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[wxsig] T238+ Modem Problems

Will Beals will at beals5.com
Tue Dec 12 03:01:49 UTC 2006


Resistor value is OK.  Installation instructions are correct, but if built
by the schematic you are OK too.  I do need to update the schematic!  And,
yes on pin 15, that symbol has the pin numbers below the signal lines which
throws me.

What are the states of the /RDY (CPU pin 22) and DET (CPU pin 11) lines?

Does the LED blink when things get locked up--other than the initial three
rapid blinks.

There isn't a lot of code between the Dr. Morgan message and the "setting up
TNC message, so hopefully will get this isolated quickly.


-----Original Message-----
From: wn0x at earthlink.net [mailto:wn0x at earthlink.net] 
Sent: Monday, December 11, 2006 7:17 PM
To: will at beals5.com; TAPR Weather Station SIG Mailing List; 'TAPR Weather
Station SIG Mailing List'
Subject: RE: [wxsig] T238+ Modem Problems


You stated the signal path is from pin 11 of the header is to pin 14 of the
MX-614, did you mean pin pin 15 of the MX-614?  Also, the schematic shows
R100 is a 100K ohm resistor, the instructions have you install a 10K ohm
resistor for R100.  What should R100 be?

I have verfied the signal path from pin 22 of of the uP to pin 15 of the

I have double checked all of my resistor & capacitor values for the modem
(with ohm meter too) and they are correct.

I am still getting hung on the "In Memory Of:" screen when the modem is
installed and the T238 is set for (modem).  With the 238 set for (modem) and
the modem not installed it proceeds to the weather display.  

BTW, it sometimes takes a few seconds of the "In Memory Of:" screen before
the weather displays.


-----Original Message-----
>From: Will Beals <will at beals5.com>
>Sent: Dec 11, 2006 5:35 PM
>To: 'TAPR Weather Station SIG Mailing List' <wxsig at lists.tapr.org>
>Subject: RE: [wxsig] T238+ Modem Problems
>By intro screen do you mean the copyright screen or the "one moment please"
>I am guessing the latter as it sounds like the T238 thinks the channel 
>is busy and waiting for it to clear before sending its "Hi, I'm here" 
>packet that broadcasts the SW version number.
>Is the busy LED lit? (suspect not or you'd have noticed) Any chance of 
>a wiring error there.  It is pin 6 of the connector, but best place is 
>pin 11 of the micro.  It should be low.
>Final wiring to check is the path from pin 14 of the MX-614 through pin 
>11 of the header to pin 22 of the micro.  This is the handshaking line 
>for bit transfers between the MX-614 and the micro.  If busted, it 
>would halt communications which is also symptomatic of your hangup.
>Good luck, let us know what happens.
>-----Original Message-----
>From: wxsig-bounces at lists.tapr.org 
>[mailto:wxsig-bounces at lists.tapr.org] On Behalf Of wn0x at earthlink.net
>Sent: Monday, December 11, 2006 2:36 PM
>To: wxsig at lists.tapr.org
>Subject: [wxsig] T238+ Modem Problems
>I am looking for suggestions to help troubleshoot my T238+modem.  
>The T283+ works fine without the modem installed.  When I have the 
>modem installed and selected for output the T238 gets stuck on the intro
>Changing the output to PEET, TNC etc eliminates the problem.
>I have checked all of the voltages on the modem and everything is correct.
>LEDs work fine.  Five volts present on all the ICs where it should be.
>Static precautions were taken during the build.
>Any suggestions?
>Rich - WN0X  - AP006
>wxsig mailing list
>wxsig at lists.tapr.org
>wxsig mailing list
>wxsig at lists.tapr.org

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