Left Front Panel Assy. wiring

[azuro]

I have manage to repair one of they keys on the fusion 6hd that was not responding to anything than pressing the key hard to it's max value. During the process, one end of the wiring under Left Front Panel Assy. (the red and black wires under the rotary pots)had gotten pulled out. I have no idea where they belong. Can anyone help me out to figure out where the wiring connects to?

[Jesse]

Maybe this will help

Please tell us how you repaired the faulty key in case some one else has the same problem.

Attachments:

[azuro]

Yup, that helps, thx for the pic. I've found a ribbon cable on the side of the circuit board attached to the keybed where the wires should go.





When testing the pots in diagnostics mode, the linearity test fails . Linearity test also fails on both wheels also. I think the ribbon cable may be damaged or not connected to the board properly.
I have no idea what that failure indicates or what signals those wires work with.

[mstsfreak]

Sept 1, 2012 15:49:14 GMT azuro said:

I have manage to repair one of they keys on the fusion 6hd that was not responding to anything than pressing the key hard to it's max value.

Can you tell me how you repaired it? I have excactly the same problem.

[Jesse]

Key failing and repair

Alesis Fusion - Key Failing and Repair upda....pdf (808.88 KB)

[azuro]

That ribbon does not have to be connected for the keys velocity to work. I had it disconnected when I fixed my key and tested it like that. I think the ribbon is for key tracking.

The diagnostics test pass for the controls when I operated them at a slower pace. Maybe it's normal behavior to fail if done too fast.

What got my key velocity fix was to clean the contacts under the key. Each key has a pair of sensors underneath it to judge the velocity of key presses.

After opening the case of the 6Hd, I unscrewed the keybed from the bottom half of the case. On the 6hd, there are about 12 screws holding the keys into place. After those are unscrewed the keys can be lifted upward, or they can be moved to another place if you disconnect all the cables. I just lifted it upward and put some cloth on the keys to protect them from the support rod right above it. Doing so, you will probably have to disconnect the wire from the ribbon cable on the side of the keys because mine got disconnected unintentionally during the process.

pic of the keybed lifted upwards:


On the 6hd, there are 2 PCB circuit boards that span the range of keys in which hold the key press sensors. I removed the screws from the board that had the malfunctioning, then I flip it over enough to inspect the other side of the board... I choose not to disconnect the grey cable from the board and just work with it connected.

here is a pic of the other side of the circuit board:



There are groups of grey rubber plunger contact switches that can be removed by hand and cleaned.
They are held in place by rubber tabs that insert into holes in the circuit board. I removed the section of plunger contacts that had the malfunctioning key by kind of pealing it off with my fingers.


I didn't see any noticeable debris underneath.
Next I cleaned the rubber plungers and the circuit board sensors with q-tips and alcohol.
After the cleaning and resitting of the plunger switches, the key began to operate properly again I should of cleaned underneath the keys while the PCB board was off, but I didn't think that about it until now.

[Jesse]

Thanks for the detailed documentation azuro, i will add this to the PDF file and repost it in case anyone else needs the information and would like to view it while they make the repair.

[parametric]

Big thanks for sharing this info azuro.

This type of contact is everywhere these days on devices we all possess - mobile phones for instance, and it is a fact of life that they DO go intermittent with normal use.

Thanks to your detailed documentation, we now have a way to fix these, which should not be beyond most users, who are unafraid to wield a screwdriver and Q-tip ;D

This is an important resource.

Many thanks . . . . Also to <Jesse>! The library is growing!

Best Regards

parametric