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Twin Peaks Tremolo troubleshooting help please

Started by AntKnee, April 05, 2017, 05:08:35 PM

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AntKnee

Tapflo pin 5 gets 0v - 7.6v
LM358 pin 1= 1.34v - 5.43v
pin 7= 1.05v - 5.42v

I'll desolder the LDRs and measure the resistance later this evening.

David, thanks again for helping!
I build, and once in a while I might sell, pedals as "Vertigo Effects".

drolo

these all look good (except pin 5 of the taplfo which should never get higher than 5V but I guess it's a typo)

AntKnee

Quote from: drolo on April 07, 2017, 08:21:35 PM
these all look good (except pin 5 of the taplfo which should never get higher than 5V but I guess it's a typo)

I don't think its a typo. I better recheck values in the morning.
I build, and once in a while I might sell, pedals as "Vertigo Effects".

AntKnee

Definitely not a typo. I have 7.6v on pin 5 of tapflo.

I desoldered the LDR side of the optocouplers and checked resistance. I have to set the rate very slow to get a steady reading. I am measuring 20 megaohm max on #1, and 10 megaohm max on #2.
I build, and once in a while I might sell, pedals as "Vertigo Effects".

drolo

but does the LDR resistance get lower with the change of the LFO voltage ?

AntKnee

The LDR resistance goes alternates from 0 to the measured resistance in sync with my tap LED.

I just swapped out LM358 for a new one, and I now have 4.8v on pin 5 of tapflo, which also alternates from 0 to 4.8 with the tap LED.
I build, and once in a while I might sell, pedals as "Vertigo Effects".

AntKnee

I missed this on my first check: R47 and R48 are supposed to be 100 ohm, I have 100k ohm. Correcting that now.
I build, and once in a while I might sell, pedals as "Vertigo Effects".

AntKnee

Resistance at LDRs is now at 400k on #1, and 200k on #2.
I build, and once in a while I might sell, pedals as "Vertigo Effects".

AntKnee

#38
After swapping R47 and R48 for the correct values, I am up and running.

I wish I would have noticed the resistor value when I checked all my components earlier. I'm not sure at this point if I also had a bad LM358 earlier, but I left my replacement in.

David, thank you for all your help throughout this troubleshooting. I greatly appreciate your help.
I build, and once in a while I might sell, pedals as "Vertigo Effects".

drolo


AntKnee

I build, and once in a while I might sell, pedals as "Vertigo Effects".