Sony PCM-7050
Thank you, Scott,
I will check the electrolytic capacitors. (There are two big ones in the
primary circuit).
What components form the kick start circuit ? I mean: Where do I look ?
Richard.
"Scott Dorsey" schreef in bericht
...
Vintage oldaudio-at-planet.nl wrote:
I got hold of a Sony PCM 7050 dat recorder in good condition.
The only thing is that sometimes the recorder does not power up.
I have been measurning the voltages on the power pc-board in the unit,
under
the power transformer, and these are OK.
Therefore I now have the idea that the switching power supply is the cause
of the problem and regularly does not "boot up".
More and more it points in that direction.
It simply does not "start"...
There are times that the PCM-7050 powers up normally and can be switched
off
and on several times without any problem.
When the PCM has been switched off for about half an hour it does not
power
up anymore.
Look at the kickstart circuit.
Does anybody have had similar problems and/or repaired the switched power
supply at the back of the unit ?
This is the typical symptom of a switcher with a kick start issue.
Are there parts in such a psu that must be checked first, I mean are there
components that regularly fail in this psu ??
Well, electrolytic caps are always suspect.
Sending the PCM to Sony service is quite complicated here and apart from
that also quite expensive.
Find a local tech who specializes in switching supplies if you are not
willing to work on it yourself. They are out there.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
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