[R-390] R-392

[Jim Whartenby]

AdamDoes "Now that it's back together, its gone" mean that the problem now is that the R-392 does not turn on at all?  None of the tube heaters now show signs of life?
Some 40 years ago, when I lived in New Jersey, I bought an R-392 for $25 at a Pennsylvania Hamfest.  The seller said that it just stopped working.  Did what was expected and tested every tube but found all to be OK.  
Noticed that with 28 volts applied, none of the tube heaters were lit so I checked the fuses on the front panel with a VOM.  Of course one was open.  Replaced the line fuse and all was well.  Sometimes a fuse will fail for no particular reason.Jim
Logic: Method used to arrive at the wrong conclusion, with confidence.  Murphy 

    On Friday, October 3, 2025 at 08:29:43 AM CDT, 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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