Trouble connecting to packet node

[N2QLT]

I am looking for a little help. I cannot seem to connect to packet DX clusters. I am using a PK-88 and logger32. When I enter a connect command, I can see all of the traffic and spots. But I am unable to connect. So, I am able to copy the nodes with no problem, but no connect. I have even tried to run high power, no luck. Perhaps I have a problem with my parameter settings? I haven't used this equipment in a while, so I am left at a loss. Any suggestions would be appreciated. Thanks!

[W8JX]

Been a long time since I did packet but timing/setup can be very important for joining a node. Listening to it is easy part.  You have to remember that the node may be hearing other stations that you are not hearing and it is not hearing you. 

[AA4PB]

Make sure your transmit audio level is correct. Too little audio and the node won't have enough signal to work with. Too much audio and your FM limiter will distort the sine wave and the node won't be able to decode it.

If you have a deviation meter then drop the audio drive way back and transmit a steady mark tone and increase the drive level until you get 3KHz of deviation. Another, less accurate, way to do it is to listen to the tone on another receiver. Bring the level up until the volume in the receiver stops increasing. Then back it down a little below that level.

[N2QLT]

Thanks for the suggestions. Here is what I found out so far. I listened to my packet transmissions on a separate receiver. During the times that I cannot connect, my transmitter is not sending that "screeching" sound. It just transmits a carrier at full power. Then, on other occasions, it sends the "screeches" and I am connected, no problem. I am not sure whether it would indicate a problem with the TNC or the transmitter. Obviously, I don't know a lot about packet. I just want to use the DX cluster. I checked all of the cables, not sure what to do next. It just seems to be random, whether it decides to work or not. But it's broken more often than not.

[AA4PB]

It seems to me that you most likely have in intermittent connection somewhere in the audio line between the TNC output and the radio input. It could be an open or a short to ground.

My first test would be to connect an amplified speaker or a set of sensitive headphones to the TNC output and make sure the audio tones are reliable at that point. If that's good then you know its either a bad connector/cable or something wrong with the radio. The calibrate command on your TNC should give you a steady single-tone (mark or space) output. With that you can wiggle cables around while listening on your other receiver to see if you can find an intermittent connection.

[N2QLT]

OK, thanks for the help. Now I'm getting somewhere. I used the cal command and the transmitter was just putting out a static kind of sound. Plugged in a mic and same result. A little while later I did the same thing and the mic sounded fine, as did the TNC tone. So, something is intermittent in the old TR-7400. Fortunately, another TR-7400 is only around 40 or 50 bucks, lower than repair cost. Thanks again!