kx 155 lcd display replacement brands

if the display is bad you are SOL. they are not available. king does offer a LCD refit, but its 2k and you still have an old radio that is getting harder and harder to find anybody to work on them. also the driver for the gas display is no longer available. the only place to get one is from one pinball supply house (yes, early digital pinball machines used the same driver chip).

I have two at the shop right now that need to be fixed and I may have to bite the bullet and just replace both radios. I was talking to TKM today as a matter of fact about their slide in replacement. it should be available the first part of the year. cost will be about 4200 bucks. not cheap, but no install cost as it slides right in the king tray and works with the 208 and 209 heads.

The KX-125 is King"s current production, low-cost NAV/COMM. The KX-125 tunes 200 NAV channels and 760 COMM channels. It has a backlit LCD display that features an internal CDI, which reduces your panel space requirements. This display shows simultaneous active and standby frequencies for both the NAV and COMM sides.

The internal CDI offers an "Auto-TO" feature that centers the needle and plots a course directly to the active VOR. There are also "TO" and "FROM" markings on the display.

An internal VOR/LOC converter is used by the internal CDI, and this circuitry allows the KX-125 to show you the current radial or bearing to the active VOR.

The KX-125 is available with two different faceplates. The Silver Crown version has silver trim, and the Crown version, seen here, has an all-black faceplate.

Trig makes good use of the limited display area. In navigation radio mode, the dividing bar moves to the left and the navigation radio window occupies most of the LCD backlit screen. VOR and ILS navigation isn’t an afterthought; in nav mode the primary knobs and buttons specifically control the function of the navigation radio. If you don’t have a CDI connected, the built-in OBS display serves as an integrated CDI for lateral course guidance. The left/right movement of the on-screen needle indicates the course position relative to the aircraft position. When the needle is in the middle, the aircraft is on the selected course. A To/From flag will be shown to indicate whether the course is inbound or outbound. The right knobs (tuning knobs) act as OBS knobs and allow you to select the desired VOR radial. In com radio mode the dividing bar moves to the right and the com radio window occupies most of the screen.

Trig understands the importance of cross-brand compatibility because of the wide variety of nav indicators that are in existing panels—everything from modern EFIS displays to analog CDIs. That’s a dollar-saver for existing panel upgrades and enticing for new kits. With composite analog nav, an OBS resolver and RS-232 serial outputs, the Trig is likely compatible with a legacy nav indicator that may already be in place—maybe a King KI 209 as a common example.

If you want out with the old CDI, Trig’s TI106 3-inch solid-state mechanical CDI can be used for primary course guidance. Priced at $2600 and made by Mid-Continent Instruments and Avionics, the LED backlit TI106 has a striking resemblance to the Garmin GI 106A. It has OBS course resolver output, which provides the compass card position as a phase reference electrical signal. It also has built-in annunciation for displaying To/From/BC/Nav/GPS mode status. With the appropriate switching relay, the indicator can be used with the Trig radio and a GPS. In fact, the radio’s lateral and vertical nav outputs can simultaneously drive up to five indicators.

To help with troubleshooting receiver failures, a catastrophic internal failure triggers a fault warning, with a brief statement of the problem. The fault may be cleared by recycling the power to the radio. Try that with your KX 155.

In a market with very few options for new traditional VHF nav/coms, we think Trig cleanly struck a series of high notes with the TX56/57. We’re particularly pleased that it has an open architecture for working with a variety of flight displays and nav indicators, uses rugged high-quality installation hardware and has plenty of useful features as standard. Moreover, Trig has a decent U.S. support network in place, has proven good quality and the radio has an industry-standard two-year warranty.

For a radio of its age (it shows it with its 32-character dot matrix alphanumeric display), it has plenty of useful features including storage capacity for 250 combined nav and com channels, plus the nav receiver displays the radial of the second (monitored) VOR station. That means you can identify an along-track intersection without retuning or flip-flopping to the other station. It’s essentially like having two VOR receivers in one box. If your radio stack is tight on space, the SL30 won’t take much of it since it stands a slim 1.3 inches tall, but it’s deep at 11.5 inches.You could, of course, source a used King KX 155, but we caution against buying one that hasn’t been recently serviced—especially ones that haven’t had display replacements. You might find a 14-volt KX 155 with internal glideslope receiver priced around $1500–$2000 (not counting indicator), but a flat-rate repair could cost double that. We think that’s a risky buy and would lean more toward a well-cared-for used SL30.

The KX155/155A outputs the lateral data (VOR/LOC) as a “composite” signal. (Sometimes, in avionics, this is incorrectly called “composite video” which is bollocks – composite video is a completely different thing.) This is a demodulated version of the VOR/LOC VHF signals and is fully in the audio band. Normally you have another box tucked away somewhere (often a KN72) which converts the composite signal into voltages that drive the HSI deviation bar, the TO/FROM flags, and the NAV (no valid signal) flag. To do this for a VOR, the KN72 needs to have the HSI course pointer position fed to it.

As I wrote previously, there might be something in the KX165A configuration options which affects its composite output. The 165A’s manuals are here and I welcome anybody to have a look at the IM and the config options. I am running around a lot now so can’t do it, and I already spent a few hours on the one I put in 2-3 years ago.