I recently picked up a Marshall Supervibe pedal of EBay sold as faulty. Looking at the main circuit board, resistor R14 had burnt out. The previous owner had removed the resistor so I don't know what it is meant to be!
Can any one help me find out the resistor value (labeled R14 on the circuit board). If you have a supervibe its easy to check. Just unscrew the 4 base plate screws and battery compartment and take a peek at the circuit board.
If any one can help I would really appreciate it.
Cheers,
CKS
You might want to run down to Radio Shack or Sears and pick up a cheap digital multimeter. Comes in handy for all kinds of stuff.
"Everybody got to elevate from the norm."
With the resistor missing, it won't be much help. He just needs the colored bands off the resistor from someone who can look, or the value from a schematic. Sorry, I don't have either the pedal or the schematic.
"A cheerful heart is good medicine."
With the resistor missing,
Doh! My bad - I shoulda read more carefully. :oops:
"Everybody got to elevate from the norm."
Yeah Ive got a multimeter. What I need is a magical multimeter that can see into the past and tell me what the resistor was.
If nobody here has one to check, I can only think of two things you could do:
1. (no risk) Find another one for a good deal on eBay. Open it up, check the resistor, put it back together, and sell it.
2. (slight risk) Try a few common resistor values, starting with 1 meg and going down. If you start high, you have a very low risk of breaking something else. You've basically got an infinitely high resistance there right now - reduce it gradually, 1M, 100K, 10K, and so on, until something starts to work.
The potential problem with #2 is that resistors almost never burn out, so I'm wondering how accurate the seller's story is. There's a chance the burnout was caused by something else in the circuit, in which case replacing it won't help. On the other hand, there's a very good chance the burnout was caused by a bad (external) power supply, so as long as you're not using a power supply from the same seller, R14 might fix it...
Ive tried #2 already although the previous owner said he tried bridging the resistor with some wire so hes probably knackered it already.
#1 is a good idea. Ive taken it a step further by asking sellers of other supervibes to open theirs up for me. Whether they can be bothered to do it and respond is a different matter.
Cheers for the help!
Here is some contact info. Who knows, if you call tech support, they might just look at the schematic & tell you what value you need. But judging from the ebay sale & the fact that it was already removed & replaced w/ a piece of wire, I have a bad feeling that the pedal may be toast by now... :roll:
Does the circuit board look burnt in that area?
Good Luck!
Marshall USA
316 South Service Road
Melville, New York
11747-3201 USA
Tel: (516) 333-9100
Fax: (516) 333-9108
The R14 resistor is a 47ohm, just checked my stepson's one as his, as it has just gone pop and I have found that C10 has just exploded a 100mfd which is right next to R14
Have replaced the cap but still not working will have to investigate more.
Regards
Don
Thanks for the help! I tried replacing the resistor and tried everything else but couldnt get the stupid thing to work. In the end I gave up on fixing it, ripped it to pieces and made it into a Big muff pi clone which is now my favourite pedal in the world! Check out my build report: http://www.cs133.co.uk/content/muff.html
Cheers,
CKS