I presume "much prone to leakage" should read "much less prone to leakage"?
Bob
Sent from my StarLink satcom terminal
On Sat, 30 Nov 2024 at 20:01, frank carcia
<carcia@...> wrote:
Guys,
I just did up a Cubic R3080 last winter changing out all the power bus caps that has the same disease.
New tantalum caps are just as bad as the old ones so I decided to replace all the 10uF power bus caps with 1uF /100V
Kemet ceramic caps I bought from Mouser. Good price break when you buy a bag of 100. The power bus bypass cap value is not critical. Everything worked fine when I am done. I think it was over 60 caps but the ceramic caps will out last me.?
While working our company decided to stop using tantalum caps. It wasn't worth the time we were spending on failure reports and unhappy customers. Frank WA1GFZ
On Saturday, November 30, 2024 at 11:10:33 AM EST, Dan Rae via groups.io <danrae@...> wrote:
Peter, I will make one well intentioned criticism of your advice,
which was to use a NiCad battery, leakage from which has destroyed
a lot of A6A2 cards.? Use instead a NiMH replacement which are
much prone to leakage.? One used to be able to get a Varda
"Mempac" German made battery that was a direct drop in replacement
for the original.? If that can't be got any more a little daughter
card can be made to fit whatever is available.? I have used many
of these Vardas over the years with excellent results.? Looking at
my remaining stock recently showed they still have charge!
I agree with the use of LEDs for edge lighting using the original
boards, but a more even result can be got with four series
connected strings of seven sideways firing LEDs with one series
100 Ohm R in each string.? Three wire links are needed, with slots
cut in the existing traces for the LEDs, see attached pic.
Assuming there has been battery leakage in the past with the
original poster's CPU, the A6A2 board would have to be cleaned and
examined very closely,? The leakage is alkaline and can be
neutralised with some dilute vinegar followed by washing with
isopropyl alcohol.? That nasty stuff gets everywhere with a
fondness for destroying VIAs, creeping up transistor and IC leads
and dissolving the copper inside the plastic body, getting into
the 34 way connector next to the battery.? Any signs of dull grey
solder or traces of blue near anything copper are bad news.
A6A2 boards can be fixed if not too badly damaged, also
new replacement boards are available.
73 - Dan
ac6ao / g3ncr
