26 January 2011

Maxon OD808 Repair

Originally posted: 24 June 2010
Maxon OD 808 Repair
I bought a Maxon OD808 overdrive on ebay for $22.50 (+$10 shipping). It was listed as not working, but because these pedals sell for $150 new and $60-$90ish used, I thought it was worth a shot.
Based on the seller mentioning a burning smell after the pedal stopped working, I assumed that he had used the wrong power supply.
I was correct. The diode that protects against reverse polarity (D5), had been thoroughly burnt, along with the adjacent DC jack and the circuit board. I read a post by someone who ruined a pedal by using a 2-amp power supply; most pedals this size use about one-tenth of that (200 mA for the math-impaired).
So it was clear that I needed to at least replace the burnt diode, so I started there. A few months ago, I disassembled a broken CF bulb to see what it looked like inside, and I ended up salvaging some parts from it. Among those parts was the diode I used to replace the fried one in this pedal (1N4001).
 So, after an investment of $32.50 + 20 minutes + $0 in parts, I have a $150 pedal, which sounds awesome.

8 comments:

Dal said...

Hey there....Ithink I may have the same problem with my OD808 too.
can you tell me which parts you had to replace? and do you have any part numbers?
would it help if I emailed you a pic of the pcb (as I now have it all in pieces and you could indicate which bits need to be replaced?)
No probs if it is too much bother.
cheerz
Dal
:)
ps I cant see any pics attached to your post, hence my question.

smrbates said...

Sorry about the pictures -- I'm not sure what happened there. Anyway, the diode is a 1N4001, available just about anywhere (Small Bear Electronics, Radio Shack, Digikey, Mouser, and so on). Good luck!

Dal said...

Hello again! thanks for the prompt reply (you may get a few messages like the 1st one as it took a few attempts to get my comment over on the website (so apologies if that happens)
The diode that is presumed to have been fried 1N4001 is that the one located directly next to the 9V power socket on the board? I have looked at loads of pcb schematics...but cant make head nor tail of them.If I sent you a pic, could you identify which one it was?
cheerz again for you help
very much appreciated
Dal
:)

smrbates said...

Yes, feel free to send a photo. You only need to post once. (he comments are moderated, so they aren't posted until I approve them.

Dal said...

Ok...nice one....now...how do I attach a pic? I cannot see anywhere that allows u to add an attachement?
(or am I missing something?)
something else that I noticed is that the led lights up when a battery/psu is connected and the bypass works fine but the pedal only malfunctions when the overdrive switch is engaged.(and does nothing)
does that still sound like a fried diode?
ta
Dal

smrbates said...

Email me directly at smrb123@yahoo.com

Paulo Marques said...

Hello, i have the same problem in my maxon, the diode on the right side of the power suplly socket has exploded.
as far as i can see, there is not other damaged components

In your case, you only replaced the diode ? it's a 1N4001 right ?

Thank you

smrbates said...

Yes, that's all I did for this repair - I replaced the diode with a 1N4001.