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| Thread ID: 46288 | 2004-06-19 05:36:00 | Power Supply | Mac D (1315) | Press F1 |
| Post ID | Timestamp | Content | User | ||
| 245972 | 2004-06-19 05:36:00 | Correct Power Supply voltage. Recently I had a reoccurring fault were by the pc would shut down and reboot for no reason. I had a look at the power supply and found some varying voltages so changed the supply from a spare ATX I had and the problem went away. Could some please tell what the correct voltage should be and what devices are used by the various voltages? Below I’ve listed my current voltages from a 250w ATX unit and the pc is working OK. CPU Temp---------- 71deg C Sys Temp------------ 52 deg C +3.3v---------------- 3.312v +5v------------------ 4.757v +12v---------------- 12.480v 5 VSB-------------- 5.832 |
Mac D (1315) | ||
| 245973 | 2004-06-19 06:54:00 | Firstly, how did you measure these voltages? If you used a multimeter, what was the quality like (quality=price=accuracy) If you used the BIOS or a computer program to report them, sorry to say thats only a very approximate indication. The actual voltages could be a long way off the reported values. |
godfather (25) | ||
| 245974 | 2004-06-19 07:07:00 | Hi Godfather I've used the BIOS to look at these voltages. Since replacing the power supply the voltages are a lot more steady than before when the machine kept crashing and rebooting. I do have a FLUKE and will compare these. Thanks. |
Mac D (1315) | ||
| 245975 | 2004-06-19 07:12:00 | From what I recall you want the voltages to be within 5-10% of what they should be, but I have seen systems work fine with worse. The numbers you have posted don't look too bad to me (assuming the sensors are calibrated correctly). What sort of readings were you getting with the old PSU? Also, those temperatures are very high. I wonder if the improved stability is coming from a better fan in the new PSU reducing the case temp (which reduces the temp of the CPU, and the temp inside the PSU) rather than the voltage output. |
bmason (508) | ||
| 245976 | 2004-06-19 07:43:00 | bmason Voltage reading from the old PSU as below. CPU--------- 59 - 60 deg C Sys Temp-- 37 - 43 Deg C +3.3v--------3.296v - 3.312v +5v---------- 4.945v - 4.784v +12v---------12.16 - 12.480v 5 VSB---------5.053 - 5.510 Also the CPU Fan changed 4687 RPM -5273 RPM New PSU voltages very stable but still a slight fan speed change. |
Mac D (1315) | ||
| 245977 | 2004-06-19 08:05:00 | Hello MacD , I'm not very experienced , but that CPU temp seems quite high to me - is it an Athlon / P4 etc ? - from what I understand temps like that could cause eratic behaviour , just a thought ....Mike W | KatiMike (242) | ||
| 245978 | 2004-06-19 08:21:00 | Voltages measured with a Fluke meter would be accurate. Good quality. Likewise to the above, thats a very high temperature. Look at improving case airflow, thats likely the cause. |
godfather (25) | ||
| 245979 | 2004-06-19 10:24:00 | That's not high for an AMD Processor - mine runs at 65 just great... Are you using p4 or duron or another processor? I understand that those are way too high for pentiums.... |
Growly (6) | ||
| 245980 | 2004-06-19 10:49:00 | >+5v---------- 4.945v - 4.784v >+12v---------12.16 - 12.480v >CPU Fan changed 4687 RPM -5273 RPM load on the 5 volt goes up which causes drop in 5 volt rail (proberly due to a too small psu) which causes 12 volt rail to go up which causes the fans to spin a bit faster. what sort of cpu are you running? and vid card etc? |
tweak'e (174) | ||
| 245981 | 2004-06-19 10:51:00 | Thanks people, just taken some time out to see the AB's do it again. I'm running a AMD Athlon XP 1800 + and will have a closer look at the heat sink and fan. |
Mac D (1315) | ||
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