OMT-CD with CDM4i issue

[daijiiwata]

I am repairing an unplayable OMT-CD with CDM4i in it.
Current Status:
Focus control has no movement.
Spindle and Radial can be controlled.
Other functions such as music selection, etc. are fully functional.

I don't have the extra units with me, so I can't inspect them further, but I am assuming that perhaps there is a problem with the pickup.
Thus a little searching I found a spindle and pickup unit that chants "CDM4/19".
My point is, are these pickups compatible?
From my preliminary research, it appears that there are many variations of the CDM4, so are they incompatible due to minor specification revisions?
If anyone knows, please let me know.

**If this is a duplicate thread, please forgive me.

[Ron Rich]

Yes-- Several CDM-4's were made-- are they interchangeable in a jukebox-- ?? Are parts of them interchangeable ?? Sorry but Phillips thinks no information is good information--very frustrating-- Ron Rich

[daijiiwata]

If you say so Ron, I am out of ideas! LOL!
That was a joke, but I also feel that it is not too expensive an investment considering the cost of the units we found, so I will consider trying.


Since the symptom is that only Focus is stuck, I wonder if I should examine it more deeply? (Explore OSDA or something...)

[Ron Rich]

Sure--If you have the ability, and the time--sure-- do so and let us know- I have never gone that far with any model CD player-- just "re-built" (changed parts), on the-12s on up-- I agree-- changing to a later model CDM is probably cost prohibitive today, considering the CD's future---
On CDM-4's the turntable had a nasty habit of slipping on it's shaft-- I corrected this with a drop of epoxy -- Ron Rich

[daijiiwata]

It's been a month since my last post, but I'm determined to order a CDM4/19OPT unit.
**In the meantime, I've been digging for other causes, but no progress!X(
I now have mixed hopes and fears about what the results will be.

By the way, just to be sure, I measured the terminal resistance of the stuck Focus and it was 96kohm.
Could it be a disconnection? Is this the cause?
Can't judge because I don't know the proper value...

[daijiiwata]

No conclusion has been reached, but here is a progress report.
Bad news and good news!

The bad news is that the test did not pass as a result of the exchange.
By comparison, there was no difference in flat cable pin combinations, etc.
However, there was no POT or resistor in the path of the CDM4/19 laser.
It may have been omitted or delegated to the main unit side.
Nevertheless, the reason why it did not pass the test is still a mystery, since no differences were found in the radial or focus paths.
(Or maybe it was a trivial cause.)

The good news is (and I can't say...) I don't know why, but the existing CDM4i focus coil has recovered.
I ran a solder check, hoping it was due to solder cracks or something just in case.
It's still running on test, but it can play CDs and no sound skipping occurs.
I have no choice but to verify the cause and rationale some more.
These situations are the most troublesome...