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looking for a pcb audio probe

Started by copachino, August 28, 2014, 08:12:50 PM

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copachino

Quote from: davent on August 29, 2014, 04:04:58 PM
Opened my 2 in 1 (2 SHO's) and the  BS170's read;  D/G/S- 6.17v/2.4v/1v and 5.63v/2.4v/0.55v. No idea what they are suppose to be but the pedal works great so no reason to suspect otherwise.

If you're pulling the bs170 you might want to install a socket for the next transistor until you get things sorted.

i have tested(yerterday), but on bypass its ok, fx on, i cant get sound iven if i put direct the probe on the output jack, also, what are you using as reference for the voltages??, ground??
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muddyfox


Let's start by checking the voltage at the 4 mentioned points. Is there a signal at board input pad?

Yes, voltages are usually taken against a ground potential.

copachino

Quote from: muddyfox on August 29, 2014, 04:26:12 PM

Let's start by checking the voltage at the 4 mentioned points. Is there a signal at board input pad?

Yes, voltages are usually taken against a ground potential.

nop i got no sound in any point, even the out pad its noise, but i will buy some alligators clip today, yesterday i was on hand and pure cable, maybe that my fault, thanks all for the fast help, maybe i can suppect of the output cap also, the fx mada a loud pop before, maybe the output cap was going bad or something, but i will try when i get home, and get you informed
Affiliations: madbeanpedals fan and pedal porn lover....

davent

For voltage readings connect one lead to a circuit ground point, for the voltage readings posted the easiest point in the pedal to access and hook into was the ground lug of the output jack.
"If you always do what you always did- you always get what you always got." - Unknown

If my photos are missing again... they're hosted by photobucket... and as of 06/2017 being held hostage... to be continued?

muddyfox


Don't worry about the output cap or output jack yet. Start from the signal input and follow it as per schematic. First, you need to have signal at input jack tip and then the in pad on the board. If you aren't getting signal there, then something is grounding your signal before it even hits the board. Let's clear this up first.

davent

Yup, you need to find out what's happening to the input signal after the switch.

Set your meter to test for continuity, hook one meter lead to the tip of the input jack, set the stomp switch for bypass, check the tip of the output jack and find the associated switch lugs for continuity. You've said that's working fine. Check it off anyways.

Still checking for continuity...leave the one meter lead connected to the input jack tip, switch the stomp switch to fx.

Start looking for continuity, first the lugs of the switch, you know the lug where it enters the switch, which lug does it go to next when switched to fx,  what is that lug connected to,  input pad- good, if it gets that far check a ground connection. You could check the ground connection right away after switching the fx to see if there is a short. The audio probe wouldn't reveal the short.

Can you find continuity anywhere else when connected to the input jack tip?

We like pedal porn too.
"If you always do what you always did- you always get what you always got." - Unknown

If my photos are missing again... they're hosted by photobucket... and as of 06/2017 being held hostage... to be continued?

copachino

Quote from: davent on August 29, 2014, 07:09:54 PM
Yup, you need to find out what's happening to the input signal after the switch.

Set your meter to test for continuity, hook one meter lead to the tip of the input jack, set the stomp switch for bypass, check the tip of the output jack and find the associated switch lugs for continuity. You've said that's working fine. Check it off anyways.

Still checking for continuity...leave the one meter lead connected to the input jack tip, switch the stomp switch to fx.

Start looking for continuity, first the lugs of the switch, you know the lug where it enters the switch, which lug does it go to next when switched to fx,  what is that lug connected to,  input pad- good, if it gets that far check a ground connection. You could check the ground connection right away after switching the fx to see if there is a short. The audio probe wouldn't reveal the short.

Can you find continuity anywhere else when connected to the input jack tip?

We like pedal porn too.


ok i will datail what i have done yet.

have already check continuity on circuit and its ok, check for a short, well the pedal was working and the pot was 1kc and swap it to 5kc, then stop working, but anyways i check and look upo for shorts, and its ok, rechange al caps just to be sure, and nothing, the only thing i have not change its the zener diode, and the tranny, tranny may be bad..

and the most rare thing its that usually when this has happened before, i get the volumen up because of the gain in the trannys(other fx like lavache and other small and easy ones where like this), and this time, i can hear that the volumen insted of going up, its gets down... so maybe a bad tranny its my issue..

man you use really different a probe, i used to start from the out to the in, to see where the signal its lost, but, everybody has its ways to work... thank all and, when a get home in a cupple of hours until i fix the demon i will not go to bed.. i cant give up on that fx, its the most easy fx i have build even the bazz fuss i build ws bigger because of the many mods i made on a personal layout, im really bad building fx(but its getting like  a vice), i always have trouble  on then, but i really learn too much of you guys.

thanks
Affiliations: madbeanpedals fan and pedal porn lover....