YANIC problem!

From CEM to VEM, from LED to lightbulb and more. If you have an electrical problem, like a broken info-centre, search for answers in this category. This is also the place to be when you expect the problem to be of an electrical nature...

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andyb2000
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YANIC problem!

Post by andyb2000 » Sun Jul 28, 2019 4:11 pm

Yet Another Info Centre problem!

Volvo480ES 2.0 1994 edition B20F engine.
Having had success with the replacement ECU, the engine now runs, so onto the other bits, one being the info centre.

When I first got the barn-car the info centre was visible if you shone a bright light at it, so was just the halogen bulb failed, replaced that and at that point it worked. Since then about 8 months have passed and now have the engine working, but the info centre has died completely, so LCD at all, backlight still working.
So I've removed the dashboard, info centre, etc, and re-flowed the majority of connector solder points, reflowed the ribbon cable connections and any other joints that looked a bit dodgy.
I've also replaced the 16v 100nF capacitors on the info centre computer board.

Put it back in the car, and still nothing. So I then started to press at the back of the board and at one moment I did get the display light up, however it wouldn't respond to changes to the info selector or do very much.
I was pressing around the red highlighted area, so suspect poor connection somewhere, my thoughts there are either the 6 pin/socket on the left that feeds signal through to the info centre LCD module itself (The green there was a telltale, I cleaned up the contacts, etc, maybe not enough? Although continuity meter seems to show good connections).
Image

I also don't have the fuel gauge lit up either, is this separate to the info centre computer, so could you get one without the other? The fact both don't work make me think it's the LCD module rather than the infocentre at fault?

I did take the whole LCD module apart too, and I'm wondering if the friction connector that presses onto the LCD itself is faulty/not making enough contact?
Image

So, I guess the questions I'm after if anyone can help:
  • should the info centre temperature, mileage work independant of the fuel gauge, proving either the infocentre computer (in white box at back of cluster) or the LCD/bar system itself?
  • What are the inputs/pin to voltage test on the console and info centre? Wiring diagram would be a big ask, but amazing if anyone has it
  • Is there a simple way to bench test? I have electronics test gear and stable/regulated 12v supply that I can apply, if there is a way of applying this safely and testing if I get an output from the infocentre display, again pin-outs would be good if anyone has them.
  • Is the infocentre/dashboard paired to the ECU? Since I've changed the ECU out is there anything to do (I doubt it being this age, I'm more used to modern cars and use opcom, autel, etc, to re-pair the relevant components)
Thanks as always folks, eventually my 480 will be back on the road!
Thanks for all your help! - Andy
Volvo480 ES 2.0 petrol - 1994 (UK RHD L-reg)

Robou
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Re: YANIC problem!

Post by Robou » Sun Jul 28, 2019 10:48 pm

When you take the infocenter fully apart you'll notice the elecrical connections to the glass substrate are made by a strip in which there are conductive parts. Both ends may have a failing contact. Clean the surfaces with whatever you find appropriate and may be you find a way to put more pressure on the connections. So far I haven't seen any directions on this subject so this is quite DIY, but I'm sure it solves many strange problems, like it did for me.
I believe member Brinkie has developed some benchmark test, last resort may be contacting him.
Too old to bother
480 Turbo midst '91

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brinkie
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Re: YANIC problem!

Post by brinkie » Mon Jul 29, 2019 7:43 am

Hi,
andyb2000 wrote:
Sun Jul 28, 2019 4:11 pm
I did take the whole LCD module apart too, and I'm wondering if the friction connector that presses onto the LCD itself is faulty/not making enough contact?
Could be. But my experience, after having dealt with dozens of instrument panels, the LCD's in later ones rarely give trouble. You could try and take the Zebrastrip out (that's how it's called, it's a flexible conductor), clean the contacts on the PCB with a glassfibre brush and put it back together again. I always put a small strip of paper between the display front and the white housing (invisible once put back into the large black housing), to generate extra pressure. I have spare displays if you need one.
If you are sure you have seen the display come alive, you can rule out a power problem.
Have you already tried to re-solder (not reflow, that only makes things worse) the five pins on the LCD board?
So, I guess the questions I'm after if anyone can help:
  • should the info centre temperature, mileage work independant of the fuel gauge, proving either the infocentre computer (in white box at back of cluster) or the LCD/bar system itself?
  • What are the inputs/pin to voltage test on the console and info centre? Wiring diagram would be a big ask, but amazing if anyone has it
  • Is there a simple way to bench test? I have electronics test gear and stable/regulated 12v supply that I can apply, if there is a way of applying this safely and testing if I get an output from the infocentre display, again pin-outs would be good if anyone has them.
  • Is the infocentre/dashboard paired to the ECU? Since I've changed the ECU out is there anything to do (I doubt it being this age, I'm more used to modern cars and use opcom, autel, etc, to re-pair the relevant components)
  • No. The microcontroller board, which is piggy-backed to the main board, generates the complete display. A control signal is fed to the display controller inside the LCD, which in turn controls the elements on the LCD. The LCD controller keeps whatever information is fed, sometimes my info centre computer crashes and then the display is frozen.
  • Everything is fed with battery voltage. The computer has an independent voltage regulator to bring the voltage down to +5V, the LCD controller just seems to take everything between 8 and 15V. If you go to the download section, you can find a service manual there. You need the information for the green and grey connectors.
  • Yes, it is very simple; connect +12V (approx. 2 amps) and ground to both the main board and the info centre computer through the corresponding pins found in the diagram. +12V: Grey connector pin 12 and 17, green connector pin 3; ground to grey connector pin 7 and green connecor pin 10. Connect a 400 Hz signal to green connector pin 6 and you have approx. 120 mph speed, a strong (>5 Vpp) 100 Hz signal to grey connector pin 15 and you have 6000 rpm.
  • Not paired in the way modern cars do. The ECU sends the injector signal to the display controller, so it can calculate actual fuel consumption. The speedometer sends a speed signal both to the display controller and the ECU. I'm not sure what the purpose of the latter is, but absence of a speed signal gives a non-critical error in the ECU (no error lamp or limp home mode will , but it is stored as an error code in ECU memory)

