wheatley@inuxi.UUCP (Steven Wheatley) (11/11/85)
Just called tapr.....a few suggestions were posted on the answering machine... 1. place tape on top of the lithium battery before installing the tnc board in the cabinet. This is to prevent the battery from touching the top of the cabinet, which could cause the battery to explode. 2. If you are using tnc2 with some radio shack computers (i think he said radio shack models 3 and 4) they suggest you remove R14, R15, and R16. If you don't, these resistors get VERY hot. I guess the radio shack computers supply a voltage on the DB25 pins 6,9, and 10, or in some other means cause a good deal of current to flow thru these R's. My note.... (Maybe it is a good idea to check the schematic for your terminal or computer to see if this will be a problem with your setup.....I guess they have heard of the Radio shack models having the problem, but there are probably more....) I am experiencing a problem, during testing, where the digital loop back test does not function properly. Another ham locally has noticed the same problem; he received the kit the same day as i. If i find out anything on this problem that may be of general interest, will post. steve wheatley ku9c inuxi!wheatley
wheatley@inuxi.UUCP (Steven Wheatley) (11/12/85)
The following was forwarded to me by n9cza....it may help you who are
putting together your tnc-2's
11/05/85
To: ALL, please give widest coverage
Fm: TAPR
Re: Problems with TNC 2 rev 2.
The first of the second shipment of TNC 2s has hit the field, and
some problems have been identified.
The following information applies only to TNCs with an ORDER
NUMBER greater than 511, those that say Rev 2 below U21.
-------
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 message 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, or 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
only to TNC 2 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.
TAPR