You could ring test the trensformer....
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"janek77" writes:
I've posted this before, but now I have some more info.
Here it is hitachi scope V1060 power supply:
http://img.photobucket.com/albums/v338/gamow/PS.gif
Seems pretty simple?
What it does, It runs fine under reduced load, ie I put 22ohms resistor in
series with the rest of the load on 55v circuit.
As is it will produce voltages 40% lower than specs.
To remove any doubt I disconnected all the loads and replaced them with
resistors.
To simmulate full load I've used :
11 ohms on 5V rail~.45A
22 ohms on12V rail~.37A
230 ohms on 55V rail~.2A
It manages to output 43V on 55V circuit , all others respectively lower too
.
Yes I've replaced all the capacitors on the primary side, actually I put 47m
instead of 39 and 100 instead of 56
Still no change.
Desoldered all the secondary diodes , They all check fine.
Checked for the ripple on the secondaries (bad caps?)
all in order.
Bgin to suspect transformer itself.
HERE I REALLY NEED HELP.
Before try to rewind the transformer , can somebody with
more experience than me look up the following waveforms?
The first one was taken with all secondary windings disconnected(I've
removed the diodes)
The second with diodes soldered back and above mentioned
resistive load reatached.
Both were taken with a scope respecive to negative of line side
capacitors(used isolation transformer ).
At point 5 (primary winding)
Here they go:
No load:
http://img.photobucket.com/albums/v3...ad-cropped.gif
Loadded:
http://img.photobucket.com/albums/v3...ded-croped.gif
Help me please.
Thanks.