Re: Two Ampliphone HV problem questions

I'd say bad flyback as I'm pretty sure it governs the step down voltage for
the heater VAC, but others more experienced than I can verify that or not
on this email list

On Sat, Feb 15, 2014 at 10:11 PM, David Shoemaker <davids@oz.net> wrote:

> 1:
>
> HVT with a cinelabs HV unit installed.
>
> Good +/- 24 V
>
> Good crackle / HV.
>
> No neck glow, testing the heater voltage at the back of the board I am
> getting ~ 13.0v AC. Roughly double what I would expect. This tube was
> working fine with the last HV I worked on but I don't have a known good at
> the moment to verify something didn't go bad there. I did continuity test
> the tube heater pins and that seems fine.
>
>
>
>
>
> 2:
>
> HVT with a Red transformer (yea I know, red = dead).
>
> I don't have a ringer handy to test it with.
>
>
>
> Good -24
>
> Bad +24 (reads around +12), I pulled the 406D out and retested, the +24
> was there.
>
>
>
> Putting the 406D back in and replaced the LM7824, no change.
>
>
>
>
>
> Suggestions?
>
>
>
> Thanks,
>
> David
>
>
>
>
>
>
>

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Received on Sun Feb 16 01:15:28 2014