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Post by Tom Maneiro on Aug 7, 2005 20:19:21 GMT -5
I've read your new page about programming on the 804x, and i dissasembled my old Acer keyboard (i need the cable to make my permanent Genesis AV cable, it has a DIN-5 plug, with ALL of the pins connected, so i only need a new AV RCA cable...). It has a tiny PCB, with a big 40-pin chip. I thinked "could this be a 804x?", but the chip is an Acer AP5504A. Since i can't find any info about this chip, could it be 804x-compatible? It seems to have different pinout (by inspecting the traces, pin 20 is GND, but pin 26 is not Vcc). I also recently got a bunch of old Trident 9440 PCI video cards. What i can do with these? For now, i took some adhesive tape, and pasted the cards to a window. Add some dead floppies, and you got a nice mural And, i got a 386SX (an AcerMate333s), that damn box has only 4MB of RAM, but boots quickly into Windows!. I need some help of what "serious thing" can i do with that machine. I must now hunt for a 80387SX (math coprocessor), some 30-pin SIMMs, a CD drive, and maybe a larger, but old HD and a soundcard (God, i did not have to destroy my two Diamond soundcards! ). What is the largest HD that i can install on these? 'cause it has a tiny Conner 3 1/2" 85MB HD, and i've heard that a 2GB disk can be installed there (and in this lands, that kind of disks is easy to find).
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Post by GiGaBiTe on Aug 8, 2005 21:37:06 GMT -5
i know alot of places around here to get what your looking for.
387 Math Co-Processor (know where one is) cd-rom drive (have some 12 x drives) 30-pin sims (have a couple, and know where to get some)
as for the hard drive, the biggest drive for those old computers is 2048 MB (2 GB) and for the really old 386's 512 MB is their limit.
also for the CD-ROM, i dont think that it will be easy to get one working. i had an old 386, and it practically refused to use it. it saw it as a network drive, so it was very hard to get mscdex.exe to recognise the driver much less the drive itself.
if you want to spend some change on the ram, they make 8 and 16 (possibly 32?) MB 30 pin simms, but are very hard to find.
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oompa loompa
I AM THE GOVERNATOR
"Git 'Er Dun!"
Posts: 1,301
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Post by oompa loompa on Aug 9, 2005 11:12:34 GMT -5
most keyboards have their own special chipset, and many of these chipsets may not be able to provide external memory access features for testing. these chipsets can vary among keyboards, like for example, i have an hp keyboard with a 40 pin motorola glue chip, and a generic keyboard with a special holtek chip, and another hp keyboard with an 8051 (useful microcontroller). this is true expecially for newer keyboards since it became cheaper to manufacture the special chipsets rather than use a generic microcontroller. most keyboards will not have an 8041/8042 variant because keyboards don't have a use for the data register port (special feature of the 8042/8041 that connects the controller to the 80x86's cpu bus).
you could probably do nothing with your acer chip if you don't know the specs. pin 26 isn't the main supply voltage for the chip, but can be used for programming the otp rom, or even placing the chip in standby on the 8041 or 8042 (8048 also)
you'll need to check motherboards for an 8041 or an 8042 (most have an 8042 manufactured by intel). older 486 and 386 motherboards you can probably get for free when companies toss these boards out
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Post by Tom Maneiro on Aug 10, 2005 15:03:15 GMT -5
i know alot of places around here to get what your looking for. also for the CD-ROM, i dont think that it will be easy to get one working. i had an old 386, and it practically refused to use it. it saw it as a network drive, so it was very hard to get mscdex.exe to recognise the driver much less the drive itself. if you want to spend some change on the ram, they make 8 and 16 (possibly 32?) MB 30 pin simms, but are very hard to find. I've tested there a Samsung 52X CDROM drive, and it worked very well! Using Cyberdrive ATAPICD drivers, my PC has no problem to use the drive... The machine has a couple of 30-pin SIMMs (2MB each SIMM?, it also has some onboard memory), for a big total of 4MB of RAM. I also want to expand the video RAM (only 256K! that is, 800x600 at only 16 colors, or 1024x768 at 4 colors...). The Video RAM expansion bank uses some litte DIP chips, what are the code of these chips? Seems to be 16-20 pin connectors, like the ol' 74LS chips... (the board supports up to 1Mb of VRAM). Can still these chips be found today? I have no (major) problems to find some 30-pin SIMMs there, but i must wait 'till October.
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Post by GiGaBiTe on Aug 18, 2005 13:49:38 GMT -5
the onboard VRAM is probably going to be a bit difficult to find. depending on what manufacturer made the video chipset. your best bet would be to either add an EISA videocard, or find the same type of EISA videocard that is integrated into the motherboard and pull the VRAM out of it and slap it in the motherboard.
if you have 4 MB of ram, and onboard memory, you probably have 1 or 2 MB of onboard memory, and the 30 pin simms are either 1 mb or 1.5 mb.
you could probably find some 8 MB 30 pin simms somewhere for a total of 32 MB if your motherboard supported them, but i have a feeling that the cap would be 2 or 4 MB per stick.
