Sinclair ZX80 / ZX81 / Z88 Forums

Can you say $77 another way? Is there a decimal equivalent? In my world there is a binary address. I set my decoder to enable a chip at a certain address in binary and then a write signal pops out the data that a Poke made. I think there is another GAP in my understanding! 77 hex = 119 dec = 011101...

I repaired one of my ZX81's several years ago, and it is still working perfectly, despite having been taken apart many times. The keyboard had stopped working due to a cracked connector cable. Here is how I repaired it... http://zx80.netai.net/zx81/ZX81KBRepair.htm Regards. Grant. :idea: Now where ...

Of the eBay bought 8 bit machines (not just ZX81's) that I have obtained I have noticed the following as common problems: Keyboard problems - membrane broken or non-functional keys :( , Tarnished connectors (e.g. expansion edge connector) - cleaning normally fixes this :D , Intermittent faults with ...

One thing I learned about computers way back when, is to always have at least one back-up copy... Of course despite knowing this, I still sometimes end up losing items that are a work in progress :cry: (a lot of the time as I am thinking, I'll just make this change then save a copy, then crash :o :s...

PokeMon wrote:Because I can produce in a smaller series I can offer a 3-package.
Maybe I can offer a 5-package as well for about 16 GBP.
But to do I want to collect some orders first.

One pack of five please. Please consider this a firm order.
Mark

Now I ordered only Prototype version with 5 pieces, resulting price will be GBP 7,00 plus GBP 2,00 postage for an envelope. FIFO order service - first in, first out. Should be delivered this month as promised. Now I found a producer in China for smaller series and I could do a smaller series which ...

Selling like hotcakes...
Three ZXpands sold today
Mark

Great pictures Andy
It looks so much better in its home environment next to a Z80 on a Zeddy PCB
Mark

Some transistor information TO-92 BC547, BC548, BC549 pinout.jpg Pinout for 2N3904 here: http://www.reprise.com/host/circuits/transistor_pinouts.asp Notice that the pinouts are not the same, but both will fit in the same holes on a circuit board 8-) Other transistor pinouts: http://hamradio.lakki.ik...

Possible transistors include

BC547B, BC547C
BC548B, BC548C
BC549B, BC549C

2N3904 should also be okay ( a very common transistor) and even available from http://www.radioshack.com (as well as many other suppliers)

http://www.digikey.com stock a good range

Mark