Explain this section / Schematic

[killivolt]

I have a Sams section of an old Zenith Chassis. I have a part of this set that the Flyback is mounted on with the H.O.T and I was thinking maybe if I supply this with correct voltages maybe I can get it to startup and make some sparks.

A little help reading this would be helpful.



**broken link removed**

 

[rumpfy]

Not sure what you are trying to do; but I suspect you want to fire the circuit up and get some HV.
Sounds to me like you have not got the rest of the TV set to connect it to.
If so, be aware that the Horizontal output system is a resonant system and resonates at a certain frequency which is set to give the required flyback time of around 12 to 14 microseconds. part of the resonant circuit includes the deflection unit and the EHT system so by disconnecting the deflection unit and the EHT, you effectively detune the Horizontal output system. These systems have a primary resonant frequency to set the flyback (retrace) time of around 45 to 55 kHz, and the EHT system is 3rd or 5th harmonically tuned to the primary resonant frequency. The affect of detuning can result in the peak voltages across the main switch, exceeding the device spec (Q12308?)
So just be aware.
hope this helps.

 

[killivolt]

I'll have to take some pics of what I have. I didn't think to let everyone see what piece of the set I have. Basically from T3205 and TX3202 including the H.O.T and flyback circuits. I thought if I inject 24.5v at point ten and a 159v at point one I might be able to get a spark? The schematic isn't and exact duplicate but is close enough to what I have; hopefully I can figure out how to get the Flyback going.

kv

 

[killivolt]

Here is what I have if you notice a good percentage of the circuits are there and can be accessed. I really should see if any of the the component listings are the same on my piece that would match the schematic but I doubt it.

As you can see I have a Black and Red wire which is the 24v and a Orange coming off the H.O.T board that I think is the 159v supply.


**broken link removed**

 

[killivolt]

So, I am off today and looking over the schematic and circuit board and it's a match I've spent time locating on all the header connectors and they match as well. I guess I lucked out on the schematic even though I don't have the exact Model of the set; just the HV module and flyback board.

I could spend time trying to match the voltages; both forward and reverse drivers are located on the flyback circuit board. Not sure how easy this will be; I'll spend a little more time finding proper grounds and also see about getting a isolation transformer to supply the 159v and the 25.4v. The problem will be the feedback from the LOPT shutdown circuit.