romair Posted July 3, 2015 Report Posted July 3, 2015 Recently my KX 165 which is my #2 comm/nav started acting strange. Intermittently the display almost goes out with the exception of a few digits. If I turn it off and on, sometimes it will go back to normal, sometimes it will persist with the display problem. I initially thought it was an overheating issue, but recently it started doing it less than 5 minutes after turning the unit on. Both the comm and radio work normally when the display acts up, I just can't see the frequencies that are dialed in. I think it might be the display, but it is strange that the display is completely normal during the intermittent times when the unit is working. Any thoughts? Quote
Piloto Posted July 4, 2015 Report Posted July 4, 2015 Like many I had the same problem. The problem is usually solved by cleaning the display contacts on the glass display. With the front bezel off the display glass is slide out. With a Q tip wetted with contact cleaner rub the contacts on the glass to clean them. Some may use a pencil eraser but you risk the chance of wiping out a contact if too much force is used. Very carefully reinsert back the display. And reinstall the bezel. José Quote
Jerry 5TJ Posted July 4, 2015 Report Posted July 4, 2015 The King Silver Crown series used a gas discharge display. A low pressure ionizing gas is sealed inside the glass display and by passing a low current through the appropriate segment it will glow. The voltage at the terminals is about 180 VDC. These radios are ~30 years old now and it is common for these displays to fail in a gradual manner, growing dimmer or with uneven illumination of the elements. Sometimes the radio's display is readable in bright light but dims to nothing at night. The display is a single module nearly the width of the radio. It is laminated glass with metal leads that fit into socket pins on a circuit board. The glass is fragile, the gas seal is essential, the leads delicate. As a test -- shine a bright flashlight at the dimmer sensor on the front panel of the KX165. The digits should glow at maximum brightness. If the digits are all visible then there is some life left in the display. Some have reported cleaning the front of the photocell helps. Yes, sometimes cleaning the leads will help. There is an internal adjustment to the display brightness, a potentiometer on the circuit board that can be reached through an access hole in the radio's aluminum case. Power the radio on the bench with a test harness -- all you need is power and ground -- and adjust that for maximum brightness. If the display is failing you'll find the adjustment is not enough but with the control at full bright it will be better. Most of the time all those efforts won't bring the display back to full operation. Then a replacement display module will be needed to fully restore the radio's utility. Display modules are sometimes available on the secondary market such as EBAY for about $300. The part number for the KX155/165 gas display module is 037-00073-0000 Quote
romair Posted July 4, 2015 Author Report Posted July 4, 2015 I cleaned the contacts, but it did not solve the problem. I then noticed that there is something rattling within the display itself. On the back side there is this glass reservoir appearing structure. Inside it there is a small coil that is freely moving around. Is that normal? Could that be the problem? Quote
carusoam Posted July 5, 2015 Report Posted July 5, 2015 Looks similar to a halogen lamp that has gone bad...? Something has been melted and then deposited on the inside surface of the tube? Best regards, -a- Quote
romair Posted July 6, 2015 Author Report Posted July 6, 2015 No, there is definitely a metal looking coil in there that is loose... Quote
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