SOLVED M800 problems..

Idroj

Active member
Hi, here we go again..

I finished building this PAL 800, and when I first turned it on I got some intermittent overdrive sound but only responsive when I strummed hard, if I played soft no sound... It almost sounded as if it was gated... Went back to it and now I have 0 sound when on and full normal sound on bypass.

This time I cleaned the pcb board 2 times before installing it... Maybe the problem is these J201s I bought on eBay? I also bought the presoldered ones from pedalpcb, just haven't put them together yet.. wanted to try the regular ones first.. Should I start there?

Any help would be greatly appreciated.

Thanks in advance.

IMG_7788.jpg IMG_7789.jpg IMG_7790.jpg IMG_7793.jpg


IMG_7794.jpg
 
This tester is ok for BJT transistors, capacitors, resistors. Not for jfets. As you can see - jfet recognized as bjt transistor (NPN)
Use digital multimeter and 9V battery. https://forum.pedalpcb.com/threads/jfets-matching-etc.1139/
So is this the setup I need to use to verify if the transistors are authentic or fakes?

Sorry, I'm VERY new to this... and looking at even simple circuits like this it's still confusing to me.. I have a cheap multimeter and a 9v battery. So should I put this together on a breadboard or use wires with alligator clips? I have both...

jfettest.jpg
 
I'm I correct if I understand that:

-The Drain (Transistor pin 1) has to connect to the + on the 9v battery.
-The Source (Transistor pin 3) has to connect to the negative of the multimeter as well as the negative of the 9v battery.
-The Gate (Transistor pin 2) doesn't connect to anything.
-The negative of the battery has to connct with the negative of the multimeter as well.
-The multimeter has to be set to V. What range?

And is this the correct pinout?

1607788623061.png
 
And that is likely the cause of my pedal not working, correct? I mean, if you install fakes, should the pedal still work but sound different or not work at all?

Also, I installed 2N5089s from that same eBay seller on my Muffin Fuzz Triangle... It sounds ok but not my favorite pedal, am I probably listening to fakes as well? I'm going to get a reading of them too and post it now.
 
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And these are the multiple readings I get from one of the 2N5089s installed on my muff.. from the same eBay seller that sold me the fake J201s.. (Readings seem to vary if I measure the exact same transistor multiple times) Do these seem fine?

IMG_7800.jpg IMG_7801.jpg IMG_7802.jpg
 
I have that tester, it recognizes real JFets...you have eBay fakes.
I would not be so sure about this. I've just tested couple of jfets with similar device.
smd - MMBFJ201, MMBF5457, 2SK208R,
tht - J201 and 2N5458.

Some smd's recognized as NPN transistor, some as NJFET. Same with tht transistors. And Some fake J201 recognized as NJFET.
Maybe it depends on the version of the software installed in the LCR meter?

That's why I do not use LCR-T4 (this particular unit I have) for jfet measurements.
And if I'm correct - the meter does not display Vp but Vgs.
 
Let me correct myself.. (had the jacks backwards) ? When ON, sounds goes through but it sounds like is gated, you have to hit the strings really hard to be able to get sound.. when fingerpicking soft, nothing.. sounds like it’s “trying” to work
 
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