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Post by Tom Maneiro on Aug 18, 2005 15:34:51 GMT -5
It seems to support up to 16MB of RAM, but i'm not sure. Manuals are here: ftp.acer.com.mx/acer/lib/folder01/escritorio/segunda%20generacion/mate/mate386/ (my model jumper settings and memory sizes are under /am38633/, but the video drivers and BIOS files are on /ms33d2/) (WARNING: spanish documents, this machine seems to be sold only on Latin America, i cannot reach these due to a restrictive proxy server in one of my university networks, that bans ZIP files ) The onboard videochip is a OAK RVGA, comes with 256KB of VRAM, and has 20-pin DIP sockets to install more VRAM. I will test soon a Epson i386SX motherboard, it has a Trident videochip, the power connector has only 6 pins (what of the connectors of a AT PSU should i plug there?), and nothing more... Also, i will try soon a 320MB HD with Win95 preloaded in my 386 box... will Win95 run there without too much delays?
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Post by Tom Maneiro on Aug 19, 2005 16:42:03 GMT -5
I got another 386... dead. A old Epson 386SX-33 box with a leaked battery that destroyed some of the PCB tracks (can these be fixed with solder, or it's time to throw that board to the trash?) Also, i got a old Maxtor HD, 390MB with at least 1MB of bad sectors... unfortunately, HDD Regenerator do not detect my harddrive on my 386 box, and SpinRite 6 only detect more bad sectors... And here are the memory settings for my AcerMate 333s: EDIT: got a burner, so i now have a spare 24X CD drive with a minor problem with tray mechanism, fixed with... a piece of thread! Now, time to hunt a dual IDE cable
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Post by GiGaBiTe on Aug 27, 2005 22:50:53 GMT -5
lol you think that 1 meg of bad sectors is wrong, i have a Fujitsu 20 gig drive with 65 megs in bad sectors X.x
and i would just throw that 386 board away, you really dont want to get any of that battery acid on you.
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Post by Tom Maneiro on Aug 28, 2005 9:07:17 GMT -5
Oh, well, i may take a piece of cord and put that PCB in a wall... nice painting!
Could a i386 be replaced? I know that soldering work will be hard, but.... at least i want to have some replacement parts from that dead board.
And about the HD, i got it for free, so i can't be too demanding. I will try to install Win95 there.
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Post by Tom Maneiro on Sept 5, 2005 23:28:31 GMT -5
386 update: i managed to install Win95 there after multiple errors with Windows setup. Finally i discovered that if i disabled something called "net setup module", i can install Windows without errors. 12 hours later, my Win95 was up, running at a decent speed.
I also got some 27c256 EPROMs from old video cards... Maybe i will buld a Genesis flash cart, but first i need a way to erase EPROMs, and a ROM writer tool+cable.
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Post by GiGaBiTe on Sept 8, 2005 21:39:50 GMT -5
motherboards with cpus soldered on them can technically be "replaced" but only with another cpu of the same type / speed.
you could probably change out the clock crystal also, but you would have to be very careful that it didnt mess with the bus speeds or else you will be dealing with a whole new world of problems.
if you were going to do that, i would get a cpu that was twice as fast as the original (ex: if original was 16 MHz, get a 33 MHz, or if was 20 or 25 MHz, get a 40 or 50 MHz) although i dont know if they make 50 MHz i386's, i have seen 40 MHz ones though.
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Post by Tom Maneiro on Oct 11, 2005 8:58:46 GMT -5
the onboard VRAM is probably going to be a bit difficult to find. depending on what manufacturer made the video chipset. your best bet would be to either add an EISA videocard, or find the same type of EISA videocard that is integrated into the motherboard and pull the VRAM out of it and slap it in the motherboard. Yesterday, i got a bunch of old motherboards that my university trashed. One of these was from a dead 286, and has some RAM chips. After a quick research, these were compatible with my "videocard" (44c256 RAM chips, 128KB per unit). I pulled the chips from the 286 board, put it on my 386, and now i have 1Mb of VRAM! Nice for 6 chips that were in a trash can after more than 10 years of not being used... The final thing to get is the SIMMs and the math coprocessor, but i found a place to get both: a lab in my university After that, my box will be complete, exploited to the limits of 1993 hardware
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oompa loompa
I AM THE GOVERNATOR
"Git 'Er Dun!"
Posts: 1,301
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Post by oompa loompa on Oct 17, 2005 16:07:15 GMT -5
there should also be some very good (yet old) computer ic chips on your 286 motherboards to build a microcomputer from scratch =P
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Post by Tom Maneiro on Oct 18, 2005 8:49:44 GMT -5
Did i mentioned that from the 286 board i got a free Mitsubish 8042?
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Post by GiGaBiTe on Oct 23, 2005 1:20:33 GMT -5
wtf? how the hell do you build a cpu out of miscelanious IC chips?
to make a simple cpu, you would need the following:
ALU -> FPU (optional) -> MMU -> (this one i forget)
if you managed to get a jerry rigged cpu together, it would probably be like 1 KHz, the parts are so far apart, you would have hell just making it do much of anything..
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