Thread
Mac IIsi a fire hazard??
I just had an incredibly scary experience with my recently acquired Mac IIsi.
I had it set up with with an Extended Keyb II, no monitor, and no mouse. I wanted to boot it to hear whether it's HD was functional.
I hit the power key on the keyb, and then saw a large electrical flash - like a firecracker - eminate from the rear of the IIsi, around near the exhaust fan. I quickly turned off it's power strip and stood there for a minute in disbelief.
I removed it's cords and then noticed a heavy, gunpower-like spell coming from the rear of the system. I brought it downstairs and opened the case, but visually there were no scorch marks, detonated caps, or fried chips on the motherboard. even the rear exterior of the case appeared fine.
What happened?
I had it set up with with an Extended Keyb II, no monitor, and no mouse. I wanted to boot it to hear whether it's HD was functional.
I hit the power key on the keyb, and then saw a large electrical flash - like a firecracker - eminate from the rear of the IIsi, around near the exhaust fan. I quickly turned off it's power strip and stood there for a minute in disbelief.
I removed it's cords and then noticed a heavy, gunpower-like spell coming from the rear of the system. I brought it downstairs and opened the case, but visually there were no scorch marks, detonated caps, or fried chips on the motherboard. even the rear exterior of the case appeared fine.
What happened?
Don't try that PSU as-is again. I also don't think it would set the Mac ablaze, but safety always comes first, especially if you've got sparks flying everywhere. Definitely repair or replace, whichever you're more comfortable with. Also, make sure it's disconnected from the wall at all times until a remedy is found!
I agree, pics are a must.
I agree, pics are a must.
I'm not totally sure if i'll rip apart the PSU for repairs, considering that my school has a whole 'nother IIsi which is slightly less hazardous. However, I am curious as to what caused this. I booted it several times earlier w/o such a severe event; perhaps it was a one-time thing, and by that I mean it's never going to boot again.
Sometimes it can be the tiniest visible break in a component that releases a massive flash of light, sparks, a stench that fills the room and enough noise to skip a few heartbeats.
This was one of those - http://en.wikipedia.org/wiki/File:No_blue_smoke.jpg
I had similar happen inside a Quadra 840AV PSU - it was a voltage regulator IC, from memory. Also rather small damage for the noise, light & sound it made
Dana
This was one of those - http://en.wikipedia.org/wiki/File:No_blue_smoke.jpg
I had similar happen inside a Quadra 840AV PSU - it was a voltage regulator IC, from memory. Also rather small damage for the noise, light & sound it made
Dana
Almost any kind of component can go kerpow like that. (Last one that happened to me was a flat-pack IC on a fairly recent hard disk's circuit board... the odor was positively unreal.) It could of been a voltage regulator IC, transistor, capacitor... I've even seen vaporized resistors and diodes.
If you crack open the power supply it'll probably be obvious what detonated, and if you replace it it'll probably be fine. (Well, possibly not. Sometimes a part will release its magic smoke because something upstream from it got shorted or failed in a way that it's letting far too much current past, so a replacement part will also go *bang*. Thus requiring some more in-depth troubleshooting.)
I'd put a nickel on it being a capacitor, or a regulator that failed because of a *shorted* capacitor. Any Mac II-series box is 20 years old now. (give or take about three years.) Computer collectors who are serious about using their machines rather than just displaying them are going to have to start accepting the fact that some parts don't last forever, and the limiting factors are more strongly correlated with age rather than how much use the machine gets. I wouldn't bet on another IIsi being any less likely to go *BANG*.
If you crack open the power supply it'll probably be obvious what detonated, and if you replace it it'll probably be fine. (Well, possibly not. Sometimes a part will release its magic smoke because something upstream from it got shorted or failed in a way that it's letting far too much current past, so a replacement part will also go *bang*. Thus requiring some more in-depth troubleshooting.)
I'd put a nickel on it being a capacitor, or a regulator that failed because of a *shorted* capacitor. Any Mac II-series box is 20 years old now. (give or take about three years.) Computer collectors who are serious about using their machines rather than just displaying them are going to have to start accepting the fact that some parts don't last forever, and the limiting factors are more strongly correlated with age rather than how much use the machine gets. I wouldn't bet on another IIsi being any less likely to go *BANG*.
For the short term I'll exchange either the network card or PSU between my two IIsi's, once I have both of them. However, when I saw this flash, it was almost wholly outside of the case, as if the flare of whatever vaporized was channeled out by the exaust fan - the IIsi doesn't have any vent on it's rear that opens to the PSU.
