Fuse is blowing - K7000 19" chassis

Pengo13

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The chassis was blowing the fuse prior to the Flyback being changed. Still blows it after the swap. Takes a good 3 seconds before it blows so this might be a clue for some. Fixed a lifted pad at D18, still no change.

Any ideas what the problem could be?
 
bad vr? bad hot? bad c36? bad other diodes?

fuse poppers are always fun. Hope you get lucky.

haven't seen you in the monitor section in ages:eek:

check all the usual suspects.

C36-38 your H.O.T. all your diodes D13-24.

the VR usually does not blow the fuse.

Peace
Buffett
 
Short

You should check the center pin of the Hot for
a short to ground. if it reads high in ohms then theres
no short on the B+ line..

If shorted remove HOT measure the center pin again
at the pcb if still shorted then pull one part at a time
untill the short has cleard no ohms should be on a B+ line
c36 and c37 and c38

Short on the bridge rectifier will blow the fuse instantly and the
fuse will be all black. most often 2 out of four diodes in the bridge
will short.
The circuit needs atleast a 1.5 amp SB fuse in it no lower.
I would be using a circuit breaker a save from blowing good fuses during testing
then once the circuit is repaired then i would replace with a fuse.

Anytime theres short on the secondary it could damage the vr ic
and it should be replace everytime theres a short on the output.
You can tell what the output voltage should on the vr ic because
the last 3 numbers printed on the part is the output voltage.


Anytime the trace is open in the bridge rectifier circuit odds are
someone did not use an isolation transformer and the current gets
so high it opens the pcb trace..

This is a Hot chassis and needs protection between the chassis ground and game
ground.if not used, it will damage these parts over and over again.
 
How do I test C38 and D18 in circuit? I just don't know how to use my tester properly. I need to get better quickly. Most of my monitor fixes are based on pure luck or research in the forum.
 
you can desolder one leg of the diode and test it, you don't have to completely remove it, not sure about the cap unless you have one of those "in-circuit cap testers", i don't think you can do it with a regular multimeter
 
D18 use your diode test.
you can leave this in circuit to test it.

without a capasatence tester the only way to test C36 is continuity or ohms.
if it is shorted it is bad.

Peace
Buffett
 
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