I've been working on reviving an old analog echo pedal. I acquired it as a basket-case project.
The brand is "CODE" but it seems to be nearly identical to the Stinger DE-80 and at least half a dozen other analog echo pedals that all have nearly the same board - several even have the same enclosure.
It's working, but only when the foot switch is held down.
I've attached the DE-80 schematic and rough drawing of the board layout, which is about 95% identical to what i have, particularly down in the lower right hand corner where the fet switching occurs.
At this point i have replaced every electrolytic cap on the board, and replaced both the 0.01uf and 0.047uf film caps in the fet switch, as well as the diode on the gate of the fet. I have experimentally replaced the fet, and replaced the two transistors with a pair of 2sc2389 with almost identical hfe that i had in the parts bin from a project that changed course.
And there's no change in behavior.
I can start replacing the resistors as well but, does anyone have any clues?
The brand is "CODE" but it seems to be nearly identical to the Stinger DE-80 and at least half a dozen other analog echo pedals that all have nearly the same board - several even have the same enclosure.
It's working, but only when the foot switch is held down.
I've attached the DE-80 schematic and rough drawing of the board layout, which is about 95% identical to what i have, particularly down in the lower right hand corner where the fet switching occurs.
At this point i have replaced every electrolytic cap on the board, and replaced both the 0.01uf and 0.047uf film caps in the fet switch, as well as the diode on the gate of the fet. I have experimentally replaced the fet, and replaced the two transistors with a pair of 2sc2389 with almost identical hfe that i had in the parts bin from a project that changed course.
And there's no change in behavior.
I can start replacing the resistors as well but, does anyone have any clues?
Attachments
*shrug* some people told me that circuit should latch.
The original switch in this thing was a subminiature push button that had taken a good sideways whack and was no longer holding together. I guess it's possible that it was a latching switch, but it was barely a switch when i acquired it. I did not know they made them that small. It's exactly the same size as the momentary switch i replaced it with.
I think this pedal spent a very long time kicking around someone's workshop without the benefit of the shared knowledge of the internet. It only took me maybe 10 minutes to find the schematic and diagram above with google, but the "CODE" brand version of this pedal is apparently exceedingly rare.
There were about 3 wires hooked up to the board when i got it, and at least one of them was wrong.
I'm tempted to build a true-bypass-relay-with-tails board and stuff it in there, and to hell with battery life.
The original switch in this thing was a subminiature push button that had taken a good sideways whack and was no longer holding together. I guess it's possible that it was a latching switch, but it was barely a switch when i acquired it. I did not know they made them that small. It's exactly the same size as the momentary switch i replaced it with.
I think this pedal spent a very long time kicking around someone's workshop without the benefit of the shared knowledge of the internet. It only took me maybe 10 minutes to find the schematic and diagram above with google, but the "CODE" brand version of this pedal is apparently exceedingly rare.
There were about 3 wires hooked up to the board when i got it, and at least one of them was wrong.
I'm tempted to build a true-bypass-relay-with-tails board and stuff it in there, and to hell with battery life.
unfortunately, the enclosure is of the BOSS style - even has the thumb screw and grommet affair for releasing the stomp lever to access the battery compartment. the switch is way off in the corner of said compartment, and it's wee head gets actuated by a padded protrusion on the underside of the lever.
It looks like NKK does actually make push-on push-off switches in the tiny size i need. Maybe the original switch was a latching switch, before someone smacked it with something.
The switch latches, not the circuit.
There are plenty on fleabay. Measure the size and search accordingly.
7 x 7mm 6-Pin Micro Miniature PCB Tactile Push Button Switch Self Latching x 10
There are plenty on fleabay. Measure the size and search accordingly.
7 x 7mm 6-Pin Micro Miniature PCB Tactile Push Button Switch Self Latching x 10
Except that won't mount through a hole in the housing.
I need something more like this:
MB2065SS1W01 NKK Switches | Mouser
or the DPDT version for a couple bucks more, and then i can use the non-relayed tails looper layout.
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