I'm pretty new to pedal building/modding so I'm not even sure what the switch is called. I've modded about 5 pedals so far and am pretty much addicted. Anyway one of the switches is stuck in the on position so where can i find a replacement?
Physically stuck or electronically stuck?
If physically Steve over at Small Bear Electronics (//www.smallbearelec.com) has suitable replacement momentary swithces.
If electronically, you have a bigger, albiet not impassable, problem.
well the switch still moves but it stays on so I guess it could be electronically stuck or the switch is just broken inside.
Hmm, ok, yeah, try replacing the switch itself and see if that fixes things. Steve'll set you up :mrgreen:
Good luck and let us know how it goes!
steve is still closed for a while... any other ideas? What happens If it's electronically stuck?
QuoteWhat happens If it's electronically stuck?
Then you'll have to identify what is the flip-flop part of the circuit and troubleshoot it - basically two transistors may need to be replaced. I think it's more likely that there is a problem with the switch itself.
testable by cutting the wires to the current switch and just touching them to one another - or by shorting across the switch contacts with a screwdriver or something momentarily
Quotetestable by cutting the wires to the current switch and just touching them to one another - or by shorting across the switch contacts with a screwdriver or something momentarily
Now I know that, but why didn't I say that?! :oops:
Oh well, it's a Monday. :x
Quote from: Samueltestable by cutting the wires to the current switch and just touching them to one another - or by shorting across the switch contacts with a screwdriver or something momentarily
What will this show me?
p.s. This site is extremely helpful!
QuoteWhat will this show me?
It will show you that the switch is not functioning properly and that the flip-flop section is functional.
Without removing anything, I tried touching the 2 solder points with a screwdriver and nothing happened. The light automatically goes on and stays on as soon as a cable is put on an imput jack.
That could mean that the switch is permanently on the "on" position. Ypu'll need to physically disconnect the switch to do this test properly, though.
ok, I'll go do that and report back.
Ok; I disconnected the switch completely. The pedal still goes on as soon as a cable is plugged in. Touching the two wires together does nothing.
Sounds like your flip-flop circuit is busted.
To be sure: test the momentary switch for continuity with a multimeter, so you know if that part works. If it does: time to learn about flip-flops, or ditch that section, buy a 3PDT, drill your pedal, and make it true bypass.
Quote from: bigjonnySounds like your flip-flop circuit is busted.
To be sure: test the momentary switch for continuity with a multimeter, so you know if that part works. If it does: time to learn about flip-flops, or ditch that section, buy a 3PDT, drill your pedal, and make it true bypass.
I basically have no Idea what any of that means. Someone said that 2 transistors would have to be replaeced? The pedal is a boss ch-1 super chorus, so If anyone would be kind enough to take a digital picture of the board and circle the transistors that need replacing in paint that'd be greatly appreciated. Also I'd need to know what transistors I have to buy and where I can get them. Apologies for my pedal n00bness.
QuoteSounds like your flip-flop circuit is busted.
Yeah, it kinda looks that way...
A flip-flop circuit is where a pair of transistors are used in place of a switch. A momentary switch activates the circuit, and one is off and the other is on. They flip-flop.
Say, are you sure that your battery is good? Sometimes those pedals don't work right on a low battery. But I'm sure you already checked that...
Yup, already thought of the battery. Same thing with a brand new 9v. It's wierd because it was working fine and I actually had the pedal sounding real good. Then It just decided to be stuck on "on" about 3 days later. If someone could inform me of which transistors need replacing and where they're located, I could just replace them.
could really use some help on this one.
I can't find a schematic for your particular pedal, but in my ds-1, they're marked as 2SC-2458. You should be able to locate them pretty easily by following the trace from the momentary switch. I think you'd be able to get a suitable replacement from radioshack. or, since it's already stuck in the always on position, you could get a 3pdt stompswitch and convert it to true bypass pretty easily.
I think the two trannies face each other also....
For a picture of them, find the thread that shows how to install a 3PDT in a boss pedal. (That's also an idea right there....scrap the bypass, and just True Bypass it).
Cheers,
Nish
If I had a picture of the insides... do you think one of you guys could tell me what I need to replace? I keep looking but really don't even know what it looks like.
