Simon's new Xantia V6 and Leaf blog

[white exec]

Well done to get both the faults fixed and diagnosed. Not half bad for a Friday!
Sorting the Ion charger a great relief. Hopefully the up-spec caps will soldier on.
What current rating was that hrc fuse, btw?

[Mandrake]

20 amps, 450 volts DC.

As I expected Amayama sent "original" Mitsubishi fuses in a Mitsubishi bag with a Mitsubishi part number. On the fuse itself it only gives its 20 amp 450V DC rating - there are no other numbers or symbols, so it's anybodies guess who actually makes them. They're quite a bit bigger than they look in photos, considerably larger than common glass fuses.

[NewcastleFalcon]

Success!

Excellent diagnosis and fix Simon, and all told the bits required inexpensive apart from the shipping and the customs! Great result for you. Will it accelerate the looking for a replacement?

Well done

REgards Neil

[Zelandeth]

Entirely possible the fuses are made in house. Don't forget that Mitsubishi make quite a bit of bigger electrical gear.

Used to make some cracking TVs too...still have a CT-2023B from the early 80s waiting patiently for its turn on the restoration operating table at some point...

[Mandrake]

Entirely possible the fuses are made in house. Don't forget that Mitsubishi make quite a bit of bigger electrical gear.

Used to make some cracking TVs too...still have a CT-2023B from the early 80s waiting patiently for its turn on the restoration operating table at some point...

Good point, although I think Mitsubishi Motors is a seperate entity to Mitsubishi Electric in the Mitsubishi group. Here is the spare fuse I have along with the faulty one:

If I'm selling the car soon I won't have any need for the spare one but I'll keep the spare fuse and capacitors in case anyone else in the UK has to do this repair and they can have them and avoid the customs snaffu I went though!

"Fuse, Motor" is misleading by the way. Although it's physically inside the motor control unit it has nothing to do with the motor and the car can still drive without it. It passes through to the onboard charger so the fuse affects charging of both the traction battery and 12 volt battery.

A 20 amp fuse would not be enough for the motor when the drive inverter can draw in excess of 150 amps!

[lexi]

So many arms that company. Diatone is another string to their bow. Made the Berryllium drivers for Yamaha in their classic NS1000M speakers, as well as their own stuff that was never sold here.

[white exec]

Not to forget Mitsubishi Paper Mills, which produced not only paper, but coated products like photographic printing plates.

Some of the Japanese companies we know for a few products, eg Fuji (film, cameras), Pentax (cameras), actually major on quite different products. Pentax make vehicle windscreens and glass, and Fuji Heavy Engineering do excavator and earth-moving plant, as well as large chunks of power stations.

Another Japanese company, Savin, is/was virtually unknown in the west. In UK, the only products visible were CRT oscilloscopes and electric drills. But, lift off the covers of almost any Japanese photocopier in the 1980s, and there were copious quantities of Savin chassis, mechanicals, drums and optical systems, sometimes alongside Sony pcb's.

Why compete when you can co-operate?

[Mandrake]

Yesterday I had a look at the gear selection problem on the Xantia and I now seem to have fixed it, however I'm not completely sure exactly what the problem was!!

I knew from changing the switch that it wasn't the switch itself faulty, it was also unlikely to be the ECU itself so it was something between the connector and the ECU. There is a relatively short run of wiring harness between the switch and ECU which lives under the battery, which can be seen here:

I decided to do some continuity testing on the wiring harness between the two connectors, so out with the battery tray and ECU, however before I even got as far as putting a multimeter on I spotted some severe corrosion on a few of the ECU pins:

Aha, that will be the problem, right ? Well, no, because the corroded pins are not the pins going to the switch that could cause the issue!

The worst corroded pins were pin 12 - which goes to the sport mode button, which was working, pin 20 - output signal for fan request, which I believe asks the engine ECU to turn on the radiator fan, and pin 21 - Analogue earth for transmission oil temperature sensor.

Not so bad but still iffy are pin 10 - brake pedal switch (which was working) and pin 15 - transmission sensor output screening.

So none of the visibly oxidised pins is anything to do with the gear lever switch unfortunately. When I did a multi-meter test of pin 9 on the ECU connector to pin 4 on the switch plug continuity was fine and no amount of twisting of the wires caused it to drop out. So that killed the broken wire theory.

