SE/30 Power issues

[MacMaster]

I have an SE/30 that seems to not be getting the 12v it needs to the logic board. It is somewhat intermittent in that I can occasionally get it to boot and read 12v out the external floppy connector but most of the time it fails to boot and I just read around 3.6v instead of 12v (as a side note, the floppy drive makes a horrible noise with this voltage). The logic board is recapped and works fine in an SE chassis.

I do read a clean 12v from the Hard Drive molex that comes from the analog board at all times and I get high voltage to the CRT. It appears there is also no issue with 5v from the external floppy connector.

Before I buy caps for the power supply, I am curious if I am looking at a simple recap of the power supply, or could there potentially be some other component failure in the power supply causing this? Or could there be an issue on the analog board?

 

[joshc]

Read all the voltages at the first connector from the power supply to the analog board, what do you get?

If your power supply is an original unit, it may need to be re-capped, yes. A lot of people do an ATX conversion with these instead now, as that means you'll get more longevity as it's giving a new PSU to your SE/30.

 

[MacMaster]

From the wiring harness coming out of the power supply, I get the following as measured from the back of the analog board while in a failure state:

Yellow +12v = 12.25v
Red +12v sweep = 12.10v
Orange +5v = 5.06v
Green -12v: -11.85v

So, while it is the original power supply (Aztec), it seems to me that it is producing the decent voltages. Booting still is intermittent as when I was preparing to test this, it chimed and looked fine several times in a row. Then it started failing again after I unhooked the logic board to add back in the drive carriage that I had previously removed. Sometimes I get a black screen, other times horizontal lines.

 

[retr01]

I agree with @joshc. Swap out with a new PSU. The Sony CR44 PSUs are better than the Astec PSUs for the SE and SE/30, but a new PSU will ensure longevity.

If your SE/30's analog and logic board have not been recapped, now would be the time. @JDW has produced wonderful new PSU and recapping videos for the SE and SE/30 analog board. @Branchus has made a great video about recapping a SE/30 logic board.

If you are unsure about recapping yourself, I recommend @AmigaOfRochester.

Cheers!

 

[MacMaster]

So interesting update on my SE/30. I was doing some more troubleshooting and it seemed that when I moved things around, it changed from working to non-working. I was testing voltages at the bottom of the logic board (at the J12 connector) with the whole machine face down and getting the same bad 3.6v where there should be 12v when I decided to check the voltages from the HD molex connector since it should be on the same rail going to the LB. The wire was already disconnected and dangling since I use a BlueSCSI and it isn't needed. When I grabbed this wire, the machine chimed and booted.

I did some closer inspection with a jeweler's loupe on the solder points where the HD molex meets the analog board and I saw some rings indicating bad solder joints. So I went to work re-doing the solder joints on the molex as well as both 12v connections from the power supply. While I was there, I re-did the joints for the flyback. The flyback was mostly ok, but there were a couple that were questionable and I figured why not.

With the re-done solder joints on the analog board, everything appears to be working consistently now.

I still plan on doing a recap of the analog board at some point and I think I will do that Seasonic replacement as in @JDW's video instead of a recap of the power supply. However, it is good to know what my issue was instead of taking the shotgun approach and recap and get a new power supply and still have issues by not spotting the shoddy solder joints.

As a tip for anyone else, I thought my solder joints were fine because they looked nice and shiny. You must inspect with a microscope or jeweler's loupe to know for sure.

 

[retr01]

Yes, that is the right spot on, @MacMaster! Cracked or degraded solder joints are challenging to see with the naked eye. Magnification helps a lot!

I am glad you got your beloved SE/30 fixed! Is everything good now? Have you run tests, such as the benchmark programs?

 

[MacMaster]

Thanks @retr01. I ran a good 40+ minutes putting it through it's paces with benchmarks and everything seems stable.

 

[retr01]

You are welcome, @MacMaster!