Temporary Resuscitation

Home shop machinist.


Last month we tackled the wobbly control stick on Kevin King’s SQ2000. This month was going to be about making an adapter to fit a new GRT Avionics panel in the space vacated by his outdated and seriously ill Blue Mountain EFIS. The GRT panel was expected to arrive in six weeks. Unfortunately, there was a slight miscommunication. Kevin thought they said six weeks, but when he checked on the delivery date, it was actually 16 weeks. D’oh!

Obviously bummed over his airplane being panel-less and grounded, we pondered the improbable: Could a couple of technophobes like us get the old panel working? At least temporarily? The issue with the Blue Mountain was that the display had become severely faded. You could make out that there was something going on, but it was so “ghosted out” (a term used to describe a faded-out screen) that it was unusable. Kevin mentioned that once it started going south, the brightness or contrast adjustments had no effect.

The ghosted out screen. If you look hard enough, you can make out the compass heading on the bottom left of the screen.

We didn’t even consider asking an avionics shop to fix it. For all the groundbreaking features Blue Mountain offered in 2003, by today’s standards it’s obsolete. So even if one could find a shop willing to look at it (doubtful), it would not be worth what they would have to charge to take it apart and inspect it.

So we decided to crack it open ourselves and have a look. Who knows? We might get lucky and find a loose wire, a corroded connection or a burned out component. But if not, Kevin was no worse off than before.

The Blue Mountain system consists of two separate components: a display assembly and a processor unit. The display assembly consists of a bezel face with four switches and two dial control pots, a liquid crystal display (LCD) screen, a circuit board and a case enclosure. The display assembly is connected to the processor unit via cable with multi-pin connectors. The processor unit is a big (about the size of two shoeboxes) and heavy metal enclosure that has a gaggle of connectors for engine monitoring, autopilot, nav/com, GPS and pitot-static systems. It is a reminder of how far electronic flight systems have come in the last 20 years: big and heavy versus compact and lightweight.

The Blue Mountain display assembly (left). The bezel frame contains the push-button controls. The LCD screen module is screwed to the enclosure with flathead screws at each corner. The main connector between the LCD panel and the circuit board is on the middle right (right). There are four connectors coming off the left side of the LCD panel, two on the top and two on the bottom that also connect to the circuit board. These are the connectors for the fluorescent backlights.

Cracking open the display assembly turned out to be easy. The bezel and dial pots were connected to the circuit board with multi-pin connectors. With the bezel off, it was simply a matter of removing four screws to separate the LCD screen from the enclosure.

All the connections between the screen and circuit board appeared to be in good order and there was no corrosion visible anywhere. A detailed inspection of the circuit board for discolored or damaged components revealed nothing.

The identifying label on the back of the panel. Kudos to Blue Mountain for leaving this sticker in place. Too often value-added resellers remove identifying labels from components to impede independent shops from identifying standard components.

But then there was an “aha” moment. A sticker on the back of the LCD screen identified it as a Sharp Electronics LCD model number LQ104V7DS01, an off-the-shelf item. A Google search confirmed this model was still available, and for as low as $88.

Kevin figured $88 was not too big a risk compared to what a repair shop might charge. We were banking on the fact that the problem was the screen itself and not the processor or a problem with the board in the display enclosure.

Kevin purchased the panel (with free shipping) from an eBay seller located in California, and four days later it arrived in what appeared to be factory-new packaging. All we had to do was plug in the connectors and fire it up.

One, two, three…it’s alive! From start-up screen to splash screen and then the active horizon and heading screens, the $88 replacement panel proved to be the treatment to give this old dog new life.

Back at the hangar, we did just that. And…it worked! So, at least for the short term, Kevin can get back in the air. Although electronics repair is not a thing for either of us, fixing the Blue Mountain turned out to be a completely mechanical job. Which proves there’s no harm in looking. In the meantime, it’s time to get back in the shop and make some chips!


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