Panasonic RJ-3700 service info

[TM86]

Recapping a Panasonic RJ-3700 without any documentation whatsoever. In my defense, I bought this thing well before I swore off buying orphan radios.

On the inside of the radio, between the PLL/VCO section and the crystal filter are two small shields around what I'm assuming are mixer circuits. I was going to pull the shields and see if there were any electrolytics inside of them, but that's proved difficult at best.

Anyone who's worked on one of these beasties know what's inside those shields? Or have a service manual they'd be willing to share?

BTW, this thing isn't in Sam's, I checked. Main board has a Mitsubishi logo on it and board number is RUP 860ZA, just in case there's a sister radio out there that does have service info available.

Board pics:


I've replaced almost all the caps already, just waiting on some 1 uF 50V ones to come in on Tuesday. There was corrosion on the legs of some of the middle sized caps (100 and 220 uF) so it was time.

 

[TM86]

Recap is done and radio seems to be working in all modes. Still looking for some kind of alignment procedure past "twist this for extree watts!" or the list of adjustment points in Secret CB.

Which I guess makes this a "bump".

 

[Lkaskel]

I researched this the other night for about a half hour. I could not find anything. I re-capped and aligned a 3600 last summer. It was an interesting radio but it was not that impressive performance wise.

 

[TM86]

I researched this the other night for about a half hour. I could not find anything. I re-capped and aligned a 3600 last summer. It was an interesting radio but it was not that impressive performance wise.

Yeah, it seems that the service info isn't all that widely available for this radio. I know it's a rare one when I can't even find a manual for sale anywhere. As far as I can tell, the RJ-3700 didn't even have an entry on cbtricks. I figured if anyone knew where to at least find the info, they would probably be here.

I don't want to resort to tweak and observe, reset if no change, but when all you've got is a hand full of adjustments gleaned from Secret CB, you make do.

 

[TM86]

So, via tweak and observe I've got the RJ-3700 on frequency in all three modes as best I can. AM was easy, once I found the right coil. For side band I had to pump in the 1k tone and observe the frequency counter. USB frequency was a little low, now should be good.

AM modulation was, of course, cranked to the max. Got the pot to tweak out of Secret CB (R129) and turned it down to a more pleasant looking envelope.

Other than an on air test, this thing is done. I'm just lucky that nothing was really broken. Just some corroded cap leads, probably due to electrolyte leakage.

It's a truly odd radio. If that was Panasonic's intention, they knocked it out of the park.

 

[Lkaskel]

So, via tweak and observe I've got the RJ-3700 on frequency in all three modes as best I can. AM was easy, once I found the right coil. For side band I had to pump in the 1k tone and observe the frequency counter. USB frequency was a little low, now should be good.

AM modulation was, of course, cranked to the max. Got the pot to tweak out of Secret CB (R129) and turned it down to a more pleasant looking envelope.

Other than an on air test, this thing is done. I'm just lucky that nothing was really broken. Just some corroded cap leads, probably due to electrolyte leakage.

It's a truly odd radio. If that was Panasonic's intention, they knocked it out of the park.

Well great job!! Thanks for keeping another radio out of the landfill!!!!

 

[Retro CB Guy]

TM86, I know this is an older post, but hey just saw it.

Here is some service material 73, Retro

 

[TM86]

TM86, I know this is an older post, but hey just saw it.

Here is some service material 73, Retro

Thanks! Now I've got the info needed if I ever have to get into the guts of the radio again.

 

[Geoffro]

Hi Retro CB Guy,
I would love a clear copy of service manual and schematic if you can kindly help out ?

Thanks in advance
Geoff

 

[TM86]

A scan of the manual from a different source. May not be as complete.