cold solder joint prob

[nosamiam]

HELP!!!! My band uses an analog synthesizer (Realistic/Moog Concertmate MG-1, if you're curious).  We're using it the day after tomorrow for a live radio date, so urgent help is needed and would REALLY be appreciated.

This thing has a slider pot that controls 'keyboard glide' a.k.a. portamento.  It has been really acting up lately so I cracked it open to have a look.  After poking around at the bottom of the main PCB I noticed that the joint on one end of the slider pot looked cold.  Eureka!! I thought I had it.  I fired up the soldering iron (while the rest of the band took a fiver) and reflowed the joint.  To my dismay, when the joint cooled, it still looked dull.  I don't get it.  All the rest of the joints, or at least the ones I looked at, were fine.

I pulled the pot and tried flowing some solder onto the terminal.  Looks good.  But the glob that is on the PCB around the hole stays dull no matter how often I reheat it.

It's really late now, so I'm not going to mess with it any more tonight.  But I'm gonna check it out tomorrow.  In the meantime, does anyone know what causes this?  If all else fails, I guess I can jumper the pot to the next component in line.

Help??

[petemoore]

I pulled the pot and tried flowing some solder onto the terminal.
 Have you tested wiper to both sides while slowly ranging the pot CW/CCW?
 I guess I can jumper the pot to the next component in line
 Sounds like 'pad trubble', when that happens I ^ do just that.

[Fp-www.Tonepad.com]

You can try removing de solder that's already there (with desoldering wick or other means) And then resolder with fresh rosin core solder.

That should do it.

Fp

[Paul Marossy]

You can try removing de solder that's already there (with desoldering wick or other means) And then resolder with fresh rosin core solder.

That should do it.

Fp

In my experience, this is the best approach. Be careful not to overheat the PCB, though.  :wink:

[nosamiam]

Ok I'm gonna go at it.  I'm sure between desolder/resolder (an obvious choice), and replacing the connection with a jumper, I should have no problems.  Hopefully that is actually the solution to the problem that prompted me to take it apart in the first place.

Thanks for the tips!