On 2/21/2016 8:36 AM, Cursitor Doom wrote:
On Sat, 20 Feb 2016 09:36:18 -0500, JC wrote:


It's not possible to test this board with it connected to the scope. On
this model, it slots inside the two main signal boards which make access
under proper, full working conditions impossible. Just *another* obstacle
I've faced with this repair.
The EHT multiplier has been totally disconnected all through my tests
except where explicitly stated otherwise.

Hi, Its been some time since I worked on these but I'm pretty sure we
ran these with the board out, turned round so you can get the connectors
on and I guess without the HT connected. Alternately put a suitable load
on the PSU.


In one of your pictures there are a couple of diodes that look messed up
(V1809 and V1811) near the bridge. They are supposed to be BY208-1000
(1000v rectifiers), I can see "40" on one, maybe 1N4007?

I like your thinking! But no, the one nearest the bridge is a BY208-1000
alright, the other one to the side of it is a BY134. They both tested
fine out of circuit.


That might be one problem, the sine voltage around T1801 is 800v, your
BY134 is a 600V diode. Also HV diodes can go reverse leaky, try a high
ohmsmeter on it (10-20 meg range). Shouldn't be any reverse leakage.

I guess you saw my next post on this? Try a load on the board before you
do any more work. It will tell you if the PSU runs silent or not under
load. The one I tried was screaming like heck then silent with a load.