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I didn't know where to put this officially, but I figure if this is the wrong spot, I'll delete/move. Buddy of mine brought me his brother's original early 80s TS9. Real deal, green components, Maxon markings, early 80s(I think '82), it works, but when turned on there's a serious output cut, like 20 dB. All the controls work, I just honestly didn't know where to start with this one. I'm good at following instructions(for the most part...), and I know how to run a multimeter, just need some direction from the experts. Thanks so much.

Couldn't help but notice the schmutz on the volume pot, good place to start there???

Probably. If it's as old as you think it is, probably a good idea to spray some contact cleaner inside all the pots before trying to analyze anything. And it sounds dumb, but make sure the problem isn't something like a dying battery.

If volume level is normal when the pedal is in bypass, then that means the input an output buffers are working just fine. If the drive and tone pots are working as expected, then that would suggest that the problem is with the volume pot.

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*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

10-4, I'll hit it with some DeoxIT.

OK, to clarify, I cleaned the pots with some DeoxIT, let it dry completely, plugged in with same results. The Volume/Tone/Drive controls all actually work as they are supposed to, which, they always have. The issue is that when the pedal is turned on, the volume output on the amp drops significantly. Still get output and controls will change the tone/drive/level. But when I turn the pedal off the amp comes back up to its expected volume level(i.e. louder than with the overdrive engaged).

Can you check voltages and audio probe?


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Pedal building is like the opposite of sex. All the fun stuff happens before you get in the box.

Sure can. I'm assuming off the pins on the IC?

So, comparing to the Classic Overdrive kit troubleshooting, the voltages on the top middle pins look no bueno, unfortunately it's directly soldered, no socket so I can't check pins without desoldering IC. 9.3v is exactly what my power supply is putting out as well.

Half of that op amp isn't working correctly--the two pins down in the 1V range should be up above 4V like the other four. Either the op amp itself is bad (I would think this is most likely, since these tend to be the most delicate & failure-prone component in a TS circuit) or something else in the circuit is causing the voltage bias on them to be much too low. I would replace the op amp if I was you, assuming that you feel comfortable doing that. I'd recommend just snipping off each leg as close to the op amp body as possible, then desolder them one at a time, clean the residual solder out of the PCB eyelets (use a solder sucker and/or desoldering braid), and solder in a new op amp. Any general purpose dual op amp should work fine; a 4558 or TL072 are commonly used in a TS circuit, but several others will work as well. Just be very careful when desoldering the pins, since it's pretty easy to lift a solder pad on these old single-sided boards.

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“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Would you solder a socket in? Or just another IC directly?

Socket, definitely.


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_________________
Pedal building is like the opposite of sex. All the fun stuff happens before you get in the box.

Yeah, a socket is always a good idea, as long as there's enough room.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Thanks for the help all!!!! New JRC 4458 and socket installed. Works like a champ!

Excellent news!

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2