cd80 doesn't work after clock update

[musicfreak]

Hello cpd gurus.

I'm in a little of a nightmare with my fantastic cd80.
I already happily updated all electrolytic caps and replaced the 5534s with opa267s.
Yesterday I finally tackled the installion of a Guido's clock removing the quartz and the related smd caps and connecting the new clock as explained by Jean-Paul in one of his old posts.
The cd tracks the cd ok with all the commands working and display giving the right information but no sound gets out.
Also the small green and red play/stop leds in the top control button don't light up any more and when I switch the unit off a loud crack is audible.

Does anyone of you (Jean-Paul?) experienced this problem before? Any clue?

Thanks for your help.

A

[poynton]

Did you do all the mods at one time or in stages ?

Andy

[musicfreak]

Nope. I like to check the effect of every single mod before to do the next one.

I changed the caps first, then after months I changed the op amps and after days (yesterday) the clock.

I connected the clock's V+ to the 10,000 uF psu cap, the clock ground to pin # 12 and the clock signal to pin # 11 of the SAA7220.

Thanks for helping.

[poynton]

It sounds like you have possibly either shorted one of the supply lines or shorted out the clock in signal.

One solution would be to revert to the original cofiguration if you still have the bits.

posting a photo might help.

Andy

[musicfreak]

Thanks Andy.

Whilst I was waiting for help I reverted to the old crystal. Of course the old caps are unusable and I used what I had at hand (220pf ceramic). Same thing. So it is definitely some accident happened during the update.

I've a pdf schema. Signal shouldn't be shortened now as the new clock not connected any more. The 7220 is worm, a sign it is passing current.

Any other clue?

Thanks again,
A

[guido]

7220 gets really worm during normal operation. I even killed one once when testing a (cd80) pcb upside down! weired...

As for the problem; check the schematics:

the power supply to the individual transistors for the led's are controlled by one transistor, which is controlled by the signal relais control. So the led for random and repeat should also not work (display schematic).

relais control is in turn the signal kill relais controlled by the dc protection circuit. Check testpoint 96 in the schematic with the dac.

So either your servo is not working and there is dc on the output (so the dc protection kicks in) or (remotely) possible a more generic power supply problem. So measure for dc on the audio signal, before the relays to check for dc.

It's not the clock. If that does not work, your cd would be spinning at warp speed.

And now it's bagge time (never mind)

[musicfreak]

Hello Guido,

thanks for coming to the rescue.

Yes, definitely, as I already pointed out, the new clock has nothing to do with the problem if not the fact that I made some stupid thing during its installation.

As you said the repeat and random leds don't work neither, even if I can see their prompt in the display.

I detached the volume control and measure pin 6 on connector 26 (that should be check point 96) on both directions (not knowing from where to count) and got +19V (18.81) on both.
Does it mean I've now to debug the servo board?


Thanks again.

A

[guido]

Originally posted by musicfreak

I detached the volume control and measure pin 6 on connector 26 (that should be check point 96) on both directions (not knowing from where to count) and got +19V (18.81) on both.
Does it mean I've now to debug the servo board?

The signal should go down to -15 during normal operation (after a small time delay), as can be seen in the drawing next to check point 96. It does not, which means that you probably have DC on the output of one of the channels.

The dc protection circuit is probably ok, but just detecting dc.
So measure the voltages on pin 6 of the second opamp of left and right channel (no 6387/6386). Any dc voltage there?

i think this is related to you opamp upgrade. Did you put them in sockets (if yes, put back some 5534's)?

[musicfreak]

I have 2.2 V on both channels on pin 6 of 6386 and 6387.

Yes I've used sockets for 6384 and 6385 but not for 6386 and 6387.

I will try to reinstall the 5534 on 6384 and 6385 but will need to get some 22pf caps to replace the smd ones. However I tested the op amp change quite for long time and it was good (very nice sounding).

As an extra info if I leave the headphone amp connected via the variable out board the 5532s in the headphone board become very hot and start smelling.

However even disconnetting the var out board there is still no sound on the fix output and the 2.2V on pins 6 of 6386 and 6387 is still present.

Are the black caps like 2402 polystyrene?

Thanks.
A

[guido]

First check the powersupply of the opamps, before you start reinstalling the 5534's (since you have no socket).

Both the signal opamps as both servo opamps.