Wanted - ZX81 Issue 3 board.
Wanted - ZX81 Issue 3 board.
Hi,
I'm after an issue 3 board in any condition with or without case
Thanks Andy
I'm after an issue 3 board in any condition with or without case
Thanks Andy
what's that Smell.... smells like fresh flux and solder fumes...
Re: Wanted - ZX81 Issue 3 board.
I'm pretty sure I can sort you out Andy.
I'll check tonight. Any particular colour, sir?
I'll check tonight. Any particular colour, sir?
Re: Wanted - ZX81 Issue 3 board.
Careful Charlie not all issue 3s were red early ones were still greensirmorris wrote:I'm pretty sure I can sort you out Andy.
I'll check tonight. Any particular colour, sir?
Re: Wanted - ZX81 Issue 3 board.
Doh now i kearn that there where 2 different colours !
@SirMorris, no any colour will do, just decided it's about time i extended my collection of Zeddies and what better way than to get a issue 3 board, since as all mine are issue 1's
Regards Andy
@SirMorris, no any colour will do, just decided it's about time i extended my collection of Zeddies and what better way than to get a issue 3 board, since as all mine are issue 1's
Regards Andy
what's that Smell.... smells like fresh flux and solder fumes...
Re: Wanted - ZX81 Issue 3 board.
I now have a question for owners of issue 3 boards.
does any of your boards have an extra resistor solder from the right side of C6 (above the CPU) ?
Thanks Andy
does any of your boards have an extra resistor solder from the right side of C6 (above the CPU) ?
Thanks Andy
what's that Smell.... smells like fresh flux and solder fumes...
Re: Wanted - ZX81 Issue 3 board.
Yes my issue3 zx81 have that resistor.
Re: Wanted - ZX81 Issue 3 board.
Me too. It's 1k resistor connecting C6 / X1 (quarz oscillator) to ground.
Re: Wanted - ZX81 Issue 3 board.
Quartz or ceramic resonator ?PokeMon wrote:Me too. It's 1k resistor connecting C6 / X1 (quarz oscillator) to ground.
reason i ask it the oscillator circuit i am using in the Replacment ULA did not work until i disconnected this ' extra ' resitor, Which is not present on the issue 1 boards.
I shal have a tinker with the circiut and see if it can be altered to work with both.
Andy
what's that Smell.... smells like fresh flux and solder fumes...
Re: Wanted - ZX81 Issue 3 board.
ceramic resonator ...
You can place a resonator on your "ULA replacement board" I think and forget the resonator on the issue one or issue 3 board ...
It's not used for something else, so why not build the oscillator on your ULA ?
The ULA is the boss of the clock ...
You can place a resonator on your "ULA replacement board" I think and forget the resonator on the issue one or issue 3 board ...
It's not used for something else, so why not build the oscillator on your ULA ?
The ULA is the boss of the clock ...