What precautions should I take when inspecting the PSU? I don't need a capcitor to discharge into my arm.
What precautions should I take when inspecting the PSU? I don't need a capcitor to discharge into my arm.
Storage location is an important consideration. If your old Mac has been stuffed in a loft, garage or anywhere damp, treat it with respect. Bring it indoors, to a nice warm and arid environment, to allow it to dry out. For about a week.
All of my psu bangs with Macs have occurred when I failed to observe the above rules.
All of my psu bangs with Macs have occurred when I failed to observe the above rules.
I have discovered the cause of the magic smoke release. It explains quite a bit (including why the flash occurred outside the case) and it may surprise you.
No, it wasn't the PSU, it's perfectly fine:
Uploaded with ImageShack.us
It was the NuBus riser card:
Apparently, when this cap (or whatever it is) blew, it sent a massive amount of voltage up the network card ribbon cable (on left). Then this excess voltage found the path of least resistance, which I believe is the RJ-45 outlet. This would explain why I saw a flash outside of the case, not exactly at the psu.
I didn't see this until I was about to pack it up - I noticed a very small scorch mark right on the pcb itself, with an orange shard of capacitor nearby. The motherboard itself has no orange-colored capacitors, and the PSU has none that are that small. A little more searching and I discovered the rest of the carcass on the NuBus card.
No, it wasn't the PSU, it's perfectly fine:
Uploaded with ImageShack.us
It was the NuBus riser card:
Apparently, when this cap (or whatever it is) blew, it sent a massive amount of voltage up the network card ribbon cable (on left). Then this excess voltage found the path of least resistance, which I believe is the RJ-45 outlet. This would explain why I saw a flash outside of the case, not exactly at the psu.
I didn't see this until I was about to pack it up - I noticed a very small scorch mark right on the pcb itself, with an orange shard of capacitor nearby. The motherboard itself has no orange-colored capacitors, and the PSU has none that are that small. A little more searching and I discovered the rest of the carcass on the NuBus card.
Ah, another one of those FRIGGEN tantalum capacitors.
tantalums are notorious for that as they age. they will short and explode. ive seen plenty of leader test equipment do this very same thing.
once one of the tantalums go, the rest will follow eventually. every single capacitor needs replaced, including the tantalum.
if the cap was just on a power rail, its LEAST LIKELY it has done any damage outside of the capacitor itself.
tantalums are notorious for that as they age. they will short and explode. ive seen plenty of leader test equipment do this very same thing.
once one of the tantalums go, the rest will follow eventually. every single capacitor needs replaced, including the tantalum.
if the cap was just on a power rail, its LEAST LIKELY it has done any damage outside of the capacitor itself.
Tantalums will go boom eventually, they cannot stand much over voltage at all by design (which you get when regulators in the PS age). I have a Daystar 040 PDS accelerator card I recieved with a blown tantalum capacitor, works fine as is but I replaced it anyway.
http://picasaweb.google.com/teozenios/NubusCards#5067908435668848786
Bottom right, hard not to miss.
http://picasaweb.google.com/teozenios/NubusCards#5067908435668848786
Bottom right, hard not to miss.
I managed to test out the IIsi's hard drive by puting it into my LC and then booting via boot floppy.
I have never heard a hard drive frantically click so loud in my life. it currently sits on my desk, dissembled for the fun of it.
So far this IIsi has been nothing but a disappointment. Riser card exploded, hard drive is faulty, memory useless for the 575, and the power supply probably doesn't regulate the voltage very well.
And I already have an auto-inject SuperDrive! Well, at least the battery isn't dead.
I have never heard a hard drive frantically click so loud in my life. it currently sits on my desk, dissembled for the fun of it.
So far this IIsi has been nothing but a disappointment. Riser card exploded, hard drive is faulty, memory useless for the 575, and the power supply probably doesn't regulate the voltage very well.
And I already have an auto-inject SuperDrive! Well, at least the battery isn't dead.
Hmm
You're consistently getting the chimes of death now?
Death chimes don't always provide video. From my experience, <50% of real death chimes show anything on the screen. The Mac must still be fairly healthy if you do get the chimes, it requires a lot of good hardware to get that far. A severely damaged Mac will not chime at all. Also, your video adapter might not be configured right, or won't work with your particular monitor. Old Macs like the IIsi often lack standard sync signals.
Do you have the board installed with the blown capacitor? Make sure to try booting with that board removed. Also try cleaning the logic board. Most of my IIsi's came with major capacitor leakage.
