(Reprinted from the newsletter of The Boston Computer Society, Sinclair-Timex User Group Newsletter)
“HIGHLIGHTS OF THE MAY MEETING”
Sue Mahoney surprised us this month by bringing a prototype of the long rumored but just announced TS-1500. The 9 1/8 by 5 3/8 by 1 3/4 inch silver box is an improved version of the TS-1000. It has moveable keys, 16K of RAM, better filtering to make tape loading and saving more reliable, and some ROM improvements (particularly the printer bug is gone). You will also be able to plug in your 16K RAM pack into it to get 32K. Sue said the T/S 1500 will list for $79.95 and will be shipped to distributors in July. The T/S will continue to be sold at its lower price. The most marked improvement we saw was in the T/S 1500 keyboard, which employs the same conductive rubber technology as the Sinclair Spectrum, but doesn’t have the Spectrum keyboard’s”squashy” feel. In addition none of the screws holding the box together were under footpads.
THE T/S 1500
As you read in the highlights, the T/S 1500 is an improved version of the T/S 1000 in T/S 2000 packaging. With a nice keyboard, 16K of RAM, and an $80 list price, they should be in the stores by August–but they won’t stay there very long. What do you do with your 16K RAM pack? Just plug it into the T/S 1500 edge connector (all the connectors are on the back,by the way) and run with 32K. In order to accomplish this nice little feat, we figured TIMEX has to redesign the custom uncomitted logic array chip (ULA or mystery chip, as we call it). Indeed they did. Instead of a 40-pin bipolar chip, it will have a 68-pin CMOS chip! CMOS technology greatly reduces the power consumption, eliminating possible heating problems, and allowing for far longer operating time from batteries. A new chip also allowed the ROM to be completely decoded to the bottom 8K of memory.
TIMEX also announced that the T/S 1500 will also feature solid-state cartridge software and 8-bit bank switching to give 64 megabytes of addressability–like the T/S 2000 series (series?). Will it use the new Z800 chip when it becomes available? The only change to the bus will be the chip select from the ROM.
The ROM will also be different. The changes will: fix ROM bug #3 (ed. note that’s the printer bug); modify the compare routines so that floating-point numbers like 13.0 are equal to 12.999999999999! Also add to the reboot routine at 03CA hex for tuning to the proper TV channel (no more switch on the bottom). None of these changes should affect the T/S 1500’s compatibility with the existing software base of the T/S 1000 and Sinclair ZX-81.
(both articles are reprinted from the Boston Computer Society, Sinclair-Timex User’s Group Newsletter, Volume 2, Issue 6, June ’83)