Footswitch LED Problem

[Wattever]

I just bought this 3 button generic footswitch that I'm trying to adapt to use with my Ibanez TN-120.

http://www.tubesandmore.com/products/P-H473

(There is a schematic on the page)

Geting the switching part to work is no problem, the trouble starts when I try to get the LED's to work

The problem I seem to be having, is that the switching relays in the amp are too sensitive and just the power going through the LED is enough to switch the relay. (Even if I touch ground with one hand, and the terminal from the relay coil with the other, it is enough to trip it )

Anyone have any suggestions on how to get around this problem without adding more than the current 4 input/output wires to the box, or replacing all the SPDT switches?

TIA

Mark

[mathd]

Just a guess like this, dont know if it could work.
Maby just a resistor across/in parallel with the relay coil, that will reduce the coil resistance. Will require more current to trigger.
You could also use external power for the leds.
What is the relay wiring looking like? is it activated by a transistor or just the coil going to ground for trigger?
If its activated by transistor you probably can change the sensitivity/input impedance.

[Wattever]

Thanks for responding.

I hadn't thought of the relays being driven by transistors, but looking at the gutshots I took of it last time I had it apart, it does appear as if each relay has a similarly located transistor. it makes a lot of sense, because I couldn't see relay coils being so easy to energise. Any idea why they would go to all the trouble of using a transistor there?

It would probably be easier to figure this out if I had a schematic for the amp, but after a lot of trying at the time I got the amp, I still haven't been able to find a schematic for it online, and any requests to Ibanez went unanswered. (Which is why I'll NEVER buy an Ibanez product again!)

The amp has a power output for the LEDs but to use it I would have to replace the wire on the footswitch with a 5 wire one. (Not sure where I would find that!)

[mathd]

Using transistor for the relay coil help the longevity of the switche(no arcing of the switche contacts), less curent on the switch contacts (high sensitivity). When you switch off a relay "if breaking contact to ground" you get a positive voltage spike from the coil that is higher that the supply voltage!. Thats why they also use a diode with a transistor to switch a relay(but some relay have build-in diode). That way you still get a positive spike on turn off, but it cannot be higher that the relay supply voltage, so the transistor is safe from overvoltage..
Without the schematic, i can't help. maby try to reverse engeener the relay circuit :p. but changing the cable will probably be easier.

It suck that ibanez will not reply with the schematic.

[Wattever]

I guess i'll try to find some kind of a 5 (or more) wire cable to replace the 4 wire one I have now.

Any suggestions? I'm thinnking maybe Cat5 network cable with 8 conductors might be the easiest to find, if i can get any that is flexible enough. A lot of it seens pretty stiff.

Yea, it sucks that Ibanez doesn't seem to have any kind of customer service. Peavey may have a reputation for making somewhat "boring" amps, but you ask them for a schematic, and from my experience, it's usually in your inbox in about an hour.

[mathd]

Am not sure, but since you have led power inside the amp.. I may have an extra option.
I did not see the circuit so i dont know if this could work.
Using a resistor from that LED power going to conductor 1 2 and 3(so you need 3 resistor) inside the amp. That will power the leds and hold the relay open when the switch is open. You just need to make it's value small enough so the leds not triggering the relay and big enough value so your not drawing ridiculous ammount of current.. And make sure the LED power voltage and conductor 1, 2 and 3 are the same(without the resistor).. With some luck, they will be the same voltage

As far as where to get cable.. probably mouser or digikey, they probably have something interesting for that.

[Wattever]

Without a schematic, I really don't want to do any more than I have to inside the amp, so I think that a new cable is the way to go.

It'll probably be a while before I get to anyplace I can find anything in the way of suitable wire, but I think it'll be the easiest fix.

I just want to get it ready to go, and hopefully sell it for enough to buy some iron and glass for my 45 project. It's too bad, it's really got some good ideas in it,(built in biasing, PTP output tubes etc.) but Ibanez's lack of customer support is a deal breaker for me.

Thanks for your help, I'll let you know when I get the footswitch and LEDs working.