[Amps] UM4001CR pin diode source - or Alpha 86 vac relay mad

[Bob Wilson, N6TV]

Correction: I meant to say, if the receiver goes dead when you switch from
STBY to OPER, replace the LittleFuse.

73,
Bob, N6TV


On Fri, Aug 7, 2020 at 1:55 PM Bob Wilson, N6TV <n6tv at arrl.net> wrote:

> If the receiver goes dead when you switch the Alpha 86 from transmit to
> operate, it usually means the LittleFuse on the receive pin bias board has
> opened.  Check that first.  It's easy to replace; just remove the top
> cover, and it is right there, near the center of the rear panel.  I had to
> replace that fuse several times, usually after transmitting on 160m;
> nothing wrong with the PIN diodes.
>
> 73,
> Bob, N6TV
>
> On Fri, Aug 7, 2020 at 4:27 AM Chris Wilson <chris at chriswilson.tv> wrote:
>
>>
>>
>>   07/08/2020 12:07
>>
>> I have an Alpha 86 here with suspected TX / RX switching pin diode
>> failure. The amps TUNE function is suspect, and switching between
>> standby and operate gives a vey attenuated RX signal in standby mode.
>> In TX it seems to operate, TUNE display aside, normally.
>>
>> The manual's schematic shows them as stud mounted UM4001CR devices. I
>> am unable to source these, does anyone know of a current source for
>> them please? Alternatively does anyone have instructions for
>> conversion to using two vac relays? Fast CW is not required, and the
>> noise of the vac relays not really a concern. Thanks.
>>
>> --
>>        Best Regards,
>>                    Chris Wilson.
>> mailto: chris at chriswilson.tv
>>
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>