OK I replaced Q913 and Q923 and I'm using an external supply of 45V
I have isolated W984, W987, W989, W972, and W991
W972 reads 35V
W984 reads 95V
W987 reads 8.5V
W989 reads -8.5
but W991 is showing 11V
I suspected Q921 but it seems to be OK.
I guess the next suspect is the LM358 in U9028 ???
The inverter stage seems to be working OK but I'm mystified by the 5V rail at 11V !!
Any suggestions welcome.
Dave
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On 17/03/2021 16:09, Ozan wrote:
C914 reads as 12uF with an ESR of 1.2 - is that reasonable ???
It is a bit low in capacitance but it is not the reason for the failure. However, I would replace it anyway since you removed it and it was stressed by high voltage.
Ozan
