The Blog

Math Coprocessors and You

Nix McRetro // 22nd March 2012 // IBM PC, Repairs, Sega

Or, more specifically, math coprocessors for the Amstrad Mega PC and my 486SLC upgrade. The ULSI US83S87 Advanced Math Coprocessor is intended for 33 MHz SX/SLC systems. This one has a 9401 date code and comes in a 68-pin PLCC package. 387SX-compatible math coprocessors use the sort of external interface... Continue reading

Amstrad Sega Mega PC 486SLC Upgrade Experiment

Nix McRetro // 21st March 2012 // IBM PC, Repairs, Sega

Amstrad Sega Mega PC 486SLC Upgrade Experiment

Browsing the internet, I came across an Amstrad PC7486SLC motherboard. I couldn’t help noticing how similar it looked to the Mega PC motherboard. Since my Mega PC was already giving me grief with its hard-drive controller, having another related Amstrad motherboard around for spare parts seemed like a pretty good... Continue reading

Amstrad Sega Mega PC 386SX Overview

Nix McRetro // 20th March 2012 // IBM PC, Sega, YouTube

Just a quick demo to show the Mega Drive and 386SX PC sections functioning as well as can be expected for their age. This is the same Mega PC I had just pulled apart after finding NiCad battery leakage and damaged motherboard traces. By this point the Sega side was... Continue reading

Amstrad Sega Mega PC Repair

Nix McRetro // 18th March 2012 // IBM PC, Repairs, Sega

Such a wonderful shade of blue. Unfortunately it has eaten the tracks on the motherboard. That’s the damage a leaking NiCad battery can do. The electrolyte is alkaline potassium hydroxide rather than acid, but it can still make an impressive mess of a motherboard. I cleaned everything up as best... Continue reading

Amstrad Sega Mega PC 386SX Arrival

Nix McRetro // 16th March 2012 // IBM PC, Repairs, Sega

It has arrived. My Amstrad Mega PC. A 386SX combined with a Sega Mega Drive. Amazing! Sadly after having a look inside it, I discovered the rechargeable NiCad date/time backup battery has leaked delicious NiCad goodness all over the motherboard. And the CPU in this particular machine is AMD, my... Continue reading