Caple C871i Bedienungsanleitung PDF herunterladen (Seite 395)

Apple II Computer Info

6. Open the case. Unplug and re-plug the Power Supply cable to the

motherboard. Turn ON power. If the machine seems to respond, try cleaning

the power supply plug and socket.

7. Pull all cards from Slots and turn ON power. If the machine 'comes

alive' one or more of your cards may have a short or may have been

cross-socketed. Clean the contacts on each card (e.g. with alcohol). With

power OFF, replug a card (be sure to line-up card and Slot contacts) and

turn ON power. Do this for each card. If a card causes the machine to

fail, it is, probably messed up. If no card produces a failure the

original problem was, likely, a card which was not properly inserted.

If the above tries get you nowhere, remove the power supply from the

'dead' machine and swap in one removed from a good machine. (Removing

power supplies is pretty easy.) If the 'dead' machine now works you will

know that the original power supply is, probably, bad.

IIe power supplies can be repaired. The bother involved varies

considerably with the cause of malfunction. For example, it is fairly

easy to identify a bad switch-- it will, usually, not snap cleanly into

position, feel crunchy, and/or have a burn spot. The repair is to replace

the switch with some AC power switch that will fit. Or, you can

permanently connect the switched lines and add an in-line switch to the

power cord.

Open the "bad" power supply. Look toward the end where the power

cord is connected. Somewhere close to the place where wires from the

switch go to the circuit board there should be a small disk-shaped

component which is not a disk capacitor. Probably, it will be black with

no markings. This is a "globar" resistor. Check it to be sure that it is

not cracked and that both leads are really connected to the disk. If it

is broken, you will need to get a replacement from an electronics supply

shop. (Tell the shop person where the globar resister comes from and

describe its size.)

Look for a fuse mounted to the circuit board. If there is one, check

it. An Ohm meter can be used to check for continuity if it is not obvious

that the fuse is blown. If the fuse is blown, replace it. Continue as

outlined in #2 above.

If the power supply has a slotted adjustment, mark its current

position and, then, turn it back and forth. Set the adjustment a bit to

one side of the original setting and plug in the power supply. If it now

seems to work the problem is/was a 'dirty' voltage adjustment control.

It's a good idea to spritz the adjustment with circuit cleaner. Check the

voltage on the +5V line with a meter and adjust it to 5 Volts. (Note:

_no_ output due to a dirty adjustment control seems unlikely. Incorrect

output is more probable; and, this could cause a IIe to not work.)

Beyond the above, you are, most likely, looking at a bombed

electrolytic capacitor or a blown main power transistor (the big silvery

thing). Unless you enjoy electronic repair work, your best course is,

probably, to get a replacement power supply.

Naturally, no ][ hardware hacker would just dump a defective

power supply unless he/she were already neck-deep in junk parts. Whether

or not a bad power supply may have some value for replacement parts

to a school depends upon who may be available to do repairs.

Apple II Computer Technical Information : Apple II Family Hardware Info

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