General: Drivers Information Module (DIM) replacement

[AndyPro]

Originally Posted by keithC70

Andy if you look at my post just a few below this one you'll see what I did. I posted photos and an explanation.

Like you I went over the board re-doing quite a few joints but the main job was in re-doing all the joints on the chip - very tiny and close together.

Everything worked correctly for about 1000 miles but now I've got occasional loss of green turn indicators. It doesn't seem to be related to time/heat in a journey, and sometimes when indicating they'll suddenly start again.

If you find out which part of the pcb relates to this I'd like to know so I can try to re-solder the relevant bits.

I had another go at the DIM last weekend and this. Last weekend I replaced the two duff bulbs, although with 2.3W bulbs rather than 3.0W due to not being able to find replacements at a decent price.

This weekend I reworked the joints that controlled the indicator lights and click sound because these started intermittantly failing. It seems that these are digitally driven from the Yazaki YG5003B chip via the topmost of the Darlington driver ICs to the right of it. I'm not sure what the Yazaki chip is but suspect it's a Programmable logic array or similar (i haven't found a copy of a datasheet for it yet though). Everything's controlled from the large MC912DG128 microcontroller IC on the top left of the board which I guess is what gets programmed when a new DIM is installed.
So, I reworked the Yazaki chip and the Darlington chips, as well as some of the nearby diodes on the other side of the board. I also reworked the speaker/buzzer at the bottom of the board just in case this is also where the click comes from. There is a relay that could be providing the indicator click, but from what datasheets i've found, it seems to be able to handle a lot of current and would be a waste to use simply to provide a click.

I'll have to do some investigating whilst the DIM is connected and running to see what's really connected to where, and I'll need to get hold of an oscilloscope to check the signals.

Andy

[jajrst]

If it helps, I believe the Yazaki chip is a voltage regulation module (vrm). They apparently overheat or become loose and its not unheard of for people to put a small heatsink onto it to keep it cool. Hope this helps

[AndyPro]

Hi jajrst,

I'm waiting on details from a several companies on the Yazaki chip - all far eastern. I doubt it's a VRM. VRMs don't tend to have about 100 pins sticking out of it. Besides, some of the the Yazaki chip's pins seems to be tied to the Microprocessor (uP) and others go to current driver chips turning on warning lights, etc., which is why I suspect it's a programmable logic array.
WARNING - Tech stuff: I suspect the uP outputs a code on the data bus on a memory address that accesses the Yazaki chip, and the internal logic of this PLA toggles or switches on/off lights, sounds, etc. based on the databus code. It's standard memory mapping practice. A PLA is used to replace dozens or possibly hundreds of other simple logic chips.

When Volvo say that the DIM can only be programmed once, I guess this programming is done on the Yazaki chip (but I need the data sheets to confirm). The uP is Electrically Eraseable so could be reprogrammed if need be (e.g. for software updates).

In normal use a PLA should not overheat, unless the output devices or contacts were drawing too much current, e.g from a solder short, or component failure. They may get hot, but so do most complex ICs. Doesn't mean they need a heatsink.

Note that the voltage regulator on the DIM is a five pin module at the edge of the board that has a temperature and overcurrent cutout circuit on it. If people are seeing their DIM resetting (dials bouncing to zero and returning to normal), then it could be that the heat sink on this regulator just needs to be tightened up to improve heat disipation, or check for foreign objects (e.g. soot, moisture, dirt) on the board.

Andy

[jajrst]

It's that 5 pin one that I was talking about lol, It's also a Yazaki chip apparently. It's the one that causes the dials to drop to 0 which makes sense to me. I'll leave this one to you though lol, you seem to know a lot more about hardware me. I'll stick to the software I can do that lol. Good luck

Some links which might be useful :

http://www.volvo-forums.com/index.ph...topic=13321&hl

http://www.volvo-forums.com/index.ph...topic=19793&hl

[Model flyer]

Hi I have just had my DIM repaired . My car is a late 02 v70 D5 and has covered 160,000 miles .It still drives like a near new car but the dim started to mess about. First was the trip reset not working properly then indicator ,clock etc . I tried resoldering the board but obviously missed an important joint as it still didn't work properly. So I took it BBA reman
http://www.bba-reman.com/catalogue/index.aspxat Rochester airport in kent . Cost £172-50 with a two year warranty . Excellent service although they are very busy and took four working days. Recommended and everything works perfectly.

[Propofol]

resoldered my chip a couple of months ago, all still working perfectly. Just need to put some new bulbs in the DIM now.

Worth a try fixing it yourself, just be careful. Incidentally I'd never done anything like this before. Sorted for the cost of an £8 soldering iron.

[bogart]

Swapped all the bulbs(lamps) for LEDs. Stupid prices for the 3W general illumination lamps of around £2 each.

[Propofol]

where did you get the LEDs from? And did you need to modify them to fit?

[bogart]

As you are probably aware there are different lamp holder colours black,blue and grey. For the blue and grey I used these.

http://cgi.ebay.co.uk/10x-T5-286-WHI...item334accc538


They need no modifying at all, a straight swap.
You can use these for all the lamps but I used a slightly different approach.

For the black holders (5off) I used these

http://www.led1.de/shop/product_info...cd-wide-c-3_98

in series with a 560 ohm resistor. I soldered directly onto the track.

The display has a very pleasant ever so slight blue tinge.
As the life of a led is measured in 10s of thousands of hours that should be it.
Plus they generate no heat compared to incandescent.

[Propofol]

Thanks mate, why did you choose to fit these ones instead in the black holders?