Rting to fix my TS9 - PLZ read...

[Phorhas]

Hey guys... in my efforts to fix my broken TS9 I came across a problem which I cannot fix...
the full story is like this: about a year ago my TS-9 suddenly went dead. the symptoms were - bypass mode was just fine but the on mide did not distort, the tone was ineffective and the volume droped by about half.

So I decided to mod it while I was opening the thing to search for the problem.

turns out it was the IC (7555 one) and I also went for the 808 output buffer mod.

NOW.. it's wierd - the Tone knob still isn't working and the volume only gets to half of what I rememberd. the Drive knob dosen't add gain but only colors the sound with harmonucs and mellow distortoin.

It ACTUALLY sound awsome - sweet OD with a rich full feeling - but - low volume and no tone knob really is buming  :cry:  .

I checked all of the pots and they're ok. I suspect the problem is with a short between Vr and Gnd. but I don't know how to find and fix it (if that IS the problem.

Well, again I come before you, gurus of FX ,and ask your help!!!!! PLZ PLZ PLZ PLZ Pretty PLZ...

Thanx ahead Dan.

[Phorhas]

C'mon guys! noone has a clue?!?!?!?

:cry:

Dan.

[brrt]

I guess you've got the schematic. Now: connect your TS-9 to a functiongenerator, turn it on, get your DMM and measure the thing step by step, starting from the input. That's the only way, because it could be many things... Also check V+ and Vr.

Brrt

[Bernt]

Phorhas!
For a start, check this out:
http://www.geofex.com/Article_Folders/TStech/tsxfram.htm#top

Kindest regards, Bernt.

[petemoore]

Check for short to ground with DMM beep. Connect its leads to the circuits battery clip terminal, if you hear a beep there's a short.
 Then connect the battery and take voltages from ground from the actives [OA and transistors..post them].
 I use my thimb as signal [him] injector, and work my way from the output toward the input, where I lose signal [thumb hum] thats where I look for a problem. This often coincides with a misbias reading on an OA pin or two, then I look there for the solution.
 I can usually find the problem withought too much a'deu, finding the solution almost invariably takes longer...sorting through resistor math and trying to find a missed value, connection, or short over a trace etc.

[george]

sounds like somethings shorted out between the drive and tone controls - I'd check the leads where they connect to the controls first then maybe check for shorts between the middle lug of the drive control and the outer lugs of the tone control - this might point to something screwy on the circuit board

hth

[Phorhas]

Thanx Guys, I'll try...

I'll post a follow-up when I'll have results

Regards,
Dan.

[Phorhas]

Hey guys, I fixed it!!!

Turns out - it was a dead OA all along. but when I desoldered it to replace it I accidently got the 22Ohm Res. to ground at the tone stack lift away and sorta "float" on top of the PCB - found it by a stroke of luck when I was trying to check the tone crkt for bugs.

Well, Now it has an 808 mod - but I'm still experimenting with differant ICs...

Thax a buch to everyone for helping!