Hi,
Having no other projects on the go at the moment I thought I would have a look at my scope with very dim display.
I have removed the HV half wave rectifier diode which is a Y10GA. when tested it appears to be failing however, I think that these HV diodes may behave a little strangely its specifications are:
Silicon Rectifier
V(RRM)(V) Rep.Pk.Rev. Voltage=6.0k
I(RM) Max.(A) Reverse Current=4.0u
@V(R) (V)(Test Condition)=6.0k
I(FSM) Max.(A) Pk.Fwd.Sur.Cur.=500m
V(FM) Max.(V) Forward Voltage=22
@I(FM) (A) (Test Condition)=5.0m
I(O) Max.(A) Output Current=5.0
So a forward drop of 22V, both my multi-meter and component tester say its broken, but I don't know if this is due to the high voltage drop. So a couple of questions:
1. What would be the best way to test the diode or is it likely broken?
2. The HT is a bout 1.9kV, could I replace the diode with a string of 1N4007's as each of these can handle 1kV, so 3 or 4 would be 3 or 4kV. Would that work or is it dangerous? The only issue I can see is the HT would be slightly higher as the diode drop would be somewhere between 4.5-6V rather than 22V. However, is this difference inconsequential compared to HT of 1900V?
Grateful for any thoughts
Cheers
Ian