EEVblog > Other Blogs

#18 Kenwood TS 940 DOT on display Chasing down the rabbit hole Pt 1

(1/3) > >>

Radio Tech:
#18 Kenwood TS 940 DOT on display Chasing down the rabbit hole Pt 1

In this video I have a TS-940 that has the dreaded dots on the display. After doing the regular checks for signals and voltages on the PLL's I decided to start looking for other issues that can cause this problem. So which is causing this problem? Bad wire connectors, cracked solder joints plus PLL unlocked. We will look at the boards and connectors in this part one series. Just some basic visual checks with our eyes. In part 2 we will go to the schematic and start checking signals and voltages.







So, if anyone objects to seeing my videos on the forum please speak up, let me know.

German_EE:
This section of the forum is supposed to alert members to other blogs, so please keep posting updates in case others miss them. As for your current task I am NOT impressed by the serviceability of the TS-940 and if I had one I would dread the moment I saw those dots on the display.

Good luck in the repair!

Radio Tech:

--- Quote from: German_EE on December 11, 2015, 09:10:15 pm ---This section of the forum is supposed to alert members to other blogs, so please keep posting updates in case others miss them. As for your current task I am NOT impressed by the serviceability of the TS-940 and if I had one I would dread the moment I saw those dots on the display.

Good luck in the repair!

--- End quote ---

Thanks,
I noticed at times folks post here and do not see it in the normal "new post" button.
But I mostly check here every time I log in.

The TS-940 can be very intimidating when the covers are removed and one looks in. But instead of having a main board and a few other boards the 940 has many boards, 6 PLL circuits. All these are tied together with many wire harness. So once you locate the problem and narrow it down to one board it is not really that hard to repair.

However age comes into the equation. Many pin connectors become corroded, insulation breaks down. Then the night mare begins  :-DD

Thanks for your reply

German_EE:
One other thing. I have two pieces of commercial equipment in my shack (a scope and a Ten-Tec transceiver) and both have a piece of paper glued on the inside of the top cover. On the paper are listed any modifications I have made so that any service tech will have a head start if something goes really bad.

Radio Tech:

--- Quote from: German_EE on December 12, 2015, 08:59:33 am ---One other thing. I have two pieces of commercial equipment in my shack (a scope and a Ten-Tec transceiver) and both have a piece of paper glued on the inside of the top cover. On the paper are listed any modifications I have made so that any service tech will have a head start if something goes really bad.

--- End quote ---

I have seen this and think it is a very good idea. Had a rig come in for repair and found a 3x5 card taped to the inside cover listing parts that have been changed. Saw a TS-520 with an actual circuit schematic draw in a very fine sharpie on the inside on the top cover. Some mod that was done to the audio circuit.
As you said it gives future techs a heads up when working on equipment. Thanks for sharing that.

Navigation

[0] Message Index

[#] Next page