Electrohome

[Larry]

About once every 10 years I get an electrohome monitor I can't fix.  Original symptom no picture.  I replaced all the electrolytics and F901.  Then the monitor blows F901.  Hot tests fine so I replace F901 and the flyback.  Now the monitor is running, the horizontal section is running but still no picture.  So, I break out the scope.  The heater voltage, the screen voltage and HV are all low about half of what they should be.  Looking at the collector of the HOT, the waveform is correct.  Every other flyback pulse is 580Vpp and 380Vpp.  I don't know where to go next cause I won't shotgun.  Suggestions?

[grantspain]

whats the b+ running at?

[Larry]

127VDC.  The pot does not change the B+.

[grantspain]

loads to check then,start with voltage regulator

[Larry]

I know the power supply has issues but the 127VDC can't be causing the problem with the low secondary voltages off the flyback.  I need to figure that out first.  Fixing the power supply should be easy but if I do it now, I'm just gonna be wasting my time.

[Ken Layton]

Could you have gotten a bad flyback right out of the box?

[Larry]

Yes but probably not.  The low secondary voltages were there with  the original flyback.  Thinking the flyback was the cause I put in a new one.  Same thing.

[Silverball84]

What about your screen pot? Aren't these separate from the flyback on electrohomes?