Advise for working on DOD circuit Boards?

[bufftonz]

Has anyone ever worked on an old 1980s DOD pedal before? It seems kinda cramped and I was wondering what is the best approach to avoid accidentally overheating up other components (i.e. chips) while trying to remove and replace other components?

1)For example there is one resistor I'm trying to take out, but the one end of the resistor is linked "by-etching" to a lead of a nearby IC chip, and there's no room to put any regular-sized heat-clamp to the lead of the chip to prevent from letting the heat flow and overheat the chip. Is there a smaller, thinner metal object that one has used to safely keep heat away from IC chips (esp. in crowded areas)?

2) And what do we do if there is a capacitor that we want to protect from heat, but there is very little space between the capacitor and the PC board itself to use a heat clamp or even tweezers? Could one clamp the lead-end on the opposite side of PC board, but will heat dissipation be the same in this case?

If anyone has ever worked on an old analog 1980s DOD compact pedal before (i.e. FX90 etc.), please feel free to lend any advise, tips, or precautions. All is welcomed, thank you.


--Chris

[petemoore]

Has anyone ever worked on an old 1980s DOD pedal before? It seems kinda cramped and I was wondering what is the best approach to avoid accidentally overheating up other components (i.e. chips) while trying to remove and replace other components?
  Yes, they' have.
  1)For example there is one resistor I'm trying to take out, but the one end of the resistor is linked "by-etching" to a lead of a nearby IC chip, and there's no room to put any regular-sized heat-clamp to the lead of the chip to prevent from letting the heat flow and overheat the chip. Is there a smaller, thinner metal object that one has used to safely keep heat away from IC chips (esp. in crowded areas)?
  I've used resistor leads and alligator clips, anything that conducts/touches and has at least some thermal mass...Perhaps the resistance you desire is lower than the installed component, ITTCase, consider reducing the value with a parallel resistance installed to the bit of lead length at the ends of the resistor above the board.
2) And what do we do if there is a capacitor that we want to protect from heat, but there is very little space between the capacitor and the PC board itself to use a heat clamp or even tweezers? Could one clamp the lead-end on the opposite side of PC board, but will heat dissipation be the same in this case?
  Take it 1/4 easy on the heat and the cap will be fine, I've baked caps pretty good with soldering them for too long and never actually had a failure from it.
  If anyone has ever worked on an old analog 1980s DOD compact pedal before (i.e. FX90 etc.), please feel free to lend any advise, tips, or precautions. All is welcomed, thank you.
  Not sure what you'd like to do with it, the chip is most sensative to temperatures, then diodes.

[bufftonz]

Hey Pete,

In case you were curious to my operation, I am in the midst of modding my DOD FX90 delay for tone/damper control --- so that it can be more versatile in the tone-colour of its echo repeats, yet that I can still have that white-noise-like analogue-ish style. I really love the quality of the FX90, unfortunately I do not have money in the moment to save for an expensive boutique analog delay pedal or even a tape echo (even a used vintage one), so I'll have to apply my DIY skills for now to get the best out of what I got for now.  :-)

[bufftonz]

I also forgot to mention that one of my main concerns was trying to avoid accidental heat flow to the leads of the IC chip, but I assumed that you were suggesting that I could use resistor leads and alligator clips to clip on to the IC chip leads? I tried the alligator clip, but no go, space is too cramped for even small alligator clip; additionally I read some forum that chips can take quite a bit of heat punishement before failing, but then I hear the opposite from you...I just wanted to be sure what the "real" story was.

Could one possibly use a bit of copper desoldering braid and tie to the IC chip leads and have at least two or three braids lead in between tied on to the lead for protection?

[Paul Perry (Frostwave)]

If I'm trying to take out a resistor, I cut one end of it first.
It's a hell of a lot easier to remove the remains of the resistor and the leg separately.
For the sake of trying to salvage a resistor, you run the risk of damaging something.
Now I know plenty of people who are agile enough & practised enough to successfully desolder anything anywhere - but that's not me.