Bad pots, Come on?

[Leif H]

My 5E3 started acting weird, the volume on the normal channel just stopped working.
I pulled the pot, it was bad. On suggestion from Tony at Teixeira Amps, I swapped the pot's for 250k to make it a little less touchy, now the bright chanel pot is doing the same thing, no volume control.

The original pot's i thought were CTS, they were solid shaft 1Meg, the new ones were from the supply house, so I would expect them to be crap, but what the schnitzel could be causing this?

It's not like I used a 300w gun to solder them, I used my wee iron (35w) and know what I'm doing with a soldering iron after 25 years of using one.

I'm going to hunt down some new pot's, I'm just wondering if anyone else has any ideas as to the cause other than crap components?

[AudioWorks]

maybe they are just very dirty and could use a bit of deoxit spray if you have not tried that yet, since you said you switched it with another control on the amp. Or they both could just be bad and it was about to fail anyways. its pretty hard to not solder a pot in correctly as long as you have good solder skill. Oh and your sure that the pot was bad then? It wasnt a bad trace or broken resistor or component leading to the pot right?

[Leif H]

maybe they are just very dirty and could use a bit of deoxit spray if you have not tried that yet, since you said you switched it with another control on the amp. Or they both could just be bad and it was about to fail anyways. its pretty hard to not solder a pot in correctly as long as you have good solder skill. Oh and your sure that the pot was bad then? It wasnt a bad trace or broken resistor or component leading to the pot right?

The pots are pretty well brand new, from last October, so no not dirty, one was from Weber, the second is from the electronics supply shop in town.

I tested the first pot before replacing it, it read wide open crom the wiper to the lugs on right or left, regardless of where I rotated the shaft.

[jrfrond]

Being an old warhorse, and remembering a day when components were GOOD, I have learned the HARD way to test EVERYTHING before I place in in-circuit. I cannot tell you how many times I have found open/jumpy pots, out of spec resistors and caps, borderline semiconductors, etc. I have armed our shop with a few specialized pieces of gear to do this, but anyone with a DVM or even an old Simpson analog meter (ahh, the 260XL...an old fave!) can do it. Believe me, it is well worth it.

And no, they DON'T make 'em like they used to. CTS might have the name, but they are really no better than Alpha or Bourns. GOOD pots aren't cheap or easy to find unless you know where to look.

DO clean your NEW pots first, unless of course, they are sealed. Many have been sitting in inventory forever, and make sure you use DeOxIt 5 spray. It's the only stuff that REALLY works.

[Leif H]

Being an old warhorse, and remembering a day when components were GOOD, I have learned the HARD way to test EVERYTHING before I place in in-circuit. I cannot tell you how many times I have found open/jumpy pots, out of spec resistors and caps, borderline semiconductors, etc. I have armed our shop with a few specialized pieces of gear to do this, but anyone with a DVM or even an old Simpson analog meter (ahh, the 260XL...an old fave!) can do it. Believe me, it is well worth it.

And no, they DON'T make 'em like they used to. CTS might have the name, but they are really no better than Alpha or Bourns. GOOD pots aren't cheap or easy to find unless you know where to look.

DO clean your NEW pots first, unless of course, they are sealed. Many have been sitting in inventory forever, and make sure you use DeOxIt 5 spray. It's the only stuff that REALLY works.

I'm in love with my 260-8 personally. I couldnt affort the XL at the time, I inherited one when someone retired, but I'm so used to mine, I see no reason to pull the other one out.
I'llgive them a spray and see what happens. Regardless I'm getting new pot's as I don't feel like having the amp go full throttle next time I plug in.

[AudioWorks]

Oh i love my 260-8 simpson great for testing those pots and sliders and tremelo circuits and other slow moving voltages. i love the parallax mirror.

[Jazz P Bass]

Potentiometer lugs

Potentiometers usually have a rivet type arraignment that connects the lugs to the resistive trace.
Rough handling can jar the connection loose.
Usually there is no coming back.
I have received pots that where just thrown in a box, bag, whatever.
Sound packing seems to be a lost art.