[R-390] R-392

Mon Oct 6 09:56:47 EDT 2025

The only "problems" connected to the R-390/URR are the 47 Ohm resistors under 
the chassis, four of them if my memory is right.
They are usually slightly charred from heat...

There is a solid state  kit available that reduces the heat from the PS. Google 
it.

No problem caps. Remember this 
wasn't a cost reduced receiver like the R-390A.

Les

----- Original Message -----
From: Adam Morehouse <morehouse90 at gmail.com>
To: Les Locklear <leslocklear at outlook.com>
Cc: R390 qth list <r-390 at mailman.qth.net>
Sent: 10/4/2025 6:59:08 PM
Subject: Re: [R-390] R-392

All back to stock, and still working. Dial accuracy is a lot better, and I'm 
pulling in all sorts of stuff on 40m with a magnetic loop in my basement. 
It's good enough. 

Now onto the R-390 this week (and beyond). It has issues, very low distorted audio. I haven't 
done much besides plug it in and bring it up slowly to test it out. 

Are there any caps/resistors in an R-390 that should be replaced off the bat? 
It seems weird without electrolytics like the R390A. 

On Sat, Oct 4, 2025 at 6:24 PM Les Locklear <leslocklear at outlook.com> wrote:

That's great! Who knows what the gremlin was, the main thing is it's working!

Les

----- Original Message -----
From: Adam Morehouse <morehouse90 at gmail.com>
To: Les Locklear <leslocklear at outlook.com>
Cc: R390 qth list <r-390 at mailman.qth.net>
Sent: 10/4/2025 5:14:36 PM
Subject: Re: [R-390] R-392

Les,  

I just took the PTO out and apart, nothing was apparently wrong, but I reflowed 
the connections for the 2 caps. Before I put the bottom decks back in, I 
noticed a connection between the bottom of the RF and the crystal 
calibrator...like a button that makes contact between them when put together. 
It was pretty smooshed and not making contact. I fixed that, and after putting 
it all together...it works. 

Loud and clear,  the dial is about 25kc off. I might stick the original RF deck 
back in and see if 
it's closer and still working, then do an alignment (my first on a R39x...) 

What a strange issue but im glad it's 
fixed. Whatever it was...

Adam 

On Sat, Oct 4, 2025, 17:22 Les Locklear <leslocklear at outlook.com> wrote:

Open the PTO 
don't be scared of it. You will probably find two small temp compensating caps, 10 pf if my memory is working. They have a tendency to
spring away from their solder connection maybe from a drop or whatever. Reflow the joint and test. I found that problem with a 1962 Amelco R-390A PTO.

Les Locklear

----- Original Message -----
From: Adam Morehouse <morehouse90 at gmail.com>
To: Jacques Fortin <jacques.f at videotron.ca>
Cc: R-390 Mailing List <r-390 at mailman.qth.net>
Sent: 10/4/2025 3:14:56 PM
Subject: Re: [R-390] R-392
________________________________________________________________________________

> Alright, so the oscillator is working. I think my problem has to do with
> the PTO.
> 
> When I bought the T-195/GRC-19 it came with a tote of parts - I swapped the
> AF/IF/Crystal Calibrator decks out - made no difference. Then I swapped RF
> decks - no difference.
> 
> I noticed the wiring harness for the big plug on the AF deck had some
> electrical tape, I unwrapped it and don't 
see any damaged wires, switches
> behind the front plate look clean, with no loose or broken wires.
> 
> But it still makes noises when I gently tap around. I left it tuned to a
> nearby AM station and flipped the unit over, and it (kinda) came to life.
> Squealing, and awful sounding - tapping around with a screwdriver,
> primarily on the PTO seems to affect it the most.
> 
> Anyone have experience with that? 
Here's a video....
> 
> https://photos.app.goo.gl/AZga9HyCqnJ1hyo18
> 
> On Fri, Oct 3, 2025 at 9:29 AM Jacques Fortin <jacques.f at videotron.ca>
> wrote:
> 
>> Hello Adam,
>> Swapping the tubes is a good idea, but that do not insure that the 1st
>> Xtal oscillator is actually working...
>> You should try to measure if there is any signal on the V401 plate.
>> This being said, I do not own a R-392, but it is similar to a R-390/URR in
>> architecture.
>> Do you have a copy of the TM11-858 or the TM11-5820-334-35 ??
>>
>> 73, Jacques, VE2JFE in Montreal
>>
>> -----Message d'origine-----
>> De : r-390-bounces at mailman.qth.net <r-390-bounces at mailman.qth.net> De la
>> part de Adam Morehouse
>> Envoyé : 2 octobre 2025 13:59
>> À : R-390 Mailing List <r-390 at mailman.qth.net>
>> Objet : Re: [R-390] R-392
>>
>> Managed to get the V401/V203 tubes out with a little bit of gorilla tape
>> as a puller. The silicone puller I bought just slips right off them...
>>
>> I swapped tubes, no changes. The switch seems to be working fine, when I
>> first start playing with this thing, if I tapped the chassis it would click
>> in the speaker, like a bad connection, etc. I took the bottom decks out,
>> and dropped the front panel and saw nothing obvious poking around. Now that
>> 
it's back together, its gone.
>>
>> A lot of the tubes do test "low" on my Heathkit TT-1 tube tester (TV-7 in
>> the pile of stuff to restore/calibrate).
>>
>>
>> V401
>>
>> 1.  -.3 / 118k
>>
>> 2.  .01 / 8.4
>>
>> 3.  5.8 / 6.2
>>
>> 4.  11.38 / 10.3
>>
>> 5.  21.9 / 1k
>>
>> 6.  21.9 / 1k
>>
>> 7.  .013 / 8.4
>>
>> V203
>>
>> 1. 0 / 107k
>>
>> 2. 0 / 3.5k
>>
>> 3. 0 / .3
>>
>> 4. 23.99 / 3.7
>>
>> 5. 10.5v / 8.8M
>>
>> 6. .17 /  OL
>>
>> 7. 23.15 / 2k
>>
>>
>> On Wed, Oct 1, 2025 at 8:08 PM Adam Morehouse <morehouse90 at gmail.com>
>> wrote:
>>
>>> Hey guys,
>>>
>>> Doing a little tinkering between classes (18 credits is awful...). I
>>> decided to try out a R-392 that came with a T-195 I bought this summer.
>>> It's 
nice and clean inside, no obvious defects - but is completely
>>> dead below 8MHz. Any idea where I should start my search when I dig into
>> this?
>>>
>>> Thanks for any help or pointers...
>>>
>>> Adam
>>>
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