The NEW Build Your Own Arcade Controls
Main => Monitor/Video Forum => Topic started by: perjmolsen on January 03, 2020, 02:10:35 pm
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Hi
I have tried to repair this old Sanwa v21 pm1723c chassis.
I have changed all the electrolytic caps on the chassis to new one with the same value as the old one.
Only one cap i did not have in my parts boxes, main PSU cap where an 680uf 200V I put in a 470uf 200V.
It is now working, but I am unable to figure out why my image is shaking a bit.
See mu video here:
https://www.youtube.com/watch?v=Yyw-MmDNxkI
I have tried to find some schematic on the chassis, but no luck.
Does any know what can cause an image to shake?
I have not messured the B+, because I do not know what it is need to be.
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Cap list
Location Org. Value mounted
c810 680uf 200v 470uf 200v
c328 220uf 63v 220uf 50v
c327 220uf 63v 220uf 50v
c303 47uf 16v 47uf 25v
c320 47 16v 47uf 25v
c311 1uf 50v
c301 3.3 50v
c335 10uf 50v
r306 10K ohms
c318 10uf 50v
c312 1 uf 50v
c313 220uf 16v
c329 33uf 16v 33uf 25v
c309 1uf 50v
c103 10uf 50v
c102 33uf25v
c107 10uf 50v
c101 10uf 50v
c321 1uf 50v
c407 100uf 200v
c104 1000uf 25v
c319 10uf 50v
c322 4.7uf 180v
c406 33uf 160v 33uf 200v
c802 22uf 160v
c402 220uf 25v
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Well suddenly I got this .. I just turned the monitor on, nothing changed.... :dizzy: :hissy:
I guess that is called vertical collapse...
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Trying to figure out why I suddenly got vertical collapse
I have checked all the polyester caps, they all check OK.
Also tested the big ceramic resistors, they are also all OK
Then i tried to see what my B+ is.. If I am testing it correct, then it is only 44.8V
I am testing with + on the middle leg at the D1555, I guess that transistor is the "HOT" and normal the B+ can be measured at the middle leg...
Can my issue now be that the only cap that I did not replace with the same as original..
one Cap in the PSU where org an 680uf 200V - I put in a 470uf 200V...
But the chassis had worked... :dizzy:
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That's horizontal collapse. Check the connections of the horizontal yoke. One side is coupled to the HOT collector, the other to the horizontal size and linearity coils.
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Hi
You where right!!! :notworthy:
I had a bad yoke connector at the PCB!
I have put some jumper across, and now i do not longer have the line "|" fromtop to bottom, but a nice picture and no more shaking! (when the connector is in the A)
https://www.youtube.com/watch?v=0De-bgg5-9E
BUT if i put the connector in the "B" i have a line "-" on the screen, but that is no issue, I just use the A connector... but strange
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Soldering isn't good. You have vertical collapse on the other header for the same reason, bad soldering on the vertical yoke pins. Try making it better overall. Bad soldering can lead to burned connectors/wires eventually.