PLEEEAAASE Help with boss sd-1 mod

[alanhoggard]

I am doing a mod to mt boss sd-1, but i cannot identify C2 and C3 on the circuit board. Can anyone help me locate the two caps.
Thanks in advance.
Alan

[MartyMart]

Flip it open, components top and leads facing away from you then C2/C3 are right edge about
half way up the board.
There will be "identifications" on the board but those caps are normally covered in brownish
glue, to hold them down.
You can pick that off with small needle nose pliers, just dont pull TOO hard !!

MM.

[alanhoggard]

Thanks, thats the problem, the caps are not marked on my pedal. it's from the 80's made in japan. can you be more specific to which caps are c2 & c3.
thanks so much

[MartyMart]

OK from back of board ( leads connect ) coming forward on the right side
you'll see three small/medium caps they are C1 C2 C3, C3 being nearest and
about half way up the board.
C1 is a 473 ( 0.047uf)
C2 is a 183 ( 0.018uf)
C3 is a 473 ( 0.047uf)

Marty 

[alanhoggard]

Thanks, Well i got all the mods done and now the pedal is only letting about half the signal through! Argghhh.
When the pedal is switched off,  the signal is only half as strong as when i plug directly into the amp.
With the pedal on it boosts the signal pretty high, but there is no sustain or bite.
Any Ideas would be great
thanks

[wampcat1]

Thanks, Well i got all the mods done and now the pedal is only letting about half the signal through! Argghhh.
When the pedal is switched off,  the signal is only half as strong as when i plug directly into the amp.
With the pedal on it boosts the signal pretty high, but there is no sustain or bite.
Any Ideas would be great
thanks

what exactly did you change? Anything other than c2 & c3?

Thanks,
Brian

[Melanhead]

probably a little late, but this will help with identifying the components, just to make sure you replaced the right caps ... It's page 2 of the service manual.

http://users.eastlink.ca/~melanhead/PIX/SD1PG2.jpg

[alanhoggard]

thanks, i am now going to try to put it back to stock. Does it matter which kind of diodes i use for d4,d5 & d6?
Thanks a ton for that page!!

[petemoore]

thanks, i am now going to try to put it back to stock. Does it matter which kind of diodes i use for d4,d5 & d6?
  Can't tell from the link what you should use, the 'other' one may be a power protection diode, on your board it'd probly be large, [square from top view], and blackish.
  The clipping diodes will change the clipping sound and output level...see 'simple mods and tricks' IIRC in FAQ.
  I liked assymetric clip in the SD, one Si > way and two Si's << way for the opamp feedback loop clipping, but these are a good place to start messing with SD OD tones, as is the value of the clipping diode HF rolloff cap [connected where the diodes connect, output and -input of OA].  Might get messy to do alot of mod swaps with a boss board, I used sockets/DIY...I dunno, maybe clip the old diodes out [this is enough to lift a trace though, dremel cut if you have it] and use testclip wires till you find the combo you want there, then desolder the diode leads and install the chosen values.
  Just be aware that a board trace can get messed up...
Thanks a ton for that page!!

[Melanhead]

thanks, i am now going to try to put it back to stock. Does it matter which kind of diodes i use for d4,d5 & d6?
Thanks a ton for that page!!

No prob ... Different type of diodes will give different results ... the stock ones are 1N916's ... If you wanna experiment use sockets instead of soldering 'em in

[8mileshigh]

When I did my SD-1 mod, which was my first attempt at using a soldering iron on a pedal, I installed one component at a time then rushed up to test before I moved on. I'm the type of guy who feels intense anxiety when playing around with store bought pedals, especially when they end up not working    If you put it back to stock, try this method and ensure you're using the right values.  Did you buy a kit ?   

What I love about the SD-1 is the germanium diode swap, WOW ! What great tone !

I hope you get it right cuz the stock SD-1 was pretty bland to my ears.
8

[alanhoggard]

Thanks for all the help, I bought a book of pedal mods, What germanium diodes did you switch to?
I did check after each component, but all i did was flip on the amp and flick the strings to check the pedal both on and off.
It wasn't until i was done that i picked up the guitar to play and noticed the the level eas weak and the od was weak:(
So now i have no idea what did it. I have most of it switched back and it still is weak. I think i ruined it, afew of the copper pads have come off the board.
Too bad it was my 80's made in japan model, oh well live and learn i guess. I think i will try replacing everything and see what happens.

[petemoore]

  What germanium diodes did you switch to?
  They all work the same.
  For further selection, DMM diode checker will tell the exact' threshold for each --->unit, for clipping though, those who've matched and mismatched the diodes of type [ge, si, etc.] don't notice Mismatched to matched combinations ... sound differences. Mostly it's what type and how many.
  They are included in the matched components I test 'n choose for octaves...don't recall wherelse that might matter.

[MartyMart]

Bummer !
Boss copper pads do lift quite easily, you have to have a good iron/tip and
get on/off as quick as poss ... I never spend more than 3/4 seconds on a pad
like that !! ( from experience of lifting a few !!! )
and when returning back to it, leave a good 30 seconds for it to cool off

MM.