Third page of Questions and Answers  

Q. I am having problems with my Kenwood DSP-100 unit. It seems to drop out or just plain go away sometimes. The unit seems to run very hot. should I install a cooling fan?

Many users of the Kenwood TS850 with the DSP-100 have had many problems and some have given up on the setup because of the problems.

The symptoms of the problem are that the audio both receive and transmit, become very intermittent and actually drops out sometimes for quite a while or just momentarily. The DSP-100 can get very hot and this seems to acerbate the problem. Many users have installed a little fan to cool the top of the DSP, but this does not seem to be much help.

The real cause in most cases has nothing to do with heat. The device was designed to be placed on top of the 850 and under most conditions the unit will not over heat. The problem is the RCA plugs on the back of the DSP unit itself. They are attached to the control board with two (2) small plastic pins and the control lugs that are soldered to the board. As the RCA plugs are used, bumped, unplugged, etc the plugs get loose. Move you finger back and forth on the plugs and if they move at all, the soldered joints to the board have  broken free of the board and will  cause the drop out and un-natural heat buildup. Push on them slightly, they should not move. 

The FIX for the problem is to take the DSP apart and carefully remove the circuit board. You do not need to disconnect any internal wire connectors. Simply fold it back and look at the two plastic jack on the board. Carefully put a low wattage soldering iron on the contacts and make sure they have continuity with the board. Put some super glue on the plastic posts as they come through the main board. Let the glue dry for a day making sure nothing drips onto another component. Turn the board over and apply some more super glue to the plastic ports around the ports everywhere except on circuit tracings. Let the glue dry for a day and put the DSP back together. Put the RCA jacks on the DSP first, very carefully and put the unit on top of your 850. Never disconnect the RCA cables from the DSP jacks again. If you most move the unit disconnect from the rig but not from the DSP. Avoid ever touching or having anything else like cables rub against of touch the RCA cables. I was having the symptoms as described all the time, for a long time. I did this fix and it has been working perfectly for over a year.