Voyager OS fm cannot be turned off

[mink99]

Dear all

Since ...some days ago... my voyager OS will always start with fm osc3->osc1 turned on, regardless of the state of the switch. Sometimes the switch (turning on and off) really turns fm off, but in most cases it does not.

Mechanical failure ?
Electronic failure ?

What can I do ?


Best regards

Kris

[modoc_333]

Dear all

Since ...some days ago... my voyager OS will always start with fm osc3->osc1 turned on, regardless of the state of the switch. Sometimes the switch (turning on and off) really turns fm off, but in most cases it does not.

Mechanical failure ?
Electronic failure ?

What can I do ?


Best regards

Kris

sounds like a bad switch to me. intermittent problems like that are rarely software. the bug is either there, or it isn't. a dirty or worn switch can react just like this though.

[EMwhite]

You say "OS" are you talking about the Old School? If so, no Operating System there so it's either switch, a connector, or something deeper in the analog board that ran afoul.

Based on my understanding, the only micro controller or code within the Old School in embedded in the Keyboard control circuit (maps key pressed into an analog voltage) and this is only for decoding the series of switches to ascertain a smooth scale of keys from bottom to top.

If you are handy/adventurous/skilled and out of warranty or any combination of the above, you can open 'er up and poke around; A simple continuity tester with the power off can test the switch but a fair amount of disassembly might be required to get in there because that switch is likely through hole mounted onto a fair sized control panel circuit board.

I no longer have my Old School but have some detailed pictures of the innards if you are interested. You will be able to get an idea of how much is in the way of getting in there from the pics. If interested, PM me with your email address.

Of course if you are uncomfortable but are in driving distance to Moog in Asheville or a capable dealer, best to have them troubleshoot. Before something else gets fried. I assume that you've pushed hard on the toggle and worked it from side to side repeatedly and confirmed that it 'feels like' the other toggle switches (e.g., not a mechanical issue). As you may know, the colored rocker is really just a switch cap sitting on top of the a typical slide switch that togged up and down.

EDIT: I just looked and all 6 contacts of the switch are accessible without any disassembly (it's a double pole, double throw switch) so a quick continuity test wit the power off could be taken care of in less than 5 minutes. All of the board traces are between the metal control panel and the circuit board but the 6 contact points are clear without any other wiring in the way (just a ribbon cable which can be moved to the side).

If the switch is not the issue, then pulling and reseating of the ribbon cable between the control panel and the analog board is the next step, beyond this, you'd need to schematic to see what ICs sit in the circuit and may either need to be reseated or replaced unless it's a passive component like a capacity which is unlikely. Many of the circuits within these analog synths leverage ICs that have two halves or more (quad) and if the IC goes south, it's possible that another function is not working also. A qualified tech can chase this down for you or if you are remote you can pull the analog board and send it to Moog if you've exhausted 'easy' fixes. Call them to discuss.

[mink99]

Thank you, I will try it does not look too complicated...

unfortunately i am not in driving distance to Moog in Asheville (Zürich in Switzerland)

[mink99]

Addition:

Just checked the switch with a resistance checker and it looked "normal". When I closed the chassis again it was off for about a minute and then "always on" again.

What I noticed is that if I turn the switch sync to osc 2 on, the fm is off, regardless of the state of the fm switch. But I can turn the fm on and off afterwards (when sync is on) and it behaves as intended. But when I switch sync off with fm also set to off , after some delay fm is back to "always on" state.

What is going on there ?

[latigid on]

You might have a bad multiplexer chip somewhere? Even though you have an analogue instrument, each control is not necessarily connected directly to its sound parameter. Or some functions will require switching several different parts of a circuit at once. If the multiplexing circuit has gone a bit haywire it could explain this odd behaviour.

[stiiiiiiive]

I once observed some similar behaviours: two close switches being kind of mixed, one controls whether th other one works or so.
I went with time and I suspect the shipping to be the cause of any physical issue inside...

Well, that does not help

[mink99]

Under repair (warranty) , will have to miss my machine for several weeks.

[stiiiiiiive]

Fot the better