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Electronics => Metrology => Topic started by: jfphp on October 21, 2021, 11:04:20 am

Title: Fluke 5700 strange stains
Post by: jfphp on October 21, 2021, 11:04:20 am

Hello,
After opening a 5700 I have found these strange stains / traces on the main CPU board and on the digital power supply board. Why these round black inserts at the beginning (cleaning with isoprop alcool) ? Any idea ? Thank you

Title: Re: Fluke 5700 strange stains
Post by: Kleinstein on October 21, 2021, 11:27:21 am

It looks like something really deteriated, maybe some kind of rubber feet to test the digital board laying flat.  If this is only the CPU part, it should not be so sensitive to leakage. IPA would be OK to try cleaning the residue. It may not help very much though. Just some mechanical cleaning may be enough.

Title: Re: Fluke 5700 strange stains
Post by: McBryce on October 21, 2021, 11:28:41 am

The holes are probably for some sort of card removal tool.

McBryce.

Title: Re: Fluke 5700 strange stains
Post by: TiN on October 21, 2021, 03:12:29 pm

Remains of PPMs crying out loud..  :-DMM

But seriously, those are silicon pads that due to age deteriorated. Typical for old 57** units.
Just clean it off with alcohol and stick new pads.