[Premium-Rx] Tantalums again

[antonio]

Thanks Dan and all for the advices, I might have underestimated the work, so I could decide what to do in the course of work. I think I've isolated the problem on boards A9A1 or A9A2, and I would like to replace all the Tantalums at least on them to prevent future failures on these cards which are the most hard to access. I thought to use 35V caps everywere.
My method for removing components, including ICs, is to use the iron at one side of the board, and a spring-operated sucker pump (I don't know how you would call it) on the other side. This cleans the hole quite well. Then I detach the leads by a delicate budging.
I got this 1792 not working. I fixed the processor board, replaced the 1st L.O. transistor (sourced from a donor 1723 exciter), replaced the dispays sourced here in Italy, and it worked until some months back. 
I could also source caps from this 1723, but I don't think it is a good idea.
Antonio I8IOV



________________________________
 From: Dan Rae <danrae at verizon.net>
To: 
Cc: premium-rx at mailman.qth.net 
Sent: Thursday, May 24, 2012 7:47 PM
Subject: Re: [Premium-Rx] Tantalums again
 
On 5/24/2012 10:29 AM, Dave Schofield wrote:
> Further to Dan's comments on the strange leads.
I've only seen that on the UK ones, not ever on anything from the US.
>
> In my early days as a TV engineer, my boss told me "never trust a blue 
> tant"...
> Pretty good advice to, they always seem much more prone to fail. Or 
> maybe I've just been unlucky :-)
>
>
I suspect the manufacturing processes were changed at some point Dave.  
I have had plenty of the old tan coloured ones fail, not just the blues, 
but never any newer ones.  I had a theory the bad ones were made by 
Thomson who ended up buying Thales who had bought Racal :^)


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