GRT HX Booting problems

I recently installed a GRT HX in my RV4. I am using an EXPbus2 for power distribution and the HX is connected to the avionics bus first position. When I power up the system the unit fails to boot most of the time. On the rare occasion it will complete booting and seems then to work normally. I have been talking to support at GRT and they suggested a voltage drop or dirty power could be the cause. I have rewired both power and ground to the efis (making sure the wiring or crimps were correct) and repeatedly checked voltage(over 12v). Even went as far as replacing the battery with a new bigger one. Still the same problem. Any suggestions would be appreciated!!!

When our HX boots up it seems to go "blank" for awhile, then eventually comes up with the welcome screen showing status and the "Accept" button - getting to the Accept point is quite a bit slower than the Mini-X that sits beside it. Is there a chance you might be calling it a failed boot when waiting a little longer would reveal it to be a normal boot with that blank screen in the process making you think the unit had "hung"?

Connect a 50 watt automotive lamp in place of the GRT HX and see if it lights up. Measure the voltage across the lamp.
Have you tried connecting the GRT HX directly to the battery?

By failure to boot up are you referring to the initial black background screen with status of the efis or referring to the efis screen after one presses enter?

HX

Don't turn on HX till after engine start.
Bob

By far, the most common cause of boot issues is power and ground wiring. We have repeatedly got units on our test bench for boot issues only to have the units work flawlessly on our bench. The issue turns out to be power and ground wiring in the airplane and there is nothing we can do about it. That is why we stress the wiring issue as much as we do.

You have thoroughly addressed the power issues that might be causing the unit to fail to boot. The next step is to send the unit back so we can test it and fix any issues with your unit.

-Marc Robertson
Project Manager
GRT Avionics

6 Gun said:

Don't turn on HX till after engine start.
Bob

Click to expand...

Agreed completely

Bavafa said:

Agreed completely

Click to expand...

On the rare occasion that I leave the EFIS switch on (SOP is to turn it on after startup) and then start the engine, the HXr will not complete the boot up. I need to power off and on again. Interestingly, the mini can deal with the low voltage and complete the boot up. I don't hold this against GRT; They make this clear in their documentation.

I do agree with Mark. You need to verify your power AND ground connection and circuitry, in your case. If feasible, it is best to put a VOM on the EFIS power wire, as close to EFIS as possible, and observe the voltage during boot up. If it drops, perform a load test without the EFIS, as the other poster suggested with bulb, to eliminate or confirm the EFIS as the culprit.

Larry

6 Gun said:

Don't turn on HX till after engine start.
Bob

Click to expand...

Well heck, I guess I'be been doing it wrong for 2,000 hours on WS, HS, and HX units then......

Seriously, I have a backup battery into the alternate power slots on the screens, and that power is isolated from the big power transient on teh main bus. I have never had a failed boot in the twelve or thirteen years I've ben flying them. My EFIS is an integral part of the aircraft - no switches, just circuit breakers. When power comes on with the master, they come on.

They work just fine.

Paul

I'm concerned by the statement '...the voltage is over 12 volts." It should be 12.6 or higher, e.g., actually closer to 13 volts. I wonder if there are some diodes in there?

Back up battery installed to power both screens and the EIS. Procedure is to power up the backup circuit and wait for the screens and EIS to boot and function. Turn on the master and start the engine. Instant engine monitoring. When everything settles down and is normal, turn on the avionics switch and everything else comes alive.

Going on five years and no boot issues.

my system

I also have a backup battery for startup of 3 HX screens in both RVs and no problems here either. 10 years on one RV and 5 years on the other.

Thanks to everyone that has replied. I have been out of town and am just now responding.

The unit was having trouble booting. It would go to the grey screen and not advance to booting or loading (the screen goes to a black at the point it is loading). We measured both voltage and amp draw during startup. We also changed both the pins in the 25 pin connector and the ground wire attachment into the grounding block.

We also hooked the HX to the battery to test with clean direct power and it would not get past the grey screen. After speaking with GRT support. They had me send the unit back to them for bench testing.

The HX has a voltage "watchdog" that provides a delay in booting as I understand. This allows for voltage to stabilize before the booting begins. It seems as if the unit was hanging up at this point. I will let you all know what I find out when GRT takes a look at it.

Again, thank you all for your help.

Rick

Booting issued resolved

Thanks again to all of you that provided advice.

It ended up being a issue with the unit that needed to have a minor program modification. The GRT people were all very helpful and solved the problem right away. They are overnighting the unit back so I will be re-installing it tomorrow.

Thanks again!