So I set to work cleaning up the pins on the ECU and connector. I had to use a combination of a bit of abrasion on the visibly white pins as well as a lot of scrubbing with a toothbrush with contact cleaner. The female holes in the plug in the middle group of pins are too small to get a multimeter probe in or anything to clean them, so the only way to clean them is to spray contact cleaner into them and then repeatedly engage and disengage the connector - which I did a couple of dozen times.

I then ran another test and found that I could now get 2nd, drive, and reverse to register, however there was quite a long delay of more than a second after going into reverse before the computer would register reverse and the car would move, and a somewhat long delay for drive as well.

I noticed that the alignment of the gear lever position seemed slightly out so fiddled with the black adjustment thingy near the lever arm until I was happy that each gear was being "lost" an equal distance either side of the correction position.

So at that point it seemed to be working however there was still something like a 1.5 second delay between putting the gear lever in reverse until the computer registered reverse and maybe a second delay before registering drive. Very strange. I tried twisting and wriggling the wiring harness where I thought it might have been broken but it had no effect.

At that point I thought I'd done all I could and was about to reassemble it when I decided to put some lithium grease on the connector to try to prevent any future corrosion. I put some grease around the rubber o-ring but also a good amount on the middle of the plug so that it would go into the individual pin holes and seal them against any battery acid leakage etc.

I then engaged and disengaged the connector a few times to work the grease in then tested it again. To my considerable surprise the 1.5 second delay was gone and it was engaging reverse and drive reliably within a fraction of a second! In fact the operation of the gear lever now seems to be perfect. So what happened ?

I don't know for sure exactly what the problem was, except that it was a bad connection between the switch and ECU... but what baffles me is that despite using plenty of contact cleaner and doing about two dozen engage/disengage cycles to wipe the contacts and thoroughly clean them, there was still a 1.5 second delay in registering reverse.

My theory is that despite all my cleaning there must have still been a very high resistance connection between the ECU plug and ECU, which together with shunt capacitors on the data input lines (which it probably has for noise suppression) creates an RC delay circuit.

So how did the grease help ? Grease is an insulator of course so I think the only reasonable explanation is that the connector was not mating correctly with the plug on the ECU due to friction and that the grease acted like a lubricant beween every pin and hole to allow the plug to push in further than it had been. Perhaps some of the pins had only just been touching at their tips instead of sliding in properly.

Tenuious I know, but I can't think of anything else. I can't get it to play up now and the delay is definitely gone. So I'm happy, as long it doesn't return!

One other thing I noticed during all this testing is that the gearbox was really "slamming" into reverse with a hard jolt so I did an auto adaptive reset and went for a 10 test drive to let it adapt. After this it now seems to be going into reverse much more gently, no more hard slam.

So the Xantia is mobile again and can go forwards and backwards, however the aircon compressor is pretty scary sounding now so I'm going to try to avoid driving it until I get the aircon compressor replaced.

[white exec]

That white pin corrosion did look like result of acid (fumes). Not the ideal location for an ECU and its connector.
Have always had reservations about using grease (insulator) on electrical connections, except for dobbing it on after everything has been cleaned up and assembled - eg on grounding points - to keep moisture out. Not practicable with this type of connector, nor is conductive grease . But know others swear by it.
Worth bagging the ECU connector in some polythene, or even a bit of self-amalgamating tape, to keep vapours out?
Those old lead (Pb) battery connectors ought to go too - getting elderly now, and they do deteriorate inside, and lose grip on the cable strands.
The delays you were getting were very odd, but must have be down to poor contacts.
If anything like our XM (which it certainly is) the car will benefit by being driven at least once or twice a month, just to keep everything clicking and mobile. These cars do seem to thrive on use.

[Mandrake]

I don't normally make a habit of putting grease in an electrical connector except if there is a risk of water or salt etc getting in past the seals - and clearly the seal on this plug isn't doing its job as that corrosion wasn't there last time I had that connector off about 6 months ago.

