[R-390] More! Trouble shooting the R390A

[Tom Norris]

For folks doing troubleshooting you can narrow down the module where  
the trouble by which fuse is blown - if you have a chassis with 3 fuses.

If the 1/4 amp fuse is blown, it is most likely a problem with bad  
capacitors, the audio deck, or very rarely shorted rectifiers. The  
1/4 amp fuse protects *all* the B+ in the radio, so if you've checked  
The Usual Suspects and it still blows (or measures wonky per Pete's  
chart) you can track it down to each module by disconnecting IF,  
Crystal, and RF decks first. If it's still a problem, it's in the  
audio deck most likely, or you overlooked on of The Usual Suspects.

If the 1/8 amp fuse is blown, the problem is either in the IF or RF  
module. The IF module, crystal deck,  and RF deck may all be  
unplugged independently to help isolate the trouble.

Using that method along with Pete's troubleshooting chart, you can  
track down the problem almost without taking the radio apart.   [note  
"almost"]

Tom NU4G


On Aug 23, 2005, at 8:05 PM, Jon wrote:
> the CAL but noticed again no audio. The lamps however lite up.  I  
> turned the
> receiver off and checked the fuses and notice the 1/8 fuse has  
> blown. My
>