11-09-2020, 03:48 PM
(This post was last modified: 11-09-2020, 03:49 PM by Murphyv310.)
Hi.
Today I decided to test the EHT unit just in case the output transformer or the internal EY51's were faulty.
Using my little DC to DC converter I set it to 6.3v for the heaters, the DC to DC converter is fed from my 12v solar supply. The HT was derived from my Radford via the variac.
The unit worked first time once the HT reached 100v, I gradually raised the HT to 250v which gives 18kv on my rather low reading Eagle EHT meter (will need to look for a better one) there was a good old fizz going on so I am confident it was around 24Kv in real terms.
I decided to recap the unit and check the resistors, all the Philips black caps were leaky but all the close tolerance resistors were just about bang on.
After replacing the caps the oscillator would start at 55v HT. There is also a little increase in EHT so I'm assuming it is now to spec.
Today I decided to test the EHT unit just in case the output transformer or the internal EY51's were faulty.
Using my little DC to DC converter I set it to 6.3v for the heaters, the DC to DC converter is fed from my 12v solar supply. The HT was derived from my Radford via the variac.
The unit worked first time once the HT reached 100v, I gradually raised the HT to 250v which gives 18kv on my rather low reading Eagle EHT meter (will need to look for a better one) there was a good old fizz going on so I am confident it was around 24Kv in real terms.
I decided to recap the unit and check the resistors, all the Philips black caps were leaky but all the close tolerance resistors were just about bang on.
After replacing the caps the oscillator would start at 55v HT. There is also a little increase in EHT so I'm assuming it is now to spec.
