wrote:
On Thu, 22 Jan 2026 10:41:41 -0800, Jeff Liebermann <jeffl@cruzio.com>
wrote:
>On Thu, 22 Jan 2026 12:36:39 +0000, Cursitor Doom <cd@notformail.com>>
wrote:
>>If you want to go hunting for noisy components, spray the suspect with>
freeze spray. If the noise disappears, you've found the culprit or at
least localized the cause.
<https://www.google.com/search?q=electronic%20freeze%20spray&udm=2>
Yeah, I've had some good results with that stuff in the past. However,
I've only used it when a fault develops after the equipment's been
switched on for a while. I then spray it to see if it 'cures' the
problem. Not sure how much use it would be in this case where the
fault is present right from switch on. :-/
Freeze spray works well with semiconductors and not so well with
capacitors and resistors. The big problem is condensation. If you
spray a PCB (printed circuit board) with freeze spray, moisture will
condense on the PCB. For any PBC or components that are not water
tolerant, it will cause the circuitry to fail until you dry off the
PCB. You can do that with a hot air gun or oven to accelerate
evaporation.
>
Pre-heating the PCB before testing with freeze spray, is a bad idea.
Most common components are not rated for thermal shock. Cracking
components, such as MLCC caps, are possible. If you've heated the PCB
to accelerate evaporation, I would let the PCB temperature drop to
room temperature before repeating the freeze spray test.
I think I'd just wait for ambient temp to do its work, tbh.
Using a heat gun or hot air blower is not that difficult. I use one
of several Type K thermocouple wire probes:
<https://www.google.com/search?udm=2&q=thermocouple%20wire%20probe>
to make sure I'm not overheating the PDB or components. I also have
several IR thermometers:
<https://www.google.com/search?q=ir%20thermometer&num=10&udm=2>
but find them awkward to use on dense PCB's. If you don't want to buy
yet another gadget, use your fingers. If the PCB is too hot to hold,
then the hot air gun is running too hot.
You're not looking for a "cure" for the distortion problem. You're>
looking for something that causes the distortion to CHANGE. It
doesn't matter if the distortion becomes better or worse. If the
component is sensitive to changes in temperature, it's a likely
culprit worthy of replacement.
Good point! Thanks, Jeffrey. You're right of course (as ever).
Y're welcome. I'm basically lazy. I like to reduce the list of
potential culprits to a reasonable number of components and then
replace everything. That's why I like recap kits (replacement
capacitor kits) which are sometimes found on eBay. It takes me less
time to replace all the caps than to figure out which one is causing
problems.
Hint: Make a shield. Punch a hole in a sheet of cardboard or>
plastic. Place the hole over the likely culprit and spray it. The
idea is to only apply freeze spray to one component at a time.
I'd go for the mask idea in the endgame as it were, but I'd just have
a spray around various small areas containing several components
first, otherwise the process would take too long. I like to zoom
in.....
:)
If speed of repair is your goal, then throw money at the problem and
replace everything.
"Good, fast, cheap. Pick any two".
--
Jeff Liebermann jeffl@cruzio.com
PO Box 272 http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272 AE6KS 831-336-2558
| Date | Sujet | # | Auteur | |
| 20 Jan 26 |  Re-Capping | 17 | Cursitor Doom | |
| 20 Jan 26 |  Re: Re-Capping | 4 | Jeff Liebermann | |
| 21 Jan 26 |   Re: Re-Capping | 3 | Cursitor Doom | |
| 25 Jan 26 |  Re: Re-Capping | 2 | John Robertson | |
| 25 Jan 26 |  Re: Re-Capping | 1 | Cursitor Doom | |
| 20 Jan 26 | Re: Re-Capping | 9 | Liz Tuddenham | |
| 21 Jan 26 | Re: Re-Capping | 8 | Cursitor Doom | |
| 21 Jan 26 | Re: Re-Capping | 7 | Liz Tuddenham | |
| 21 Jan 26 | Re: Re-Capping | 6 | Cursitor Doom | |
| 22 Jan 26 | Re: Re-Capping | 5 | Jeff Liebermann | |
| 22 Jan 26 | Re: Re-Capping | 4 | Cursitor Doom | |
| 22 Jan 26 | Re: Re-Capping | 3 | Jeff Liebermann | |
| 22 Jan 26 | Re: Re-Capping | 2 | Cursitor Doom | |
| 23 Jan 26 | Re: Re-Capping | 1 | Jeff Liebermann | |
| 21 Jan 26 | Re: Re-Capping | 3 | Phil Hobbs | |
| 21 Jan 26 | Re: Re-Capping | 2 | Cursitor Doom | |
| 21 Jan 26 | Re: Re-Capping | 1 | Phil Hobbs |
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