Possible cure for TS440 showing dots only on display

The most common reason for the the display to show only dots, is that one of the phase locked loops is not locked. So take of the top cover. You will be looking at the IF unit. This board is mounted in a hinged frame. It hinges on two screws near the front pannel sides. So remove the other two screws near the final unit instead and hinge the IF board towards you. You now uncovered the PLL unit.
There are five PLL's on this board. Each one has a pin indicating if its loop is locked or not. So get out a volt meter and set it for 5 volts full scale. Now check pin 2 for each of the following IC's. IC18, IC1, IC4, IC9. Also check pin 7 of IC17. If all the loops are locked, you would see a steady voltage there in the neighbourhood of 4.7 volts. If any of the loops is not locked, one of these pins has a voltage well below 1 volt.
Note the IC number so you can look up which VCO you may have to tune a bit so it will lock again.
IC18 VCO#5 T20
IC1 VCO#4 T1
IC4 VCO#3 T2
IC9 VCO#2 T9
The above are all located on the PLL board.
The VCO for IC17 is actualy one out of four different VCO's selected on the RF board. Which one of these depends on what band is
If you have display dots on all the bands, then you have no problem with the PLL made up with IC17. So you only have to adjust either T1, T2, T9 or T20.
Now here it goes. Make sure you have an alignment tool that isn't to small or to large for the slots in the slugs in the coils (T1, T2, etc.) Also, absolutely don't turn any other coil than the one that belongs to the unlocked PLL. If you do so anyway without a service manual and proper equip- ment, then you are likely stupid.
Only turn the indicated slug. First turn it 1/4 clock wise and see if it is ok now. If not, turn it 1/4 counter clockwise and see if it works.
I suggest that you don't try more than one half turn either way. If you think that it needs to go that far, it likely has an other problem.
If the display dot problem only shows up on some but not all band, send me a note and I will see if I can help you.
The correct way would be to use a good voltmeter and follow the service manual for this adjustment. But in most cases, the above will do fine. I don't work for Kwood, I don't have a 440. Just a service manual for one. But I did cure some of the above problems. GW1NGL NA7KR Kevin Roberts Ham Radio

Page last updated on 09/10/2012 by Kevin Roberts NA7KR a colection of Ham Radio and Electronic Information