Sinclair ZX80 / ZX81 / Z88 Forums

you dont NEED to remove the modulator board from its case..but if you must...easiest is to remove the thing completely from the main board, remove its bottom cover, and there are a few solder points where the board ground is connected to the case, unsolder them, the 47 ohm to the phono contact, and ...

aarrggh, another modulator butchered, absolutely unnecessary, you can fit the ccb externally or even on top of the modulator case....

why change the regulator? is it faulty? if not, leave the original in... and as for capacitor polarity..i have come across some that have a + sign within a red arrow , but they were quite old, probably some of the first of that style..?!

..it does..... i'm not sure who originated this design but looks identical (and probably is) to the Maplin zx81 hires graphics board...maybe it originated from there?! there is(was) the full article on the net a while back....

oo, only just seen this! blimey, nearly 5 years ago! many thanks! and no, i still havent got it working yet!

i think so, i tried using a zx81 rom in a zx80 and it works, apart from no 'slow' mode, as to be expected...

those are ram 'options' either one big 2k 8bit (6116 or similar) or 4 1k 4bit (2114 or similar) , to make 2k ram...depends on what they could get at the time i suppose!

genuine sinclair packs dont use it directly, memotech ones certainly do,and have a zener across the 11v ish 9v line, so dont stick more than 12v in or they'll be a bang, puff of smoke and 8 dead 4116s no idea what others do but i bet a lot of them did the same as memotech !

nooo, dont scrap a ts1500! whats wrong with it?

that 'high' 11v may be needed if the zx is used with some non sinclair rampacks as they derive the '12v' supply for the 4116's direct from the '9v' (11v) line....