SGI: Hardware

After having a bad day yesterday resurrecting an Indigo, I thought I'd ask you all if you've got any hardware-related "oops" moments to share. I'll kick it off with my own story:

Several months ago, I was able to score a reasonably-priced Indigo R4K off of eBay. It was nearly local and had skins in almost perfect condition. (Missing a latch on the drive door, but otherwise very nice for its age.) But it didn't boot due to the typical TOD clock battery problem. I finally got around to replacing the battery this weekend. (Largely because I'd been waiting to amass enough of a shopping list to make it worthwhile to order supplies from DigiKey. I wasn't going to pay $8 shipping just to get a $6 battery!) De-soldering the old one and soldering in the new battery wasn't too big a deal. Put the motherboard back in, hooked up the serial cable, flipped the power switch. Saw a green light and nothing else. No boot tune. No output in minicom.

Now I'm not exactly skilled at soldering so my first thought was that I had killed the motherboard with too much heat, damaged another nearby component, or otherwise made things worse with my amateurish use of the soldering iron. A quick search led to this thread and in particular the last post there where SAQ suggests cleaning & re-seating the PM1 CPU module. That's when I realized that the PM1 was still sitting on my desk, unconnected to anything.

Oops!

My enthusiam to test my soldering job had apparently gotten the best of me, and I'd missed the rather important step of re-attaching the CPU. Funny how computers don't work so well without CPUs. After fixing that oversight, it boots up to the PROM menu just fine, I can run hinv, etc. All is good.

So, now that I've told my story do any of you have similar tales of silly mistakes you've made while repairing hardware? Something that caused you to initially panic thinking you'd made things worse when in reality it was just a minor problem or skipped step that had a happy ending after all. If you can stop laughing at me long enough to post your stories, I'd sure like to know I'm not alone!

hehe reminds me of a friend of mine, sorry not SGI tho but still funny

while troubleshooting his PC, he disassemble it and assemble it only with basic components (motherboard, RAM, HD, CPU and PSU) it didn't power up.. while cursing and blaming the PSU fault, he found out later the other end of the power cable was not plugged on the outlet.. too late, already cursing the PSU

My sister took her macbook(pro) to microcenter for warranty work... they sent us a letter dated 22 june that it was ready for pickup... the paperwork with the machine said microcenter got the computer back from apple almost two months before that... now she's moved to an exotic locale for the summer, left on the 11th or thereabouts so I had to pick it up for her, and she is stuck without a computer until she gets back.

This is just a long string of misfortunes microcenter has applied to her poor little computer, which has been in the shop many times. They've put almost $4k of parts in it, and everytime they return it "fixed" there is a new problem. (first, for an innocuous dead pixel, then no hard drive, then no battery, then no wireless card) finally after the missing wifi card, we force them to send it to apple to have it fixed properly. which they did, and then sit on it for two months.

I think all that is left of the original machine is the keyboard and trackpad assembly. they've even changed out the chassis after stripping out a bunch of screw bosses. They've also "lost" the power supply and provided her with a new one, free of charge, which was nice

It's soooo nice to have a computer with a shiny new LCD screen with no dead pixel... only to display a HDD error message and nothing else. and have screws rattling around inside. And then you return it, and get it back with a working disk, and suddenly the battery only lasts for about... oh, half a second... when it worked perfectly beforehand... and later, with the new battery, suddenly, the airport card doesn't show up anywhere with any utility.. and if we look inside there is an empty slot where it used to be. Ugh.

jpstewart wrote: do any of you have similar tales of silly mistakes you've made while repairing hardware?

A couple of years ago I tried to revive an R3000 Indigo with TOD issues. In the IP12 Indigo, the battery isn't soldered into the mainboard, but held in place with a rubber strap. While wrestling the strap to put the new battery in place, I manage to install it with the pins inverted.

This fried some of the circuitry because now the TOD problem was permanent

Come to think of it: maybe I wasn't the first to do this, and maybe that's why the R4000 Indigo has the battery soldered into the mainboard ...

A couple (20-25 ) of years ago, I once planned to install more RAM in my first 286, that my father brought me from his office. I was so happy that I forgot a screw inside. Unfortunately it was silently laying on the motherboard, contact several pins. When I turned the power supply on (cas still opened...) I saw a nice flash and then... nothing !

Fortunately, the computer worked again, but I had to depress the reset button before turning it on, then wait for at least 3 seconds before relasing reset and... biip biip... let it start. At least it worked every 3-4 attempts.

It never happened to me once again... guess why ! I certainly learned from this mistake...

Been in "power on ... no output! ... oh s**t! .... oops, forgot to re-plug [power or graphics-out]" territory several times.

