Help to repair oscilloscope Philips PM3207 (Algemeen)

door edison , Aveiro - Portugal, 02-11-2020, 01:11 (1487 dagen geleden)

Hi.
I need help to repair the power supply of a oscilloscope PM3207.
The oscilloscope came to me with a lot of problems with the power supply (the old owner tried to repair it without success).

I now have all the correct voltages except HT. In the HT circuit I found the diode V800 and transistor V801 burned. I Replaced the CI D801 and diodes V802 and V803 with new ones and checked all the other components (one by one) and they are all OK.
Now whenever I turn on the power, the V801 transistor burns...

What is wrong, for that to happen?
Is the CRT broken?

Many thanks.
Regards.
Carlos

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From PORTUGAL, with regards
Carlos