Author Topic: Faulty MXR Smart Gate!? (Read 6269 times)

Johnny Competent · « **on:** February 13, 2008, 08:44:25 PM »

Hi everyone, I'm new - glad to be here.

Right, I recently acquired an MXR smart gate, but... No sound comes out of it.

It powers on and the 'gate' LED responds to the guitar being played, and its response varies according to the setting of the pot.

Its just that no sound comes out. The in and out leads are definately in the right jack sockets.
I have tested the pot, footswitch, in & out jacks with a multimeter and they seem fine. Admitedly I dont know what the readings across them are supposed to be, but they are all showing something.

Does anyone have any idea what might be wrong with it?? I cant work it out.

Cheers for your help.

HTH AMPS · « **Reply #1 on:** February 13, 2008, 09:14:07 PM »

I'll go out on a limb and say it's the footswitch - my mate has one and the footswitch is broken in the ON position (no biggie since he always leaves in on anyway). I had the same pedal and the footswitch was flakey too.

Have you traced the signal from the input and identified where in the circuit it stops? - that's what you need to do first.

Johnny Competent · « **Reply #2 on:** February 17, 2008, 03:36:19 PM »

Ok, so I changed the foot switch and its no that.

I tried to trace the circuit to see where it fails, but i got a bit lost, think its a bit complex for me.

Oh well, I'll persevere!

Cheers.

Dr Death · « **Reply #3 on:** February 28, 2008, 08:55:59 AM »

Hi - I've just repaired one of these with exactly the same fault. It usually is on the power supply side (particularly with SMD builds), although a duff footswitch (as mentioned is an earlier reply) is a common fault to. If you have yours in bits, you will see there are 2 pcbs crammed full of the little blighters. On the pcb that holds the gate control and all the LEDs got to the area that has the mains adaptor connection point. From the negative pin, you will see with a suitable magnifying glass the track initially goes to 2 resistors. The second resistor is marked 102 (1K ohm). It was here the the fault was, a multimeter showed total open circuit. Using a standard resistor on end I tack-soldered directly onto the existing tag points and walla, all was well. Multi-metering across the initial SMDs of these power supplies IMHO and experience will, in 95% of cases show up the culprit as either a resistor, fuset or electrolytic. Hope this helps.

Johnny Competent · « **Reply #4 on:** March 01, 2008, 11:31:53 AM »

Wow, most comprehensive answer ever. And it worked a treat.

Thanks a lot!

Now I'm gonna go listen to how quiet my setup is.

Dr Death · « **Reply #5 on:** March 01, 2008, 05:51:36 PM »

Thank you - This is obviously an Achilles heel with the unit.