Product: M-16 Memory Module
From: Byte-Back Co.,
Rte 3, Box 147
Brodie Road
Leesville SC 29070
803/532-5812
Price: M-16 Kit $59.95
Wired and Tested $69.95
(P&H) $4.95
Byte-Back‘s M-16, like its Sinclair counterpart, is a small black box that plugs directly into edge connector in back of the ZX81 or TS1000 computer to provide 16K RAM memory.
I made several comparisons with Sinclair’s 16K RAM pack. First, M-16’s overall proportions are larger (4 3/4″ x 3 3/4″ x 1″). M-16’s internal lay-out is not Sinclair’s “folded over” configuration, giving a less compact unit.
In spite of M-16’s additional height, it is more securely attached. After 4 months, I have yet to experience system crashes because of poor connection between computer and memory pack.
Byte-Back designed their 16K RAMs with open edge connectors to let you stack up to 3 units in series, giving up to 48K memory. According to their literature and schematics, slight differences exist in strapping second and third units–specify this information if you order additional units. If you already own Sinclair’s 16K RAM, you can expand to 32K or 48K using Byte-Back’s unit (or units).
I can’t speak for Byte-Back’s service record, but I can praise their recognition that most of their customers work on their kits at night. With this in mind, someone staffs the phones at all times.
Everything works fine in BASIC whether in FAST or SLOW modes. The computer also runs in assembly language in FAST mode. The system did crash when I tried to run an assembly operation in SLOW mode.
I called Byte-Back at 11:00pm on a Saturday and believe it or not, I spoke with someone who gave me quick, informative advice. Some earlier units with SLOW mode problems could be returned for repair at no cost. The telepone advisor also offered to explain the simple modification so I could try to repair it myself. I chose the latter option and am pleased to report that it now works perfectly.
I left my ZX81 and attached M-16 plugged in for several days at a time with no overheating problems. It uses the original Sinclair ZX81 power supply.
Completely satisfied with Byte-Back’s product, I give them high recommendations. Their 90-day warranty (even on kits), their economical price and the expertise of their telephone assistants make them an excellent company to do business with.