[AT] Not quite an antiques problem...

Tue Dec 20 18:28:30 PST 2022

All I want for Christmas is a five amp fuse!

Some (most?) of you are old enough to remember the Spike Jones (And His 
City Slickers) song of the fifties: "All I want for Christmas is My New 
Front Teeth", and will be able to fit the new words to the tune.

To reprise: I had planned to pull some plastic off looking for earth 
connections, but some of the screws are impossible to get at without 
major surgery - so I went back to the book.

There was mention of 25 and 60 amp fuse links on the left side, but 
since I couldn't work out where that was, I went back to the fuse 
diagram - and noticed a 5A off to the side of the fuse block, below the 
empty spares slots. I had overlooked it yesterday, and was surprised & 
pleased when I pulled it coz it was blown - and it controlled the ECU.

Had to try three places to buy a replacement, but when it went in & the 
key was turned - the sun shone, the birds sang, the gentle summer 
breeze blew, and all was well with the world and the "Yellow Lexus."

On reflection: since a number of services had failed at the same time, 
it was clear there was a fault common to all of them.  My first thought 
was an earthing problem coz of the months of damp weather & non-use, and 
Farmer's saying "Check the grounds! Check the grounds!"

In addition, when we were last in Hong Kong a few years ago, our China 
Airlines A320 was sick.  We were in business class (thanks Qantas 
Frequent Flyer) and could see into the cockpit.  The second officer came 
to us to say that the aircraft had "lost "several thousand litres of 
fuel from both wing tanks.  Since there was none on the apron, he was 
assuming an electronics problem.  In due course a couple of techs 
arrived, pulled and replaced a pair of large boxes from the rack between 
the cockpit seats, but  continued to dither.  Apparently the two new 
computers did not solve the problem. It occurred to this mug farmer that 
it would be rather unusual for two separate computers to fail 
simultaneously.  What is common to both would be the sensors, assuming 
they shared a common earth connection.  Who knows!

Overnight I contemplated what was common between the failed JZ140 
systems, and again it came down to grounds - or power supply.  Since I 
had no easy way of checking for a common power supply, I was left with 
bad grounds - until the overlooked fuse was discovered.

Now it's back to hay baling this arvo; putting everything back in the 
JZ140 can wait.

JV

------ Original Message ------
From: "Dennis Johnson" <moscowengnr at outlook.com>
To: "Antique Tractor Email Discussion Group" 
<at at lists.antique-tractor.com>
Sent: Tuesday, 20 Dec, 2022 At 1:37 PM
Subject: Re: [AT] Not quite an antiques problem...

John,

I had a Start/Stop issue come up today. Not sure if this relates to your 
situation, but is worth sharing anyway.
I was moving my Hustler Super Z out of the way so I could get tractor 
out of the garage and clean up to insulate walls. Got the Super Z to 
start, and then would initially, but die whenever I moved a lever. Found 
out the key was sticking in the start mode, so when I moved any lever, 
the “do not start with drive engaged” circuitry kicked in and killed the 
engine. Restarted and manually moved the key to the run position and all 
was well. (On the Super Z) Not sure this is your issue, but easy to 
check.
Went to start my IH 2504 and not so good luck. It is not firing. 
Guessing I need points and condenser, but was in a hurry so I pulled it 
out of the shop for now,
Does anyone know if there is a conversion kit to switch out points to 
some electronic pointless system to make spark on an IH 2504 or 504 
tractor??

Thanks
Dennis

Sent from my iPad

> On Dec 19, 2022, at 2:54 PM, John Maddock <agtronixjv at bigpond.com> 
> wrote:
>
> 
> ....but a puzzle for the brains trust, never the less!
>
> JCB JZ140 excavator, (9500 hrs) electrical problem.
>
> Briefly:  machine has not been used for most of the winter, but I’ve 
> topped up the batteries twice each month.  Noted at the last charging 
> session a week ago that  one of the batteries took a long time to 
> reach full charge.
>
> Today, the electronic monitor screen showed low battery voltage & the 
> starter motor refused to operate.
>
> Connected 24v from external batteries & everything sprang to life as 
> normal.
>
> Moved the machine maybe 5.0 m to lift and reposition some equipment, 
> then moved it 5.0m back again, the engine running for maybe 15 mins. 
> Aircon was on at the same time to wet the compressor seals.  Decided 
> to check the battery state, so killed the engine and re-started it - 
> just.  Tried again, and the screen showed low battery voltage and 
> flywheel sensor fault.
>
> Reconnected the jumper batteries - and observed the following:
>
> 1. “Dead” electronic monitor unit; no screen, no symbols.
> 2. A very dim LED on the Emergency Stop button. (Usually, that has to 
> be used as well as the switch to stop the engine. No idea why; been 
> that way since I bought the machine).  In addition, pressing the 
> button did not switch off the dim LED, as it normally would.
> 3. The engine starts - and stops instantly.
> 4. The throttle arm does not move; it is unclear if it remains in the 
> “engine stop” position and as a result the engine is somehow running 
> briefly on residual fuel.  The run/instant stop is repeatable, not a 
> oncer.
> 5. Switching to “limp mode” makes no difference to any of the above.
>
> I’ve:
> 1  checked the fuse for ECU-STD, EMS Battery Supply; multimeter said 
> its ok.
> 2 disconnected the onboard batteries; now running completely on fully 
> charged, external, jumpered batteries.
> 3 Read the service manual carefully.  It suggests checking 
> input/output voltages at several input/output points on the ECU.
> Considering Farmer's frequent calls "Check the grounds, check the 
> grounds" does this sound like an earthing fault at a point common to 
> all the observed irregularities?
>
> JV
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