[Milsurplus] Harris RF-110A A6?

[J. Forster]

Have you put a DMM on the thing to see which voltages rise and which don't?
That'd sure help narrow it down. Shotgun parts replacement is a BAD idea.

-John

===============


> Hello all. Been troubleshooting a bias supply problem for over 6 months.
> I'm
> close to the end of my rope doing the component-level troubleshooting so I
> thought I'd send out a call.
>
> Anyone have a spare A6 board that they would care to sell?  I might as
> well
> get a spare A5 board too in case the problem is somewhere there. I don't
> think it is.
>
> Let me know what you have!
> thanks
>
> 73 Eugene W2HX
>
> PS. In case you're interested in the details:
>
> 1. The final bias is fine in AB1 mode. The problem is only in CW/RATT
> mode.
> 2. overtime, the bias increases until the tubes start to conduct. Typical
> range for the grid voltage in CW/RATT goes from -90VDC when first started
> up
> and slowly drifts to about -72 and the tubes are conducting.
> 3. I have pulled the tubes, so this is not the cause
> 4. I do not have to have the HV on for the bias voltage to shift
> 5. I have replaced several components over time with no improvement
>
>
>
>
>
>
>
>
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