Good idea to drain them first, I will do that. Having never encountered snap-ins before I don't know, but from the way you describe removal I suspect they are snap-in, as the leads are quite tightly against the sides of the holes and won't move even if I have heated them up. I hope that cutting the tops off will eventually expose the individual pins so they will be more easily removed.
Regards Rob From: dwight [mailto:dkel...@hotmail.com] Sent: 29 August 2017 22:25 To: r...@jarratt.me.uk; Rob Jarratt <robert.jarr...@ntlworld.com>; General Discussion: On-Topic and Off-Topic Posts <cctalk@classiccmp.org> Subject: Re: PSU Input Rectifier Question They would have electrolyte in them. It is mildly corrosive as it is mostly a borate solution. You can drill a couple holes in the tops of the case and drain them. Since you say you've unsoldered the bases, are they wire or snap in. If snap in, you must get the lead clear of any solder touching the edge of the hole before you can think of any prying. Dwight _____ From: cctalk <cctalk-boun...@classiccmp.org <mailto:cctalk-boun...@classiccmp.org> > on behalf of Rob Jarratt via cctalk <cctalk@classiccmp.org <mailto:cctalk@classiccmp.org> > Sent: Tuesday, August 29, 2017 1:01:14 PM To: 'Maciej W. Rozycki'; 'General Discussion: On-Topic and Off-Topic Posts' Subject: RE: PSU Input Rectifier Question > -----Original Message----- > From: Maciej W. Rozycki [mailto:ma...@linux-mips.org] > Sent: 29 August 2017 01:06 > To: r...@jarratt.me.uk <mailto:r...@jarratt.me.uk> ; Rob Jarratt <robert.jarr...@ntlworld.com <mailto:robert.jarr...@ntlworld.com> >; General > Discussion: On-Topic and Off-Topic Posts <cctalk@classiccmp.org <mailto:cctalk@classiccmp.org> > > Cc: 'Tapley, Mark' <mtap...@swri.edu <mailto:mtap...@swri.edu> > > Subject: RE: PSU Input Rectifier Question > > On Tue, 29 Aug 2017, Rob Jarratt via cctalk wrote: > > > Not really no. The base of the capacitors is actually touching the > > board, so I can't get under it to cut anything anyway, which is why I > > am thinking I would have to cut the tops off them. Even if I could cut > > one of the leads, I can't solder a capacitor underneath as that is > > where the board is mounted into the enclosure, there is only room for > > the mounting standoffs on the underside. > > If you need to replace the caps anyway, then I think just cutting through the > outer PET sleeve should do as chances are it's only the sleeve that's got glued > and not the leads or the closing cap. Then you might be able to just pull the > inner aluminium can containing the capacitor itself from the sleeve and with > the component proper out of the way get rid of any remains from the PCB. > Thanks Maciej, I would just like to make doubly sure, before cutting into the outer body of the caps, am I likely to hit any gotchas? Just how wet are they inside, do I need to take any precautions with the electrolyte? > NB the originals are just snap-in capacitors AFAIK, e.g. Chemi-Con KMH series > (I can't figure that out from your photos and luckily none of my H7878s has > failed so far, so I haven't made this a part list for this PSU for myself), still > manufactured, so modern replacements should do. With the PCB hole > diameter supposed to be 2mm by the manufacturer's spec I wouldn't be > bothered with a small lead pitch variation, you can always bend the leads > slightly as there's some space between the closing cap and the rim that rests > against the PCB. > I did wonder if there would be enough tolerance. I have never encountered these snap-in ones before, I don't know what they are like. Sounds like I can try some snap-ins, which widens the choice immeasurably. > Also I would't be bothered about the LED holder getting damaged; it's a > standard piece, available online. I can dig out the part numbers, separate for > individual pieces of the holder (you can match different kinds against each > other, depending on your needs), if that would help; I ordered a bunch a while > ago for my own use. > I found some LED holders/clips which do seem to fit the bill, although I am not sure I see how you get the old LED out, unless you have to break the thing. Regards Rob
