Author Topic: Blown caps on 30 yo old perfectly working equipment - odd  (Read 2169 times)

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Offline T4P

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Blown caps on 30 yo old perfectly working equipment - odd
« on: October 09, 2012, 06:20:31 pm »

- Go figure  :P
30 yo old caps, only slightly bulging  :o On one side only, the other side's electros are safe but i can't be too sure without a ESR measurement, the capacitance has really gone south anyway
 

Offline SeanB

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Re: Blown caps on 30 yo old perfectly working equipment - odd
« Reply #1 on: October 09, 2012, 06:42:48 pm »
Just replace them all and the PSU will be good for another 30 years then.
 

Offline free_electron

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Re: Blown caps on 30 yo old perfectly working equipment - odd
« Reply #2 on: October 09, 2012, 06:46:39 pm »
that transistor at the bottom of the picture under the cables doesn;t look to healthy too.. case is bubbling ... ( or is it a dab of glue they squireted on the nut ? )
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Any comments, or points of view expressed, are my own and not endorsed , induced or compensated by my employer(s).
 

Offline T4P

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Re: Blown caps on 30 yo old perfectly working equipment - odd
« Reply #3 on: October 09, 2012, 07:15:51 pm »
that transistor at the bottom of the picture under the cables doesn;t look to healthy too.. case is bubbling ... ( or is it a dab of glue they squireted on the nut ? )
Glue! They are VERY obnoxious in the 80s for glue everywhere ... The screws get glued, the wires get glued the seven segments get glued the fuse holder gets glued ... Was that the 80s ?  :P
But i think i broke something in the process ... the voltmeters don't show anything anymore
Just replace them all and the PSU will be good for another 30 years then.
Just replaced the ceramic caps ... Couldn't find any 50V 3300uF in ma box, time to grab some of 'em ( the current 2200uF don't seem to excite me )
 

Offline SeanB

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Re: Blown caps on 30 yo old perfectly working equipment - odd
« Reply #4 on: October 09, 2012, 07:26:52 pm »
Green goop, it probably would be cooler if there was a flat aluminium plate there to provide a flat mounting surface under it, along with more than the token smear it has. Your 5V rail would then be actually capable of supplying 1A for more than 20 seconds.
 

Offline IanB

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Re: Blown caps on 30 yo old perfectly working equipment - odd
« Reply #5 on: October 09, 2012, 08:00:38 pm »
The ceramic cap looks very exploded underneath the diode at the bottom of the board. Did it go bang when it failed?
I'm not an EE--what am I doing here?
 

Offline T4P

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Re: Blown caps on 30 yo old perfectly working equipment - odd
« Reply #6 on: October 10, 2012, 08:59:29 am »
No idea but i guess it's seen better days i only this used PSU this year ... the opposite board had it's ceramic cap blow even more violently leaving all sorts of scorched marks
Green goop, it probably would be cooler if there was a flat aluminium plate there to provide a flat mounting surface under it, along with more than the token smear it has. Your 5V rail would then be actually capable of supplying 1A for more than 20 seconds.
It just supplies the 5v rail to the ICL7106 and the display so it only needs the contact with the case and it's fully steel ...
The output 5V rail is on a actual heatsink connected to the case, EEVBlog member digsys's 8203 was worse, the regulator was standing in the air running way over-temp!
« Last Edit: October 10, 2012, 09:02:26 am by T4P »
 


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