WGk7500 - completely dead

87 t-66

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I have a K7500 that I have re-capped, reflowed, installed a known good flyback and HOT, that is completely dead when turned on. There is no B+, no neck glow, etc. I am getting 120V AC in, but no DC to any of the test points. The fuse is good. The troubleshooting guide says to test:

Q101 - good
Q704 - cant find this on the pcb
D101 - good
U101 - not sure how to test this
R104 - good
D102 - good
D104 - good
T701 - not sure how to test this
T700 - not sure how to test this
Q703 - good
U701 - not sure how to test this
R880 - good
R120 - good

Any ideas on where to go next would be appreciated. Thank you.
 
I've been pulling and testing parts in/before the power supply section and haven't found anything open/shorted. Need some info on where to meter to help isolate/segment that section and hopefully find out what's wrong. (I think that's where the problem is)
 
From past experience if everything else in the power supply tests
good then U101 has failed. Q101 is a MOSFET and can't be tested
properly with a meter.

I always replaced both in pairs.

Do you have the K7401/K7501 flowchart ?

JD
 
it was U101! i swapped it out and it fired right up. thanks again!

"You must spread some Reputation around before giving it to pcjohn again."
 
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