Help, did my friend fry my Lowrider

[glops]

I let my friend borrow a couple of pedals for recording but he said he didn't use them because he didn't have the right power supply. Now that they are returned my Lowrider has a weird power problem. I measured the jack with my one spot and got no reading. I changed out the DC jack and have the same issue when I connect the 9v wire coming from the board to the jack. When I disconnect it, I get a good 9volt reading. Now, if my friend "accidentally" used a power supply with way too many volts would fried components cause this to happen? It seems like i would still get a proper measurement when the 9v wire was connected. This is annoying.

Thanks for any help,
Richard

[TwistdDeth]

He could have use the wrong polarity, like center positive instead of center negative. Just a thought.

[Om_Audio]

He could have use the wrong polarity, like center positive instead of center negative. Just a thought.

Learning about the polarity markings on power supplies and pedals changed my life. And has since saved the lives of more than a few pedals and devices since! Also learning mA ratings are "flexible" was liberating.

Hope you get it sorted,
C

[jkokura]

If it were just the wrong polarity, it could just be a fried diode. Check the polarity protection diode first.

Jacob

[Om_Audio]

Check the polarity protection diode first.

Jacob

Is a polarity protection diode standard on most projects? Good to know if so! Sorry for the interruption.
C

[eldanko]

Check the polarity protection diode first.

Jacob

Is a polarity protection diode standard on most projects? Good to know if so! Sorry for the interruption.
C

Yep.  It's D1 on most of the MadBean projects - 99% of the time a 1N4001 on the BOM.  Definitely look there for signs of trouble first!

[madbean]

In the case of the LR, it's actually D7 and it is a 1n4148. Lift that out and try powering it up. If it works, just replace that diode. BTW: 1N4001 is fine there, too.

[glops]

Thanks, guys. I'll try D7 tomorrow. I hope that's it, I really love that pedal and would hate to bury it!

[TwistdDeth]

He could have use the wrong polarity, like center positive instead of center negative. Just a thought.

Learning about the polarity markings on power supplies and pedals changed my life. And has since saved the lives of more than a few pedals and devices since! Also learning mA ratings are "flexible" was liberating.

Hope you get it sorted,
C

I learned my lesson the hard way with a Dr. Rock O.D. I bought a wall wart that came without the secondary plug. I got confused as to which wire was positive, I thought the Striped wire was negative. Plugged in the Dr. Rock to test it, psssffffffffttttt and a little puff of smoke marked the death of the Doc.

[glops]

Aha! I finally got back to it tonight. Lifted D7, no dice. Reflowed some joints. One of the IC sockets was accidentally unsoldered. Still nothing.

THEN, I noticed my 220 uf cap was rated at 6.3 volts! Replaced it and then I finally got something with the circuit engaged. Lots of whining ang hiss. Replaced the ICs and bingo! My fup from the beginning actually helped in the long run. Before, the circuit had some weird flubbing subsonic noise and now the pedal sounds like it sound and really good!

[Om_Audio]

Good work mang!