<PBALG@CUNYVM.BITNET> (06/10/91)
My friend has an ibm at compatible 286 Fountain. He has no power. I noticed in my pc that all seems to be within the power supply. Are there typically circuit breakers or fuses inside? Are there servicable relays? Any advice? If all else fails, any recommendations for replacement power supplies?
oneel@heawk1.gsfc.nasa.gov ( Bruce Oneel ) (06/10/91)
In article <91160.170739PBALG@CUNYVM.BITNET> PBALG@CUNYVM.BITNET writes:
My friend has an ibm at compatible 286 Fountain. He has no power.
I noticed in my pc that all seems to be within the power supply.
Are there typically circuit breakers or fuses inside? Are there servicable
relays? Any advice?
If all else fails, any recommendations for replacement power supplies?
The local compu-usa store sells power supplies for $40-$60.
Switching power supplies are not to be played with. They are not
joking when they tell you not to touch them on the warning labels.
They don't have transformers to isolate you from the 120V mains so a
mistake could fry you and/or your computer. $40 is cheeeeep given the
options.
bruce
p.s. I assume that since you are asking this type of question you've
never worked on these before. If you have, my apoligies. And yes,
there probably is a fuse. Even so, it blew for a reason and for $40
the PS probably should be replaced.
--
Bruce O'Neel oneel@heasfs.gsfc.nasa.gov
NASA/GSFC/STX/Code 664edhall@rand.org (Ed Hall) (06/11/91)
In article <ONEEL.91Jun10091204@heawk1.gsfc.nasa.gov> oneel@heawk1.gsfc.nasa.gov ( Bruce Oneel ) writes: >Switching power supplies are not to be played with. They are not >joking when they tell you not to touch them on the warning labels. >They don't have transformers to isolate you from the 120V mains so a >mistake could fry you and/or your computer. $40 is cheeeeep given the >options. Once having had a significant fraction of a 25MHz '386 system fried by a failed power supply, I strongly second the advice. Even if you manage to repair the supply, it may not be so kind the next time it fails (i.e. one strike and it's out)! Also, saving money in replacement power supplies might be false economy. -Ed Hall edhall@rand.org
edhall@rand.org (Ed Hall) (06/11/91)
In article <ONEEL.91Jun10091204@heawk1.gsfc.nasa.gov> oneel@heawk1.gsfc.nasa.gov ( Bruce Oneel ) writes: >Switching power supplies are not to be played with. They are not >joking when they tell you not to touch them on the warning labels. >They don't have transformers to isolate you from the 120V mains so a >mistake could fry you and/or your computer. $40 is cheeeeep given the >options. Once having had a significant fraction of a 25MHz '386 system fried by a failed power supply, I strongly second the advice. Even if you manage to repair the supply, it may not be so kind the next time it fails (i.e. one strike and it's out)! Also, saving money in buying replacement power supplies might be false economy. These are high-power devices which typically drive their components near their design limits. $40 might be too cheeeep... -Ed Hall edhall@rand.org
mlord@bwdls58.bnr.ca (Mark Lord) (06/14/91)
<>Switching power supplies are not to be played with. They are not <>joking when they tell you not to touch them on the warning labels. <>They don't have transformers to isolate you from the 120V mains so a <>mistake could fry you and/or your computer. $40 is cheeeeep given the <>options. < <Once having had a significant fraction of a 25MHz '386 system fried <by a failed power supply, I strongly second the advice. Even if you <manage to repair the supply, it may not be so kind the next time it <fails (i.e. one strike and it's out)! Just to keep the discussion more balanced, it might be useful to know that at least somebody (me) has successfully repaired switching power supplies and *not* had any further problems with them. Twice, in fact (different supplies). -Mark -- In support of a sustainable planet, I prefer to repair&reuse rather than simply "throw away" broken items. But what does one do with an ancient Apple-II clone that still works, anyway?
edhall@rand.org (Ed Hall) (06/15/91)
In article <7079@bwdls58.bnr.ca> mlord@bwdls58.bnr.ca (Mark Lord) writes: [I originally wrote:] ><Once having had a significant fraction of a 25MHz '386 system fried ><by a failed power supply, I strongly second the advice. Even if you ><manage to repair the supply, it may not be so kind the next time it ><fails (i.e. one strike and it's out)! > >Just to keep the discussion more balanced, it might be useful to know that >at least somebody (me) has successfully repaired switching power supplies >and *not* had any further problems with them. Twice, in fact (different >supplies). Hey, so have I. In fact, the supply which turned my system into a toaster had previously blown the -12V rectifier. A couple of diodes and a new filter cap (who knows what sort of surge the old one received when the original diodes went...) and everything worked just fine. That is, until some months later... BTW, I checked my replacement diodes after the second failure (which were on a relatively uncharred part of the circuit board) and they were still good. Just a single data point, mind you, but I like to think that the first failure was a warning... -Ed Hall edhall@rand.org
teexpjs@ioe.lon.ac.uk (PHILIP SMITH) (06/18/91)
In <1991Jun14.182515.24877@rand.org> edhall@rand.org (Ed Hall) writes: >>Just to keep the discussion more balanced, it might be useful to know that >>at least somebody (me) has successfully repaired switching power supplies ... >Hey, so have I. In fact, the supply which turned my system into a >toaster had previously blown the -12V rectifier. A couple of diodes ... I put in two new diodes in a friend's switch-mode power supply and as far as I know it is still working. Saved him 150 pounds. Sometimes you can be lucky! P.J.Smith, MSSL, UK