IIsi different logic board revisions?

[JC8080]

Looking at my IIsi boards, I have one 820-0301-04, and one 820-0301-A. Both boards have the onboard ROMs. The 04 board PCB is noticeably darker than the A board. Does anyone know the difference between IIsi LB revisions? Just out of curiosity.

 

[bigmessowires]

Post some photos of the two versions for comparison?

 

[Phipli]

Hum. What is the serial number on the 04 board - aren't numbers normally pre-production? If it is a prototype or seed machine we should be able to tell from the serial number.

 

[JC8080]

I don't have a good pic of the "A" board, but I can get one later if you would like. The "04" board has the purple heat-sync and 50mhz crystal, those were added by a previous owner. I don't think this is a prototype board since it has the onboard ROMs. I would think a prototype board would not, since the original boards did not. I also just checked and see that the image on Bruce's recap page shows the "04" board as well.

820-0301-04


820-0301-A

 

[volvo242gt]

I think the "A" board is a later version. Back in the '90s, I had two IIsi machines. First one had the darker green board installed. It also had problems with both the contacts for the speaker and power LED, and the contacts on the fan, the latter of which were what killed the board. Fan stopped working, so, like an idiot, I tapped the fan downward while the machine was running. Fan started working, but, the machine crashed at the same time. Never booted again. Suspect the contacts shorted out the external SCSI connector and may've fried the SCSI chip. The replacement machine had the earlier board with the lighter green color to it. That one, strangely enough, had no problems with the speaker or the fan. Also had a nicer case. Moved my 230MB hard drive over to it, added 16MB of RAM, bumping it up to 17MB, and continued using it for another 1.5 years, before I picked up a IIci. At that time, it went to a friend, as a 5/40 machine to replace his dying Classic.