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Old 27th July 2011, 06:27 PM   #41
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Thanks Mooly, and thanks eserviceinfo.com . I'll read through that later
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Old 28th July 2011, 12:29 PM   #42
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Mostly when I try and move it from service mode 0 to service mode 1, the laser tries to focus and then the CD moves slightly but it drops back to mode 0 again. Occasionally it remains in mode 1 and when in this state I have been able to measure between 48-76mV between TP1 and TP2 (across the 4k7 R3102). With 48mV there is 1.09V at across R3104 (the 18R feeding the laser supply BC338). So it looks like when it works it works (!) but I don't know why it seems to be loosing focus most of the time and dropping back to mode 0. Any suggeestions ?
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Old 28th July 2011, 05:13 PM   #43
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Quote:
Originally Posted by memu51 View Post
I have tried to find a schematic of the Micromega Solo and have not been able to locate one which make sorting it more difficult.

I would appreciate it if someone has one or who knows where one might be located!

I have attached a pic of the main board - has anyone seen one before? the chips do not seem to ties up with those mentioned

David
check out post #9 about
Schematic for this beautiful Micromega Solo, Trio and CD f1 (first edition) wanted
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Old 29th July 2011, 10:56 AM   #44
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Quote:
Originally Posted by JonHarrison View Post
........... Any suggeestions ?
Not really. You say the motor is OK now. Maybe it is just a faulty pickup... I know they are reliable but sometimes it's easy to overlook or convince yourself it's not. If the disc doesn't even spin up to speed (presumably because focus is lost) then it doesn't even get as far as being a "data processing fault" to my way of thinking.
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Old 29th July 2011, 06:49 PM   #45
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I had a look around the focus circuit with a scope this afternoon, there is significant 100Hz ripple on the FElag pin so I've taken the main board out and I'm going to work my way back through the power supplies next.
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Old 30th July 2011, 06:22 AM   #46
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That sounds highly promising... don't forget to "scope" the grounds to... you never know.
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Old 30th July 2011, 06:04 PM   #47
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Having removed the bulk caps on the main pcb which are responsible for the CDM-4 supplies ...

Roederstein EKS series 1000uF/25V datasheet spec for ESR 0.19R and today's value 0.66R

Roederstein EKS series 3300uF/16V datasheet spec for ESR 0.08R and today's value 48R and as if that wasn't bad enough the other one was off the scale ! They should really have fitted 25V parts here

Problem solved
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Old 30th July 2011, 06:25 PM   #48
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That's brilliant Jon... well done.

You know, when fixing stuff "was the day job" (TV/Video/Audio) I insisted on using a scope for everything. Checking HT rails in TV's etc. You'd be surprised how many weird faults that found. Or running round all the pins on an IC... and seeing the clock or ground or whatever modulated by something. We didn't have the luxury of an E.S.R. meter then

Happy days though...
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Old 31st July 2011, 10:42 AM   #49
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Quote:
Originally Posted by JonHarrison View Post
Having removed the bulk caps on the main pcb which are responsible for the CDM-4 supplies ...
Roederstein EKS series 1000uF/25V datasheet spec for ESR 0.19R and today's value 0.66R
Roederstein EKS series 3300uF/16V datasheet spec for ESR 0.08R and today's value 48R and as if that wasn't bad enough the other one was off the scale ! They should really have fitted 25V parts here
Problem solved
Good observations. This observations also of interest for this threads:
Best electrolytic capacitors
myths and facts on electrolytic capacitors in audio circuits
I assume, that the term "today's value" is refer to your old and faulty cap devices and not to new cap devices from currently production, what is also not rule-out with cheap manufacturers from China and India.
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Old 31st July 2011, 11:15 AM   #50
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Correct, "today's value" is what those 20 year old Roederstein's measure today (well yesterday!). Needless to say the Panasonic FC/FM I replaced them with have better ripple current handling and measure better than the Roederstein's did when they were new.
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