Yet another thread on fixing a Line 6 Stompbox!

[eddhall]

Hello all,

I recently bought a Line 6 MM4 faulty on ebay for £30, the seller described it as not turning on (he/she didn't have a power supply and battery contacts are rusted, thought it would be a case of just plugging it in right!).

I have had a look inside and a probe around after reading another thread, I have checked U14, U20 and U21, all of which are outputting the correct voltage (U21 outputs ~4.9VDC)...

Unfortunately that's where the other thread ended... does anyone have any advice?

[eddhall]

Anyone know if there are any guides online to fix them?  How easy is it to get line 6 parts?

[m4j0rbumm3r]

All I can say is I have successfully repaired a DL4 for a friend.

In that case, there was a 3.6V 2W Zener diode that was fried. That exact component proved difficult to obtain, so I got two 3.9V 1.3W ones instead and placed those in parallel. The higher maximum power wouldn't cause problems obviously, but about the 3.9V I was unsure. But apparantly it was close enough to the original 3.6V, because the pedal came back to life after the replacement.

Hope this helps..

[eddhall]

Hey,

Thanks for the reply, which is the zener diode?  There are 3 near the power input, is it the bigger one (the other two are identical)?  I don't suppose you know what it should be outputting so I can test it?

Edd

[m4j0rbumm3r]

Well, I neither have the pedal nor the schematic. But, you could try searching the web for the schem, the specs of the diodes in the schem, and how to test zeners using a multimeter.

If I recall correctly, the one I replaced in the DL4 showed close to zero resistance across its leads in either direction, which was a giveaway it was faulty. Well, that and the fact it looked burnt.