[R-390] Broken Line Input Wire in R390?

[Barry]

Jim,

Thank you so much for posting the link to that video!  It made me realize that the A connection on the inside of FL101 wasn't where I thought it was.  I had not noticed that the letters for the connections are stamped on the housing and the A terminal was almost out of sight from the vantage point of looking at it from the bottom side of the radio.

The good news is the wire from FL101-A to P118-1 is not broken after all and the only thing wrong is that FL101's connection from "A" on the socket to the "A" connection point inside the radio is open and that eliminates having to find/fix a broken wire inside a cable which I think would have been the messier task.

It's also interesting to me that it appears that "My Messy Lab" guy didn't need to remove the PTO and the bracket that it mounts on in order to completely remove FL101.  I need to try that again and see if perhaps I can do the same as that would also make this job a bit easier.

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: Monday, October 17, 2022 7:59:35 PM
> Subject: Re: [R-390] Broken Line Input Wire in R390?

> R-391 repair, https://www.youtube.com/watch?v=pr8pXFtA_IU  at about the 12
> minute point.
> Perhaps an better method then using a torch to open FL101 is to use a hot plate
> to bring the soldered seam to the melting point and then use a soldering iron
> to heat the joint above the reflow point and to help remove the cover.
>   Hopefully, the paint will not blister or burn.Jim
> 
> Logic: Method used to arrive at the wrong conclusion, with confidence.  Murphy
> 
> -----Original Message-----
> From: Barry <n4buq at knology.net>
> To: R-390 Mailing List <r-390 at mailman.qth.net>
> Sent: Mon, Oct 17, 2022 1:13 pm
> Subject: [R-390] Broken Line Input Wire in R390?
> 
> As I've mentioned, I was observing "chattering" of the antenna relay when in
> STANDBY mode and, thinking the problem was likely the selenium rectifier on
> it's way out, I replaced it with a silicon bridge.  Something I hadn't
> mentioned, though, was when the relay was chattering, the dial lamps were
> flickering seeming in time to the chattering.  I chalked that up to both
> possibly being the old rectifier but in retrospect, I'm wondering if the root
> of the problem was really something else.
> 
> When I started testing the new silicon bridge, I noticed the STANDBY lamp
> flickering was still present; however, it only lasted a very short time at
> which point I lost all power.  I've traced what I think is a broken wire that
> runs from the internal connection on the "A" side of FL101 to P118-1 (no
> continuity between those two points).  Furthermore, the A side of the line
> input filter is also showing a very high resistance from the A input to the A
> output and I'm thinking that the chattering/flickering was actually a rapidly
> intermittent short in the wire from FL101 to P119-1 which has now opened
> completely and, probably, took out the inductor of the A side of FL101 with it.
> 
> If this is the case, then I'm a bit surprised that a wire as large as that would
> have developed a fracture (stress or otherwise) or some other type of short and
> am wondering if I'm missing something.  As far as I can tell, that wire goes
> directly from FL101 to P118 through a large cable but until I can pull FL101,
> the PTO, and the mounting bracket, I'm not sure I can get a clear picture of
> that cable.
> 
> Anyone have this sort of issue before and can elaborate on it?  If it is a
> broken wire in that cable, that's going to be a "fun" job patching it (but only
> for very small values of "fun").
> 
> Thanks,
> Barry - N4BUQ
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