Anyone recognize this addition?

[Redbeard U812]

Friend found a 148gtl in a junk car and we opened it up wondering why it wasn't working. There seems to be an added board of some type attached to the right side, enclosed in metal. It has two pots for adjustment. There are four mini jacks on the back of unit for some reason. I figure its a sound board? Does anyone recognize it? Searched online but am unable to identify it.

 

[sonoma]

have never seen this one but looks like it is going to the audio circuit. what does the switch on the right rear do. at least it looks like a toggle switch.

 

[Redbeard U812]

have never seen this one but looks like it is going to the audio circuit. what does the switch on the right rear do. at least it looks like a toggle switch.

I forgot about that....Ummm. We don't know. Grey wire connects to mic jack and some of the others look to be up around RF meter. Those jacks got us baffled because they are grounded to chassis. Like the old telephone operator in Mayberry.

Unit doesn't work. Lights come on but no one is home. No TX or RX.

 

[999]

Could one of the jacks on the back be for an external meter? and maybe a keying circuit for an old tube amp?
Just throwing out ideas here...

 

[Chevboy0167]

SMT echo in that box maybe???

 

[Redbeard U812]

I guessed meter thing myself, but he's convinced they are a switching set up of some kind. I doubt it. Have some other pics but unable to transfer them from phone to comp.

Exterior cover has "C" and "S" marked at hole locations. I figure is an echo or some kind of board out of a D104 desk mic. retro fitted.

 

[Handy Andy]

IT may also be a compressor for the Mic audio - seen some compressors in shielded boxes with "C" meaning the compression and "S" meaning Signal (or Sound) level so you set compression and then trimmed signal output to maximize the audio without having the limiter trimming of and ruining the effect.

 

[999]

Direct injection?

 

[9C1Driver]

Looks like it's an SP1A, here is a link.

http://www.topguntec.com/tgt_sp_1a.htm

 

[sonoma]

it has 2 holes in the case as if there is 2 vr's in it for adjustment. strange looking thing for sure with all the wires going to the back of the radio plugs.

 

[9C1Driver]

Yea it looks like there are two yellow VR pots that match up to the pic of the Top Gun SP1A.

 

[Redbeard U812]

We looked at his radio today and upon closer inspection driver and final had been replaced previously by whomever had it before. I'm pretty sure they had the SP-1A cranked tight on the audio and caused failure again. Lots of solder jobs and some gobs on board. After reading the SP-1a thread I'm sure that is what is there. Figure it's good for SSB if used correctly, but whoever had it before prolly turned it up to max modulation and toasted some parts in there. Kav put it back one the shelf. Covers left off, screws somewhere. It will be there for a long time, in pieces, because he never puts things back together if they need fix'n. Poor radio will be covered in saw dust and cob webs before it goes into a garbage can 10 years from now degrading from rot and neglect. Sold him my Siltronix 1011D years ago when it worked, drifted a bit but worked. He had to turn it up or some dumb shit, blew the final and never replaced it. Now it sits on a table in a barn with 5-6 other radios rotting. Rats need homes too I guess.

 

[Low_Boy]

SP1A

 

[Captain Kilowatt]

SP1A

Agreed. Definitely looks like an SP1-A to me.