Go to the top of the page and check out the GEOFEX link. Click on the technology of the Tube Screamer link (upper left) - there is a brief, very informative, explanation of how the flip flop circuit works in the Tube Screamer. This is a good place to start for the on/off circuit.
AL
There are also some pages on www.epanorama.net that talk about flip-flop circuits...
Am I thinking wrong or will the pedal be fixed if I replace the two transistors? I don't want to drill and put a 3PDT switch in. Are the transistors on the main circuit board? Paul, I notice no your webpage you have a ch-1 in your rig? Would you mind opening it up when you get a chance and pointing me in the right direction? I don't know what these transistors look like and can't exactly read a schematic yet.
I wouldn't be able to get to it for a few days.
That's fine... If you get to it just pm or e-mail me. I'd greatly appreciate it.
If I might make a recomendation. Since you seem to have an interest in building modifying and repairing effect pedals, it might be in your best interest to go over some of the information on geofex or similar sites. it's only going to benefit you to learn how to read a schematic or how the flip flop switching system works. I just started workign with pedals myself, and I found those sites to be a great resource.
Quote from: zac102If I might make a recomendation. Since you seem to have an interest in building modifying and repairing effect pedals, it might be in your best interest to go over some of the information on geofex or similar sites. it's only going to benefit you to learn how to read a schematic or how the flip flop switching system works. I just started workign with pedals myself, and I found those sites to be a great resource.
That is a great suggestion and I will do much research in the future. But right now I really just need a quick fix for this pedal.
urgh...I hate you...now I have to dig out my DS-1...Do you have the replacement parts?
Cheers,
Nish
I'm sure boss is lazy, so the buffer in each pedal is porbably all the same. In my DS-1 the buffer flip flop transistors are 2SC2458-GR's. They are smaller than all the other trannies on the board, and are side by side facing opposite directions...
Hope that helps..
Nish
P.S. The flip flops at the bottom of this schem...
http://fuzzcentral.tripod.com/ds1/DS1_Modified.gif
:wink:
Quote from: sir_modulusI'm sure boss is lazy, so the buffer in each pedal is porbably all the same. In my DS-1 the buffer flip flop transistors are 2SC2458-GR's. They are smaller than all the other trannies on the board, and are side by side facing opposite directions...
Hope that helps..
Nish
P.S. The flip flops at the bottom of this schem...
http://fuzzcentral.tripod.com/ds1/DS1_Modified.gif
:wink:
I'm terribly sorry about all this but I don't even know what a transistor looks like :oops: I don't have the replacement parts because I don't know what I need other than the fact that they're transistors. I know caps,diodes,resistors..etc... but not transistors...
p.s. the link you posted goes to a blank page.
That's cuz tripod.com has a policy about linking directly to images. Go here (http://fuzzcentral.tripod.com/DS1.html).
I'm getting slow-to-no response from fuzzcentral, now, however for whatever reason.
Modern transistors look like this (http://images.google.com/images?q=transistor). Specifically, like this (http://www.periodictableonline.org/images/transistor.gif) when used in stompboxes.
these are the only two next to each other and facing opposite directions....are these the ones that need replacing? Will that fix my problem?
(http://www.guitar.com/Discuss/img/1300/4828287/m4828289-3290.jpg)
that's probably the transistor set, BUT to be sure, you should find a copy of your pedal's schematic, and see if those are electrically close to the switch. there should be a call-out on the board like Q1 for each transistor that will corresond to its location on the schematic.
also, that might not be the issue. all things considered, its probably a bad transistor, but I would imagine that another component in that section of the circuit could be at fault. again, it might help you a good deal to read up on how the circuit works, how to read schematics, and how to identify components.
Well, I found a schematic and to my untrained eyes it looks that "Q8" and "Q9" are electronically close to the on/off. Here's the schematic http://www.generalguitargadgets.com/boss/BossCH-1.gif Could you plese confirm this?
Q8 and 9 are where those circled transistors are too.
Yep, it's Q8 & Q9 that do the flip-flopping.
Thanks! So I should replace those and it should be good? Now I just need to know what transistors I need to buy... they just say c945 p73e on the side. The quickest place to get them would be radioshack so if anyonw would be kind enough to look here http://www.radioshack.com/category.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F011%5F002%5F017%5F000&Page=1 and tell me which ones I need, I can go to the store tomorrow and fix this thing.