You're consistently getting the chimes of death now?
Death chimes don't always provide video. From my experience, <50% of real death chimes show anything on the screen. The Mac must still be fairly healthy if you do get the chimes, it requires a lot of good hardware to get that far. A severely damaged Mac will not chime at all. Also, your video adapter might not be configured right, or won't work with your particular monitor. Old Macs like the IIsi often lack standard sync signals.
Do you have the board installed with the blown capacitor? Make sure to try booting with that board removed. Also try cleaning the logic board. Most of my IIsi's came with major capacitor leakage.
I do not have that card installed - of course I removed it. The motherboard appears to be pretty clean. I managed to get it to boot without death chimes, by removing all of the memory modules, and even read a boot floppy, but it halts after a point. Still no display - my adapter has multiple modes - would it be helpful if I posted a pic of it here?
Sure, that would help, maybe one of us could find a clue and provide more suggestions. Also, if possible, try it with several different monitors. I have a graphite Studio Display and an LCD that will NOT work with IIci or IIsi, yet I have a couple of other Trinitrons that work perfectly or partially (green/washed out/etc). Some screens are more picky than others.
The way it sometimes works and sometimes doesn't screams "bad caps" to me. I'd at least run it in the dishwasher to remove any invisible leakage and conductive particles. Or replace the caps. A sloppy power supply could also cause the crashing and capacitor explosion you've witnessed.
The way it sometimes works and sometimes doesn't screams "bad caps" to me. I'd at least run it in the dishwasher to remove any invisible leakage and conductive particles. Or replace the caps. A sloppy power supply could also cause the crashing and capacitor explosion you've witnessed.
Here's the ebay page for the converter I bought, the one in the pics is identical to what I have:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=260625981691&ssPageName=STRK:MEWNX:IT
Currently I'm using an IBM monitor, my only spare, although i've got a Dell CRT in the garage I could drag out. I'll try it on that and my LCD's as well. Heck, I could even try it on my TV :lol: big screen System 7!
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=260625981691&ssPageName=STRK:MEWNX:IT
Currently I'm using an IBM monitor, my only spare, although i've got a Dell CRT in the garage I could drag out. I'll try it on that and my LCD's as well. Heck, I could even try it on my TV :lol: big screen System 7!
I used to have exactly that video converter... what setting are you using? I would try the "13 inch 640x480" setting, not any of the multimode ones. I don't think the IIsi supports any higher than 640x480 (see Here. The IIsi can use *at most* 320k of onboard RAM for video. ) and it *may* predate the Macs that supported "normal" VGA monitors.
Fair warnings, LCD monitors may not care for the "13 inch" mode, but most CRTs should at least pretend to work.
Fair warnings, LCD monitors may not care for the "13 inch" mode, but most CRTs should at least pretend to work.
This thread is getting too long and unweildly, but... did you try that? I don't know if the IIsi is one of them, but a number of 68k Macs won't produce video unless they have a working PRAM battery. (LCs fall into that category.)
Googling around it does appear that the IIsi uses composite sync rather than vga-standard seperate horizontal and vertical sync. Some (many?) Multisync CRTs can accept composite sync on their hsync pin, but since I don't own any machines that old I can't comment on whether that might be a feature that's becoming extinct. If you were looking for a monitor just for this purpose that's not the original equipment I'd recommend a medium-to-high-end early-mid 90's vintage NEC or similar. Anything made after 2000 or so I wouldn't *bet* on unless it was really high end. (IE, was made to work with UNIX workstations or the like.) A composite-sync friendly monitor is all that will work with a "gutless" adapter like what you have. They used to sell adapters which contained active components to seperate the sync signals so you could use monitors which didn't support composite sync... you may have a challenge finding one. (Apple apparently sold an adapter *themselves* to allow the IIsi to work with newer Apple monitors. Stacking one of those with your switching adapter might work...)
Or your monitors and adapter may be adequate and the machine is simpy dead. RIP?
You can put the adapter back in after you remove the blown tant. I know it's more risky running without the filtering but it should still be fine. The blast mark you saw on the main board was just residue from the tant when it was still smouldering. I had the same marks on a 5160 when it started blowing up tants all over the ISA bus but it still worked fine.
I owned a IIsi once and I do recall that the onboard video was very picky about monitor frequencies and resolutions so I just stuck with a mac display and got around all this multisync monitor BS.
I owned a IIsi once and I do recall that the onboard video was very picky about monitor frequencies and resolutions so I just stuck with a mac display and got around all this multisync monitor BS.