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Old 04-24-2024, 01:58 PM
CRTs CRTs is offline
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Join Date: Feb 2024
Posts: 4
Thanks everyone for the suggestions, I reached out to those two vendors but did not have any luck.

It's been suggested that there was never a cross for this part, and once NOS from the OEM was exhausted, thats it.

Feeling like a needle in a haystack situation now.

We're 95% confident the flyback is bad at this point. Per the retired tech who's been excellent at guiding and assisting me with this repair -

Once the sweep circuit is started we have decent amplitude of waveform going to the base of the horizontal output transistor. The transistor is working because there is a greatly amplified waveform at the collector; not enough, but very much more than the base. Also – the 220vdc source is flyback derived, but the waveform at that diode is only around 100v p-p. It is a single diode rectifier circuit (half wave) so we need to see around 200 vpp coming off the FBT to make 220DC.



Another also – the HV is produced by the winding of the flyback rectified by 4 internal diodes, per the Sams. Using the diode check function of my Fluke 73, I cannot measure any conduction regardless of what direction the probes are attached; very probable open HV winding inside the FBT.
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