JPI EDM-930

[Lrn2Fly]

I've been chasing an intermittent problem with my JPI  EDM-930 in my "E" model lately.  It cropped up a few weeks ago coming home from a long trip, and has progressively gotten worse since then.  Details:

 

The AMPS meter would be fine at 2 amps nominal during cruise, then all of a sudden aggressively spike up and down. This eventually became a steady high charge rate of 120 amps, well exceeding the alternator capability, resulting in e RED X over the AMPS gauge.

 

The VOLTS gauge would remain at 13.7 nominal during the entire event.

 

The other indications, such as EGT & CHT would be very erratic when this was happening.

 

Turbulence would aggravate the problem, so clearly a loose connection was at work here.

 

I could make the problem go away by pressing on the bottom right hand screw holding the JPI in place. Yes, this took a while to nail down, but suffice to say, I could make the problem go away by pressing the screw, and as soon as I let go, the problem returned. Replicated quite a few times.

 

Upon removal of the JPI to look for a poor ground or some other loose connection, we heard a washer flopping around inside the JPI.  Well, the washer was from one of the posts that the connectors screw into, but after opening the JPI back panel, we saw this grounding strap going to a power SCR/transistor that had broken.

 

Problem solved.

 

If anyone happens to have a similar problem, this is a good place to start.  Easily fixed. 

 

JPI notified - wonder if they will respond?

[carusoam]

Let us know what response you get.

Are you using that device for primary type instrumentation?

Best regards,

-a-

[HRM]

 

 

JPI notified - wonder if they will respond?

 

 

They better respond. The design thought was that vibration would not be enough to break that copper strap. It may be that out of many JPI units you got one that had a tight strap. You also have an aircraft with it's fair share of vibration to the panel.  

 

I suggest an SB. They may go for an AD (the horror). 

[Mooneymite]

Thanks for taking the time to share!  This sort of thing makes Mooneyspace invaluable.

[Piloto]

On the picture I could not see the solder pads for the SCR pins. You should email this picture to JPI. Just to confirm the SCR location.

 

José 

[Lood]

JPI notified - wonder if they will respond?

 

 

They probably will, but don't be in any hurry...

[Bob_Belville]

I've found them to be fairly responsive. At least until they're stumped. 

[Lrn2Fly]

JPI responded yesterday. I attached the JPG file on my original email, and asked for their input.

Their initial response was more concerned with warranties and that field repairs are not covered under the 3 year warranty. This was very disappointing but not a big surprise. As an experienced and capable electronics tech, the fix was easy and effective, so a return to JPI was not necessary. They seemed to have greater concern over the field repair than the fact that the device was not useable prior to the fix.

The EDM is, in fact, the primary instrument, with no backups. This is, of course, a calculated risk of having a digital screen in the panel with so much banking on it. It's no different than having a Garmin 430 or other multi-functioned box. I love my EDM and I will still keep it and rely heavily on it.

I doubt that they will issue a SB, let alone an AD, for this. My response to them was I hoped they would keep track of such occurrences and if it's an ongoing problem, to take corrective action for such a critical safety of flight issue. Since my EDM has been out of warranty for about 6 months, I expect nothing, but it sure would be nice if JPI would stand behind their product. It's not like I irresponsibly opened the box and jammed a soldering iron onto a circuit board.

My hope is that all of us on the space with these units (and we are a plentiful group) may benefit and be able to identify any future problem BEFORE bad things happen. Be careful out there gang!

Sam Lindsay, CFI/II/MEI

[carusoam]

For perspective...

My stock equipment in my C didn't fair any better...

MP gauge broke it's connection to the engine.

RPM gauge threw it's needle one day.

Good to have a back up?

I'm happy that an AD doesn't effect this kind of stuff, better to have a warranty...

-a-

[Bob_Belville]

Dave, I don't know about features, the 900 is smaller and cheaper... and I think newer. I do not recall talking about the 900 when I bought the 930 2 years ago. I just visited the JPI site and did not learn much.

[Marauder]

To add to Bob's comment, it has the same form factor as the 830s. The price also dropped over the past year. I believe it was in the $5k range last year when I looked at them.

[Bob_Belville]

Sam, it this case I think I would have used the opportunity to return the unit to JPI.

