On 30/11/02 11:59 am, "(PCI PowerMacs)" <[EMAIL PROTECTED]> wrote:
> From: [EMAIL PROTECTED] > Message-ID: <[EMAIL PROTECTED]> > Date: Sat, 30 Nov 2002 03:41:06 EST > Subject: Re: Power Supply Issue > > > In a message dated 11/30/02 12:37:32 AM, [EMAIL PROTECTED] > writes: > > << > Most PSU's of the 800/840 type I see are usually OK if they start the Mac, > with the exception of when their internal main reservoir capacitors lose > value. They then start the Mac, and as drives spin up can't supply the > current and switch off. >>> > > Fortunately, there are only one dual cap or two single caps, and these are in > the primary (converter) section. > > Sadly, they're usually 105 degree C rated, and most replacements are only 85 > degree C rated. > > The caps in the secondary (inverter) side are special low ESR type, and these > seldom fail. You are correct. The capacitors I've had problems with are in the inverter primary circuitry. I would never use 85deg C caps in a PSU. Here in the UK I buy 105 deg C types from RS Components and Farnel. In these power supplies the capacitors on the output rails never fail. Not so on power supplies used in non Apple equipment where they are common failures. Other common problems we see here you wouldn't get is the PSU auto switching to 115V on our 230V mains, taking out the MOV's across each primary reservoir capacitor and blowing the fuse. Steve Bell -- PCI-PowerMacs is sponsored by <http://lowendmac.com/> and... Small Dog Electronics http://www.smalldog.com | Refurbished Drives | -- Sonnet & PowerLogix Upgrades - start at $169 | & CDRWs on Sale! | Support Low End Mac <http://lowendmac.com/lists/support.html> PCI-PowerMacs list info: <http://lowendmac.com/lists/pci-powermacs.shtml> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive:<http://www.mail-archive.com/pci-powermacs%40mail.maclaunch.com/> Using a Mac? Free email & more at Applelinks! http://www.applelinks.com
