EHT

[Gregory]

How do you tell the difference between a EHT and a EHT with a back to back Diod's if you do not have any specks.
How do you test the EHT with back to back Diods to find out if it is faulty.
On a normal EHT you can use a shorten turns tester. But on a Diod one it dos not work.
Can power be supplied by means of a Veriac to the EHT that is off the board and measure the voltage on each turn.

 

[Nigel Goodwin]

How do you tell the difference between a EHT and a EHT with a back to back Diod's if you do not have any specks.
How do you test the EHT with back to back Diods to find out if it is faulty.
On a normal EHT you can use a shorten turns tester. But on a Diod one it dos not work.
Can power be supplied by means of a Veriac to the EHT that is off the board and measure the voltage on each turn.

As you don't have your location filled in, I've no idea what country you might be in (and if English is your first language or not).

So I've no idea if the confusing questions are as a result of your poor English?, or lack of Electronics knowledge?.

EHT stands for 'Extra High Tension', so your questions don't make any sense.

I'm 'presuming' you are refering to the 'Line Output Transformer' (LOPTX) used to generate the EHT in TV's and monitors?.

If the rectifiers are inside the transformer (either a direct rectifier or diode split transformer) there isn't really any passive way of testing them. A 'shorted turn' tester, which 'rings' the transformer usually won't find faulty rectifiers.

I find the easiest way is to scope the waveform on the collector of the LOPT transistor, using a suitable scope with a x10 probe. With this you can see the damped waveform caused by shorted turns or faulty rectifiers.

Depending on the particular make and model, LOPTX's are an extremely common failing, and often are very expensive.