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Tourbus no modulation

Started by 3knobfury, August 07, 2022, 11:38:50 AM

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3knobfury

Mkay good folks, Tourbus is all but complete. Everything is working except for the modulation. I have verified component values around IC4 and IC5 and reflowed the joints. I have swapped both ICs w/o change. Voltages track on IC5, but IC4 is reading -13.52v on pin 3. The only other voltage oddities are on pins 1-3 of IC3 which are reading in the 100-200mV range. I have also verified component values and reflowed around this IC as well. I can get modulation if I manually move the mod knob. I stayed with the stock switch. Same for both mod types. Presuming LFO is locked up, but not sure why. Pics of board are attached. Footswitch is stock wiring config, no issues with audio passing. Your help is greatly appreciated.


3knobfury

Well I said that I attached photos, but like so many before me, I am thwarted by the file type and size limitations.

gordo

On mine, the only way I could get modulation to work was to jumper the rate pot pads.
Gordy Power
How loud is too loud?  What?

3knobfury

#3
Quote from: gordo on August 07, 2022, 02:09:39 PM
On mine, the only way I could get modulation to work was to jumper the rate pot pads.

Thanks for the info. And that was using the switch and not the rate pot?
Edit: nevermind, that was a dumb question

3knobfury

Quote from: gordo on August 07, 2022, 02:09:39 PM
On mine, the only way I could get modulation to work was to jumper the rate pot pads.

That did the trick, glorious modulation ensues! Thanks Gordo.

gordo

Glad I could help.  I troubleshot till I was blue in the face and then had a look at the schematic and had that "aha" moment.  I think maybe you and I are the only ones that built this without the mods :-)
Gordy Power
How loud is too loud?  What?

peccary

If you text the photos you want to use to yourself and then save them from your messages they should be compressed enough to upload here.

3knobfury

Quote from: gordo on August 07, 2022, 04:36:52 PM
Glad I could help.  I troubleshot till I was blue in the face and then had a look at the schematic and had that "aha" moment.  I think maybe you and I are the only ones that built this without the mods :-)

Ha. I have done my fair share of pedal modding so if I decide I need more, the option is always there. I am enjoying as is for the moment.

3knobfury

Quote from: peccary on August 07, 2022, 05:19:02 PM
If you text the photos you want to use to yourself and then save them from your messages they should be compressed enough to upload here.

Thanks for the tip Peccary. I do my best to stay out of the troubleshooting threads, but if the need arises, now I know.