How to tell if a flyback is good? - Videokarma.org TV - Video

#1 09-28-2006, 12:42 PM

I'm looking into a used flyback for my Predicta, but before I buy from the guy, I was wondering if the flyback shows continuity, is that a good sign? I can't sub it into my TV before I buy, but the flyback doesn't appear to have any burned areas visible.

Thanks,
Joe

blue_lateral · #2 09-28-2006, 01:25 PM

Thats the toughest part to test in a TV. Flybacks can be tested using a "ringing test". They make pieces of test equipment just for this, and I understand it can also be done with a scope that has an external sweep output.

The trouble is, if you havent been testing a bunch of flybacks lately, I doubt you would get any useful results. YMMV. You may just have to risk it. It should show continuity, though.

John

#3 09-29-2006, 09:33 AM

Most Predicta flybacks are presumed to be bad because
the outer insulation has flacked off. I have found very few actual bad ones. Sometimes the hv lead has broken away.You can usually find the end and resolder it to the flyback and then epoxy the metal clip it and the 1X2 lead attach to. Make sure you have continuity betwee the 1x2 lead and the 12 or 6BQ6 plate lead.When the epoxy is dry,remove as much of the old insulation on the coil as posible and coat the whole coil with black GE RTV.
The best way to test one is with a flyback tester which excites it and measures the Q of the flyback.

Tubejunke · #4 09-30-2006, 11:22 PM

Today at a big Antique show I bought an Eico model 944 Flyback and Yoke tester. The thing seems to work as far as the "continuity" test. Same as Ohm meter. Other than that I dont know what to do with the things more usefull "shorts" test. It would be nice to find a user manual for this rig. Also I would think one would need the techical data or schematic for test points on different transformers. I would think, and hope that this piece of equipment is good for checking power transformers.

Any info on this unit or use of this unit would be greatly apreciated....

CDFixer · #5 10-01-2006, 12:12 AM

Install the flyback, then grab the HV lead firmly in your right hand while using you left to turn the unit on.

If your hair stands on end and your heart stops

the flyback is good, if not then it is bad.

blue_lateral · #6 10-01-2006, 02:04 AM

Quote:

Originally Posted by Tubejunke

Today at a big Antique show I bought an Eico model 944 Flyback and Yoke tester. The thing seems to work as far as the "continuity" test. Same as Ohm meter. Other than that I dont know what to do with the things more usefull "shorts" test. It would be nice to find a user manual for this rig. Also I would think one would need the techical data or schematic for test points on different transformers. I would think, and hope that this piece of equipment is good for checking power transformers.

Any info on this unit or use of this unit would be greatly apreciated....

The manual is on BAMA:
ftp://bama.sbc.edu/downloads/eico/944/

John

Tubejunke · #7 10-01-2006, 07:39 PM

Hey, thanks a mil for the tip! I tried once to download the file but ended up with an error message saying that my reader could not do its thing. Hey John, did you view the file with no problem? I'll try again tomorrow. Out of time for now....Monday's comin fast.....

blue_lateral · #8 10-01-2006, 08:02 PM

Yes, I did view it ok. I'm on Linux, though so unless you are too, all bets are off. There is a mirror of BAMA here, BTW: http://bama.edebris.com/manuals/

I have seen situations where the file was corrupt on one, but fine on the other. If it still doesnt work, post back or PM me, and I'll email it to you.

John