Timex Sinclair 1000 repair

[JKnightandKARR]

Well, the composite mod is here, SMALL lil sucker!! Has 2 adj pots and a jumper to invert the colors, also have schematics, what I was thinking is, I have 2 ZX=81s, I have a 7" LCD monitor, add battery and we have a laptop... That shouldn't be hard at all.

[granz]

Hah, nice. I remember back in the early '80s when I had my ZX-81, I thought about hooking up a tiny television to my system and having a "laptop." Actually, in 1986, I did take a Timex 2068 (color version of the TS-1000) and mount it inside a 50 caliber ammunition can along with a cassette tape recorder and a battery operated television that we bought from Sears. It was my own personal Commodore SX-64 "clone." I actually took my portable computer with me on a deployment to Homestead AFB (near Miami, Florida.) It was pretty cool writing programs on my portable inside our work shelter (a 6' x 8' x 10' box that fits in the back of an M-35 deuce-and-a-half)


The trouble was that the "portable" computer was so heavy (probably heavier than the Kaypro, or Osborne, computers that became popular about that time) that I could feel my arm getting longer every time that I carried it.  

[JKnightandKARR]

I got the parts, now install n figure out the config switches...

[granz]

Nice, hopefully that will get your computer up and running.

[JKnightandKARR]

Hah, nice. I remember back in the early '80s when I had my ZX-81, I thought about hooking up a tiny television to my system and having a "laptop." Actually, in 1986, I did take a Timex 2068 (color version of the TS-1000) and mount it inside a 50 caliber ammunition can along with a cassette tape recorder and a battery operated television that we bought from Sears. It was my own personal Commodore SX-64 "clone." I actually took my portable computer with me on a deployment to Homestead AFB (near Miami, Florida.) It was pretty cool writing programs on my portable inside our work shelter (a 6' x 8' x 10' box that fits in the back of an M-35 deuce-and-a-half)


The trouble was that the "portable" computer was so heavy (probably heavier than the Kaypro, or Osborne, computers that became popular about that time) that I could feel my arm getting longer every time that I carried it.  

That's cool. Atleast your console TV wasn't in danger of theft. Lol

[granz]

That's cool. Atleast your console TV wasn't in danger of theft. Lol

That picture was the shelter - our telephone switching system (300 line switch) was in one, and another was converted into our mobile workshop. Our squadron was a tactical (mobile) communications unit.

My computer was just inside one of the .50 cal ammo cans. It used a truly portable television as the monitor. The TV ran off of ten C-cells, or a 120VAC cord. I never had a console TV - my parents did, but not me.

[JKnightandKARR]

That's cool. Atleast your console TV wasn't in danger of theft. Lol

That picture was the shelter - our telephone switching system (300 line switch) was in one, and another was converted into our mobile workshop. Our squadron was a tactical (mobile) communications unit.

My computer was just inside one of the .50 cal ammo cans. It used a truly portable television as the monitor. The TV ran off of ten C-cells, or a 120VAC cord. I never had a console TV - my parents did, but not me.

I figured. lol OK, I don't know if not having a console tv is a good thing or a bad thing... lol

[granz]

Our console television was about three feet tall, about five feet left-to-right and about two feet front-to-back. If I recall correctly, it was about a twenty-five inch screen. It probably weighed over 120 Lbs, and took two adults to move it. The thing took up the entire back of our early-1970s station wagon (I.E.big car.) So, no, having a console TV is not such a good thing. Our current television has a sixty-five inch screen and (other than the awkwardness of physical size) can be lifted by a single person.

[JKnightandKARR]

Our console television was about three feet tall, about five feet left-to-right and about two feet front-to-back. If I recall correctly, it was about a twenty-five inch screen. It probably weighed over 120 Lbs, and took two adults to move it. The thing took up the entire back of our early-1970s station wagon (I.E.big car.) So, no, having a console TV is not such a good thing. Our current television has a sixty-five inch screen and (other than the awkwardness of physical size) can be lifted by a single person.

Trust me I know, had one growing up, till 1999 to be exact.

[JKnightandKARR]

@granz @Chris Savage @MicroNut
https://vdrivezx.com/wp-content/uploads/2019/12/vla81_user_manual_v1.3-1.pdf
Suggestions what to set SW3/SW4 to? I know SW1/SW2 outta be set to ON/OFF for the backporch signal, but kinda confused on the other 2 switches.

[granz]

The manual is not very clear - it appears that you can only use this with an internal 32K RAM upgrade. But if you go to the product page (https://vdrivezx.com/vla81/) and look at the second picture (the first one showing the motherboard) it shows a Mostek 4118 1K x 8-bit RAM chip. You can see that all of switches are turned off.

I would start off with that configuration (all switches off) and see what happens. In the worst case, you only have fifteen other possibilities to try.  You may also want to pick up a 62256 32K RAM chip and upgrade your TS-1000, per page four of the manual. That may be the best option.

[JKnightandKARR]

The manual is not very clear - it appears that you can only use this with an internal 32K RAM upgrade. But if you go to the product page (https://vdrivezx.com/vla81/) and look at the second picture (the first one showing the motherboard) it shows a Mostek 4118 1K x 8-bit RAM chip. You can see that all of switches are turned off.

I would start off with that configuration (all switches off) and see what happens. In the worst case, you only have fifteen other possibilities to try.  You may also want to pick up a 62256 32K RAM chip and upgrade your TS-1000, per page four of the manual. That may be the best option.

Thanks SW1/SW2 are for backporch signal mainly so only total of 4 lol

[granz]

Thanks SW1/SW2 are for backporch signal mainly so only total of 4 lol

Yep, I was thinking (since all the switches are off in the photos, rather than the on & off that you discovered) that in the worst case, you would only have sixteen possibilities to try. By all means, go ahead and start off with the choice you had, and count through those four possibilities.

[Chris Savage]

You may also want to pick up a 62256 32K RAM chip and upgrade your TS-1000, per page four of the manual. That may be the best option.

If you don't have a 62256 and need one, I can send you one. I have a drawer of them. Every Z80 system I ever built has one installed. It was just easy to simply split the 64K address space into 32K ROM and 32K RAM.

[granz]

Yeah, and you can get quite a bit of software into 32K of ROM.

On the "office"-type Z-80 systems, the ROM could be used to copy a boot program into upper memory (RAM) and have that switch out the ROM and switch in RAM to lower memory. That is how CP/M got to use all 64K of memory in pure RAM.