[TenTec] Orion II Won't Power Up

[Gary Follett]

D116 is a 16 volt Zener diode on the I/O board, near the power connector. Its job is to prevent the radio from turning on if supply voltage exceeds 16 volts.

Gary

W0DVN

> On Jan 18, 2020, at 9:55 PM, Bernie Skoch via TenTec <tentec at contesting.com> wrote:
> 
> Thanks.  Where and what type is D116?
> 
> 
> -----Original Message-----
> From: Gary Follett <dukeshifi at comcast.net>
> To: Discussion of Ten-Tec Equipment <tentec at 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 at contesting.com> wrote:
>> 
>> 5KP15A
> 
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