    It is very helpful if you can source a piece of wiring loom with the green and grey connectors in the car. This way you can solder 68 ohm resistors to the sensor inputs, make proper cables to the power supply and signal generators, etc. If you really like doing that stuff, and like to repair instrument clusters for others, I can send you a load of spares and you can become the UK Dashboard Repair Hero :lol:
Robert.

Present cars: 1994 Volvo 480 GT 2.0i Vase Green, 2010 Volvo V70 2.0F Momentum Mystic Silver
Past: 1981 Talbot-Matra Murena 2.2 Rouge Mephisto, 1995 Volvo 480 GT 2.0i Paris Blue

jifflemon
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Re: YANIC problem!

Post by jifflemon » Mon Jul 29, 2019 7:50 am

brinkie wrote:
Mon Jul 29, 2019 7:43 am
I can send you a load of spares and you can become the UK Dashboard Repair Hero :lol:
Image

andyb2000
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Re: YANIC problem!

Post by andyb2000 » Tue Jul 30, 2019 2:23 pm

Thank you for the details help, really good info, and thanks brinkie, I'd hoped you'd pop a note on there being the authoritative source of information.
Yes I resoldered, not re-flowed, I should have been more specific, I used good ol' fashioned solder, the dangerous type :lol:

I tried to get the downloads from the main site but they're all timing out for me, anyone else can check/confirm too? If anyone can get to them if you can send them to me that would be appreciated. I'll try again from a mobile connection later. (I work for an ISP, so my work and home share address ranges)

With that info I'm going to take a closer look at the zebrastrip as I'm thinking that may be the issue, good idea on the strip of paper, I was thinking similar to create more force as it felt quite loose when removing the clips, I'll try probing for the supply voltage down to the +5v to check that part first as that's the easier components.

I like the idea of a spare wiring loom and connectors, depending on how far I get I might go down this route, and not sure I'm ready for a bulk of repairs heading my way! I'll keep notes though as if I can help others!
Thanks for all your help! - Andy
Volvo480 ES 2.0 petrol - 1994 (UK RHD L-reg)

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brinkie
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Re: YANIC problem!

Post by brinkie » Wed Jul 31, 2019 7:52 am

I do not work for an ISP, but I do have access to the www.volvo480register.nl website; when I find time (I really need to try and invent a TARDIS :lol:) I will upload all documents there.
Any scrap car from MY1989 and onwards will supply you the mating connectors for your instrument cluster. There is someone on this forum breaking a car, so maybe he is willing to part from a wiring loom. :)
Robert.

Present cars: 1994 Volvo 480 GT 2.0i Vase Green, 2010 Volvo V70 2.0F Momentum Mystic Silver
Past: 1981 Talbot-Matra Murena 2.2 Rouge Mephisto, 1995 Volvo 480 GT 2.0i Paris Blue

andyb2000
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Posts: 40
Joined: Wed Sep 12, 2018 12:04 pm
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Re: YANIC problem!

Post by andyb2000 » Tue Aug 20, 2019 12:36 pm

Hi folks,

slow progress on my Info centre work, I've managed to purchase a wiring loom (Thanks Benjamin) so I can rig this up on my bench and work it out. Had the whole thing apart again, checking all pins and joints for problems and so far nothing looking faulty to me.
Put it all back together after my tinkering, taking it apart, refitting, checking connectors, etc, and still no luck with it.

I'm going to set up for testing it on my bench and work from there, I'm also going to look out for a spare infocentre/dashboard that I can use as secondary whilst working on it to figure it all out. Fingers crossed!

(Now onto the mechanics of the car, brakes and suspension components)
Thanks for all your help! - Andy
Volvo480 ES 2.0 petrol - 1994 (UK RHD L-reg)

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