Mac IIsi a fire hazard??

#31 Sat, 16 Oct 2010 - 19:30

I tried every mode. None of them work, and I think the converter DOES work - when I plug in my Dell CRT into the connector itself, the color test screen disappears.

Could a dead PRAM battery be causing this? Or is my IIsi ready for harvesting?

#32 Sat, 16 Oct 2010 - 22:52

I tried every mode.

All 64 of them? (2^ 8) With a restart in between? That would have taken a while.

First, change your PRAM battery. Second, try a similar aged Mac monitor, and/or follow Gorgonop's suggestions. use the oldest VGA monitor you can find.

#33 Sun, 17 Oct 2010 - 02:39

No, I tried every listed mode, :lol: . Honestly I'm running out of patience; tomorrow I'm getting a new IIsi, and I know that one works.

#34 Sun, 17 Oct 2010 - 04:04

Perfect! Swap parts between the two to narrow things down, then you can have TWO working IIsis! Or at least plenty of spare parts.

Sir Bunsen: I believe you meant 2^6, but indeed 64 possible combinations is spot-on.

#35 Mon, 18 Oct 2010 - 17:28

I believe you meant 2^6

Indeed. i don't know why I typed 8 instead, as 6 was what I was working from.

#36 Mon, 18 Oct 2010 - 18:15

First, change your PRAM battery.

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?

#37 Fri, 29 Oct 2010 - 23:36

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.

#38 Wed, 3 Nov 2010 - 12:06

Actually, I decided to give up xx( . The IIsi has been harvested, and now it's logic board (presumably dead. Outside of no video, it would never load any boot disks or boot w/o death chime with memory installed) and case lay in the garbage.

#39 Wed, 3 Nov 2010 - 16:01

You should put it on the trading post, free + shipping. Someone may want parts or do a case mod, etc. It's a dandy little Mac.