Re: LF13331 Symptoms

On Tue, 14 Oct 1997, Zonn wrote:

> It could be the LF13331 but it sounds unlikely. Weird because it really
> sounds like an output transistor. Did you do a doide check on all the
> pre-driver transistors? Making sure they all had decent Base-Emitter
> and Base-Collector readings and no shorts?

        Yeah, that's what I meant by "those three transistors" -- the 3
transistors in the -Y deflection section. I checked them (they checked
OK) but replaced them all anyways after I got frustrated.
 
> Another thing you might try is to make sure the power resistors are all
> reading the proper value. Cinematronics does have short circuit
> protection built in, if one of these resistor values changed to a higher
> value (or opened up), the output would go into short circuit protection
> mode and cut off your picture.

        Ahhhhh, this makes a lot of sense.
 
        But, just out of curiousity, what are the typical symptoms of a
bad LF13331?

Joe
Received on Tue Oct 14 10:54:12 1997