Overheating

[BobD]

Has anyone had experience of overheating of the display affecting the Transponder, GPS and Flarm Source ?
All these devices are connected via the Serial Ports. On my new display, I found that that all devices went off-line at the beginning of a return flight, after the aircraft had been sitting for about an hour, at the airfield following a flight. After about 10 minutes in the air, the displays came back online.
I thought it must be a problem with the Serial Ports on my Display, but the same problem has happened on a loan Skyview display. This has the hallmark of an overheating problem, but I cannot find anything on the Forum about anyone else suffering this problem.
I have three small fans in the top of my Instrument Panel, drawing air from inside and blowing it onto the front window, but maybe I need to make some openings at the bottom of the Panel to allow a better flow of cooling air ?

 

[Raymo]

I believe the unit will tell you the internal temperature.

Yes, you may need better airflow for cooling. I have a 80MM computer fan mounted in mine but the bottom of the panel is completely open. No issues with over-heating.

 

[dlloyd]

I have flown many days when the OAT is 35C. At least once I got in the hot plane and the OAT showed 38C. No fun, but not problem as far as the displays. You show 18C at 2500. I have never heard of anyone with a display problem due to heat. Something else going on.

 

[Dynon]

That does look like a serial port oriented issue, but the fact that it happened on a second SV display points more towards some kind of connectivity problem. We don't know of any heat-related issues that cause serial comm issues (even if the equipment is hot). I'd start by looking at the wiring on both the serial ports of the affected devices, and also the power supply that goes to the GPS receiver.

 

[BobD]

Whilst the OAT read 18, the inside temperature was more like high 20's, low 30's.
My Transponder is wired is located in the baggage bay behind the P1 seat, and the GPS is located in the overhead central panel (Europa XS). The wiring for these runs from the back of the display around the side of the cockpit. If I recall correctly, I left the wiring loom as received, and looped it around itself behind the panel, rather than shortening it. Could this cause a problem ?
Strangely, the loan unit I have suffers worse from this problem than my original unit.
I use PilotAware on Serial Port 2 to provide Flarm Traffic, and this also drops in and out intermittently.
I will re-install my original unit. Then, on my next flight, I plan to remove a 2 1/4 inch instrument blanking plate, to see if this gives extra airflow to the rear of the panel, to see if this makes a difference, before cutting holes in the bottom of the panel.
Thanks for the comments, and any more suggestion would be gratefully received.

 

[airguy]

I've had dozens of flights this summer with OAT in 100-105 F range, with the airplane heatsoaked on the ramp, and have not experienced any issue with the displays. I would suspect you have a poor connection somewhere on a cable that is being affected by the heat, rather than the display itself.

 

[swatson999]

Concur on the wiring issue...I've not had one come out completely, but the D-SUB connectors can sometimes have the knurled knobs or screws that hold them in place loosen up, so I'd start by checking all of my D-SUB connections to each box (and make it a regular inspection item, or somehow safety them in place if hard to access).

If not that, check the pins for secure locking into the connector, and then ring the wires for end-to-end continuity.

 

[BobD]

I re-fitted my original Display yesterday, and went for a 1 hour flight. Prior to the flight, I removed a 2 1/4 inch blanking plate from the panel front to aid airflow.
On start up all was OK (GPS, Transponder and Flarm feed), and solid for the full flight. I then had a 3 hour layover, before returning. On start up, the GPS immediately failed, although the Transponder came back online, as did the Flarm feed (PilotAware). 20 minutes into the return flight, the GPS came back on-line.
So it looks like the additional ventilation helped, but I would have though that everything should be fully cooled down after a 3 hour layover.
I guess the next step is to reduce the wound up wiring behind the panel, and replace the bullet type cable connectors with a MIL plug. Just checked in my bit box, and I have a spare 9 pin MIL plug. I need 10 connections

 

[Garrett]

If you can't fix it with a hammer it's an electrical problem.

 

[BobD]

Just an update on the original problem.
During a flight a week ago, I lost power to my Display, and also eventually ran out of power on the BBU (no problem as I was expecting it, and had a backup instrument to use). On trying to trace the problem, by putting my Meter onto the power pins on the Display 37 pin D Connector, I found I was getting approx 6-7 volts only on pins 1 & 20 (the + power pins), instead of the expected 12v. I eventually traced the problem back to a dirty connector on one of the MIL plugs I used, so replace the female side of the connector. In two flights since then, the unit has been rock solid, so this would seem to confirm that it was a power issue, not an overheating problem.

I also found that I had a bad connection on my PilotAware to Serial Port 2 connection (my soldering this time), and replacing this has also resolved my Traffic Feed problem.

Many Thanks to Danny at Mendelssohn's for his help and advice along the way - great Support !