Re: TECH: dead Amplifone (missing 20KHz?)

Karl,
Missed your first message but a bad xfmr can cause distortion of the collector
waveform. Does the output get hot? If you have a red xfmr change it.

Karl Doe wrote:

> Hi
>
> A big thanks to those who've already offered advice on my HV board, my
> diagnostics have got me this far:
>
> I don't have a square wave at the base of the BU406D: I DO have a 20KHz
> square wave when measured at the base of Q2 (MPS-U07) but at the collector
> it's mangled: here's some ASCII art (it's not strictly accurate but
> hopefully gives an idea):
>
> --- --- --- --- --- ---
> \ / \ / \ / \ / \ /
> \/ \/ \/ \/ \/
>
> I'm testing with the BU406D removed and the HVT in place (as in the FAQ).
>
> I've replaced Q2, the voltage regs (and verified +- 24v correct) , C1, and
> tested all of the resistors. But I still have the same problem so what am I
> missing??
>
> Cheers,
>
> Karl.
>
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Received on Sat Nov 16 19:03:51 2002