Re[3]: HV transformers

-----Original Message-----
From: John Robertson <jrr@flippers.com>
To: vectorlist@synthcom.com
Date: Sun, 17 Sep 2000 16:02:39 -0700
Subject: Re[2]: VECTOR: HV transformers

> At 01:38 PM 9/17/00, peter jones wrote:
>
> >...
> >
> >also be VERY suspicious of MYLAR capacitors.
> >DU-PONT dont like people saying this - but mylar can-never be made without
> >defects. they where ok for there time, but i replace them with polyester now.
>
> Does this mean I need to break out my 70's leisure suit to fix monitors
> now? I think it is polyester.
>
> Perhaps you meant polypropylene?
>
> John :-#)#
>

ha-ha good one!
if i get out my 70's polyester stuff it would be my pram-cover!!!

anyway getting serious.
I repair a lot of switching power-supplys for satellite receivers.
this has shown-up the problem with mylar caps.

and no. - i dont mean polyprop' caps, i mean multi-layer metalised polyester-film.

(the little 3x8mm plastic boxes usually yellow) :)

mylar caps dont like hi-current pulses. the cavitys in the aluminium vapour-layer cause heating between the layers and the cap expands and goes dark-green to brown in colour, sometimes cracking the resin in the proccess.

MYLAR - DONT TRUST THEM!!!!!!!!!!

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Received on Tue Sep 19 04:40:47 2000