Help! I think my SE/SE30 power supply is dead!

[phreakout]

I went to turn it on a few minutes ago and got no sign of life. No display, no startup tone, no click noise, no fan. I will provide voltage readings in a short while, when I get back from work.

Does anyone have a spare working PSU you are willing to part with? The original is a SONY model CR-44 or Apple part number 699-5047. I'll buy it if you do. Also, if it's the analog board, the original part is Apple part number 820-0206-B or 630-0147. It matches up with a raster board (Circuit board attached to the neck of the CRT) Apple part number 820-0207-A or 630-0169.

Any thoughts? I'd like to keep this soldier alive and fighting.

Thank you.

73s de Phreakout. :rambo:

 

[JDW]

You need to check voltages on your PSU before doing anything else. In the past, I posted detailed PSU voltages that you should have a look at.

Check the voltages at the floppy connector on the back of the SE/30, as shown in this photo. My photo is showing the point to test the 5v line. If you are seeing something less than 4.85v, you may want to tweak the voltage adjustment POT inside the SE/30's PSU (which means you have to open the PSU to do it). Even if your 12v line rises to 12.5v or falls to 11.9v, it's nothing to worry about. And in my experience, the 5v line is good to go from 4.75v to about 5.15v.

 

[phreakout]

Okay. I've checked the AC power cord and I'm getting power from the wall. About 120.2VAC. So I will rule that part out.

I've went ahead and pulled the power supply unit and the analog board from the SE/SE30. I put my voltmeter (DMM) on P3 connector. Pin 1 is black (+5Vdc) according to the diagram/label. Black probe is on Pin 1 and Red probe is on Pin 4, which is orange (-12Vdc). Output voltage from this is 5.34Vdc. Red probe is moved to Pin 5 (yellow); voltage is +13.89Vdc. Pin 2 (black) and Pin 3 (black) are for carrying +12V for the disk(s) and sweep. They show about 13.84 Vdc when the red probe is on yellow Pin 5 and black is on Pin 2 and Pin 3. Obviously, these are the peak voltages without other loads connected.

Power supply is a SONY model CR-44 (Apple part number: 699-5047. This is an original power supply for an SE, but I've used it no problem with an SE/30 logic board.

I'm going to assume that the power supply at this point is working fine and I should be focused on the analog board. No burnt smell on PSU or indication inside and out of fried electronics.

Any thoughts?

73s de Phreakout. :rambo:

 

[JDW]

If you hadn't mentioned that your fan wasn't spinning, I would have suggested you swap out the logic board. But if the fan isn't spinning and now that you have confirmed all is well with the PSU, clearly your analog board is suspect.

Page 149 of Larry Pina's excellent The Dead Mac Scrolls talks about an SE/30 with no startup bong, black display, completed dead (no fan or other noise). But it suggests the problem in this case is likely the Sony PSU. Then on page 50 it talks about a case where the fan and hard drive spin but everything else dead, in which case it suggests replacing R22 (470k-ohm 1/2W 5%) on the analog board. Those are the only two cases in the entire book that closely resemble your description, unfortunately.

If you had another known-good SE/30 you could swap out things one by one to ultimate determine the root problem. But it would appear that you lack such parts. But if you are in the US, then it wouldn't cost much to purchase something like off EBAY. For me in Japan, now that USPS no long does ocean/surface mail, such would be impossible. I'm glad I ordered my vintage Mac systems when I did, at a time shipping from the US to Japan was reasonable!

 

[phreakout]

OK, this is real weirdness, JDW.

I just reattached the power supply unit back up to the analog board and unplugged everything from the board except the power supply. I turned it on. Lo and behold, the fan is spinning.

So just picture in your mind the PSU and analog board laying on a workbench outside of the Mac, the video board (P2), hard drive power cable (P5), CRT yoke cable (P1) and logic board cable (P3) are totally disconnected from the analog board. I add AC power and turn the power switch to on. The cooling fan starts spinning and remains spinning until I shut the power off. Obviously, without the remainder items connected, it takes the fan about 3 seconds before it stops spinning, compared to instant off with everything hooked up and running. There's no sign of anything being fried or unusual noises, squeaks, zaps, etc.

I am telling you this now: I haven't done a single thing to the analog board or power supply, as far as soldering and replacement parts. All I've done up to now is check that there is output power from the PSU. I did earlier double check that the fuse inside the power supply was good (and it still is). Also, I did run continuity for the switch inside the PSU, along with the wires going from the AC jack to the switch. All that was found good, too.

I don't know if anyone has encountered this in the past. JDW, I don't have a copy of "The Dead Mac Scrolls", though I really should get one. I'm going to wait for a response before deciding to put it all back together and trying again.

73s de Phreakout. :?: :-/ : :rambo: |)

 

[JDW]

It appears that you took the PSU voltages while the PSU was disconnected from everything else? If so, I strongly suggest you put it all back together and take voltages from the floppy connector on the back, using a paperclip, as one of my previous posts in this thread directs. You can then get a truer picture of whether your PSU is driving the system at 5v and 12v. If you are only getting 4.5v or 10v while the system is all connected (i.e., the PSU is loaded), then you need to adjust the voltage in the upward direction.

If your computer is acting flakey when you connect and disconnect and connect, then it is likely your connectors are suspect. It could be a broken set of solder joints. You have to look closely to tell for sure.

 

[phreakout]

Okay. I've reassembled the SE/30 and did a voltage measurement just as JDW mentioned. I am getting between 5.00V and 5.01V DC through the floppy port. The SE/30 is powered on, startup chime good and booted into System 7.0.1. Of course, I should have checked it earlier on. :

Things seem to be back in order. If this happens again, I'll repost and double-check EVERYTHING.

Thank you all for your responses and recommendations. It seems just disassembling and reassembling all the parts somehow got it back up and running. :-/

73s de Phreakout. :rambo:

 

[JDW]

It seems just disassembling and reassembling all the parts somehow got it back up and running.

Strong evidence of bad solder joins on a connector somewhere.

 

[Mycatisbigfoot]

It could of just been a wire that was lose, but happy the computer is working know

 

[phreakout]

It seems just disassembling and reassembling all the parts somehow got it back up and running.

Strong evidence of bad solder joints on a connector somewhere.

You may be right about that. What I'll do is keep an eye on it. If it happens again, I'll pull it apart and start redoing every solder joint on that machine.

73s de Phreakout. :rambo: