JCM 2000 TSL 100 Momentary Switch Button...

[DrGonz78]

5 Button switch pedal for JCM 2000 TSL100 >>Okay, I have this foot switch that I have tried about 2 replacement switches that don't work. It is the one where there are five buttons: Clean, Dirty, Lead:: FX, Reverb. The Dirty switch was busted years ago and now I have been looking for the right part for replacement since October. If anyone has replaced this switch and knows which is the correct one to get then let me know.
Thanks so much in advance.

[Enzo]

photos photos photos...


Get out the ohm meter, find out if the switches work as switches or not. Zero ohms across closed contacts, and open reading or at least high resistance across open contacts. Your problem may be electronic rather than the switches themselves. A bad transistor back in the amp could be shutting you down.

[DrGonz78]

When I say the switch was "busted" it was mechanically destroyed. The tip of the plastic part that hits the metal contact flipper broke. So, for years I just used clean/dirty and was able to get around the problem since I did not use the lead channel.

To be more specific I have purchased a couple of these replacement parts over ebay for a few bucks each. Not a lot of wasted cash but still not the part I needed. The first switch was this one... Which I was not sure but it looks identical to pc mount version. So, I installed it. It works... Kinda... You start out in clean and switch to dirty>>> Good! Then switch to lead or clean and it jumps back and stays on dirty. But if you tap it twice then the next time you hit clean or lead it will switch.

1pcs PEDAL EFFECT Enclosure Box Stomp Foot Switch,102P | eBay

I then tried to order this other one and it did not work at all. So, I put the other one back in and want to sell the amp head & foot switch.

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From all the searches I had done could find one thread and I am searching for that one right now. Someone had recommended this other switch but it had no picture. In that one web forum the guy said they are really hard to find... But I would hate to try to sell that amp and say "hey just click the button twice."

Edit ADDED>>>
Although, yes Enzo my next guess might be checking the amp, but not until I can explain the part situation...

[DrGonz78]

Here is a link to a marshall forum where a guy describes the same symptom.

Marshall TSL601 Footswitch parts - Marshall Amp Forum

There is a guy that recommends one part Part # WSW-SPDT-MPB on this site.

https://taweber.powweb.com/store/sword.htm

So could the problem be the other switches are for 9-12v foot pedals and this one is 4a/125v? Maybe I need WSW-DPDT-PB or the WSW-3PDT-PB? This one has been driving me nuts lol!

[Enzo]

Think this through. The stomp switch (click on, click off - a latching switch) works, but you have to click it twice. SO the circuit functions. That is a classic explanation of a latching switch where a momentary ought to be.

Imagine a sustain switch on a keyboard. It is a momentary switch. Hold it on, the unit sustains. Let it go, the unit stops sustaining. Now imagine how it would work if you used a latching switch - a stomp switch. You step on the switch and the unit sustains, but take your foot off the switch, it STILL sustains until you click it off, because it latched ON when you first pressed it. You have to press it again to turn sustain off.

You need a momentary switch.

[DrGonz78]

I started figuring out that part out a while back when I bought the first switch. Then I bought the momentary switch (off/on) and it does not work at all... The latching on/on one works.

Basically, I believe it is because there is the 4a/125v switch and a 9v switch version. I am using the 9v version made for foot pedals. But why does one of these 9v switches even work at all? It's just strange that one works and the other won't.

Also, there is a PCB board in the foot switch and that makes the replacement depend on it's accommodating size to fit.

I will try to order the weber part and let you all know if the 3rd time is a charm. Thanks again.

[Jazz P Bass]

More Info for item P-H503-PC
Let go of the voltage rating of the switch.
It has nothing to do with it.

[g1]

Then I bought the momentary switch (off/on) and it does not work at all... The latching on/on one works.

Then either it is the wrong type or you have more than one problem. The switch JazzP linked should work.
Otherwise, make sure the front panel switches on the amp are set properly "To allow proper operation it is important to remember that both channel mode pushswitches on the front panel (located between the Clean and Crunch / Lead channels) MUST be pushed IN."
Also, there are 2 types of switches in the footswitch. The reverb and FX are latching type. The 3 channel/OD switches must ALL be momentary or it will not work properly. Make sure none of them have been swapped around or replaced with the wrong type.

[Enzo]

Did you check the momentary swithc that didn't work with an ohm meter? MAybe the switch itself is defective.

g-one makes an important point, ALL the momentary switches must be that type. A latching switch in place of one can affect the operation of the others.

[DrGonz78]

Okay I am sending these photos and the ohms measurements. I am not really sure that the switch is working and don't really feel this tell me anything yet. But maybe you guys can help clear anything up. I measured these two pins since it was the only place where resistance showed up. I measured the first time and got 1 ohm. Then I clicked the switch and measured .5 ohm. As I measured the ohms reading would eventually settle to .5 ohms either way after measuring for a time period. I was trying to show that when measured right away there was a bit of a difference right after the switch was pushed.

Edit: It really is just .5ohm on the far two... Either way it is pushed...

[DrGonz78]

Another thing to mention would be when I measure the two pins (up above picture) at the 20M setting, it will read 0.00. I then will take the test lead and remove it from middle pin then put it on the left outer pin. At that point it shoots up from 1.00-19.99M and then to 1. To repeat that reading I then need to test the two right side pins and get it to 0.00(ground). So, this makes me think that this switch is probably just a bad apple.

Edit: Not really making sense here sorry... ^^^ This is not why it is bad...

I will remove my other switch from the marshall pedal and test it to compare. Thanks for all the help you guys provide.

Edit: I removed the other working switch and measure the far right two legs and get .5 ohms. Then click the switch and I they open up... Then the far left two get .5ohms. So, that is the latching switch and has a different type of rocker. I am pulling these things apart to try to figure out if I can jimmy it back to a working condition...

My question is... on the "momentary" switch the far right legs measure .5 ohms. If it were functioning correctly what would happen when I click the button? I am thinking that they would open up...???

[Enzo]

Maybe it is just me, but I am looking at the switch in the top photo, and having a hard time seeing the switch in the two photos with meter as being the same switch. I looks like a different one to my eyes.

In any case, if you are having a hard time getting consistent resistance readings, use a couple clip wires. CLip wires to the two probes, and then clip the free ends to the switch terminals. Now you don;t have to hold them there.

Or is that what I am seeing, some sort of black thing in the center, is that a clip?

Look at the photo of the switch alone. Three terminals in a row. The center one is the common. The center one will normally connect to one of the end ones and not the other end one. Gro center to the first would be the "normally closed" contacts, and from center to the unconnected one the "normally open" contacts. When you press the switch on a momentary, the two end ones trade jobs as long as the button is held. That is to say the normally closed set of contacts open, and the normally open set closes. So from center to top for example might read infinite ohms until the buttom is pressed, then it reads less than 1 ohm, as close to zero ohms as posible. If it is a latching switch, the two end pins trade contact with the center each time you push and stays that way until pushed again.

SO connect the meter to the center and one end pins. If momentary type, then pressing the switch in and out should make the reading on the ohm meter change from very low resistance to infinite - back and forth. If it stays at 1 ohm or less no matter what, then the switch is shorted. If a latching type switch, the readings do the same thing, except they stay whichever way until the switch is pushed again.

Momentary and latching switches work exactly the same as each other except for the fact the latching ones stay in each condition until the next push. In other words electrically the same, mechanically different.

[DrGonz78]

Ok I solved the problem... This might take some explaining but... okay here it goes.
For example, in this picture you see me testing a known good switch...
and the suspect switch>>> (Edit: the 2nd pic is not of a latching switch (which would make sense) but it is a momentary switch. The two right legs are grounded on the 2nd pic but on the original switch from 1st pic (original working switch "Lead" from the pedal) the left two legs are the grounds. So these are just totally opposite each other would never work in the circuit correctly.)

Sorry I should have use clip leads for my pictures and I will in the future... Yes that black ugly thing is an alligator clip. Anyway in the first pic the left & center legs being measured and in the second pic it is center & right legs. The left and center are sharing the ground on all of them (on the circuit board) except this "suspect" switch is not the same. Looking at the circuit board it makes no sense that they suddenly changed one switch to be backwards. So, I got thinking that I could open this "suspect" switch and reverse the flipper so that it would make it the same as the others. First, I opened one of the good switches to see which direction the flipper was going, and it was opposite to the "suspect" switch. So, I opened up the switch to flip the flipper (I know no better name for it...) and got the switch put back together. Then I was able to test the switch and it was behaving just like the other two. Enzo, I figured out that you keep the test leads on as you click the switch and then read your meter. They all performed the same, just as you had described. So, I read your post after doing all that.

Then I resoldered them to the board and presto it is switching channels! They do drive on the opposite side of the roads from us in England... Not sure why this worked but I am gonna look more at it tomorrow. I could totally be wrong here and the middle dirty channel button is a special switch, but that makes no sense to me. Really weird that any of this worked.

[g1]

Don't worry about the circuit board, it is done that way for a reason.
It sounds like you are describing a latching switch. A momentary switch will only change the meter reading WHILE you are holding down the switch. Hook up your meter to the switch. If you have a continuity beeper setting it will be easier. One meter probe to the center pin, the other meter probe to whichever outside pin gives you no beep or OL reading on your meter. Push the switch and release. Does the meter beep or now show low resistance (like the .7 ohm in your picture)? If press and release changed the meter reading then it is a latching switch. For a momentary switch the meter reading should only change while you are pressing the switch. When you release it, the meter reading will go back to what it was reading when you weren't pressing it.
The FX and reverb switches need to be latching type, the other 3 need to be momentary.

[DrGonz78]

Last night I spent a few hours of time just analyzing the heck out of the momentary and the latching switch to understand the mechanical differences. What my picture above illustrates is that the "new" part that I ordered was backwards...

The first picture shows a known good switch "Lead" momentary switch, and the that second picture shows "New" replacement" momentary switch. As I was analyzing the old working switches, the two legs that shared a common ground were not the same as they were on the "New" switch. When I would put in the "new" momentary switch it would pull from clean or lead and not make the switch. I figured out that you hook up the the ohm's meter and test the common legs of a momentary switch as you click the button. It will read about .5 ohms and then click (hold) of the button the meter will show an open displaying 1 as infinite and then back to .5 ohms upon the release. Then I read Enzo's post after this and realized that it was all starting to make sense. I also analyzed how the latching switch throws it legs from center to the left or then the right leg. (Essentially this is what both momentary & latching switches do... except a momentary only latches for a moment and the latching one stays in position until it is pushed again.) This is just me looking at this particular model of switch that has 3 legs. So, I actually opened up the switch and made it reversed so it would match the other working switches. Essentially, in the end I had 3 switches that tested the same and were working momentary types.

Now I can use the foot switch and it is working fine. Not sure why marshall has switches that are completely different than what is typically found out there... And for sure the switch that I have is a momentary... I had tried both. The flipper metal part in the momentary & latching switches are totally different and I completely understand now what is going on as you click that little button.

The Reverb & FX are 6 legged switches and are good. I have been using this amp for about 9 years now so I am the only one that has had his grubby hands on the foot switch. I had brought to a shop here in Phoenix, AZ but never to fix the foot switch.