 

I sent mine back chasing irratic oil pressure data. They found nothing wrong with the box or the transducer but they updated the firmware which among other thinks allowed me to flop the RPM and MAP positions which I like. It cost me shipping cost one way and about 10 days of down time, they tested and turned it around in 1 day. As I recall, your firmware rev is older than what mine was.

[Bob_Belville]

They're probably feeling a little heat from the competition. Donald Kay swears by his which I think is an EI MVP 50.

[N601RX]

I have the 900.  Both are primary.  The main difference is the size of the display and cost difference of the units. The 930 also has a text based remote annunciator, while the 900 just has a remote yellow/red LED combo.  The 900 mounts in a standard round hole, the 930 requires a cutout.  The software features of each are very similar.

[TWinter]

I really like my JPI. On the other hand I had TWO probes fail this year. One CHT and the oil temp. We called JPI and warranty was the main concern from JPI. The install was only about 18 months in with about 100 +/- hours so the answer was yes. JPI was very confident that there must be a bad install connection since two probes were acting up. According to them..."This never happens. you must download your data and send it in before they would consider a warranty or replace the probes"..Yes I had to pay for shipping. They received the data and said, "Well, I guess you do have two bad probes". While I have found the JPI to be a great tool and is now a very important part of my flying experience... I think they will have to change the term, "This never happens, two probes failing". Kind of felt like the burden of proof was put on us. I still would like to upgrade to the 900 or 930, but hope JPI will accept the fact "shitz happens" and its possible for anything mechanical/electrical become defective.    

[Bob_Belville]

BTW, when I got my 930 back with new firmware I found that the RAD kicks out, goes blank, when I start the engine. My avionics guru says that it is indeed a function of the firmware change. I have learned to simply recycle the 930 CB after starting engine which reinitializes the RAD. JPI wants the unit to bypass the master but that apparently means the CB would be @ the battery and not accessible to the pilot, not very good, osistm.  

[N601RX]

JPI also has a 2nd power input that can be used to power the unit in the event something happens to the Circuit breaker that is located at the battery.  I have the primary input wired directly to a CB mounted beside the battery and then the secondary power input is from the avionics bus. These power inputs are isolated inside the JPI so they cannot cross feed each other.

[carusoam]

More incidences of why people like EI...

There stuff isn't any better, but their people are.

My JPI is decades old with no issues.

People with the EI stuff go out of their way to talk about their service.

Best regards,

-a-

[Bob_Belville]

David,

 

Tthe owner of the avionics shop who did my panel including the 930 will be here Saturday. He and Lynn Mace our local A&P shop owner can give you better answers and advice but I think you'll get all new probes. (There is some recovery value in your 450 and 700.)

 

The labor for the 930 was 36 hours in my case including:"Remove all existing engine instruments and replace with the JPI EDM 930 engine monitoring system. Remove fuel senders from fuel talks, and install after overhaul." 

 

The pic is the 3 transducers for MAP. FP, and OP mounted on the firewall which keeps oil and fuel line out of the cabin, if that has not been done previosly. That's a very good thing in our vintage models.

[carusoam]

Nice install Bob!

Getting flammable liquids out of the cockpit is a great idea.

Best regards,

-a-

[8kcab]

BTW, when I got my 930 back with new firmware I found that the RAD kicks out, goes blank, when I start the engine. My avionics guru says that it is indeed a function of the firmware change. I have learned to simply recycle the 930 CB after starting engine which reinitializes the RAD. JPI wants the unit to bypass the master but that apparently means the CB would be @ the battery and not accessible to the pilot, not very good, osistm.

Same here! When I start the engine the RAD goes blank. Any suggestions to fix that in the long term?

[Bob_Belville]

I still have to recycle the EDM CB about half the time. When the engine starts quickly the RAD usually stays on.

 

When I get a chance I need to fly over to the avionics shop to have the GTN750 firmware updated. Perhaps they'll know something they can tweak with the EDM.

[8kcab]

Thanks Bob!! Please let us know...

[N601RX]

Did they run the power wire all the way back to the master relay like the manual calls for? It sounds like they may not have and the voltage is dropping to low while cranking.

[8kcab]

Thx n601rx! I'll check this out...