L200+ return to original

20 Studio, 50+, 50PA, 50R, L100, B100, L120, L120PA, L120R, 120 SLAVE, B120, B150, L150, L200, B200, Concord, and SMF

L200+ return to original

Postby BruceF on Sun Dec 13, 2015 3:27 pm

Hello all

I have come across an L200+ that has had some things done to it that don't appear to original, e.g. jumper across resistor, resistor piggyback on another resistor, ground switch wired different than schematic(I have removed it and added 3 wire grounded chord).

I would appreciate any help on getting this unit back in shape. As I go I will post some pictures.

Some things I have already corrected:
1. replace power chord with grounded unit.(dedicated ground bolt adjacent to entry into chassis)
2. removed ground switch.
3. replaced 50 ohm grid resistor on one of the power tubes with 100 ohm 6.5 watt unit.(the two tubes on this side had been severely overheated with one even melting a hole in the glass.

I plugged this into my current limiter and powered on with no tubes in and had high voltage on caps and filament heater voltage on tube sockets. Forgot to check bias voltage but will do that today.

thank you.
BruceF
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Re: L200+ return to original

Postby Vucinic on Thu Apr 21, 2016 7:49 am

Hi Bruce,

I own SC 200+ Mark4 and I support you in returning to original. I changing my mind a long time because I play OD and SC is a best Clean Amp ever. at the end I decide to do what you do:) .
But I did not have the guts to do it my self.
I pick up schematics from http://soundcitysite.com/sc_200_plus.gif and go to good engineer for checking components.
I think that we are close and I try it with 3 x GEC KT88 (very old) and 1x Ei 6550 with lower bias.
I order new Quad matched JJ KT88 tubs and one ECC81 and ECC83 other ECC83 was Good.
After installing those tubes we going to see where we are.

Try to contact John "Papa Dog". He help me a lot.

Good luck

Bozo
Vucinic
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Location: Skopje, Macedonia, EU


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