Danelectro Rocky Road Ramp footswitch problem

zilla · Post by **zilla** » 13 Mar 2017, 14:58

hi All,

I'm in the process of rehousing a Danelectro Rocky Road and have run into an issue. i've been trying to bugfix this on and off for a few weeks thinking that taking a break and coming back with a fresh set of eyes might help but i'm still stuck.

The problem is with the ramp footswitch - it seems to be non-functional.

I replaced the original momentary switches with more robust momentary switches. thinking that it was the switch i've tried replacing the switch but i get the same result.

I've followed the trace to the IC and checked continuity of the trace and it's all good. It goes thru 3 vias before connecting to the daughterboard.

I've run a scraper pick between the pads to make sure there were no solder bridges and everything was clean.

i've tried tapping the IC pin with a grounded probe but still nothing. i can tap the other pins and make the effect turn on and off and change the from low to high speed on the toggle switch (the yellow wire on the daughterboard)

So i'm thinking that either the IC is damaged (it's on a daughterboard and the whole daughterboard is covered in goop) or i'm tone deaf and can't hear the difference?

Here are photos of the board and the schematic that i found here in a different thread. The schematic is a bit useless because the pin numbering doesn't match with the physical pins on the daughterboard.

Anyone have any insight?

thanks!

aionios · Post by **aionios** » 13 Mar 2017, 16:23

What type of footswitch did you replace it with? Only a tactile type will work since the microprocessor doesn't have any debouncing code. So if you use a full size momentary switch like the Carling type then the ramping function will only work some of the time since it doesn't register the same as a button press.

Chances are slim that the IC itself is bad, though, because the IC controls the clock and bypass as well. Not too often that you'll see one function fail and others still work when dealing with microcontrollers. So I'd continue to look elsewhere.

Other than that... it is a fairly subtle function, and the Ramping Speed switch determines whether the transition is slow or fast. Slow transition is barely audible, but fast is moreso. There aren't any other indications that it worked other than hearing the speed change gradually.

zilla · Post by **zilla** » 13 Mar 2017, 16:52

I'm using one of these momentary switches:

what switch should I be using?

aionios · Post by **aionios** » 13 Mar 2017, 21:36

Yep, that type will not work. Electrically, it sends several 'pulses' of connect/disconnect since there is a physical bounce when the contacts swing together.
This wouldn't be visible if you watched it, but on an electrical level, it confuses a microcontroller that is watching for a single change in voltage.

A tactile switch does not exhibit any bouncing, but the downside is that they always have to have an external actuator (like the one for the Rocky Road).

I am guessing that the original tactile switch was legitimately bad. The new one isn't a proper replacement so that's probably the main issue here.

Here are tactile switches. You'll have to find one that is the same size as the original if you want to restore the original functionality. Not sure what size the Rocky Road uses or if it's even standard.
http://smallbear-electronics.mybigcomme ... witches-1/

zilla · Post by **zilla** » 13 Mar 2017, 21:44

Thanks.

The main reason for the re-house was because the original switches were flimsy and didn't work well.

The Line6 delay units use a tactile switch with a spring actuator. any idea where i can find something like that, or something similar to the momentary switch for the on/off functionality?

aionios · Post by **aionios** » 14 Mar 2017, 14:45

Small Bear has some actuators there that should work (http://smallbear-electronics.mybigcomme ... for-b-o-b/) but I don't quite know how to tell you to mount the tactile switch. Usually it would be PCB mounted.