RM4 midi not functioning - fuses? can I fix this myself?

[twenty4_7spy]

First off, my apologies if this has been covered before, but a search of the forum did not yield specific information. Here is the situation I am facing:

-all midi connections made with std 5-pin cable (not using the powered pins)
-bought a Voodoo Lab Ground Control Pro last week, new, and set devices for midi program change as follows: RM4, channel 01, TC G Major 2 channel 02, using the 4 Program change, 8 instant loop option for the switches.
-G Maj , set to receive on ch 02, responds to program change just fine when directly connected to the GC Pro.
-opened RM4, confirmed/reset dip switches to receive on ch 01. No go, using the std technique of holding the gray button after selecting a program on the GC Pro. Tried all midi dip switch settings, still no go.
-Connected the G Maj to midi thru on the RM4, the G Maj stops receiving midi messages.

I bought the RM4 used, and I think I've proved that the midi function is DOA. I have heard about fuses inside the RM4, and I would like to try replacing them. The trouble is, which ones? There are a bank of them on the "mainboard" and they all look good to me.

Any help is greatly appreciated. Obviously, I need to get this fixed, and if it takes a professional to service it, so be it.

Thanks,

Matt

 

[m0jo]

I've heard that plugging in the footswitch while the unit is turned on might blow the midi chip..
I don't know the fine of it though.

There is a midi fuse AFAIK but once again I don't know which one

The midi chip is on a footer though so if it really is blown I think you could get a replacement from Randall and replace it quite easily.
That is after removing the 25-million screw that hold the top plate in plate haha

Here's a (not very good) picture of the midi board

 

[twenty4_7spy]

Since I do not know the history of my RM4, it is certainly possible/likely that the midi inputs were "misused" at some point.

I have sent an email to Randall support; we will see what they say.

Matt

 

[Mister Joshua]

Did you try using the TCE first then daisy chaining out to the RM4. I have a similar setup with a TCE G System and some RM4's but everything is on channel 1. It may be like the old DX7's where they only operate on one channel at a time up to and including the THRU. If that is the case then the THRU on the RM4 will only transmit on the channel that is coming into the IN.

SO: try these things.
Set everything to one channel. See if everything works.
Put the TCE first.
If not then come back and we'll try the next set of steps.
Peace, Joshua

 

[twenty4_7spy]

Joshua,

Thanks for the advice, the RM4 will not respond to any midi message on any channel (I tried them all, changing the dip switches and programming the GC Pro) even when the RM4 is directly connected to the foot switch.

Now, and suddenly, the TC GM2 is not responding to the foot switch either. Boo!

This should not be so hard to get right. Still working on it.

Matt

 

[twenty4_7spy]

UPDATE: heard from ryan @us musiccorp today, who stated that there was a fuse on the midi board itself. Mine, of course, does not appear to have one. I could be missing it though.

Anyway, the response was fast - next weekday. I sent him a picture, hopefully something will come out of it.

Matt

 

[twenty4_7spy]

Well I am in a bit of midi hell, I can't seem to make anything listen to the GC Pro and respond to program changes.

And the midi board HAS a "plug in" style fuse, which I am going to replace. But first I need to prove to myself that I know how to configure boxes to talk to each other.

MIDI sure seems simple, but plug-and-play it aint.

Also, usmusiccorp has been EXTREMELY responsive on this, and Ryan even sent me a schematic - without my asking. I am impressed.

Matt

 

[m0jo]

Are you sure it's not the GCP that's acting funny?

I'd try hooking it up to something that lets you monitor midi messages (for instance PC interface + some program that lets you do this).
Just to make sure that's doing its job, since you said other things aren't reacting either.

 

[JKD]

If your GC Maj is responding to the GCP then pretty sure it's the Randall MIDI board fuse....they don't look like a standard glass fuse it's a small red cylinder I believe...may even be soldered in place?

 

[twenty4_7spy]

Thanks everyone for the input, I have everything working now, but I'm not sure why . . . Here's what happened:

-bought a GCX for loop control
-plugged the GC Pro into it, no go, I was more sure than ever that something was broke, probably the GC and the RM4
-READ THE MANUAL for the GCX, and realized that 9V power come down the MIDI cable to the GC Pro
-unplugged the wall-wort to the GC

-AND-

-the GC Pro began transmitting MIDI messages, the RM4 began to respond, etc etc

:::RTFM:::

BUT, this outcome doesn't explain why nothing would work pre-GCX. I guess some questions should not be asked.

Now I have 8(!) loops to fill with pedals and such. It's all good!

Matt