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Can I clean old disintegrated foam from 3.5 mm connectors in cal kits?

Question asked by drkirkby on Feb 17, 2013
Calibration kits supplied by HP and even Agilent today, both use a foam to protect the compontents in the wooden boxes Certinaly the stuff used in the old HP kits disintegrates, and becomes like glue given enough time. Having just bought new foam from Agilent, it looks the same and will probably suffer the same in years to come. 

Some of you may have seen the pictures I posted of a 85050B 7 mm cal kit with the foam broken up. Luckily the components did not appear to suffer any damage except a low-band APC-7 load, which I happen to have a spare of. 

I've also got a 85052B 3.5 mm 26.5 GHz cal kit. Some idiot did not have the sence to put the caps on the RF connectors, so needless to say the black foam has found its way into the 3.5 mm connectors. 

Does anyone know of a way of removing that foam, without dstroying the RF components - lowband loads, opens, shorts and sliding loads? 

A couple of people has suggested an ultasonic cleaner, though the best chemical to use is not obvious. Current Agilent manuals say to use Isopropyl alcohol, whereas an old manual on an 85050A says to use trichlorotrifluoroethane. 

I don't know if trichlorotrifluoroethane acutally does a better job, but Isopropyl alcohol is considered less harmful to the environment. To be honest, given the amount i'd use and the fact I don't ever intend doing this again, I don't think the use of CFCs will be a major environmental disaster. 

Any tips on what may work, and would be dangerous to the connectors would be welcome. 

I'd obviously take the step of trying this on the cheapest component (3.5 adapters) before doing it on the most expensive (sliding loads). 

I've tried  Isopropyl alcohol, *without* an ultrasonic cleaner, and found that had zero effect. 

I should be getting good at cleaning up old cal kits. I've succeeded with N and APC-7, but 3.5 connectors are an order of magnitude more tricky, and the cal kit is in a worst state than others I've done. 

If someone suggests something, and it happens to destroy the connectors, I'm not going to come after you.