TNC2.6

b: TNC2 Upgrade Fixes
Fm: Eric Rosenberg WA6YBT 73307,110

     If you've been reading the threads lately, you've heard about
problems upgrading TNC-2 Rev 1 (4 LEDs on the front panel) from 1.1.3 to
1.1.4 firmware. As it happens, there are three miscues in the TAPR
supplied instructions. I've to put together an addendum/errata to the
TAPR upgrade instructions based on the suggestions made by Dennis
Wojtasiak, N9EYI here on Hamnet.
     They are as follows: Step 3: Cut trace from U12 pin 2. There is a
trace on the top AND bottom of the board. TAPR refers only to the trace
on the top of the board. To get the TNC to sign on (before changing the
firmware EPROM), you'll also have to cut the trace from U12 pin 2 on the
BOTTOM of the board. Step 6: Remove jumper at pin 25 between pins 26 and
28. This is, in fact, a (large) trace, not a jumper. Step 8: Cut the
trace at U25 pin 1. You can't. It doesn't exist!! When I followed the
TAPR instructions, my TNC (as with Barry, KB1PA) didn't sign on, while
the STA/CON/PWR lights all stayed on. On cutting the U12 trace on the
bottom side of the board the TNC worked perfectly! I hope this is of
some help.

73, Eric Rosenberg, WA6YBT