SOLVED Pharmacist help please!

[innerlight]

Hi all!
I have just finished building the Pharmacist. This is my first time sourcing my own parts and drilling the enclosure.
I took my time and kept the soldering pretty neat i think? Be gentle!

The pedal works (and sounds great) on the regular side, however the LED has a slight flicker to it when engaged, like there could be a bridge somewhere I cant see. The BOOST side however does not work at all. When engaged, the LED comes on but there is no signal at all. I have tried to adjust the trimmer and knobs with no change.
I have re-flowed all solder points, and looked around for a bridge somewhere to no avail.
If someone could take a look or offer any advice, id be beyond appreciative!
I am a novice but I have a DMM, so I could troubleshoot with directives.
I'm also wondering if I've installed a wrong component some place?
The part that does work sounds FANTASTIC! I really want to get this up and running, so PLEASE HELP ME!
Thanks, Christian

 

[EGRENIER]

QQ, where did you source your 2N5457, there has been many cases of fake ones from non-reputable sources...

 

[innerlight]

I got it all from Tayda and @fig so no worries there

 

[Bricksnbeatles]

It’s possible that a single pole on your 3pdt fried, making it so that either the input or output of the boost switch stays on the normal channel, disrupting your signal. With your meter, check continuity between the common lugs and the switched lugs of the boost switch, and then again after you’ve clicked the switch. Since a failed switch is probably the easiest thing to diagnose and not exactly unheard of, it’ll be best to rule that out first.

 

[Chuck D. Bones]

Is everyone satisfied that all the right parts are installed?

If so, let's see if Q6 and Q7 are biased correctly. Set the BOOST trimmer to full CCW. Set the BOOST stomp switch to "normal." Apply power and measure the voltage on Q6-D (pin closest to Q7). Then measure the voltage on Q6-S (middle pin). Then set the BOOST trimmer to full CW and repeat the measurements. Report your findings.

 

[innerlight]

I’m going to check this out this weekend. Thanks so much all. I’ll report back soon as I have info

 

[Chuck D. Bones]

And check the voltage on Q7-D (pin closest to C21). Should be around +17V.

 

[innerlight]

And check the voltage on Q7-D (pin closest to C21). Should be around +17V.

Hey Im a bit of a novice, just want to clarify the "D" part- which leg would this be of Q7? Thanks

 

[Chuck D. Bones]

It's the pin closest to C21.

 

[innerlight]

Is everyone satisfied that all the right parts are installed?

If so, let's see if Q6 and Q7 are biased correctly. Set the BOOST trimmer to full CCW. Set the BOOST stomp switch to "normal." Apply power and measure the voltage on Q6-D (pin closest to Q7). Then measure the voltage on Q6-S (middle pin). Then set the BOOST trimmer to full CW and repeat the measurements. Report your findings.

Oh and by "normal" do you mean 12 O'clock on the pot? Or do you mean not engaged on the 3pdt booster switch? Sorry, im learning here!

 

[Chuck D. Bones]

I mean BOOST not engaged.

 

[innerlight]

It's the pin closest to C21.

Thanks!

 

[innerlight]

It's the pin closest to C21.

Thanks!

 

[innerlight]

I am completely stuck after much googling.
I am attempting to “Apply power and measure the voltage on Q6. Then measure the voltage on Q6-S”. I understand the parts I need to measure, however can someone tell me which setting my DMM needs to be on to measure voltage on a transistor, and also what legs on the transistor the + and - probes need to be touching?
Many many thanks! This is a steeper learning curve than I was expecting!

 

[Harry Klippton]

Set your meter to measure DC volts. Put the - probe on the ground lug of your DC jack in the pedal, and the + probe to each leg of the transistor and note the voltage on each one

 

[innerlight]

Set your meter to measure DC volts. Put the - probe on the ground lug of your DC jack in the pedal, and the + probe to each leg of the transistor and note the voltage on each one

Thank you so very much. Will do

 

[innerlight]

Is everyone satisfied that all the right parts are installed?

If so, let's see if Q6 and Q7 are biased correctly. Set the BOOST trimmer to full CCW. Set the BOOST stomp switch to "normal." Apply power and measure the voltage on Q6-D (pin closest to Q7). Then measure the voltage on Q6-S (middle pin). Then set the BOOST trimmer to full CW and repeat the measurements. Report your findings.

Ok @Chuck D. Bones just did this!

Full CCW:
Q6D= 9.2
Q6S= 0.669
Q7D= 17.43

Full CW:
Q6D=08.55
Q6S= 028.4
Q7D=17.37

 

[innerlight]

Just chasing, anyone?

 

[innerlight]

I think I got components right, however it’s hard for me to be sure and I may have made a silly mistake

 

[Chuck D. Bones]

Ok @Chuck D. Bones just did this!

Full CCW:
Q6D= 9.2
Q6S= 0.669
Q7D= 17.43

Full CW:
Q6D=08.55
Q6S= 028.4
Q7D=17.37

The 2nd Q6S measurement is mV, right?

Those measurements look good, Q6 & Q7 are biasing correctly.

Recheck your wiring and solder joints to the MACH SCHAU (BOOST) stompswitch.
Recheck the solder joints around C18, C19, R32-R37.
Check C18 for cracks or other damage. I do not recommend using disk ceramic caps, they are fragile, noisy & unreliable. Do you have any spare film caps in the range of 1nF?