FAC0392%UOFT01.BITNET@WISCVM.ARPA (11/14/85)
From: FAC0392%UOFT01.BITNET@WISCVM.ARPA (Len Brady)
Received this today with my TNC-2 Revision 2 front panel (lovely!)
Re: Problems with TNC 2 Rev. 2
The first of the second shipmentof TNC 2s has hit the field, and
some problems have been identified.
The following information applies only to TNCs with an ORDER
NUMBER greater that 511, those that say Rev 2 below U21.
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Symptom: During the test on page 44, the STA light fails to go
out.
Solution: The manual fails to tell you to install U24, the second
6264-L. Remove power and install this chip.
-----------
Symptom: The digital loopback test on pages 47 & 48 fails. No
CONNECTED nessage is displayed.
Solution: SOME, not all, of the state machine proms (U6) were
programmed incorrectly, To see if this is your problem, perform
the following steps:
1) Remove power
2) Remove U5 (74HC374) and U6 (2716 marked STATE) and place on
the black protective foam.
3) Install a jumper between U21 pins 13 and 14
4) Install a jumper between U21 pins 12 and 15.
5) Check for shorts.
6) Apply power, try digital loopback test again..
If the test succeeds, you have a bad U6. To double check, swap
U6 with any other working state machine, either from a TNC 2
rev 1 board, a working TNC 2 rev 2, of the K9NG 9600 baud modem
board.
If your U6 is bad, put it on a small piece of the black foam, put
the chip and foam in the small box your sockets came in, and send
the box back to TAPR. We will return it ASAP by first class mail.
------------
Symptom: Your front panel is missing.
Solution: No one got one. A sheet notifying you of this was
left out of the box. The panels will be sent to you via first
class mail by the end of the week.
------------
Symptom: Your board says Rev 2, but the manual says Rev 3.
Solution: Replace Rev 3 with Rev 2 in the manual. There is no
Rev 3.
------------
We apologize for these problems. Remember, the preceding applies
5nly to TNC order numbers greater than 511 (rev 2). Owners of
TNC 2 rev 1 (order numbers less than 512) will want to be sure to
see the next PSR, it contains information on how to upgrade your
TNC to Rev 2. PSR should be mailed in the next 7 days.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++
Good luck to all and see you on packet soon. 73,
Len KF8J <FAC0392@UOFT01.BITNET>