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1. 06:25 AM - Re: KLX-135A Comm Radio Issue (Christopher Cee Stone)
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| Subject: | Re: KLX-135A Comm Radio Issue |
I've had a similar experience with failing electrolytic aluminum can caps.
Interesting in that all the failures have been in aluminum radial leaded
caps. Never have had a failure of axial leaded. Also the failures were in
power circuits and the voltage rating was near the working voltage.
Nominal circuit voltage of 14 volts used a 25 volt part.
Thanks for your post, another good data point.
Chris
RV-8 x 2, Long EZ
On Mon, Apr 22, 2024 at 10:32=AFPM Gary VanRemortel <garyvanremortel@
gmail.com>
wrote:
> Just a report from the field regarding aging avionics devices with
> electrolytic capacitors.
>
> Like many of you early builders, I installed the Bendix king KLX-135A
> panel mount GPS/Comm when I built my RV-6A S/N 22665 in the mid to late
> '90s. Electrolytic capacitors have a finite life of somewhere between 20
> and 30yrs regardless of hours of operation. Over the years the unit had
> performed well, having just the need for a replacement Tadiran battery on
> the Digital Board, new LCD and replacement of the optical sensors on freq
> selector.
>
> Yesterday the unit died on the taxiway, accompanied by the pungent toaste
d
> fish smell of a fried electrolytic capacitor. I bought the entire
> operation and maintenance binder for the unit many years ago off Ebay, so
> have all the service info, parts lists, assembly drawings and schematics.
> Upon disassy C1 (47uF 50V) on the Power Supply Assy had exploded, leavin
g
> a fried hole nearly all the way thru the PCB and dielectric everywhere.
It
> had clearly shorted. C1 is the power filter on the DC input power line s
o
> it charges up every time power is cycled ON. I repaired the PCB with epo
xy
> and reinstalled a better capacitor with higher voltage rating. The
> shorting of C1 on the Power Supply PCB took out the axial leaded fuse F1
on
> the comm/receiver PCB and these are readily available from Amazon for abo
ut
> $1 apiece (Littelfuse 251007
> https://www.amazon.com/dp/B00LQSF6NQ?psc=1&ref=ppx_yo2ov_dt_b_product
_details
> )
>
> It may be wise to inspect your unit if yours is as old as mine is. Blue
> skies.
>
> -GV
>
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