Investigating my amiga A500's hard drive, or, why the hell is that cable there

Legacy & Vintage
1

Well today I had some time so I decided I would open up the hard drive that I got with my amiga 500.I was hoping that I could figure out why the scsi cable on it is retardedly long but… well I still don’t have an answer. The only thing I can come up with is the guy had another amiga or an ibm pc, and just had more partitions on here than I realized, and used it as an external drive for his other machines? I really have no idea.

So anyways:

IMG_20191026_110325
IMG_20191026_110325.jpg4032×2268 1.88 MB

The drive undergoing “surgery”

IMG_20191026_110337
IMG_20191026_110337.jpg4032×2268 1.9 MB

IMG_20191026_110409
IMG_20191026_110409.jpg4032×2268 2.01 MB

Beefy hand made switch o3o

IMG_20191026_110421
IMG_20191026_110421.jpg4032×2268 2.17 MB
Dedidaded wam. According to the jumpers on the board its 4mb? Plus another 2mb in the trap door expansion (with RTC 2023 battery)

IMG_20191026_111357
IMG_20191026_111357.jpg4032×2268 2.06 MB

IMG_20191026_110730
IMG_20191026_110730.jpg4032×2268 2.28 MB

hdd model if anyone wants to know

Then, to my surprise, theres a 286 sitting in here waiting to be used.

IMG_20191026_111015
IMG_20191026_111015.jpg4032×2268 2.76 MB

IMG_20191026_111021
IMG_20191026_111021.jpg4032×2268 2.75 MB

with copro slot o:

IMG_20191026_111025
IMG_20191026_111025.jpg4032×2268 2.74 MB

IMG_20191026_111210
IMG_20191026_111210.jpg4032×2268 3.32 MB

and then heres shots from around the board. I wish I knew what the different chips actually did, especially that flashable one and the amd one. But, I don’t know where to look up old chips like this.

IMG_20191026_111048
IMG_20191026_111048.jpg4032×2268 3.24 MB

IMG_20191026_111054
IMG_20191026_111054.jpg4032×2268 2.98 MB

IMG_20191026_111129
IMG_20191026_111129.jpg4032×2268 1.79 MB

IMG_20191026_111543
IMG_20191026_111543.jpg4032×2268 2.27 MB

IMG_20191026_111639
IMG_20191026_111639.jpg4032×2268 2.11 MB

IMG_20191026_111841
IMG_20191026_111841.jpg4032×2268 2.1 MB

Then I found this botch job. The drive works fine so I’m not going to fuck with it (keep your fake ocd to yourselves btw)

But I still don’t know why the cable is so damn long. I’m eventually going to take a crack at getting a scsi card for my amiga 2000 and plugging it in to there and seeing what happens… But at the current moment I am plenty happy with it being almost a meter long.

I’ve also just been meaning to crack the irive open and look inside.

Now you may want to ask, aremis, what the fuck is a 286 doing in a hard drive.

Well, back in the day when the A500 came out, it had an expansion slot on the side. This hard drive is called a “Sidecar Expansion”. There were tons of different ones made for all sorts of random crap. However, here in america, there were only so many to choose from because A: shipping be cray cray from the UK, and B: the amiga market here was miniscule even compared to somewhere like norway where they had the Dragon 32 and 64 that was pushed heavily by every shop possible. It just didn’t sell here for some reason.

So GVP (Great Valley Products), to the most of my knowledge, tried to fill the gap for the low end consumer market. They would put out sidecars that could greatly enhance your amiga. When the IBM PC and its compatibles were taking over america, a lot of the other companies that put out hardware had to either became compatible somehow, or die. Many did in some regards, including Atari’s Computer Branch (RIP Jack T), Commodore, Texas Instruments computer division, and all the weird formats that had built up in the hobbyist sector. Only the big competitors (IBM, MS, Apple) were getting big with their tech output later in the 90’s, but Amiga users wanted upgrades.

So for the sake of compatibility, this… “accelerator”? was put out to, I guess, run office software. I would assume MS office or something but I really don’t know to be honest. And for the life of me I’m trying to think of anything I’d actually want to do with a 286 and I can’t really think of much. Run doom and 4FPS in a letterbox window? Play commander keen? I just don’t know what to do with such a mishmash of hardware like this. Mayble I’ll learn 8086 and 80286 machine code and port shit.

Suggestions welcome.

Anyways that was my morning.

4 Likes
2

Very nice, very nice indeed :slight_smile:

As for my FAKE OCD, well I have to say you didn’t use enough thermal paste :stuck_out_tongue:

3

For a capacitor?

4

It’s not the component it’s the fact not enough paste was used :wink:

I love how Tech Jesus always toughts his favorite thermal paste.

5

Looks like a nicely populated unit, must have cost someone a load of $$$ back in the day. The RAM in there should be recognised as proper Fast RAM and therefore boost the 68000 performance by around 30% making the A500 as fast as an A2000 which usually came with Fast RAM as standard. Trapdoor RAM on the A500 was usually only recognised as Slow (or ranger) RAM which meant only the CPU can use it, but has to do so via an address space that is shared with the onboard chip RAM. Better than no expansion but kinda crap in that the custom chipset can’t use it and the CPU is still bottlenecked and can’t strecth its legs.

There were quite a few 80286 adds on released for the Amiga, mostly to allow MS-DOS office software to be used at home with support for 720K DD floppies and 16 colour CGA or pseudo 4 colour VGA modes (I say psuedo as they would use a PAL or NTSC interlace mode to get to 640x480 without needing a 31.5KHz VGA monitor). The best thing about most of them was that you could run MS-DOS from inside Amiga workbench e.g. no need to dual boot. There’s a few vids up on Youtube with people playing around with other ones. This trapdoor one is a dual boot one though: https://youtu.be/W1KTRlFdT4I I think yours is probably better - like the ATonce emulators.

No idea why the cable is so long, you are probably correct - a bodge to allow the HDD to be accessed by another machine and then be plugged back into the Amiga. All in all a nice bit of kit and a good job its now with someone who will get it working again :smiley: