Good morning Peter,
It is the S05K150 VDR it conducts at ca.250VDC
.
I used the S05 because it has a lower capacity than
the stronger VDR's.
I think the S07K150 RS ordercode 204-2040
will work as well, but I did not try this one.
I have seen several S05K150 at digikey.
The VDR DC value must have the half of the ACpp level.
In my Bush with the PL38 I have 400VppAC sitting
on 200VDC.
So the peak voltage is 600V and with the voltage
drop of the VDR you get 600V-250V= 350V (Ug2 CRT)
When you switch off the TV, the VDR discharges the
g2 cap a little bit down to 250V, so there is enough
voltage to discharge the EHT . This circuit is a burning
point suspression (is this the right word for Brennfleck-
unterdrückung?) [=switch off spot suppression].
And the VDR makes an additional positive voltage
in this case 150VDC to the 200VDC.
This kind of generating DC from the H-flyback pulses
is used in later applicationes with the for ex.PL500
to generate a negativ g1 voltage to regulate
H-with and EHT
.
Kind regards
Darius