T912 storage oscilloscope - No 2.7 KV high Voltage


Attilio
 

Greetings to all,
I have an old T912 that no longer shows traces on the CRT screen.
I checked and the 2.7 KV on the cathode of the CRT is missing. By disconnecting the diodes CR463 and CR465 from the T460 HV transformer, the negative rectified T460 output voltages are present (- 120 Vdc and - 220 Vdc are respectively - 150 Vdc and - 210 Vdc), by reconnecting CR463 and / or CR465 these voltages drop around - 14 Vdc.
I tried CR463 and CR465 diodes and apparently they look good, the T460 transformer I don't know how to test it not having the dc resistance values ​​of the windings.
On T460 I have between pin 9 and pin 10 about 145 ohm and between pin 1 (gnd) and pin 8 about 142 ohm.

Do you have any suggestions / advice for me to try to fix it.

Thanks
-- Cheers
Attilio

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