Sourcing Capacitors for my H7140 PSU
robert.jarratt at ntlworld.com
Sat Jul 24 16:17:22 CDT 2021
Well I don't know as I have asked a company to do the work. They seem to think the PSU will work with the originals but perhaps that they are not performing very well? I suppose I should ask them to keep the originals. I did wonder about reforming them.
> -----Original Message-----
> From: cctalk <cctalk-bounces at classiccmp.org> On Behalf Of Jay Jaeger via
> Sent: 24 July 2021 13:52
> To: cctalk at classiccmp.org
> Subject: Re: Sourcing Capacitors for my H7140 PSU
> On 7/23/2021 11:48 AM, Rob Jarratt via cctalk wrote:
> > I gave up trying to repair this PSU myself and I have got someone to
> > do it professionally. It seems they have it working well but think
> > that two capacitors should still be replaced. I think these are the
> > two big "Coke Can" sized filter capacitors. The trouble is they seem
> > to be unable to find any. The spec for them is 4500uf 200v DxH 76mm x
> 145mm Qty. 2.
> Some particular reason you want to replace them? Perhaps instead measure
> their ESR and if that measures OK, maybe just reform them (I do realize that
> at 200v the reforming would be harder than for most.)
> I had a capacitor fail in my H7140 many years go, but it was not one of the
> larger caps. I generally turn on my 11/24 every few months to do something
> or other, so it tends to stay pretty happy.
> My experience, aside from the bad capacitors from 1999-2003 swelling up
> and failing, and maybe two tantalums total (one recent one in a 3270 PC that
> decided to short and release its "magic smoke") I haven't had very many
> electrolytics fail - fewer than five - that actually needed replacing - one of
> which was a smaller cap in my H7140.
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