Forum upgrade to SMF 2.1.2, still working on re-theming.

Main Menu
Welcome to Solid State Guitar Amp Forum | DIY Guitar Amplifiers. Please login or sign up.

May 25, 2022, 07:49:36 PM

Login with username, password and session length

Recent Posts


Seeking Roland Micro Cube Schematic

Started by Clyde, April 14, 2018, 12:30:26 PM

Previous topic - Next topic


Anyone have anything on a Roland Micro Cube COSM ( discontinued early model w/o the i-Cube link feature)?  Roland doesn't want to share with non-authorized folks & I can find nothing on the web.

I have one of these that has as bad amp selector rotary switch (internal contacts broken).  Trying to locate a replacement but the only markings on the existing switch is the maker 'Alpha' with '4J1' stenciled on the back.  Anyone have a part # for a potential replacement?  Amp has 7 'amp sim' positions, so I am guessing that a 7 pos replacement like this one might work:
or this:


Jazz P Bass


Roland might.  I just have to wait for Monday when their parts dept opens up.  In the meantime I thought I'd ask around with the intent of going thru Mouser rather than Roland to get a replacement.


Roland seems to wants to deal with 'authorized service' shops and not so much with DIY repair.  At least with schematics and internal components/parts.  So... I ended up with this Alps 7 pos switch from Mouser.  Works perfectly.

There were also 2 ea 1K ohm 0603 SMD resistors that were open.  These were 2 of 8 located on the amp selector baby board that the switch was mounted on. Replaced same and all is well. 

Initial problem was only two of the amp select choices was working.  The above replacements corrected the issue.  But in poking around the rest of the amp I could not help notice the Alps pots are not held together by much.  Closer inspection led me to believe that this amp had been dropped on its top or stacked with something on top that placed pressure on the control knobs and pushed the back out of some of the pots (selector switch included).  I'll be replacing these Alps with something more robust. 


Hi, I have the same problem, I've just taken apart the amp, measured the SMD resistors from the amp selector board (the one with the rotary switch) and all read something, I also measured the legs of the rotary switch and I also get values, however I get weird readings from the three wires that go to the bigger board, can you tell me what values it should output when cycling to the various positions? That way I may just replace the whole board with a potentiometer of the appropriate value to make it work (without the clicks of course)