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2024-03-17 01:10:18 +01:00
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@@ -181,5 +181,5 @@ The BOM of revision 1.10 has a small correction farnells order code for RP1 is n
# someone requested a TS1000 version
The only difference with the ZX-81 hardware wise that for PCB needs to be fixed is that the RF modulator of the TS1000 is different, and has the RCA output on the other end of the modulator, so the enclosure of the TS1000 has the hole for the modulator near the back of the enclosure instead of next to the other connectors. Other changes were that the TS1000 had 2K or RAM, and a 60Hz refresh rate, but because the ZX81+38 already has 16K (32K if enabled) and has a jumper for 50 or 60Hz refres, no other hardware changes are needed.I had a look at the layout, and it seems possible to move the crystal and the 74HC04 down to make place for the RCA connector. This version will get its own project, named TS1000plus41.
# Correction in placement file for better tape loading and saving
I was told that a Facebook poster in the ZX-81 owners group claimed he found an error in the component placement drawing, after investigation I found not one, but two errors! The creating of this drawing is a completely manual process, so human errors can occur, and in fact the drawing has been repaired several times. This latest drawing now show that the resistor that was R59 and was labeled 47K was in fact 10K, and the resistor R56 that was labeled 10K was in fact 47K. So I wisakenly swapped the two values. These two errors change the levels of the output voltage and input voltage (needed) for the cassette input and output levels, so if you have difficulty with loading or saving please check you have placed the right resistor values for R59 and R56. The component placement drawing is now correct (March 17, 2024) the values in the schematic, and BOM remain correct.
# Correction in placement file swapping the values of R56 and R59 for better tape loading and saving
I was told that a Facebook poster in the ZX-81 owners group claimed he found an error in the component placement drawing, after investigation I found not one, but two errors! The creating of this drawing is a completely manual process, so human errors can occur, and in fact the drawing has been repaired several times. This latest drawing now show that the resistor that is R59 and was labelled 47K was in fact 10K, and the resistor R56 that was labelled 10K was in fact 47K. So I wisakenly swapped the two resistor values, because I mis-identified them while creating the drawing. These two errors change the levels of the output voltage and input voltage (needed) for the cassette input and output levels, so if you have difficulty with loading or saving please check you have placed the right resistor values for R59 and R56. The component placement drawing is now correct (March 17, 2024) the values in the schematic, and BOM remain correct. I'm now a member of the ZX-81 owners facebook group, so you can ask me questions there!