Looking for someone to repair my rev 0 II

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Looking for someone to repair my rev 0 II

My rev 0 has died and the repair appears to be beyond my capabilities. I can't clearly identify what has failed, other than that it is not a socketed component. I'm a hack with a soldering iron and I don't want to risk screwing up such a nice machine.

So, if you have the skills and would be interested in taking on some repair work, please PM me.

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Re: Looking for someone to repair my rev 0 II

Post what your symptoms are. Maybe someone here can help shortcut the troubleshooting and help you repair it on your own.

Cheers,
Corey

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Re: Looking for someone to repair my rev 0 II

Powers up, but no boot, no beep, no video. I went through the troubleshooting steps in the original Apple service notes, but lacking an oscilloscope, there are some things I can't check.

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Re: Looking for someone to repair my rev 0 II

Sounds bad - I think it's past it. Give you $100 for it though as it might be useful for spare parts Wink

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Re: Looking for someone to repair my rev 0 II

Now hold on...

The doctors have not called a time of death yet.

Powers up, but no beep and no video?
Does the POWER Light come on?
All the ROMs are in place?
Is all the RAM in place?
On the right side of the D0 Rom should be a 74LS138 chip. Is it there?
All the ROMs run through it.
A little troubleshooting is in order.

Steven Smile

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Re: Looking for someone to repair my rev 0 II

I was of course joking - I'd troubleshoot a rev 0 till the cows come home (or until it's fixed)!

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Re: Looking for someone to repair my rev 0 II

Yeah, I have gone through every socketed component with known good spares. Power light comes on, tried a set of ROMs from a working II+, swapped in RAM from the same machine. I removed all socketed chips, tried a spare, cleaned and replaced.

I am pretty sure the fix is going to require skills that surpass mine, but I am more than willing to take suggestions. I'm even game for obtaining better test gear and learning how to use it, as there is certainly no rush, but my electronics skills are pretty thin.

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Re: Looking for someone to repair my rev 0 II

So power light yes...

Did you pull all the cards, keyboard, and all banks of ram except the first one?

Did you try a different power supply? Just incase the it has a problem?

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Re: Looking for someone to repair my rev 0 II

I have not pulled the keyboard or filled only the first bank of RAM. I'll give those a shot.

No cards installed and I did try a known good power supply.

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Re: Looking for someone to repair my rev 0 II

BillW, where are you in the world? Our club (MARCH -- Mid-Atlantic Retro Computing Hobbyists) is having a vintage computer repair workshop on May 18-19 at our museum in central New Jersey. Corey and plenty of other Apple II experts will be there.

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Re: Looking for someone to repair my rev 0 II

On the Olympic Peninsula in WA - about as far away as I can be in the continental US. Wink

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Re: Looking for someone to repair my rev 0 II

Hello billw,
i just went through your explenations of symptoms....
if you gave the "basic configuration" ( meaning only first row of RAM - most towards the keyboard -
no cards in - just keyboard and monitor plugged ) all chips checked ( or swapped ) ...
then there is only very few left to troubleshoot....
in such case i would guess very much that the trouble is located very close in the CPU area:
CPU itself or the clocking pulses themselve ( area A1 )....
so probably the crystal of the clocking circuitary (EDIT: It´s the device in the metal case with marking of: 14,318 ), or one of the 2 transistors or one of the ceramiccapacitors might be damaged.
Another known issue is that the 74S86 ( location B2 ) might be to slow... that might be solved by replacing it with a 74F86.
But i do agree that the task will be difficult without an oscilloscope.....
is there no chance to borough one for a day or a pal who might assist you with one ?
I´d bet that the cause is a CPU not reading the BIOS from the ROM because the CPU won´t step ahead with the cycles
or the clockcircuitary not delivering the cycleclocks....
otherwise you would at least have some kind of chaotic display.....
sincerely speedyG

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Re: Looking for someone to repair my rev 0 II

I had a board with a clock crystal that somehow failed with that exact symptom.

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Re: Looking for someone to repair my rev 0 II

Thanks guys. I'll look into those possibilities. Probably won't have an update until the weekend.

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Re: Looking for someone to repair my rev 0 II

some great recommendations above.

are you seeing any signs of rust on the socket connectors or on the bottom of the board? a little gunk in a socket may pose problems as well.

this may sound silly, but have you confirmed that the bulb/keyboard is still working (perhaps on another known good system)?

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