Added info: If D116 is shorted, it will not pop the fuse because it is looking
at a 1K load resistor. If you did get a transient at the antenna, it is not
unreasonable to think that D116 would fail.
It is possible Q77 failed as well but that is a really common 2N3904.
Gary
> On Jan 18, 2020, at 9:55 PM, Bernie Skoch via TenTec <tentec@contesting.com>
> wrote:
>
> Thanks. Where and what type is D116?
>
>
> -----Original Message-----
> From: Gary Follett <dukeshifi@comcast.net>
> To: Discussion of Ten-Tec Equipment <tentec@contesting.com>
> Sent: Sat, Jan 18, 2020 9:47 pm
> Subject: Re: [TenTec] Orion II Won't Power Up
>
> The 5KP15A device is designed specifically to protect sensitive electronic
> equipment from voltage transients induced by lightning and other transient
> voltage events. Its job it is to short the supply of the transient to ground
> in a picosecond (1E-12 seconds).
>
> Failure of this part in the open mode would have no effect on radio
> operation. If shorted, it would pop the main fuse, but only if the relay K1
> were on. Since you do not hear that relay clicking on, the transient
> suppressor is not even in the circuit.
>
> If D116 were shorted, it would put Q77 base high, pulling Q23 base low. This
> would override the Power Switch turn on signal at J8 on the I/O board and
> this would prevent the power switch from turning the radio on.
>
> Gary
>
> W0DVN
>
>> On Jan 18, 2020, at 9:14 PM, Bernie Skoch via TenTec <tentec@contesting.com>
>> wrote:
>>
>> 5KP15A
>
> _______________________________________________
> TenTec mailing list
> TenTec@contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
> _______________________________________________
> TenTec mailing list
> TenTec@contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|