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Is there anyone that can help with a poorly Sony CDP-R1?

S

schneiderhan

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Hi all,

I recently (two years ago) fulfilled a long held dream to own the Sony CDP-R1 and DAS-R1, a legendary high-end CD pairing from the late 80s. The sound is sublime, absolutely beautiful. However, recently the CDP-R1 stopped working and the fault is exactly as described in this post - it turns on but that's about it. It's with my tech at the moment, he's tried swopping out the OKI CPU (MSM6408) for another but that didn't solve it. This breakdown is obviously not unique, but it does seem unique to this model which is more complex than it's cheaper breathren. If anyone has any ideas, or has successfully fixed a similarly broken CDP-R1 I would love to hear from you, as I am somewhat heartbroken at the moment!

BW
 
When the main micro is playing dead, I would check that:
  1. it has a nice stable (5 V) power supply (pin 42) and ground (pin 21)
  2. the crystal oscillator is oscillating (pins 9/10)
  3. the reset line (pin 11) briefly goes low on power up and then goes back high
A leaky electrolytic used for timing in the reset circuit is not a particularly rare thing. Speaking of which, it doesn't appear that Sony used any SMD ones (which were notorious on those days), but watch out for goldcaps that may have gone leaky (of which the units sports no fewer than two, 4700 µF C709 and 47000 µF C831, both @ 5.5 V).

Since a service manual seems to be available online, I would be pretty confident that some methodical fault-finding with a scope should track down the problem.

Hmm, it appears MSM6408 is IC227, Mechanism Control. Why the heck would you start with that? The area to check first would be around IC703 (CXP5058H-071Q), the main brains of the operation that's also responsible for the display. Does it get Vcc at pin 34? Does it get its 4 MHz clock at pin 31 from the oscillator in IC702? What does the reset line (pin 32 on IC703 and 22 on IC702) do?

If you're looking for the reset circuit, that is all the way over in the power supply section. The signal is buffered by IC804 and originates around Q802. If that doesn't work as expected, C829 would be a real hot candidate if you ask me. As an aside, IC804 (along with IC704) is on a different 5 V regulator than IC702/703, so it's worth checking both!
 
Here is a service manual in case you have not acquired one yet. ON second thought the file size it too large so if you want the service manual private me and we can do the email thing.
 
@schneiderhan make sure the sensor switches in the mechanism are all working properly while you are at it repairing that unit. If the switches are resistive or intermittent the unit will appear brainless. So pay attention to those.
 
Thanks everyone for all your help. We have the service manual but these suggestions are fantastically useful.
 
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