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HP-85A Dead
12-08-2014, 02:30 PM
Post: #3
RE: HP-85A Dead
hi Cruff. well I made a simple test, first I remove the i/o chip and measure the voltage and only a little change in -5volts. when I remove the CPU I observe the same behavior in -5 volt so I suspect the twos are bad!
also I don't have an idea how much those chips come warm so also today a make a test at -5Volts, and this consists in remove the chips and charge it with dummy loads to see if the PSU have a problem.
The most estrange is this machine running ok, but for a day to another not working anymore.

i not have the data sheet of those chips to see the normal heat generated, but the mine are really hot.

i can find a couple of online stores with these chips "refurbished" each near 50 bucks
so after the make a test of the psu testing i order the couples.

thanks for the repply!
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Messages In This Thread
HP-85A Dead - juanjo_r - 12-07-2014, 04:15 AM
RE: HP-85A Dead - cruff - 12-07-2014, 10:10 PM
RE: HP-85A Dead - juanjo_r - 12-08-2014 02:30 PM

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