MutronIII LDR replacement.

[mongo]

I got one of these for really cheap and everything is working  but I dont get ANY SWEEP from the unit. I reckon this is because the original LDR thingie is out of service (any other tip is very welcome)

can I replace this component (wich is a large cilinder with a strange configuration:4 "terminals" on one side and 2 on the other) with a newer LDR? maybe 2?

any tips are welcome and thank you in advance.


Andy



 

[ulysses]

sounds like an optoisolator with 1led and 2ldr's in one package.

you could try replacing with the 2prong end with a standard red led and the other 4 prongs with 2 ldr's.

cheers
ulysses

[smallbearelec]

The OEM part is a Hamamatsu P873-13, and I still have some left--my SKU 2514 at smallbearelec.com. In case that is not the problem, note the article at GEOFEX.com that analyzes the circuit of this pedal. You might want to dig in with a meter and confirm what the problem is before you spend money unnecessarily.

SD

[mongo]

Thanks for the answer!

any idea of the values of the LDR's?

Thanx! andy

[mongo]

The OEM part is a Hamamatsu P873-13, and I still have some left--my SKU 2514 at smallbearelec.com. In case that is not the problem, note the article at GEOFEX.com that analyzes the circuit of this pedal. You might want to dig in with a meter and confirm what the problem is before you spend money unnecessarily.

SD

Thanx for your answer!

I almost sure that this is teh problem because when the circuit is "ON" I can hear the filters working but not sweeping, much like a wha pedal  that you let just in a single position without rocking it... most likely this is the problem.

I'll check out the article as well, thank you!

Andy

[Dingleberry Electronics]

Hi.

I made a mutron clone using two NSL-32 optoisolators made by Silonex company.
Got them from Farnell about 2,50€ each, Probably about 3 USD.
Works absolutely fantastic. Probably any led/ldr combination will work somehow but might need a little tweaking.
You would find this article very helpful:
http://www.geofex.com/PCB_layouts/Layouts/neutronpub.pdf

-T

[mongo]

Here are the guts of the beast:

[slacker]

Easiest way to see if it's the optoisolator that's broken is to disconnect the LED side of it and put in an LED instead. This should then flash as you play if it doesn't then the problem is with the envelope follower part of the circuit, which is probably more likely than than having a broken optoisolator.

[mongo]

Easiest way to see if it's the optoisolator that's broken is to disconnect the LED side of it and put in an LED instead. This should then flash as you play if it doesn't then the problem is with the envelope follower part of the circuit, which is probably more likely than than having a broken optoisolator.

genious! of course of course thank you very much