How do you open this Roland VGA-7 modeling amp?

[Randall]

I am trying to get to the controls on this stupidly designed Roland VGA-7 amp. The first problem is the speaker wires that come up thru the hole in the sealed speaker cab are not on connectors in the chassis, and the hole is very small that 8 wires are crammed in. I can get the chassis out just enough to partially set it on the top of the cab. What were they thinking?

Second is once I figure how to get to the chasssis so I can work on it, the front panel access looks horrifying. It would appear that it is attached by 5 metal bars that screw to the top of the front to the top of the back chassis, with some screws on the bottom of the front panel to the bottom of the chassis. Then there areseveral wiring harnesses some on connectors, some not, with very littl slack or room to get a finger in. Who makes these? All I want to do is clean the controls, not a major disassembly.

Anyone have any insight or know how to get a service manual?

[Randall]

Never mind, I got into it. I sat the chassis back heat sinks on a chair snugged up against the cab with the controls facing up. Then I removed the 5 front bottom screws, and the 5 top screws attaching the chassis to the five struts. Then I removed the input jacks nuts and two 2mm allen screws on the GK IN jack, whatever that is. Disconnected 2 connectors at the end of the front panel board, and two at the DSP board and lifted the front panel off. Then removed about 20 screws at the back of the two control board, as well as two 2mm allen screws at the front display. For anyone using this procedure, note that the black momentary switches are set on sticky tape to hold them in place during assembly I assume, and need to be coaxed a bit to get the boards up, but they will come free.

Not an easy unit to service. I had a bad pot, and swapped it with another one. Put it back partially back together, and found problem followed the pot, so now I must find one. So will be off/on, off/on by the time I am done. I'd rather be fishing.

[Enzo]

If you found a way, great. Just an observation. SOmetimes with a chassis hanging vertically out the back of a cab, I put the cab on its face so now the chassis sits on the rear panel with gravity not fighting me.

Also, sometimes when I have something like a PV Classic 30, where the chassis wants to flop down, I turn the amp on its side, so now the chassis can stand on end rather than hang.

[Bloomfield]

GK in jack could be for a guitar synth pickup, seeming how it is a Roland. Good that you got it apart anyway.

[g1]

It's for their optional GK-2A divided pickup.

[Randall]

It needs a pot that Roland no longer has available. It's one of those square green Alphas, 3 leg, B10K. I think I found a suitable sub at Mouser. When it arrives in two weeks, if it fits, I hope I remember how to put it back together. This thread will help.

[Enzo]

What dimension on the pot body, just as a backup, I have a large selection of such.