SOLVED VIIB ramp mode issue

[sticky1138]

I built the VIIB a while ago and finally got around to messing with it. It sounds great but seems to have a switching issue. True-bypass mode functions as it should, but in ramp mode, some weird things happen.

Every once in a while, when holding down the footswitch, the LED will blink rapidly between the two colors. Then the switch function flips so that holding it down passes the clean signal and letting go activates the effect. This happens without warning, usually after a few holds of the footswitch. Sometimes it will flip back and function as it’s supposed to.

Any ideas on what might be happening?

 

[Robert]

Then the switch function flips so that holding it down passes the clean signal and letting go activates the effect.

This part might be normal. The footswitch always behaves like this.

Holding down the footswitch while the effect is bypassed will activate it until you release the footswitch.
Holding down the footswitch while the effect is active will bypass it until you release the footswitch.

Tapping the footswitch toggles active/bypass like normal.

Rapid blinking between red/blue while holding down the footswitch sounds like it could be a dodgy footswitch.

 

[Robert]

I should clarify, there is no "ramp mode"...

Ramping is always possible by holding down the footswitch, regardless of whether you are in true-bypass or classic mode.

The two modes determine whether the effect is hard-bypassed by a relay or buffered bypass (simply killing the modulation) like the original.

Regardless of whether the effect is activated by tapping or holding the footswitch (or buffered/true bypass), the vibrato still ramps up.

 

[sticky1138]

I didn't realize the mode is the bypass mechanism and not the footswitch function, i.e. you can do either a quick on-off tap or a hold in either mode. Makes more sense.

Looking at it again, I'm noticing that after a holding for a certain amount of time (maybe 15 seconds, more or less), the effect will spontaneously cut out back to the clean signal. Is there a maximum hold time, or another sign of a faulty switch?

 

[Robert]

Sounds like a bad switch to me, it should hold indefinitely.

If you have an alligator clip you could clip across the switch lugs, if it holds as expected you can suspect the switch is the problem.

 

[sticky1138]

Looks like it was the switch after all. I put in a new one and it seems to work fine now. I also moved around the LED leads, which might have been brushing against the chrome bezel I used, since it's not really intended to accommodate three leads.