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Loophole problem

Started by drezdn, July 31, 2011, 04:02:23 AM

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drezdn

I've finally finished assembling the loophole, but I'm having some issues with it. If the record switch is engaged, both the record light and the play light are both on. Additionally, when just the play switch is on, it plays back just a loop of static (it's definitely playing "something" back though).  The filter, vol and dry knobs all seem to be working fine.

I'll post gutshots in the morning and also try to see what signal I'm getting at pin 20.

madbean

Quote from: drezdn on July 31, 2011, 04:02:23 AM
I've finally finished assembling the loophole, but I'm having some issues with it. If the record switch is engaged, both the record light and the play light are both on.

This is normal. You can see the same thing in the video: http://www.madbeanpedals.com/forum/index.php?topic=2354.0

The playback switch is actually an "enable" switch. When you toggle the record switch it enables the device at the same time (kinda weird, but that's how it works).

As for static, that part isn't right, obviously. You may need to audio probe the ISD chip to see what's going in and coming out.

drezdn

Good to know that there's one less problem to trouble shoot.

I got out the signal probe. I got audio going in at pin 20. At pin 14, when the play button is off, it's silent. when the play button is engaged, it makes the static sound. I'll post pictures as soon as I find the camera.

I have a back up IC3, would it be worth it to just try switching the chips?

drezdn


drezdn

In trying to follow the help rules... The only parts substitution I may have made was using a 78l05 in place of the 7805.

bigmufffuzzwizz

#5
Quote from: drezdn on July 31, 2011, 04:09:13 PM
In trying to follow the help rules... The only parts substitution I may have made was using a 78l05 in place of the 7805.
I believe they have a different pin-out. Did you take note of that?

EDIT: http://www.national.com/ds/LM/LM340.pdf On the 7805 To-220 package the pins read L-to-R (In,GND,Out) and the 78l05 the pins read L-to-R (Out,GND,In) http://www.national.com/ds/LM/LM78L05.pdf.
Owner and operator of Magic Pedals

drezdn

I'll take out the one that's in there, stick a socket in, and then reverse it and see what happens.

The 78L05 did get pretty hot when I was troubleshooting another problem, so it could definitely be backwards.

madbean

Are you getting 5v out of that regulator? I'm betting that's the problem based on what you said.

drezdn

I flipped the 78l05 around and replaced IC3 and know everything works. :D

Thanks for the help guys!

bigmufffuzzwizz

Quote from: drezdn on July 31, 2011, 05:18:15 PM
I flipped the 78l05 around and replaced IC3 and know everything works. :D

Thanks for the help guys!

That's great it was so simple.  Glad to help.
Owner and operator of Magic Pedals