

Thanks again guys,

Austin

Edit: I forgot to add that yes, the beomaster can still control it by remote control.  All the functions seem to work fine.  I can stop, play, skip tracks, and so forth.  It's just the sound - nothing but ringing. 

It could be a grounding problem, maybe from the chassis to the CD deck. Try re-seating all plugs/connectors.

It could also be that the muting circuit started to oscillate or an unstable power supply, both probably cap problems. I would put an oscilloscope to the signal path and power supply rails to see where it comes from. I agree with the other Martin, this is one fault that is definitely not caused by C2103.

Martin

Well I tried wiggling all the wires and connectors while it was playing, and there was no difference in sound.  Martin, are there any specific capacitors you'd suggest replacing, before I go through the trouble of lugging home an oscilloscope from work?

Thanks again,

Austin

The scope will help you, I think. Check for clean power supply voltages, muting circuits etc.

Martin

Ok, I have the scope.  On the line level audio pins, there's a 0.3V oscillation that looks to be about 0.2ms wavelength (5kHz).  It's an old scope though, and I can't get it to trigger correctly (of course it's probably my fault rather than the scope's), so I'm not positive on the 5kHz as the wave keeps moving around rapidly.

I then looked at the power supply.  In my moment of genius I was excited to see a 120Hz oscillation on the power supply lines, before I realized that I was just looking at the doubled power line frequency being output by the full-wave bridge rectifiers.  I didn't look at the lines past the outputs of the regulators, which I'll do tomorrow since I need to get to bed.

Austin 

Hey again Martin, do you know how much voltage ripple is typical on the power supply lines?  It was a couple days ago that I checked, but I think I remember it being about +/- 20mV.

Thanks again,

Austin 

Well the last several posts got deleted during the forum crash, but anyway, I used the scope to look at the 3 power pins on the DAC, and all 3 lines are nice and flat, although one of the voltages 1V high.  But I've never seen something like a 1V difference actually cause a problem, so I don't think that's it.  So that's where I stand right now, clean power going to the DAC, but still seeing a ringing coming out of its analog outputs.  I also put the scope across the 100nF decoupling caps on the DAC, and didn't see any ripple there.  Can the DAC chip actually go bad?  I suppose there could be an error on the digital side too, but I'd have no clue how to debug a digital error.

Austin 

A digital fault is not very likely but of course it can happen. More likely a faulty DAC (Digital to Analogue Converter).

Try putting a 100uF and a 100nF parallel across the power supply to the DAC, physically close to it.

Martin

Yes I'm thinking of trying that Peter, but I still wanted to try to rule out other possibilities before just buying a new chip.

Austin

The price Peter mentions is not that drastic, I think. Worth a try anyways and based on what you describe, it would also be the first thing I'd replace.

Martin

Well I bought a new DAC from that seller.  Fortunately got it from him for $20 shipped.  Unfortunately it didn't change anything.  *cries* stupid cd player!

I did try the digital output awhile back, and that works perfectly, so that would lead me to think the problem had to be at the analog portion.  And since I saw the ringing on the analog out pins of the DAC I figured it was the DAC.  I'll go look at the schematic again now though and start working from the digital output onward.

Austin 

Did you try to introduce the caps across the power supply physically near the DAC ?

Martin