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HunterCupp

macrumors regular
Original poster
Feb 13, 2014
140
8
Circleville, OH
Bringing This Thread Back

Hello, all.

I'm pretty sure that my Apple ]['s PSU has a problem. MacTech68 mentioned popped filter caps. I still have the problem that makes nothing show on the screen, or indicate power (startup beep). The only thing that I get when I turn it on is a click/loud pop from the PSU that happens 4/10 times of powering it on. Something else that kind of gave me a laugh was that after a few attempts of turning it on, it had a constant clicking in the PSU that after about 5 seconds caused my power to go out and made me have to go flip my breaker switch. I never thought about it being a power supply problem, I believed that I fried some chips. I also managed to break half of the chips that I attempted to take out about 6 months ago. I don't know much about diagnosing PSU problems, but I'm going to open it up and post a few pictures. Maybe someone will be able to help. If it is a problem with the PSU, and I repair it, will the Apple ][ still power on even without a few critical ROM chips that I will be replacing sooner or later? Just so i would be able to know if it was a PSU problem?

Thanks,
-Hunter
 

havokalien

macrumors 6502a
Apr 27, 2006
649
51
Kelso, Wa
broken chips

Without the chips it won't boot.

It may power on but nothing most likely will happen. It doesn't have any way to tell itself to access anything or do anything without chips.
 

tdiaz

macrumors 6502
Feb 7, 2006
477
72
Depending on what's missing it may do nothing at power up, or could show random characters.

I wouldn't be ruling anything out until you have a complete motherboard or know the power supply is working.

Now, if the thing was in front of me, I could probably say with certainty that the PSU is, or is not, working, in that condition.

If the keyboard light comes on, it's a pretty good indicator that it is working. If you have a volt meter.. sometimes as little as $2.00 from Harbor Freight, with battery! ;)

The black wires are ground. Stick the black probe in that one, and the others will be as indicated on the front of the PSU, +5/-5 +12/-12 ..

The PSU needs to plugged into a load to get accurate readings from it.
 

HunterCupp

macrumors regular
Original poster
Feb 13, 2014
140
8
Circleville, OH
Depending on what's missing it may do nothing at power up, or could show random characters.

I wouldn't be ruling anything out until you have a complete motherboard or know the power supply is working.

tdiaz

I took a look at it earlier today. It appears to only be missing the two far right ROM chips.

Looking back into this thread, they've always been missing, even before this issue.

When I turn it on, it does nothing at all. No characters on the monitor, no startup beep, no keyboard light, nothing. Nothing except for the click/pop that the PSU sometimes makes when turned on.

If you would like more insight on how this problem came to be, I would suggest looking at the earlier bits of this thread.

Thanks,
-Hunter
 

MacTech68

macrumors 68020
Mar 16, 2008
2,363
199
Australia, Perth
Hmmm. I'm wondering if the mains switch has failed. Seen a few of those.

I thought in an earlier post you said the keyboard light WAS illuminating. I guess that has changed? :confused:
 

HunterCupp

macrumors regular
Original poster
Feb 13, 2014
140
8
Circleville, OH
Hmmm. I'm wondering if the mains switch has failed. Seen a few of those.

I thought in an earlier post you said the keyboard light WAS illuminating. I guess that has changed? :confused:

MacTech68

I see where I said that. I'm not sure, I'll check it out as soon as I can. From when I've tested it recently, I don't think it has illuminated. I may have posted that in error, still not sure though.

Thanks,
-Hunter
 

havokalien

macrumors 6502a
Apr 27, 2006
649
51
Kelso, Wa
capacitors

on the underside of the keyboard depending on which keyboard revision is a board with capacitors that fail. may want to take a look there also.
 

HunterCupp

macrumors regular
Original poster
Feb 13, 2014
140
8
Circleville, OH
on the underside of the keyboard depending on which keyboard revision is a board with capacitors that fail. may want to take a look there also.

havokalien

Although I have moved to a different issue (Nothing happening when I attempt to turn the Apple ][ on), I am still willing to fix the keyboard, thanks for your input. Do you think I would be able to plug it into my Apple //e to see if it is functional?

Thanks,
-Hunter
 

HunterCupp

macrumors regular
Original poster
Feb 13, 2014
140
8
Circleville, OH
Hello, all.

I have turned my Apple ][ on, and the power light does NOT illuminate. I'm assuming that shows that the power is not reaching the keyboard? So, it may be a PSU issue?

Thanks,
-Hunter
 

MacTech68

macrumors 68020
Mar 16, 2008
2,363
199
Australia, Perth
Hello, all.

I have turned my Apple ][ on, and the power light does NOT illuminate. I'm assuming that shows that the power is not reaching the keyboard? So, it may be a PSU issue?

Thanks,
-Hunter

If the keyboard is plugged into the motherboard (correctly) then yes, PSU is suspect.
 

MacTech68

macrumors 68020
Mar 16, 2008
2,363
199
Australia, Perth
if you have a multimeter, check one of the ICs for 5 volts.

Check Pin 7 and pin 14 of a 14pin IC (NOT RAM). That is, opposite corners. Pin 7 will be ground, Pin 14 will be +5 volts. If you don't know which pin is pin 7, just check the other two diagonal pins.

If you get nothing, it's time to open the PSU. If it's NEVER been apart before, it MAY be riveted together. The bottom plate is secured by 3 or 4 screws (or rivets) along each side.

Pics (once you get it open) MIGHT alert us to the problem.
 

greycon

macrumors newbie
May 19, 2015
1
0
Did you solve it?

Hi, did you ever get your Apple II working? If not, what's the current status?
 

HunterCupp

macrumors regular
Original poster
Feb 13, 2014
140
8
Circleville, OH
Hi, did you ever get your Apple II working? If not, what's the current status?

greycon,

I never did get the Apple II working. It's still just sitting on a desk where it has been since the issue started, getting a bit dusty.

I didn't have the time to look into the issue further and basically gave up. I would love to get it working though.

Thanks,
-Hunter
 

HunterCupp

macrumors regular
Original poster
Feb 13, 2014
140
8
Circleville, OH
Not from this distance :eek:

;)

Do you have any other means of communication? Skype, for example. I could set up a one-way (assuming you wouldn't want to be shown) video conference so you could instruct me in real time on what you would advise to have done. (Multi meter testing, checking individual components for visible damage, etc)
 
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