KPC3 Won't Turn On

[VE6TBW]

Hello.

I'm trying to get on the air with APRS.  Initially I'd like to use my old Kantronics KPC3 TNC in Kiss mode, Xastir on Linux and my VX-7R radio.  After getting familiar using this gear I will probably move up to better equipment.

I haven't used my TNC in many years.  When I tried to turn it on I ran into a problem, it seemed to be completely dead.  No lights on the front panel and no data coming from the serial port to my console.  I did some troubleshooting and was able to get it to show some signs of life.

If I remove the RAM Backup Battery, and hold the the reset button down then turn it on, the green power light will turn on and from the serial port I get the following message

Code:

CHECKSUM OK
                                                                 
RAM ERROR
                                                                     
  0K BYTES
                                                                   
REPLACE TEST JUMPER

That is as far as I've been able to get.  Interestingly the moment I replace the RAM backup battery I once again can't turn the device on.  I push the power button but get no lights and no data from the serial port.

I've tried powering the device from the internal 9V battery connector, and from an external 9V power supply.  I've also tried a couple of fresh CR2032 coin batteries in the RAM Backup Battery.  None of the jumpers appear to be incorrect, and there doesn't appear to be any damage to the board.  I know this device was working the last time I used it (although that was about 10 years ago).

The KPC3 has 128KB RAM installed and also has the Dallas DS1215 real time clock installed.

Any thoughts?

If I don't get any joy here I may purchase a TNC-X from these people http://www.tnc-x.com/, however I'd love to get my KPC3 going again.  I may also go with one of the dedicated APRS devices from Argent data systems.

Any help would be very much appreciated

Thank you
Craig.

[WE0Z]

Craig- The KPC3Plus uses the Toshiba TC551001BPL-70L CMOS RAM chip and I assume the KPC3 non-plus uses the same one. Since it is CMOS it's likely it has suffered static zap. You can also try prying the chipout of socket and reseating it. At any rate the chip can be found still. The following link is a start I have no idea how much it is but it probably is not that much and would be worth trying.
Bob WE0Z
Kansas City


www.mentorelectronics.com/HTML_Renew_T.asp

[AA4PB]

Are you sure the RAM backup battery is good? If its completely shot it could have the RAM in an undermined state. Measure the battery voltage with it in the circuit and see if it is correct. There are lots of other possibilities, but that's where I'd start.