From: Ian Stirling
Subject: Re: cheap IR camera?
Date: Wed, 25 Sep 2002 16:58:20 +0000 (UTC)
NNTP-Posting-Date: Wed, 25 Sep 2002 16:58:20 +0000 (UTC)
User-Agent: tin/1.5.6-20000803 ("Dust") (UNIX) (Linux/2.4.18 (i686))
Mike Harrison wrote:
> On Thu, 19 Sep 2002 16:39:33 +0000 (UTC), Ian Stirling
>>In sci.electronics.design Ian Stirling wrote:
>>> In sci.electronics.design George Gonzalez wrote:
>>>> Lately I've been resuscitating a pallet-load of Tek 465 and 475 scopes.
>>>> Most of the rest have shorted tantalum capacitors from one of the power
>>>> supplies (-8, -15, +5, +15) to ground. These are a bit difficult to find,
>>>> as there are many caps sprinkled around the boards. The method I'm using
>>>> now is to push a few amps into the shorted power bus with an external power
>>>> supply, then feel around for warm or hot capacitors.
>>> As others have said, IR cameras are expensive.
>>> If you have a shorted decoupling capacitor, then if you poke around looking
>>> at all the cap negatives, then the one you want will have the highest
>>> positive voltage.
> ..but infrared thermometers are a LOT cheaper - you can get some with
> laser sights, but I don't know if they are useful at such close
> You might be able to get one of these and hack the optics for your
> purpose - for this type of application, perhaps you could add an
> acoustic output for rapid location of hotspots by scanning around..?
>>Alternatively, if you stick it in the freezer, generate frost on it, then
>>do the test, that could also indicate warm bits.
> ..and get moisture all over the board... Maybe use CO2, which
> evaporates from solif to gas - a quick blast with a CO2 fire
> extinguisher could be an easy way to reveal hotspots!
Moisture isn't really bad, as long as you evaporate it afterwards.
Probably not a good idea on second thoughts, for other reasons.
http://inquisitor.i.am/ | mailto:firstname.lastname@example.org | Ian Stirling.
Acting is merely the art of stopping a large number of people from coughing
- Sir Ralph Richardson