TNC2.9
I have my 2nd TNC2 running here as of tonite. I have populated it with
all CMOS parts, including a Toshiba TMPZ84C40P which is a CMOS Z80 SIO/O
plus 27C64's in all 3 EPROM sockets. Total current drain including LED's
is 80 ma! Without LED's it is closer to 65 ma, i.e. about 1 watt.

I have also modified this TNC so that the CPU is running at 5 MHz instead
of 2.5 MHz. This involves selecting the non-default jumper position at
JMP2 (i.e. the end nearest the TAPR "cactus" logo). I have noticed that
the time-of-day clock is losing pulses, presumably because the 1200 Hz
interrupts are occasionally being missed. It will be interesting to see if
the higher-speed clock option using JMP2 solves the missing interrupt
problem.

Oh, yes -- the 2nd TNC2 came up running fine except for the perennial
bad 74HCT4066 problem; everything else went like clockwork.

73, Tom
KB5ZU at 850922/2311: Last msg # 7536, 63 active msgs