Re: SW Aplifone repair, Part 2

Shortly will have the FBT testor in stock...otherwise if you have access
to an audio signal generator ad a scope you can feed the flyback with
the audio signal @ 19,00KhZ (or so), at about 10 volts, and check what
the other output lines on the FBT look like. They should be either
higher or lower amplitude, corresponding to their relative voltages in a
"Working" FBT. So if the original FBT has a 60V input swing, and one
output is about 400V, then with 10V in, you should get about 68V out of
the "400"v section. IF the signal is rather degraded, then the FBT is
shorted on at least one turn. The scope is so you can look at the input
signal and compare it to the output, they should look similar (a sine
wave hopefuly)

John :-#)#

Dave Turner wrote:
>
> Well, here is the latest on trying to figure out if my HV Transformer is
> bad on my Star Wars Amplifone. I post this in hopes that it will give
> someone a clue to say "Yep, it's bad" as I can't really afford the
> replacement right now.
>
> Got a Zanen Cap Kit and installed it on my Deflection PCB and my "Good"
> HV board. I have two HV boards, one did nothing, the other blew VR1 with
> the obligitory smoke. Putting the cap kit in and replacing VR1 did not
> change things... the new VR1 heated up VERY rapidly so I cut power. This
> is what it did before.
>
> I then swapped the HV Transformers. The one that blew VR1 on the first
> board, seriously blew VR1 on the second board. So I am ready to call
> that flyback bad.
>
> Meanwhile on the HV board with the cap kit, I noticed VR1 and VR2
> heating up, but what I would consider at a normal rate. Still no picture
> nor could I see the heater in the neck. I did notice when I pulled the
> board that the part near the HV transformer that looks like a voltage
> regulator (with the heat sink) was VERY hot... way too hot to touch.
>
> That is about all I got to this weekend. I do suspect the HV transformer
> in this case, but would like to exhaust all possibilities before
> ordering another. Maybe by the time I save that much cash Zanen will
> have theirs ready! Yes, it will probably take me that long! :-(
>
> Thanks for the help. -Dave

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