6101 MIDI Repair

[Mike_LA]

So now that I am in a holding pattern for a min, what are your thoughts on my other question,

"Would changing the diodes in the footswitch effect the circuit in any way?".

M

[Anitoli]

So now that I am in a holding pattern for a min, what are your thoughts on my other question,

"Would changing the diodes in the footswitch effect the circuit in any way?".

M

You mean the led's? If so i have changed all my FS's to match the LED colors on the heads and they work fine.

[Mike_LA]

You mean the led's? If so i have changed all my FS's to match the LED colors on the heads and they work fine.

Ahh, good. That's what I thought but this happenned while the upgraded footswitch was in use for the first time with this unit.

Once we get this sorted I'm going to do a side by side test with this and the other 6101 since they run different power tubes.

I don't think I can hear the difference between the EL-84s and the 6L6GCs but we will find out.

Hope to see the new ic today . . . .

M

[Anitoli]

Did you use regular 3mm led's?

[Mike_LA]

Did you use regular 3mm led's?

Yes 3mm leds, though they are brighter than the oem red ones.

The very first one I did, I used 5mm leds and made the holes in the face plate a little bigger.

[Mike_LA]

Ok Pete, I have the new ICs installed.

Just reinstall the board and fire it up or slowly dial it up on my rheostat and read the voltage where the transistor fried, or?

[Anitoli]

Ok Pete, I have the new ICs installed.

Just reinstall the board and fire it up or slowly dial it up on my rheostat and read the voltage where the transistor fried, or?

Just turn it on with everything hooked up the way it should be.

[Mike_LA]

Ok, it works.
Foot switch works.
Going to leave it on for a few hours, I will report back.

Thnx Pete

[Anitoli]

Awesome. Should be good to go now.

[Mike_LA]

Crushing defeat

Put the head back in the cab

Same problem
No LEDs
No channel control

Going to take it back out of the cab and check the transistor on the power board again.
I thought there would be more of an issue since it had recently been replaced
When I was switching channels I heard a popping at the switches that seemed louder than it should have. Might be something there ...

[Mike_LA]

<> <>


OK, loose connector.
I took the head out and wiggled all the connectors and it works.
Might put a dab of hot glue on them before it goes back in the cab.

Now, as to the popping sound. Only when I go from green to yellow is there a pronounced pop.
No other combination, should this be a cause for concern?

M

[Anitoli]

The pop seems to come from the relay that turns the damping on and off. The easy work around to that is to set the auto damping to low which allows the presence control to function on all 3 channels and bypasses the relay. I don't have a source for that relay at the moment. But that usually is the issue.

Glad you got it sorted out.

Instead of hot glue ( which can be a BITCH to get apart again) i use silicone RTV on the push on connectors. It's tacky and strong enough to keep the connectors together but still doesn't require too much effort to get apart/off if necessary.

[Mike_LA]

Ok, so as long as the head was out of the cab and plugged in I decided to do a little chop stick research.

It has a hum that is most noticeable on the yellow channel so I thought I'd move the wires a little to see if there was a reduction in hum.
Nothing there but then I heard a little background crackle which I attributed to tube socket contacts. I reseated the tubes a little. Then, since I've had an issue with loosening spade connectors I started to check them with the chop stick.





Nothing till I got to the power board, when I tapped a capacitor, the midi board went off, I tapped it again, midi board on, I shut it OFF.

Think I need to recap the power board or at least reflow the connections

[Anitoli]

What capacitor was it?

[Mike_LA]

What capacitor was it?

I think it was C407 but it took me by surprise and i was afraid of frying the new chips so I shut it down.

I guess it shouldn't damage the chips, still getting the same voltage.

I will fire it up again and test further