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| Thread ID: 46715 | 2004-07-03 03:58:00 | Rackmount Switch Power Supply | Growly (6) | Press F1 |
| Post ID | Timestamp | Content | User | ||
| 249382 | 2004-07-04 08:56:00 | Hey billy, Yes there is a 240V to 5V transformer on there, and it does indeed feed a bridge rectifier (three terminal - father just finished explaining). I'm not sure how to check the AC voltages for stability (hehehe, tried and got shocked. ouch) but I do know that the output voltages are very unstable. The needle on the multimeter was having a fit. We suspect that this is the reason the switch is constantly resetting .... Thanks very much man |
Growly (6) | ||
| 249383 | 2004-07-04 09:44:00 | If you got a shock, you were on the 230 volt side, you wouldn't feel the transformer output unless you had sensitive skin and wet hands. best you take extra care while doing your checks. The bridge rectifier should have four terminals, 2 for ac in, one each for + & - out unless the transformer has three wires on the output to allow the use of a two diode full wave rectifier. That would be unusual because a centre-tapped transformer is more expensive to make. If you see three terminals that should be the regulator device. It may be the regulator that is at fault, but I would look at any large value capacitors connected on the output and perhaps parallel them with a similar value to see if the output stabilises. At the moment my bet is hedged at 50/50 regulator/capacitor. Cheers Billy 8-{) |
Billy T (70) | ||
| 249384 | 2004-07-04 09:47:00 | that's why I said it might be firmware related - the main board itself could be sending some kind of weird feedback to the PSU which is causing the whole thing to loop itself into a spastic fit Of course the way to determine this is to open the working switch, swap the PSU sections and see what happens I'll take a look tomorrow and see if I can get a picture of the PSU in the third switch billy |
whetu (237) | ||
| 249385 | 2004-07-04 10:04:00 | You guys rule. Hmmmm - I will swap power supplies now. |
Growly (6) | ||
| 249386 | 2004-07-04 10:27:00 | It is done. Well that proves it, the working PSU showed no problems - except the fan was broken - but that comes later. |
Growly (6) | ||
| 249387 | 2004-07-04 10:32:00 | ARGH. Time to tediously make my own circuit diagram... | Growly (6) | ||
| 249388 | 2004-07-04 11:22:00 | They work fine without the fan... however I wouldnt do that for your upcoming lan when the switch will be fairly busy. Be interesting to see how toasty it gets though... I considered modding my third one but even a slim 80mm fan is a touch big... considering a 60mm at the moment... Replacement fans can be had for 20 odd bucks from trickie dickies or jaycar *mutters about highway robbery* hmmm just remembered I get nice discounts at DSE :D |
whetu (237) | ||
| 249389 | 2004-07-04 12:18:00 | really???? elaborate.... ;) Well i dont plan on using this broken one - so far we only have like 15 poeple coming anyway @_@ Im considering ripping apart an old PC power supply right abouts now... |
Growly (6) | ||
| 249390 | 2004-07-04 12:44:00 | I know some people..... Anyway, try running the 5v rail for the switch off the 5v rail of a standard PSU... see what that does... It'd be a bit ghetto, but if it works you could make a tidy little workaround with about 5 minutes of soldering, heatshrinking and the drilling of one hole |
whetu (237) | ||
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