intel mds 225 sick main board?

[1ajs]

got a mds 225 here that does weird things when the main board is pluged in

but when its removed it works

trying to figure out where to start on figuring out whats wrong with it?

i get a high pitch noise and the button 7 led stays on the front panel the board has

 

[1ajs]

not sure where to start looking on figuring out whats wrong with this board??

 

[Chuck(G)]

Does the MDS troubleshooting manual shed any light?

 

[twolazy]

Well if it was me, first thing I would do is tear her down and give the machine a good dusting/cleaning and reseating of all chips. Check all solder joints for signs of corrosion/rat dung/ etc. If it all looks clean, then I would proceed to check all tantalum caps. If all test good, then I would check all electrolytic caps that were 1500uf /25v and under for leakage. If all seem to be ok, then next step be to test any mosfets and switches. Last phase be checking any tranistors before finally checking the ic's. Chances the high pitch noise is most likely a cap or bad switch imho, mostly likely in part of the noise filtering circuitry for the power supply. Trace the power lines back to where they junction to your main ground, near the voltage regulators. Chances are the caps near that location are bad...

 

[1ajs]

ok well goten it mostly torn down but one of the screws striped on me agg whats one do about that?

 

[Chuck(G)]

If the screw is stuck and stripped, carefully drill it out with a smaller bit and re-tap the hole.

 

[bluethunder]

If there is some of the screw head left, automotive valve lappping compund works wonders for getting half stripped screws out. Dip the end of the driver in the gritty paste.

If the screw isn't countersunk, sometimes you can put a slot in the screw head with a dremel, and use a driver (with lapping compound) to twist it out.

Otherwise, like Chuck said, about your only option is to drill it out. You might have some luck with just drilling the head off the screw, removing the panel, and the using visegrips on the exposed remnants of the screw to twist it out.

 

[1ajs]

found a work around leaving the screw in and getting everything els outa the case

checked all the pin outs on the cable that runs from the backplane to the back baord apears to be good

psu looks good to me from what i can tell going over it with the meter


i had reset all the chips on the cpu board witch no change before i tore it down.