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Started by Rock64, August 08, 2023, 07:47:27 PM

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Rock64

Hello, I was scrolling through this site and I did not reach the bottom of the page. It goes on forever. How on earth do we keep this place organized? Anyways, I do not own any Roland or Boss synth gear. Unless you count 2 1984 Hamer Phantoms with obsolete synth built in. However I am a devout Boss/Roland user. At least the GT line. I decided to join since many times I was searching for answers and I very often find a thread in a post here.

I was searching for ways to modify an EV-5 and I found quite a bit of info here about it. Seems old news around these parts now but I've been tinkering with a used EV-5 I bought some time ago but it doesn't seem to work right. I took it apart and reassembled it according to the schematic but it does not function properly.

I reviewed most all of the available info here about this subject but the issue is not specifically addressed so I will ask.

There are both the B10K(pedal) and B50K(side) pots and they are wired exactly like all schematics say but I only get about 44% travel out of it since the mechanism only rotates the shaft that much. If I manually turn the pot with my fingers it works great 0-100 but the pedal is not capable of this. What do I do to make it work correctly? It's gotta be so stupid simple but I can't figure it out.

Sorry if this is not the right place to drop this query.

Brent Flash

Welcome to the group Rock64! :)

Elantric

#2
Quote from: Rock64 on August 08, 2023, 07:47:27 PMHello, I was scrolling through this site and I did not reach the bottom of the page. It goes on forever. How on earth do we keep this place organized? Anyways, I do not own any Roland or Boss synth gear. Unless you count 2 1984 Hamer Phantoms with obsolete synth built in. However I am a devout Boss/Roland user. At least the GT line. I decided to join since many times I was searching for answers and I very often find a thread in a post here.

I was searching for ways to modify an EV-5 and I found quite a bit of info here about it. Seems old news around these parts now but I've been tinkering with a used EV-5 I bought some time ago but it doesn't seem to work right. I took it apart and reassembled it according to the schematic but it does not function properly.

I reviewed most all of the available info here about this subject but the issue is not specifically addressed so I will ask.

There are both the B10K(pedal) and B50K(side) pots and they are wired exactly like all schematics say but I only get about 44% travel out of it since the mechanism only rotates the shaft that much. If I manually turn the pot with my fingers it works great 0-100 but the pedal is not capable of this. What do I do to make it work correctly? It's gotta be so stupid simple but I can't figure it out.

Sorry if this is not the right place to drop this query.

On genuine EV-5, you must employ the genuine factory custom taper 10k pot. Its special as its not the typical 270 degree arc full linear taper across all 270 degrees. Its more like 10k linear taper across 180 degrees, which reflects the actual extant of physical range the EV-5 treadle movement from Toe Up to Toe Down .

Read design note on lower left



Pedal volume pot in Roland EV-5 pedal is special taper 10kB pot.
Original part code for ordering from nearest Roland authorized service is :
13229702 EWH4JA230B14 10kB S

Roland EV-5 SERVICE NOTES
https://www.synthxl.com/wp-content/uploads/2020/04/Boss-EV-5-FV-60-Service-Manual.pdf

Expression Pedals
https://www.vguitarforums.com/smf/index.php?topic=33.0

gumtown

Someone in the past could have replaced the 10K pot with the wrong type.
Check your wiring to the 10K pot goes to the correct way around to the two outer pins,
 the wrong way around could throw the range beyond the physical limits of the pedal actuator.
That will also reverse the action, but the A/B polarity switch should correct that.
Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

Elantric

#4


Verify the lever actuator for EV-5  expression pedal Potentiometer VR1 ( on the left in pic above) is tight, and still in the correct location to expose a 10k DC resistance across full wiper sweep Toe up to toe down when measured on TRS plug Tip & Sleeve.

And verify the side 50k ( min vol) pot VR2 is full counter clockwise

Rock64

Quote from: Elantric on August 08, 2023, 10:41:45 PMOn genuine EV-5, you must employ the genuine factory custom taper 10k pot. Its special as its not the typical 270 degree arc full linear taper across all 270 degrees. Its more like 10k linear taper across 180 degrees, which reflects the actual extant of physical range the EV-5 treadle movement from Toe Up to Toe Down .

That explains a lot. If this is the case then how could anyone clone an EV-5 without the special pot? All the schematics clearly state (linear) and aftermarket products given shouldn't work any better.

Are these pots really custom or just logarithmic tapers?

As far as someone changing the pot before me, that's entirely possible but the original wires are present and I compared the wiring to an unaltered properly functioning EV-5 and its wired as it should be.

Elantric

Quote from: Rock64 on August 09, 2023, 08:20:52 PMThat explains a lot. If this is the case then how could anyone clone an EV-5 without the special pot? All the schematics clearly state (linear) and aftermarket products given shouldn't work any better.



VOX Wah wah pedal TYPES expression pedals  with rack and pinion gears or Ernie ball string type will rotate potentiometer 250 degrees