1994-ish: plugged a homemade cable (pins still bare as I'd not fixed the rubber shroud) into an IEC outlet on the back of PSU, forgetting that the IEC "in" was live and that PSU (Acorn Archimedes A310) passed the 240V straight through - ouch, smell of scorched flesh, etc.

1995/6: disassembled an Acorn A5000 to swap HDs, reassembled and powered on. PSU fan started but nothing else. Re-opened case to find that I had forgotten to reconnect PSU to m/b. These days I don't bother disconnecting it!

No doubt the most interesting one will come back to mind just after I hit 'submit' ...

Oh and I'm sure everybody here remembers these painful lessons...
a) the CRT's aquadag likes to build up a big charge the instant you remove the ultor short
b) The reason it's called a flyback transformer is because when you touch it you magically "fly back" across the room with all the swiftness and grace of a jungle cat.

guardian452 wrote: b) The reason it's called a flyback transformer is because when you touch it you magically "fly back" across the room with all the swiftness and grace of a jungle cat.

Reminds me when my former boss was sensing a signal in a mass spectrometer (300W RF generator) and jumped back 300cm... (not more because he was stopped by a wall) because he touched the ground with the one hand and slipped on the sensor with the other one

guardian452 wrote: Oh and I'm sure everybody here remembers these painful lessons...
a) the CRT's aquadag likes to build up a big charge the instant you remove the ultor short
b) The reason it's called a flyback transformer is because when you touch it you magically "fly back" across the room with all the swiftness and grace of a jungle cat.

Its a rather invigorating , if not re-animating experience. You have pins and needles for hours afterwards. It REALLY lets you know that you are still alive

Not sure if it qualifies as repair horror story but I once put a screwdriver through the CPU fan of my alpha (while it was running). It was the middle of the night, I had an early start (night shift) and the damn fan grille was rattling like a buzzsaw. Sleepily I went to tighten the screws and whoops...

That really sucked, it was one of those nice Panaflo hydrodynamic wave bearing fans. Stock, still running perfectly (if a bit loosely) since 1995ish. I had a heck of a time finding a replacement fan that ran at (at least) 4000 RPM (trial-and-error how fast it needed to run not to trigger a "dead fan" situation).

I remember to accidentally plug a 125V computer PSU in a European 220V socket. The PSU was mounted in a SuperMicro dual Xeon Pentium III, very expensive at the moment, and it literally exploded (it was great because they did not install a fuse). I had to replace most of the components, substitute some tracks in the circuit and also the BIOS of the motherboard. Luckily, the computer resumed operation after this . There are many other horror histories because I am usually repairing old stuff but this was, by far, the worst.

[[C|-|E]] wrote: I remember to accidentally plug a 125V computer PSU in a European 220V socket. The PSU was mounted in a SuperMicro dual Xeon Pentium III, very expensive at the moment, and it literally exploded (it was great because they did not install a fuse). I had to replace most of the components, substitute some tracks in the circuit and also the BIOS of the motherboard. Luckily, the computer resumed operation after this . There are many other horror histories because I am usually repairing old stuff but this was, by far, the worst.

hehe reminds me of my experience with a new Keithley Instrument from US. I thought our local engineer already adjusted it for 220V, so i plug it in, poof!! good thing there is internal fuse hehe so lucky me, just change the fuse and set it to correct input AC

Not a real repair story, but I did something similar when I tested a new 4D deskside. Since it was from the US I removed the plastic on the back and did take a good look at the PSU to check for the 115/230V setting. Obviously not good enough, because after starting just fine lights in the room went out during POST.

Result: PSU needs repair, system works fine with replacement PSU.

At work we bought a couple of 22,000 volt 20 amp DC charging power supplies, which at the high end are consuming 440,000 watts from the AC line. Our facilities engineer didn't read the fine print in the manual that described the peak inrush requirement, so the first time we used it we knocked our substation offline. This was the substation that powered about half of our manufacturing facility, around a thousand guys. We had to lease a jet to fly replacement parts in from California, so production was down for about 12 hours. The next day our facilities guy said we're good to try it again, so we fired it back up and the exact same thing happened! Oh, the ignominy...

We had a transformer explode at the adjacent power substation where I work. This occurred, of course, while we were in the process of replacing the batteries on most of our UPS. Technicians switched us over to the secondary transformer and had power back up shortly, but we had to spend the rest of the day and part of the next day replacing damaged equipment, restoring from backup tapes and replacing drives that wouldn't spin up again for some reason. When all was said and done, servers restored, networks operational, the technicians began to replace the primary (blown) transformer, but instead of pulling the fuse of the blown transformer, they mistakenly pulled the fuse to to the secondary one and took us down hard and with out UPS backup again.