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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: spirantho on September 03, 2012, 07:42:52 PM
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Do I get a prize for the most indecipherable yet still meaningful post title? :)
A while back I received a broken A2386SX bridgeboard. Once I'd removed the floppy controller chip, it sprang into life (try removing it if you get the low 1-1-3 beep error!). All 25MHz of 386SX power was available to me... but naturally the temptation of the 486SLC/2 50MHz upgrade was too much. But it was always unreliable.
Today I succumbed to another temptation - take the 386SX off and replace it.
I now have a 50MHz 486SLC/2 bridgeboard! The pictures below from DrHardware's SysInfo show the speed increase. I can now run Doom with a large window (even full screen is playable), and Ultima VII now works well.
If I can get more of the chips (I had to desolder this one from the upgrade!) I can upgrade other A2386SXs to 50MHz 486 too. The problem is getting hold of the chips. Unfortunately most 486SLC/2 chips are no good, and nor are the cheap 486SLC/e-V chips on eBay for the same reason - they're 3.3V. I need 5V 486SLC/2 chips like the GoldenGate 486SLC-2/50 uses and - handily enough - the Cyrix 386->486SLC2 upgrades use.
And in case anyone is going to ask "Why?" - because I can. :)
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Fantastic work mate :)
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Great stuff.
You've actually upgraded the system to the point here it might be used for reasoably modern software.
This would be the only kind of bridgeboard I'd find useful.
Let me know if you find any more 486SLC/2 processor.
It might be worth stashing one for eventual use.
Jim
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I think "useful" may be streching things a bit. :) But it does allow me to run Win95 - although the 16-bit data bus still keeps things a bit too slow to be comfortable. Definitely not unusable, but I'd not want to use it all day. Plus it only has 8MB RAM (although I may build a SIMM adaptor to get 16MB one day).
I wonder how Linux would run on it - obviously it would need to be one of the distros meant for older machines as newer Linuces are even more demanding than Windows, but a simple Linux installation may be possible.
The hard disk is actually a 4GB Disk-On-Module, by the way, connected to a FutureIDE ISA card that supports DMA as well as PIO, so disk access is actually pretty good, which helps to make Windows usable.
If anyone does ever find a 486SLC/2 chip lying around do please let me know - getting the bridgeboard is the easy bit, it's the chip that's hard. Unfortunately ONLY the Cyrix 486SLC/2 chip will work as a replacement, so the IBM and TI chips are useless unless they're on an upgrade board, when they can fit over the old CPU (but that's less funky :) )
For reference, I think this chip is roughly equivalent to a 486SX 25... but that opens up most PC software up to the mid 90's or so, which is pretty good for an Amiga!
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>And in case anyone is going to ask "Why?" - because I can.
me like :)
Tom UK
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Just like my A500T running Blizz 2060 @57 MHz. Because it's possible.