madbeanpedals::forum

Projects => Tech Help - Etcher's Paradise => Topic started by: pgodfrin on March 18, 2021, 02:01:57 AM

Title: Measuring voltages ...
Post by: pgodfrin on March 18, 2021, 02:01:57 AM
Folks,
I've learned my lesson on measuring voltages. I've got a Dimension P I've etched from a mask from Effects Layouts. It worked at bench test. After a test install in the 125B it stopped working. Grrrr.
So having learned my lesson I checked the voltages. There's two pt2399 and a tl072, voltage controlled with an lm78l05 trans. The voltages checked out at just about 5V. No explanation why the chorus effect wasn't working. Took it all apart, reflowed a few solders, rechecked the voltages - wow - 2V at pin 1. I sat back, thought about it for a minute, then checked again - 3V. What? Then about 2 minutes later, 5V. Now I'm scratching my head - AND I still don't have a chorus effect.

Seems to me I have a wonky capacitor somewhere. But wth do I know...

So - is my guess correct, or is there something else I should check.?
thanks,
pg
Title: Re: Measuring voltages ...
Post by: pgodfrin on March 18, 2021, 12:12:05 PM
Or the lm78l05?
Title: Re: Measuring voltages ...
Post by: pgodfrin on March 18, 2021, 11:07:37 PM
Ugh, never mind. Tried different tl072, pr2399, reflow. I have no idea, starting over.
peace,
pg
Title: Re: Measuring voltages ...
Post by: gordo on March 18, 2021, 11:10:48 PM
Oh man I hate those troubleshootings.  I think I might still have the etch kicking around here somewhere but don't recall what I did with it.  I'll look and if it helps I can measure voltages.
Title: Re: Measuring voltages ...
Post by: Zerro on April 12, 2021, 12:46:55 PM
That power stab you have assigned 78l05: do you mean 7805 or 78L05??? First one is good, second one is wrong - it gives only 100mA current. For those cockroaches PT23... this may be too low output.