OK, I did a test run and hooked up the speaker + to the gray wire and - to the black. With the preamp out going to the RCA input. It passed the signal at a good volume but was pulsating. Is it possible that this is a tremolo amp? Something doesn't seem right . I have another amp that looks similar to this one only stereo. I'll try a test with that one and see what happens.

Thanks for the reply. Of course it is a RCA jack and not a RF jack . I would like to keep it simple and you just gave me enough info to do a test run. This wasn't the main amp in this organ, i'm not sure what it powered but the main amp is  much larger and stereo. The speakers i pulled from this old Lowrey were 2-12 inch CTS with large alnico mags, 1- 6 x 9 CTS in the Leslie unit, and 1- 15 x 4 heavy Jensen horn. Definitely a good score.
 I'll pass a signal through this amp and report back 1st chance.

I have been picking up these unwanted organs for the speakers and now i have a shelf full of different amps and i figure this could be a great learning tool. I'm thinking that it could be a mono block amp for home audio or a simple guitar amp. I am pretty sure that the RF jack is an input. I'm not sure how to treat the 4 wires going to the connector. The gray wire runs off the CB and is marked amp out. The black wire is a ground. and the red and blue wires run to different large resistors. How would i hook up a simple tone and volume? I could use some general knowledge of what i have here.  
 Now i know this probably won't be a preferred design. But i'm hoping it will help me to start understanding the basics.
Anyone willing to help me put these to good use? These organs are real easy to find for free if you have the man power to move them.

Mike

  Thanks teemuk, Right after i started this thread i ordered the 4- 2n3055's and 4- .5ohm 5 watt resisters, i kind of knew i wasn't going to get away with that. I still think i should have got some kind of output with these other values but it could just be my ignorance showing.
  Thanks for the manual, this is obviously going to be a big help. I will update the thread for future enthusiasts to reference.

  Hello, a friend of mine brought me an acoustic amp that had a blown fuse. I replaced the fuse with the amp open and noticed the resistor (.5ohm 5watts) across one of the transistors was glowing bright red. I shut her down and replaced the 2n3055 with a mj15022 (higher rating) and replaced the .5ohm with a .33 ohm. when i fired it up the two transistors on the side i replaced got alot hotter than the other two but nothing fried or glowed in the short time i had it on. There was no output from the amp at all (Had speaker and guitar hooked up). I have repaired several tube amps but am at a loss with SS. Might be easier with a schematic but i couldn't find one online without having to buy it.
  I really would appreciate some input, this is a favor for a buddy. 

OK, i got a chance to dig back into this amp and i figured i would start from scratch. I checked the voltages across the secondary leads of the transformer. From center tap, each side showed 39vac and had 79vac across the outer two. I am guessing this is normal-ish. I plan on replacing all 4 bridge diodes but what value would i buy? the stock diodes have 56 and 6a4 written on them. They seem cheap enough so i want to purchase good ones. Can i buy them by voltage and amperage ratings? I will have to find a way to test the power transistors or just replace them also.
   I really don't want to give up on this.

thanks,
Mike.

Quote from: J M Fahey on September 09, 2009, 02:39:29 PM
Yes, the .02x1400V ceramic or polyester goes from one primary wire to the other as drawn to lower the "off" spark;  *or* across the switch contacts to it does not turn off instantly but some current flows through it a few extra milliseconds, also softening the spark. Really what *should* be used there is a capacitor rated "250V AC" by Underwriters Laboratories (that UL sticker you see in the back of most amps) which in practice translates into a capacitor with a *DC* rating of at least 3 or 4 times the AC outlet voltage.
630V (a common rating) is reasonable for a 120V line; for 220/240 you'll need at least 1200V, preferably 1500V if available.

That right there is a big help and good information, i had some long work days this week but i will take a picture of the board and post it before this weeks over. Please stay tuned.

J M Fahey, thanks for the reply. I am sure also there are other issues but wanted to get it back together so all can be sorted out. I'll follow your steps after work and report back. Any thoughts on the 1400v ceramic? I am thinking it either goes across the 120vac or from the black to a ground.

Thank you much,
Mike.

Even a hand drawn diagram showing everything from the input side of the PT to the filter caps would be great. Somebody has got to have one of these amps. I heard they have a great sound, when working

Hello all, I really need some expert knowledge to keep me from destroying this thing. I bought new filter caps and started to replace them by pulling one of the old ones without marking the polarity :duh I just assumed the board would be marked and it wasn't, I know i know. I tried to find a schematic but nothing anywhere because not many where made before Fender bought Sunn and they're pretty rare i guess.
   Can any one tell me for sure if the two filter caps should be in parallel or series??? I was sure it was series but it just pops fuses. Also there is a large ceramic cap (.02uf 1400vdc) located near the transformer that was disconnected by owner and i'm not sure where it fits in.
   This amp was originally a combo that was reboxed as a separate head by the current owner and couldn't get it to work. When i got it it just hummed what appeared to be a straight dc signal to the speaker. I am not really a tech but have fixed simple stuff in the past so i am trying to help a buddy out.
   If anybody can help it would be most appreciated and i would really like to learn more of the technical side of amp repair.

Thanks,
Mike.