<html class="apple-mail-supports-explicit-dark-mode"><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div dir="ltr"></div><div dir="ltr">I have no experience with this style PSU. My approach to dead lunchbox PSUs is to stuff the guts from a PC\u2019s ATX PSU into the IPX\u2019s PSU chassis. (Don\u2019t have the sun4m lunchboxes\u2019 momentary on working, but I have the parts.)</div><div dir="ltr"><br></div><div dir="ltr">When you say \u2018video\u2019, you mean 13W3 video, right? If so, have you tried looking at booting with a serial console and see if there is any helpful output there?</div><div dir="ltr"><br></div><div dir="ltr">alan</div><div dir="ltr"><br><blockquote type="cite">On May 27, 2026, at 18:41, Daniel Williams via rescue <rescue@sunhelp.org> wrote:<br><br></blockquote></div><blockquote type="cite"><div dir="ltr">\ufeff<div dir="auto">Have you tried starting that specific IPX with the recapped original PSU? I wouldn't think the 12V supply being slightly low would cause it to not boot.<div dir="auto"><br></div><div dir="auto">~Daniel</div></div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">On Wed, May 27, 2026, 06:23 vom513 via rescue <<a href="mailto:rescue@sunhelp.org">rescue@sunhelp.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hello all,<br>
<br>
First a bit of admin/update:<br>
<br>
Original project (now RO):<br>
<br>
<a href="https://github.com/hanshuebner/ipx-psu-replacement" rel="noreferrer noreferrer" target="_blank">https://github.com/hanshuebner/ipx-psu-replacement</a><br>
<br>
New home:<br>
<br>
<a href="https://code.netzhansa.com/hanshuebner/ipx-psu-replacement" rel="noreferrer noreferrer" target="_blank">https://code.netzhansa.com/hanshuebner/ipx-psu-replacement</a><br>
<br>
On that note - the new site doesn\u2019t seem to allow creation of a user account (it\u2019s a \u201cprivate hosted\u201d platform ?). I reached out to him via the email listed on Github and no reply yet hence posting here\u2026<br>
<br>
I built one of these a ways back - and originally it seemed to work. Now it doesn\u2019t. The behavior is that the IPX chimes and gets a green power LED - but never any video. I\u2019m guessing that the system is never \u201cturning over\u201d (i.e. CPU at least).<br>
<br>
On the bench - I notice that the +12 is actually 11.7. +5 / -12 seem okay. Real Sun PSU (recapped) gives me a hair over 12. hanshuebner will power up and supply voltage with no load. Original Sun won\u2019t (I connected an old Seagate 1G SCSI to molex to get it to come up). Technically the MeanWell 12v module in the hanshuebner is in spec I think (+/- 3% ?). Regardless a data point in comparing the new vs. old.<br>
<br>
A few more notes on my particular IPX:<br>
<br>
- I have a PowerUP 80mhz CPU<br>
- I have the (officially not supported) 501-1823 32mb memory SBUS card<br>
- I do not have an internal HDD. I run from an external (and externally powered) ZuluSCSI<br>
<br>
So finally I was wondering if anyone who has built this has any insight or general electronics insight to what I am seeing.<br>
<br>
My only two stabs in the dark are that the 11.7 vs. >= 12 is an issue. Also the SENS line (which is connected) could have an issue ?. Beyond that I have no idea what it could be or what to test. I have thoroughly inspected the board for bridges / bad solder / blown caps etc.<br>
<br>
Thanks.<br>
<br>
<br>
_______________________________________________<br>
rescue list - <a href="http://sunhelp.org/mailman/listinfo/rescue_sunhelp.org" rel="noreferrer noreferrer" target="_blank">http://sunhelp.org/mailman/listinfo/rescue_sunhelp.org</a><br>
</blockquote></div>
<span>_______________________________________________</span><br><span>rescue list - http://sunhelp.org/mailman/listinfo/rescue_sunhelp.org</span><br></div></blockquote></body></html>