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Jumpstarting Mac II Causes Only Quick LED Flicker

reodraca

Active member
I'm attempting to test a Macintosh II that I'm about to begin working on. When I use my half double A battery to attempt a jumpstart by touching the end white wire pin and the case metal, all I get is a quick fan spin, a flicker, and the speaker making the usual popping sound when power is applied.

That tells me that the power supply is working, but something is preventing it to fully start up. The board is a Rev. A, which means it has no leaky caps, and it looks like it's in great shape.

Could it be that I'm not touching the jumpstart wires for long enough? Or could it be an unforeseen problem with the board? I was under the impression that it would still boot up but do the 4 note death chime if it had a hardware issue.

Thanks in advance for any assistance.
 

Juror22

Well-known member
Your 'half double A battery' is actually one of the 3.6V batteries, correct? And you are using pos. to white wire and neg. to case, also? I'm guessing that you already covered the basics, but just checking.

And yes, you may need to 'linger' for a moment to get it to catch. One of the boards that I tested last weekend seemed to take longer than the other to jump (just touching for an instant did not work if I recall). I'm going to spend some more time this weekend looking at mine again, as well, so I will check to see which board seemed to hesitate like this. I suspect mine may be the older board as well, although I was dealing with two different power supplies and I suppose that it could be related to that.
 

reodraca

Active member
Your 'half double A battery' is actually one of the 3.6V batteries, correct? And you are using pos. to white wire and neg. to case, also? I'm guessing that you already covered the basics, but just checking.

And yes, you may need to 'linger' for a moment to get it to catch. One of the boards that I tested last weekend seemed to take longer than the other to jump (just touching for an instant did not work if I recall). I'm going to spend some more time this weekend looking at mine again, as well, so I will check to see which board seemed to hesitate like this. I suspect mine may be the older board as well, although I was dealing with two different power supplies and I suppose that it could be related to that.
Yes. It's a PRAM battery I pulled from another working Mac, and I'm touching the positive to the white wire terminal and the negative to the case metal. I'll try to prolong contact once I get back home, and I'll also see if cleaning the contacts of the very dirty, very ancient Mac II power supply connector and board helps.

My power supply is the one made by Sony, which I believe is the original one, and the Astec ones are second source.

I look forward to any updates you give that may help me. Thank you for responding.
 

reodraca

Active member
Your 'half double A battery' is actually one of the 3.6V batteries, correct? And you are using pos. to white wire and neg. to case, also? I'm guessing that you already covered the basics, but just checking.

And yes, you may need to 'linger' for a moment to get it to catch. One of the boards that I tested last weekend seemed to take longer than the other to jump (just touching for an instant did not work if I recall). I'm going to spend some more time this weekend looking at mine again, as well, so I will check to see which board seemed to hesitate like this. I suspect mine may be the older board as well, although I was dealing with two different power supplies and I suppose that it could be related to that.
I strengthened the wires and held them to the pin and case for longer. It fired up but, sadly, I got a death chime. Now I just need to get a monitor to plug into it.
 

Juror22

Well-known member
Oh, and you should try reseating all the RAM . I had a board that was unhappy and it booted after I removed all the RAM, cleaned the contacts and replugged it back in.
 

reodraca

Active member
Oh, and you should try reseating all the RAM . I had a board that was unhappy and it booted after I removed all the RAM, cleaned the contacts and replugged it back in.
Unfortunately, now it won't even jumpstart. It shut off after playing the death chime again and now no matter how long I jump it, it remains silent.
 
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