68kMLA Classic Interface

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SE/30 turning on very slowly
Posted by: q700fan on 2024-04-03 17:25:05 I have an SE/30 that turns on very slowly. I don't mean the memory test, what I mean is that when I flip the switch it sometimes takes a full minute or two before the chime occurs. It is almost like a capacitor in the power supply or on the analog board needs to charge up or something. Is this a common fault and has anybody else experienced this?
Posted by: rickrob on 2024-04-03 18:05:17 Have you checked the power supply voltages? You can check them on the 19 pin floppy connector
Posted by: q700fan on 2024-04-03 18:30:56 +5.00 V and +12.3 V read fine The -12.0 V gives me 0.0V Note that these readings are after it has booted up
Posted by: rickrob on 2024-04-03 19:29:46 What are the voltages on power up, when you have no chime? Has any work been done on this machine-- re cap logic board or analog board?
Posted by: q700fan on 2024-04-03 19:33:40 Logic board was recapped by a previous owner. I'll need to leave the machine unplugged overnight to get the no chime scenario and check it tomorrow.
Posted by: q700fan on 2024-04-04 05:53:59 All readings are 0.0 V until the things springs to life a couple minutes after being turned on. Obviously a power supply issue- but what specifically?
Posted by: 3lectr1cPPC on 2024-04-04 06:14:43 A PSU taking a while to start up sounds like a textbook case of weak capacitors to me, but with power supplies it could always be something else. Unless you're really good at troubleshooting switch mode power supplies, I'd recommend just recapping it. Console5 has cap kits: https://console5.com/store/computer-cap-kits/mac-68k-cap-kits/se-30.html Make sure you get the one that matches the brand of PSU you have. As an alternative option, or if a recap doesn't fix it, you can also just replace the original supply with a modern unit with a bit of work.
Posted by: rickrob on 2024-04-04 17:46:45 I would re-cap the analog board and power supply, or This thread has lots of info about using a modern power supply. https://68kmla.org/bb/index.php?threads/modern-psu-for-the-se-30.30945/ I did this on one of my SE/30's with a Seasonic SSP-250SUB. Installed it in the Astec case. If you have an Astec Power supply this might be an option. The Astec's have good ventilation.
Posted by: rickrob on 2024-04-04 18:00:16 Seasonic in the Astec case.
Posted by: thlnk3r on 2024-04-05 09:01:51 Seasonic in the Astec case. View attachment 72086 View attachment 72084 View attachment 72085 Rick, This is pretty awesome. I did something similar with my Q950. Would you mind sharing the pin-out for the SE/30 to 24pin connector?
Posted by: rickrob on 2024-04-05 17:38:37 Rick, This is pretty awesome. I did something similar with my Q950. Would you mind sharing the pin-out for the SE/30 to 24pin connector? The power supply is in a machine, but I can make a drawing from the info and pics I have.
Posted by: thlnk3r on 2024-04-05 22:06:02 The power supply is in a machine, but I can make a drawing from the info and pics I have. Thanks. Really appreciate it. I mean I can probably figure it out from one of your posted images but I just want to be sure ...
Posted by: s_pupp on 2024-04-06 07:51:08 See also this thread regarding psu alternatives, including the Seasonic.
Posted by: q700fan on 2024-04-06 12:06:55 I replaced the PSU with another unit and everything works fine now. What a pain though.
Posted by: rickrob on 2024-04-11 09:28:37 Rick, This is pretty awesome. I did something similar with my Q950. Would you mind sharing the pin-out for the SE/30 to 24pin connector? I drew this up from the info I had-- please double check this and let me know if anything is incorrect.
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