[R-390] Dial Light Wires Fried

[Renee K6FSB]

I wonder if someone installed wrong bulbs causing excessive current...hmmmmm
Renée

On 2/11/26 7:57 AM, Thomas Hoyer via R-390 wrote:
>   Thanks for the sanity check Bob.
> I've re-run the wires using the correct color code wire and lacing cord. On the first radio I figured eh, mistake on somebody's part. On the second radio I said Hmmmm..... When I looked at my R391, that was bought as a project and has been on the shelf for a couple years, and saw the same thing - WTH? Is this a trend?
> I personally have one R390 and had another at one point but those didn't have this issue, nor have I seen it on any of my (multiple) R390A's or on any of the ones that I've worked on for others.
> Either way, the first two have been rewired as described and I'll rewire the R391 when that gets bench time.
> For those working one these radios its something to look out for.
> TomW3TA
> PS:a couple pics in my post on ARF
> https://antiqueradios.com/forums/viewtopic.php?t=454874
>
>      On Wednesday, February 11, 2026 at 10:31:33 AM EST, Bob kb8tq <kb8tq at n1k.org> wrote:
>
>   Hi
>
> Is it common on an R390 or a R390A? It’s not anything I have seen on either radio.
>
> Best guess:
>
> Filament windings put out a lot of current. The chassis wires are rarely rated to handle
> the max output of the transformer. How much current is that? The fuse will eventually
> blow at some power level. A military grade transformer probably can deliver all that power
> to the filament winding
>
> Pilot light wiring runs around on the front panel. It’s the least protected part of the radio.
> Having this or that “wander in” and create a short is a very real possibility.
>
> Does this ever happen in the real world? Yes indeed it does. Back in my early years
> fiddling around on various radios, I did it at least once.
>
> Bob
>
>> On Feb 11, 2026, at 7:36 AM, Tom via R-390 <r-390 at mailman.qth.net> wrote:
>>
>> Is it "common" for the wires to the dial lights to be fried on an R390? I've
>> had three in here the last few months and each one has had the wires fried.
>>
>>
>>
>> Tom
>>
>> W3TA
>>
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