[R-390] Troubleshooting Question

[Barry]

Hi Rodger,

Going way out on a limb here, have you tested the rectifier tubes for shorts?  Perhaps something is sagging and shorting after the filament(s) get hot.

Thanks,
Barry - N4BUQ

----- Original Message -----
> From: "R-390 Mailing List" <r-390 at mailman.qth.net>
> To: "R-390 Mailing List" <r-390 at mailman.qth.net>
> Sent: Friday, October 29, 2021 11:54:57 PM
> Subject: [R-390] Troubleshooting Question

> Hey All,
> 
> 
> 
> I have an R-390 (non A) that has developed the following problem.  When I
> turn it on, it warms up and works normally for about a minute or so.  Then
> without warning, it shuts down.  Lights out, no B+, etc.  It does the exact
> same thing every time I turn it on.  Any thoughts on where to begin
> troubleshooting?  How to easily isolate the B+ from the modules, etc. ?  For
> the minute that it's on after warming up, the B+ reads 185 volts.
> 
> 
> 
> Thanks in advance for any advice.
> 
> 
> 
> Rodger
> 
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