Search found 287 matches

by gammaray
Mon Dec 11, 2017 9:45 pm
Forum: Hardware
Topic: Slower than Slow. I mean 25 hertz slow;-)
Replies: 4
Views: 80

Re: Slower than Slow. I mean 25 hertz slow;-)

What about an input / output bit mapped memory circuit?

http://www.user.dccnet.com/wrigter/inde ... XRAMIO.htm

Use PAUSE and delay loops to control timing of lights ( need transistors for driving LED ) and read/write data...
by gammaray
Mon Dec 11, 2017 8:27 pm
Forum: SALES
Topic: ZXpand enclosures available
Replies: 17
Views: 847

Re: ZXpand enclosures available

Hello, I am having a tough time figuring out what ZXpand version I have, could you look at this picture and let me know? I am 99% sure I have the long pin version I just need a few opinions before I commit to buying. Many thanks. https://www.dropbox.com/s/ew2hml536qxwqfc/2017-04-01%2007.17.22.jpg?d...
by gammaray
Mon Dec 11, 2017 8:21 pm
Forum: Hardware
Topic: ZX81 rebuild
Replies: 108
Views: 2470

Re: ZX81 rebuild

Good thing I am a spectator coaching the game from general seating! I know it takes more effort and brains than I have to actually do it. :cry:
by gammaray
Mon Dec 11, 2017 3:27 pm
Forum: Hardware
Topic: ZX81 rebuild
Replies: 108
Views: 2470

Re: ZX81 rebuild

Is there a ZTX313 at TR1 position too? I would use a ZTX313 on both TR1 & TR2.

As Wilf wrote me once "...check the pin out...(again)"

Good luck!
by gammaray
Sat Dec 09, 2017 12:39 am
Forum: Sinclair Misc
Topic: Bobs stuff is down
Replies: 5
Views: 208

Re: Bobs stuff is down

I sent a query to Bob on FactBook.

Charles
by gammaray
Fri Dec 08, 2017 3:18 pm
Forum: Hardware
Topic: ZX81 rebuild
Replies: 108
Views: 2470

Re: ZX81 rebuild

Its more stress than panic. This was supposed to be fun but has rapidly developed into a ‘mare. That is why everything is called "work"! "I have to work on something." "i have to finish working on something." "Something is not working, I have to work it." "I am going to work." "I wish that guy woul...
by gammaray
Wed Dec 06, 2017 3:19 pm
Forum: Hardware
Topic: ZX81 rebuild
Replies: 108
Views: 2470

Re: ZX81 rebuild

I was going to ask this but I thought it was a stupid question and wasn't my place and didn't want to risk being wrong since the drawing I had led me to believe it was the same. I installed a trans' backwards once to make a "Why Wait" circuit and strangely still got the speed increase but the top sc...
by gammaray
Tue Dec 05, 2017 5:43 pm
Forum: Hardware
Topic: Improving Timex/Sinclair Tape Loading
Replies: 60
Views: 2030

Re: Improving Timex/Sinclair Tape Loading

Did we need to send money or be patient or take some helpful action?
by gammaray
Tue Dec 05, 2017 5:39 pm
Forum: Hardware
Topic: ZX81 rebuild
Replies: 108
Views: 2470

Re: ZX81 rebuild

How about testing with a base resistor less than that and adding a variable pot in series. Testing for middle of the road operation then get accurate ohms and then maybe a math. model given the char's of this TR2 and the ZTX313.

Then again maybe I shouldn't be so lazy and do it myself....
by gammaray
Mon Dec 04, 2017 3:39 pm
Forum: Development
Topic: TAZMANIAC
Replies: 21
Views: 380

Re: TAZMANIAC

That is true.
Once you have ZXPand with RAM built in the case there is no way to add UDG externaly.
That speaks against internal ZXPand (or add internal UDG as well)
Kind regards Paul
Now I may be really running out of room! Must give pause...