*** M E M O R U M ***

Keep in mind that due to the location of the TMS9929A chip on the board, there is very little space above it due to the keyboard and the slope of the case. IIRC Dave has already had a play with a/one of the TMS9918 emulators. This is not an area that I myself have experimented with much, as I have v...

Hello Chris Welcome to our forum :D The MTX500 and MTX512 models to the U.K. specification only have composite video and RF/UHF outputs. Internally they use the TMS9929A video chip which only outputs YPbPr video signals (monochrome video and two colour difference signals). The YPbPr signals are then...

It is possible to use a single ROM (EPROM/EEPROM/flash) chip. But as Martin says, some extra control circuitry is needed. So: The single large ROM chip needs a logic low on its /CS (or /CE or /E depending on what the manufacturer called the control input) when the /CS line is low for ROM socket A, R...

Claus, is your board wired like the one in this topic?

Mark

So what you want (I assume) is to change the board and the wiring so that it can take the more modern 27C512 EPROMs.

Mark

But the yellow bodge wires make it look pretty

Thing is, as said above, unless you have a spare set of working mask ROM chips, you actually need wiring with any EPROM chip type.

Mark

With 4116 DRAM chips (and equivalents) they must have the -5V supply. This supply is a bias supply to ensure that the silicon junctions in the chip work correctly. If the -5V is not present when the +12V supply is present (even if this is out of tolerance), they may be damaged. If they get hot reall...

Rifa X2 suppression capacitors going bang and releasing smelly smoke is rather common in Acorn BBC Micros and for various other computers and other electrical/electronic equipment. Including Sharp computers. The Rifa type are well known for self destructing. They use paper in their construction. Whe...

I have one operational MTX set up. However, due to having more "retro" computers than space, often it's got Sinclair computers on top of it and in front of it :? :roll: :oops: And let's not talk about trying to find a way to have enough monitors/TV's in a small 'computer' room crammed full...

What da yah mean? An angle grinder or jigsaw can quickly separate those RAM boards from the main board

And you appear not to have posted the "after" photo

Mark