Moog Music Forum

.
It seems that my modulation control is broken in some way. I can select a source and destination OK but when I try and select a controller option and associated amount nothing changes.

For example if I select LFO as my source, pitch as my destination, mod wheel as the controller starting with an amount of say 2, activating the mod wheel has no effect. When I change the source and or destination the expected effect can be heard but when trying any of the controllers; mod wheel, velocity, pressure, envolopes etc.non of these have any control effect.

I have had a quick check on the internals for any cable disconnects but everthing appears OK.

Am I missing something here, any ideas on how to debug this issue further or have I got a big problem with my Voyager OS.

Any ideas, gudance, thoughts would be most appreciated.

Hi John-

I assume you tried turning the amount to maximum and still same result? Are both mod busses behaving this way?

Markyboard wrote:Hi John

I assume you tried turning the amount to maximum and still same result? Are both mod busses behaving this way?

Yes, when the problem first occurred earlier today it was with Mod Bus 1 and 2, increasing the amount value had no effect. I have since been trying to debug the problem further. I've been using an expression pedal on Mod 1 / 2 CV inputs, Mod Bus 2 has started to function using the expression pedal as a contoller and also the mod wheel appears to working.

Mod Bus 1 is still having issues with some controll functions responding but no the same as on Mod Bus 2. Bizarrely the Amount setting has to be around 0 / 1 for any modualtions to take effect, increasing the Amount value decreases the modulation to nothing.

At the moment my head hurts!!

Don’t hurt your head John. Your descriptions and troubleshooting thus far are very good. Here’s what I think based on my knowledge of the original Voyager and other synths with similar architecture. The fact that both of your mod busses are affected tells me the problem lies in the front end where the controller signals are multiplexed (i.e selected) before being routed to their destination. The actual voltage control inputs (velocity, mod wheel, pressure etc) are common to both independent bus multiplexers (or Mux for short). Each of the front panel controller knobs provide the selection signals (address lines) to determine which voltage control input gets through each Mux to its selected destination.

The only way I can see both busses affected is if the connector/connection common to both Mux inputs or address lines is bad or one of those Mux parts itself is bad interfering with the other one as well. If possible I might try to identify the cable that goes from the front panel to those Mux parts and re-seat it. Not sure how difficult this is to do without documentation and such. Anything further down in the signal path such as the amount controls would not affect both mod busses.

Anyway that’s what I think- hope it some how helps.

Markyboard wrote:Don’t hurt your head John. Your descriptions and troubleshooting thus far are very good. Here’s what I think based on my knowledge of the original Voyager and other synths with similar architecture. The fact that both of your mod busses are affected tells me the problem lies in the front end where the controller signals are multiplexed (i.e selected) before being routed to their destination. The actual voltage control inputs (velocity, mod wheel, pressure etc) are common to both independent bus multiplexers (or Mux for short). Each of the front panel controller knobs provide the selection signals (address lines) to determine which voltage control input gets through each Mux to its selected destination.

The only way I can see both busses affected is if the connector/connection common to both Mux inputs or address lines is bad or one of those Mux parts itself is bad interfering with the other one as well. If possible I might try to identify the cable that goes from the front panel to those Mux parts and re-seat it. Not sure how difficult this is to do without documentation and such. Anything further down in the signal path such as the amount controls would not affect both mod busses.

Anyway that’s what I think- hope it some how helps.

Thanks for your thought and ideas on how dig deeper. Things have progressed over the weekend. From dialogue with some other Voyager owners the problem it seems is more than likeky down to the previously reported Voyager Texas Instrument chip problem. From the list of issues that that are attributed to the chip failure are; Mod buss no longer functional and Source/Destination assignment no longer functional. This certainly ties in with the problems I have been experiencing so my next stop will be Moog service to see what can be done.

Thanks again for your help with this.

Markyboard wrote:Don’t hurt your head John. Your descriptions and troubleshooting thus far are very good. Here’s what I think based on my knowledge of the original Voyager and other synths with similar architecture. The fact that both of your mod busses are affected tells me the problem lies in the front end where the controller signals are multiplexed (i.e selected) before being routed to their destination. The actual voltage control inputs (velocity, mod wheel, pressure etc) are common to both independent bus multiplexers (or Mux for short). Each of the front panel controller knobs provide the selection signals (address lines) to determine which voltage control input gets through each Mux to its selected destination.

The only way I can see both busses affected is if the connector/connection common to both Mux inputs or address lines is bad or one of those Mux parts itself is bad interfering with the other one as well. If possible I might try to identify the cable that goes from the front panel to those Mux parts and re-seat it. Not sure how difficult this is to do without documentation and such. Anything further down in the signal path such as the amount controls would not affect both mod busses.

Anyway that’s what I think- hope it some how helps.

Good news! Pleased to say that Moog have approved warranty repair for Mod problem.

Well doen Moog, excellent customer service and support.