EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: mianchen on November 13, 2013, 11:26:45 pm
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I got hold of a Gossen MetraHit 23s that was advertised as "working order", only to find it not working at all except DC mA, A stop watch and pulse gen.
Here are some pictures of its guts.
(https://www.eevblog.com/forum/testgear/gossen-metrahit-23s-rescued-from-leaked-battery-death/?action=dlattach;attach=67017;image)
(https://www.eevblog.com/forum/testgear/gossen-metrahit-23s-rescued-from-leaked-battery-death/?action=dlattach;attach=67019;image)
(https://www.eevblog.com/forum/testgear/gossen-metrahit-23s-rescued-from-leaked-battery-death/?action=dlattach;attach=67021;image)
(https://www.eevblog.com/forum/testgear/gossen-metrahit-23s-rescued-from-leaked-battery-death/?action=dlattach;attach=67023;image)
(https://www.eevblog.com/forum/testgear/gossen-metrahit-23s-rescued-from-leaked-battery-death/?action=dlattach;attach=67025;image)
(https://www.eevblog.com/forum/testgear/gossen-metrahit-23s-rescued-from-leaked-battery-death/?action=dlattach;attach=67027;image)
(https://www.eevblog.com/forum/testgear/gossen-metrahit-23s-rescued-from-leaked-battery-death/?action=dlattach;attach=67029;image)
Other functions didn't work at all, here's what happened when measuring 10V DC
(https://www.eevblog.com/forum/testgear/gossen-metrahit-23s-rescued-from-leaked-battery-death/?action=dlattach;attach=67031;image)
I took the whole thing apart, washed and scrapped off the horrible stuff, here is part of the repair board
(https://www.eevblog.com/forum/testgear/gossen-metrahit-23s-rescued-from-leaked-battery-death/?action=dlattach;attach=67033;image)
Took me more than 4 hours from washing, drying to repair...and the hard work paid off:
Measuring 2.5V DC
(https://www.eevblog.com/forum/testgear/gossen-metrahit-23s-rescued-from-leaked-battery-death/?action=dlattach;attach=67035;image)
10V DC
(https://www.eevblog.com/forum/testgear/gossen-metrahit-23s-rescued-from-leaked-battery-death/?action=dlattach;attach=67037;image)
240V mains AC
(https://www.eevblog.com/forum/testgear/gossen-metrahit-23s-rescued-from-leaked-battery-death/?action=dlattach;attach=67039;image)
DC Amp
(https://www.eevblog.com/forum/testgear/gossen-metrahit-23s-rescued-from-leaked-battery-death/?action=dlattach;attach=67041;image)
I am happy :) :-DMM :-DMM :-DMM
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Use an old toothbrush and isopropyl alcohol to clean it up and get rid of all that crud. Lets us know if it improves.
Will
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Nice :-DMM rescue. :-+
What all did you have to do besides clean the leaked acid off of everything?
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Good job, maybe change your 10 V pic :).
Leaked battery gunk always gives me a scare when first discovered in a prized bit of gear.
Found a HP25 calc. in the bin yesterday, just took it apart and yes its toast >:( damn nicads.
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Nice :-DMM rescue. :-+
What all did you have to do besides clean the leaked acid off of everything?
I had to repair many traces that're eaten up by the leakage. The PCB is a 4 layer board, I had to use strong light from the opposite side to figure out the connections. It was painful especially when some of the vias were gone. I repaired 13 traces in total.
I also desoldered some of the big components (eg. pic 3) to be able to reach and clean off the &£^$£ hidden underneath.
I was lucky, as soon as I finished, powered it on - everything was back to normal. I was worried that I might have missed something or connected something wrong - but I didn't :-DMM
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Good job, maybe change your 10 V pic :).
done
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It was painful especially when some of the vias were gone. I repaired 13 traces in total.
Great repair job. The strong light is a good repair tip.