Guru
Joined: 12/08/2011
Location: AustraliaPosts: 357
| Posted: 03:48am 17 Jan 2023 |
Hi All
Q9 was short across C E so replaced and that's now ok.
But The voltages are still way out.
R20 (center rail) = 0.015V on good board and -10.16 on bad board.
The Z1 diode pack is basically 3 diodes (4002) in series mounted on a small board
which is then held against the heatsink with a spring loaded screw.
I guess the 3 diodes create a higher voltage tolerance and provides additional resistance.
The good board measures about 11 K ohm
The bad one 10+ M ohm.
Will get some and see how I go and let you know.