Hi, everyone, quick question, can someone jog my memory as I can't remember for the life of me, on a universal tripler there was an extra connection called diode and it was usually connected to ground, what was it's purpose????
The reason I ask is I fitted a brand new universal tripler to a Redifudion MK 4 and it only lasted about 3 hours and the tripler has failed, I connected the diode lead to ground. Was this right or not.
@michael-dranfield I can’t remember either but looking at the circuit on the side of this universal tripler, grounding that wire would put a large reverse voltage across the diode, so I would think no to grounding it.
So much forgotten.
Frank
It’s a long time ago but I think it was there to flatten the top of the pulse from the overwind, don’t quote me but I think it helped with regulation. Some sets did have the anode of the diode earthed, the ITT FT110 chassis for one definitely does.
John.
I was wrong about flattening the pulse, it's to prevent overswing but it does help EHT regulation.
Have a look at page 12 here.
John.
Here is a circuit from the Oz Pye 34 which used that same tripler.
Many thanks for everyones replies, I had a look at the Television magazine 1977 and it's a clipper diode which can either be connected to earth or to a C/R network to provide the A1 voltage. I need to make some more checks now as the testing of the clipper diode which could have gone short circuit is brought out to 2 pins of the tripler, looking at the datasheet for the tripler I fitted the clipper diode is shown as a smaller component than the EHT diodes.
Hi Michael, it was me who you purchased the tripler from. I will send you a replacement tomorrow, Malc.
Hl, many thanks for that but no need to send a replacement, it wasn't yours that was faulty, it was the crap HR one I fitted previously, only lasted 3 hours, HR stuff was always shite back in its day, Konig were far superior, what I plan to do now it it's possible is dissolve the resin in the HR unit so I can see what's gone wrong.Hi Michael, it was me who you purchased the tripler from. I will send you a replacement tomorrow, Malc.
OK, so I found what's gone wrong with my brand new but crap HR tripler, it's not component failure but a high voltage discharge path from the last diode in the chain to either the diode or earth wire, I have pointed in out in the photo.
Also as suspected the high voltage divider resistor is housed in the thin end of the tripler, I have managed to recover this in one piece so use full for making a new tripler.
Caps seem to vary widely in value from 600 to over 700pf and diodes are marked with just a few letters at random so all in all I would say made with very poor quality parts.
