Need Schematic for Univox U202R

[RybCage]

I need schems if anyone out there can share them with me. I am in process of restoring a cool old Univox 202r, w/6973 power tubes. Replaced most of caps & tubes but still having issues with the reverb & trem features. When I turn up the reverb it begins to squeal. Trem not working. It seems like the preamp is not quite right since the first 12ax7 carries a lot of vibration making it seem microphonic. I have tried several other tubes in this socket but get same results on all, even with a 12at7.
When I got it someone had replaced a few caps so I am wondering if they did something wrong, used wrong values, reversed polarity? need schem to figure it out.

I have read this amp may be a copy of a 60's Magnatone but can't confirm that & have not seen any Magnatone schem that looks like this or even uses same tube lineup here
3 ea-12AX7, 1 ea-6AN8,1 ea-6AV6, 2 ea-6973 ,1 ea-6CA4 rectifier

[RybCage]

I replaced some of the 12ax7, & got a new set of EH6973 tubes. This greatly improved overall stability, reduced a lot of the microphonics. Prior to this I could tap about anywhere on the chassis or any tubes which telegraphed thru the amp. While the squealing is somewhat minimized there is still a lot of hiss type noise when I turn up the reverb past 1 or 2. I checked the resistance on the reverb pan & it looks like it is within operating range, cleaned the RCA jacks.
Still scrounging the net for the schematic. Univox.org has nothing like this although they feature pics of this amp.
I can tell this is going to be worth the effort since it already starting to sound really rich, thick & creamy. I would love to get the reverb & tremolo working without hissing & squealing. I probably need to replace the old carbon comp resistors since they are over 50 yrs old & known noisy culprits.

[Jazz P Bass]

I don't know if this is close.
Same output tubes. Reverb & Tremelo.
Univox 255R.
Give it a look.

[RybCage]

Thanks for sharing this. I will look over it once I get back home to see how it compares. The tube lineup is slightly different for what I assume is the reverb & trem but hopefully some of this will apply.

[Lesthornton]

I know this a very old thread...

I've got a mostly gutted U202R and looking to put it back to stcok, (or as close is possible). I have the 305R schematic and the 255R, but THIS 202R has a 12AX7 for the reverb driver, transformer less. the tank is an a short single spring in a Z pattern. it's one of the ones that has the line "Made by beautiful girls in....". near as i can tell the input impedance is about 800 and the output is 2575. Does anyone have a gutshot of one of these? i know it's pretty far fetched, and I CAN redesign the reverb driver if needed, but the preamps are different than the 305R and the 255R as well. and they are missing most of the resistors so i don't know if they were grid leak or cathode biased.

[vintagekiki]

https://reverb.com/item/20702845-1963-univox-model-u-202r-all-tube-guitar-amp-with-reverb-tremolo-rare

https://images.reverb.com/image/upload/s--sc2Dlbnj--/f_auto,t_large/v1553011507/yvvpmwfjtlz72bhuquvk.jpg
Univox 202R

http://www.offsetguitars.com/forums/viewtopic.php?t=51861
New Univox 202R Day

https://www.tiffe.de/roehren/u255r.gif

https://elektrotanya.com/univox_255r.pdf/download.html

http://web.archive.org/web/20160509075902/http://vintageunivox.com/pics/schematics/u255r.gif

https://www.gearslutz.com/board/attachments/geekslutz-forum/264869d1322422349-wanted-univox-u-305r-schematic-u-305r.jpg