dead motherboard

[novicedad]

recently returned from local computer repair guys who told me problem was due to power rails blown. Solution buy one of their second hand systems to replace my old second hand system. I can get my hands on another motherboard from ALMOST identical system so would like to know what will need to be done to swap boards.System is a Dell Optiplex 745 and replacement motherboard is from a Dell Optiplex 755. The two are physically identical but there are subtle differences in the boards.Both are Foxconn LS-36 old board is E4400 Core 2 Duo SLA 98 Malay 2.00ghz/2M/800/06 replacement is Core 2 Duo 6300 SL9TA Malay 1.86ghz/2M/1066/06. Operating system is Windows 7 Pro with 40gb hard drive and 2gb RAM. No extras just the basic system. Can this be done without too much trouble I am a newcomer to this and need to be " lead by the hand " thru the process

[jazz836062]

A couple things: 1. My first instinct to the word "Power Rails" is the Power supply, not the mobo (Quick google search backed that up) 2. Replacing the power supply is really easy, replacing the mobo is less easy but still doable.

This probably needs to be moved to the Hardware forum instead of the windows 7 forum. They would be more able to help you.

[Jintan]

I agree with jazz - I have seen that term many times, but also thought it referred to the cpu, which surely is much less expensive that a motherboard replacement.

Web searching shows that as a small form factor pc, so have to ask if there is any activity at all when you press the power button. Those are a kinda hybrid pc/laptop system, and too often they have capacitor problems, that cause the onboard graphics to fail.



(Image linked from thenakedpc.com)

Those small form pc's can have just one slightly swollen cap, and things go wrong. It has been my experience that it is not the power supply that is the problem.

For those two boards you mention, they use different cpu's, though the same Socket 775, so there is a possibility what you suggest might work. Maybe one of the other pros here can chime in on that.

[novicedad]

I have just started my computer and was confronted with a couple of errors on the screen. Yes to my surprise the screen actually appeared ! Starting to really doubt the integrity of my local computer repair guy! Anyway error was something about battery level low and previous fan failure. I did notice that when I came home with my computer the other day the CMOS battery had been removed and the rams were out. Happened to have a batt in the drawer so put it in and replaced the rams this morning and it started .Am now in safe mode and not sure what I should do next. Any advice on how to proceed from here would be appreciated

[Murf]

If the CMOS battery is taken out, then the system re-sets itself to defaults. You need to get into BIOS SETUP and check the date and time as they are probably off. See if you have a way to set to Optimize defaults, each BIOS is different so the wording could be different.

So the computer genius took out the CMOS battery and never replaced it? Took out the memory? Did they give you back the memory? If that is the case then they would go on the top of my crap list.

Since the computer does now boot and you can get into Safe Mode then one could assume the power supply is good.

[novicedad]

Just want to say thanks to all for your help. Since reading tutorials and others problems my computer knowledge has expanded ten fold. My computer seems to be working fine now. I went into the bios and yes the date and time were wrong so I reset these and my computer was searching for a floppy drive on start up that doesnt exist so I fixed that too. I guess it reset to defaults. Now on start up I get no bios beeps at all and computer boots up fine. Went back to see local computer guys and he was rather embarrassed and could only suggest I might check power settings in bios to see if any fluctuations. Other than that he didnt have much to say. Dont think I will go back ! just log on and check with you guys in future. Cheers for the help and will send a subscription

[Murf]

Computer guru in my opinion, was a scam to get you to buy parts you probably didn't need. Glad its running OK.