I am not familiar with those transistor markings. I doubt that RadioShack would have a direct replacement, and in a store for that matter. One of their switching transistors may work.
Anyone else have any ideas?
Well, JD's GGG schem (that looks like a scan from BOSS) says Q8 & Q9 can be 2SC1685R or 2SC945. I'd see how to find those.
Mouser has a cross-reference (http://www.mouser.com/index.cfm?&handler=data.listcategory&D=*2sc945*&terms=2sc945&Ntt=*2sc945*&Dk=1&Ns=MfgrPartNumber%7c%7cSField&N=0&crc=true) (functional equivalent) for the 2SC945.
Also keep in mind:
Quote from: KCollinsSo I should replace those and it should be good?
Quote from: zac102all things considered, its probably a bad transistor, but I would imagine that another component in that section of the circuit could be at fault.
Its worth trying to replace these, but there's no guarantee this will work. It's essentially a wild stab in the dark, guided by a bit of logic.
QuoteIt's essentially a wild stab in the dark, guided by a bit of logic.
Oh, you mean a S.W.A.G.?! (Scientific Wild A$$ Guess) :lol:
I'm also thinking that it's possible that the transistors are actually good, but the bias voltage may be thrown of somehow, so they're not switching like they're supposed to be...
S.O.A.B. It seems that the damn on/off LED was shorting or something....With the tiny LED circuit unscrewed from the pedal it works fine.
Well, that saves you some headache fixing it! :wink:
I have spent hours trying to figure out why something wasn't working only to find out it was something stupid like that. :x
I know, I apologize for any migrains. It was working fine for days after I modded it and then all of a sudden it wouldn't turn off! I wou'ld've never thought the on/off LED somehow moved.
It makes sense actually. It was probably shorting out the power supply to the flip-flop transistors... 8)
I'm just glad I can use it again. It sounds so good now!
I had a similar problem with my ds-1. my friend gave it to me as a sort of "if you can make this work it's yours kind of thing." it wouldn't turn on, but then when I opened it up to inspect it, everything worked fine. what was happening was that the board was shorting against the bottom of the case. the low cost solution was to coat the panel with electrical tap. the other problem was that the momentary switch wasn't returning to origin. I took that apart before I tried to replace it, the internal spring had slipped off of its seat and kinked, I just bent it back and I haven't had a problem since. If I had to guess what happend to the pedal, he stomped on it a little too hard, broke the switch, and then when it stopped working properly, he just threw it across the room.
I got a vintage ampeg from him dirt cheap($10) in a similar manner. when I got it, it was missing the power tubes, the chasis was bent, all of the shock mounts and a knob were broken, it had a blown fuse, and the rectifier was bad(the tube had white junk on the inside of it, which I didn't think was right). If I had to guess what happend, I'd say that the rectifier went, took the fuse with it, and when it stopped working, he threw it, causing the chasis to fly out of the head, and possibly causing the power tubes to go along with it. after checking the electronics for shorts and bad components, geting a voltage reading off of the power transformer, and in general just looking for other possible failure modes, I concluded that my friend is an idiot, replaced the tubes and fuses, and fired it up. it sounds awesome now, and the prices of old ampegs are on the rise. I made out like a bandit.
Obviously, I don't let this guy near my stuff anymore.
kinda similar, except there was no gear throwing here :shock:
QuoteI got a vintage ampeg from him dirt cheap($10) in a similar manner. when I got it, it was missing the power tubes, the chasis was bent, all of the shock mounts and a knob were broken, it had a blown fuse, and the rectifier was bad(the tube had white junk on the inside of it, which I didn't think was right). If I had to guess what happend, I'd say that the rectifier went, took the fuse with it, and when it stopped working, he threw it, causing the chasis to fly out of the head, and possibly causing the power tubes to go along with it. after checking the electronics for shorts and bad components, geting a voltage reading off of the power transformer, and in general just looking for other possible failure modes, I concluded that my friend is an idiot, replaced the tubes and fuses, and fired it up. it sounds awesome now, and the prices of old ampegs are on the rise. I made out like a bandit.
Sounds like this guy has an anger problem... :shock:
pretty much, all of his gear is in pretty rough shape. he just dropped 2 grand on a dsl100 full stack, I say it lasts a year or less.