1999 HRD loud pop channell select button

[KVH1]

Working on the HRD which had the usual problems leaky caps, poor solder joints, power resistors overheating board.
Everything is working now on both channels but when I switch between clean and drive I get a loud pop.
With or without guitar plugged in and it doesn't matter what level volume is at.
I've googled and read many suggestions but no solutions. I've also read where this is normal for this amp.
Any suggestions would be helpful. Does your HRD do this?

thanks Ken

[KVH1]

I checked C50 with one leg pulled it's good. It's in the channel switching circuit

[KVH1]

I don't have a footswitch but took a guitar cord and shorted the ground to tip while in the jack and it still makes a pop.
Ideas?

[KVH1]

I also notice the red more drive light goes on when cable is in foot switch jack. Is this normal?

[Don]

I also notice the red more drive light goes on when cable is in foot switch jack. Is this normal?

I haven't looked at the schematic. It sounds like it's a stereo jack. The tip of a stereo cable would change the channels, the ring would select more drive, and the sleeve would be ground. In this case, I'll bet that the contact for more drive is being grounded by the use of a mono cable.

[Bill Moore]

They use a series of diodes to regulate the voltage sent to the switching IC, don't know how it would act with a short!

https://www.thefenderforum.com/forum...switch-problem

[KVH1]

Thanks Bill and Don I've read the relays go bad on these also.

[KVH1]

So today I removed the K2 relay from board. Pop is gone and also red more drive button doesn't go on when cable is in the footswitch input.
Can I assume it's the relay or simply breaking connection to something else that is bad?

[Bill Moore]

I'm having trouble copying, and pasteing the schematic for the switch with my ancient Win 7 computer. Let me try this link which shows the function, shorting a 1/4" jack won't produce the voltages necesary to switch the IC which switches the relay!
https://line6.com/support/topic/5712...ot-rod-deluxe/

[KVH1]

I'm having trouble copying, and pasteing the schematic for the switch with my ancient Win 7 computer. Let me try this link which shows the function, shorting a 1/4" jack won't produce the voltages necesary to switch the IC which switches the relay!
https://line6.com/support/topic/5712...ot-rod-deluxe/

When I did short it with cable it did pop but didn't get to try playing to see if it switched. If relay clicked the pop covered it up.
Thanks for the link. There are a few things I miss about Windows 7