Recent content by PJS

The -9V pin on the charge pump is not measuring -9V. That -9v connects directly to the power pins on the op amps, and you measured -9V on both of those (or close enough). That does suggest to me that the charge pump can deliver -9v, but doesn't always. I would definitely be looking at the...

I had a problem on a different FV-1 pedal once where it would work fine on the internal programs but not external. The pins on the FV-1 had continuity to the pins on the EEPROM according to the multimeter. When I retouched the solder on the FV-1 pins it suddenly worked. The high speeds of the...

If the rate LED is steady then the LFO is not running. Look around there to see for wrong components etc. Also check the voltages on the op ap that drives the LFO

Pin 1 and pin 2 of both ICs should be the same, and should be sitting at 4.5V. It should be biased at that voltage by the 1M resistor on pin3. Pin 3 is the correct voltage, so I wold be looking for an incorrect component value or a short around the feedback network (R30, C13/16/17, drive pot...

I know from experience that those TRACO modules can take a fair bit of abuse and survive, so there is a good chance it is fine. I have before tested them on a breadboard just by providing voltage in the specified range to the correct pins and measuring the output pins. For me at the time I got...

And the full successful answer seems to be: 2.2M resistor from input to ground on the DI circuit. C2 becomes 220nF film cap, R6 becomes 1M and there are now 100k resistors to ground on the outputs to ground - from the junction between the 10uF caps and 100 ohm resistors. No more switch noise.

FWIW I did try soldering a 100k resistor in parallel with R12 and if anything that made it worse

OK. Another question but still on the Drebbel thumping. I have 4 of these that don't thump when switched, but 2 that do. The difference is that the 2 that thump have a DI out in the box as well. I am assuming that this is the problem - just looking for ideas on solutions. The DI has a...

Fingers crossed it stays that way

Those voltages do look fine

The ICs should have 0V on pin 4, 9V on pin 8, and something close to 4.5V on the other pins.

What voltage readings are you getting on your ICs? Also, I can see you have used pot dust covers on the single gang pots. If you have spares I have successfully cut one down to go on a dual gang pot before.

I don't have time to work artwork for someone else, but Inkscape is free. You may be able to re-jig your design yourself if need be.

On the ICs with the arch, that is the pin one indicator. The other marks are mould ejector pin marks

The board also has the option to solder SMT transistors directly to the main PCB rather than using the adapter board. Either will work fine though, and what you have proposed looks right