<div dir="ltr"><div>You may want to consider checking the PS caps with an ESR (Equivalent Series Resistance) meter. High ESR caps can cause voltage drops, internal heating that changes the capacitance and filtering effectiveness at high frequencies. In many cases one can check the ESR with the capacitor in place but it is best to have it disconnected from the circuit. The caps on the MB can also be checked. OTOH, given the age of the boards and PS, you might want to just replace them all.</div><div>It sort of depends on your vision of the future for the system.</div><div>Good luck</div></div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">On Mon, Dec 15, 2025 at 9:45\u202fAM HP van Braam via rescue <<a href="mailto:rescue@sunhelp.org">rescue@sunhelp.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><u></u>
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<p style="padding:0px;margin:0px;min-height:11pt;font-family:arial,helvetica,sans-serif;font-size:11pt">Okay, I have measured voltages on all of the big caps, and they all have cromulent and stable voltages. So that just leaves the forest of SMD caps in the bottom right of the board.<br><br>I'll be replacing those on Wednesday on one of the boards... Wish me luck... :)</p>
<p style="padding:0px;margin:0px;min-height:11pt;font-family:arial,helvetica,sans-serif;font-size:11pt"><span style="font-size:11pt;font-family:arial,helvetica,sans-serif"><br></span></p>
<p style="padding:0px;margin:0px;min-height:11pt;font-family:arial,helvetica,sans-serif;font-size:11pt"><span style="font-size:11pt;font-family:arial,helvetica,sans-serif">- HP</span></p>
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<blockquote style="border-left:2px solid rgb(50,95,186);padding-left:5px;margin:0px 5px"><span style="font-family:tahoma,arial,helvetica,sans-serif;font-size:10pt">-----Original message-----<br><span><strong>From:</strong> John Hudak via rescue <<a href="mailto:rescue@sunhelp.org" target="_blank">rescue@sunhelp.org</a>></span><br><span><strong>Sent:</strong> Sunday December 14th, 2025 1:27</span><br><span><strong>To:</strong> The Rescue List <<a href="mailto:rescue@sunhelp.org" target="_blank">rescue@sunhelp.org</a>></span><br><span><strong>Cc:</strong> John Hudak <<a href="mailto:jjhudak@gmail.com" target="_blank">jjhudak@gmail.com</a>></span><br><span><strong>Subject:</strong> Re: [rescue] Help me rescue my Sun Ultra 10 (2x)</span><br><br></span>
<div dir="ltr">I think that is a valid problem. </div>
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<div class="gmail_attr" dir="ltr">On Sat, Dec 13, 2025 at 6:43\u202fPM Dan Moisa via rescue <<a href="mailto:rescue@sunhelp.org" title="mailto:rescue@sunhelp.org
Click the link to open the URL in a new window." rel="noopener" target="_blank">rescue@sunhelp.org</a>> wrote:<br></div>
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<div dir="ltr">I have a 3/80 that is flaky in a very similar way, I'm suspecting on-board caps at this point.
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<div>Dan.</div>
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<div class="gmail_attr" dir="ltr">On Sat, Dec 13, 2025 at 3:40\u202fPM HP van Braam via rescue <<a href="mailto:rescue@sunhelp.org" title="mailto:rescue@sunhelp.org
Click the link to open the URL in a new window." rel="noopener" target="_blank">rescue@sunhelp.org</a>> wrote:<br></div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hello all,<br> <br> Well I guess I celebrated a bit too early... The Ultra 10 worked for a<br> day or two but today it was running VTS while I was having dinner, I<br> came back to it on the ok prompt, presumably having crashed.<br> <br> When I tried rebooting the machine now I'm back where I started. With<br> the power led staying off when booting the machine. I've tried moving<br> my now one new NVRAM chip to the other board, but this also does not<br> work.<br> <br> The same thing happened as the first time too. Earlier today the<br> machine booted but complained about NVRAM contents. Then I re-did the<br> whole nvram mkp stuff, and `banner` was happy again. But later the<br> machine did fail again.<br> <br> Now, I did use a 48T58Y and not a 48T58 (without the Y), is there any<br> chance that that just didn't work right? <br> <br> Thanks! <br> <br> - HP<br> <br> On Tue, 2025-12-09 at 20:18 +0000, HP van Braam wrote:<br> > Hello!<br> > <br> > I have two Sun Ultra 10s with the same fault, and they came to get<br> > the same fault in the same way.<br> > <br> > They both did the following:<br> > <br> > * Started to get IDProm errors<br> > * Used the "normal" instructions for fixing this<br> > * Some time later after a reboot things started to go wrong<br> > <br> > This sort of worked for a moment, but now when I apply power to<br> > either machine the power led stays off (most of the time) in the very<br> > rares time when the power led does turn on I can't succesfully boot<br> > the machines. Sometimes they end up booting into Solaris but they are<br> > not stable.<br> > <br> > For instance even dtlogin will just start and cycle on and off until<br> > ultimately the system hangs entirely. At this point pressing stop+a<br> > and resetting usually doesn't boot correctly.<br> > <br> > Swapping around ram/CPUs/power supplies between the two systems has<br> > no effect. Removing the AFB doesn't really seem to change anything<br> > either.<br> > <br> > It seems kind of unlikely that both computers have the same obscure<br> > hardware fault in the same component, I hope this is all just the<br> > IDProm fucking up.<br> > <br> > I tried both of the IDProm chips in my minipro reader and they seem<br> > to not really read that same each time. And writing data to the chips<br> > doesn't seem to "stick".<br> > <br> > Help would be very much appreciated! Thank you! <br> > <br> > - HP<br> <br> _______________________________________________<br> rescue list - <a href="http://sunhelp.org/mailman/listinfo/rescue_sunhelp.org" title="http://sunhelp.org/mailman/listinfo/rescue_sunhelp.org
Click the link to open the URL in a new window." rel="noopener" target="_blank">http://sunhelp.org/mailman/listinfo/rescue_sunhelp.org</a><br></blockquote>
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