Grease is a good insulator but the theory is that a thin grease like this will simply give way when mating sliding contacts so that the pins still mechanically touch at contact points and the grease fills in the microscopic gaps around the contact points that otherwise wouldn't be touching anyway and prevents water, salt air etc reaching the pins.

In this case I think the positive effect has come from the lubricating properties allowing the connector to mate together better as it has a hook at one end and a lever arm at the other end, the hook end of the connector barely moves, and there is also quite a bit of slack in the mechanism. So I think it's possible that not all the pins along the plug were sliding into contact as far as they should.

In any case it seems to have fixed it so I'll take the win!

[myglaren]

I thought that using Vaseline on the pins of the 12V downlighters I have seemed decidedly suspect but the bulbs were lasting no time at all so tried it and it is fine.
I expected them not to work at all but they did and do. The explanation being that the Vaseline improves thermal conductivity in the pins reducing the heat from the filament - which should reduce the light output but that is unnoticeable if it is a thing. The bulbs certainly do last a lot longer though.

[white exec]

Interesting. Many high-current (12v, 24v) lamps have pins that run hot, and not much in the way of thermal sink, so the heat just builds up in the contacts. This can cause pins/contacts to actually oxidise, acquire resistance, and get into a viscious circle of more heat and contact failure.

Back in the 80s, I was heavily involved in AV, and many projectors used a 24v 250W 6.3 bi-pin halogen lamp, the A1/223. Lamps bought from Philips and Osram all had gold-plated pins as standard, and these never oxidised. Some other makes moved to steel pins, or lightly nickel-plated ones, and there was an epidemic of both lamp failure and, worse, lamp-holder burn-out, where the pins and contacts literally incinerated, unable to cope with the 10A load. Hundreds (likely thousands) of slide and OH projectors had to have their lampholders replaced. Philips and Osram responded well, and kept gold-plated versions of the lamps available, but only after complaints were raised at national level in the UK and elsewhere.

12v 50W halogen downlighters could also be susceptible in cheap lampholders, so using grease/vaseline on the pins, to help deter oxidation, makes sense. High melting point conductive (copper) grease might be even better, if carefully (!) applied. Some really good LED downlighter bulbs now available, where 7W = 50W equivalent. Some are even dimmable. Leroy Merlin do some particularly good warm white ones, which make a good replacement for 12v MR16's.

[myglaren]

I'm gradually replacing mine with LED downlighters. Have piles of halogen bulbs to wade through first though.
And have a couple of projectors with expensive Osram halogen bulbs. Great care needed to cool them down before moving the projector. One day I will buy a film scanner and convert all the slides and negatives - if I live that long.

[white exec]

On projector lamps (and filament lamps in general), there is an essential choice: mains voltage or low voltage.
Mains voltage lamps have the disadvantage of needing a long filament, which is inevitably thin and delicate, and needs careful handling, especially when hot.
Low voltage lamps (usually 12v or 24v) have thick, chunky filaments, and are inherently much more rubost, don't need much in the way of post-cooling, and can withstand vibration well.

Lamp life used to be as low as 25h for the 230v 650W A1/233 'peanut' bulb used in overhead projectors, and cost around £6.50 each. In contrast, the 24v 250W A1/223 had a better light output, a smaller filament (so better image focus), a life of 50-100h, and a then cost of just £1.25.

We discovered that many of our mains voltage projectors could be easily converted to the 24v lamp, by simply fitting a transformer and an appropriate lampholder . . . which actually slotted into the old lampholder, and brought the new 'point source' filament into exactly the right place. We authored a set of printed instructions for doing this, and I remember mailing out almost 2000 sets of these worldwide in the late '70s. No internet back then!

Such low-voltage conversions are still possible to do, where there could be an embarrassingly expensive mains voltage lamp. Mains voltage downlighter bulbs might be cheap and transformerless, but they are nasty, compared to the 12v option. Fortunately, mains voltage LED downlighters are now available.

[myglaren]

I bought some LED downlighter bulbs a while back. Fitted one and the light was dark blue
Thought it must be mains (no indication on bulb or packaging), tried it in the mains and it worked admirably, very bright light - for half a second - oops.
I had forgotten that the downlighters have a 12V AC supply.

The last projector bulb I bought was £35, for a Rollei 35mm + 6x6cm projector