Is my LCD dying?

dikidera · Post by **dikidera** » 27 Nov 2023, 01:44

On my S60 odometer, the LCD that displays fuel consumption and messages seems to have started to have characters disappear?

It's supposed to be a 32 character display, but it feels like I am down to 30. My program was constantly writing to the display and then one day one character was missing at the end. Then I compacted my writing to 31 and then again one day another character at the end disappeared. Now I believe I am limited to 30.

02V70 · Post by **02V70** » 29 Nov 2023, 23:21

The common problem with these instrument clusters is that the soldering starts to weaken over time leading to a bunch of issues. For me, it was so bad that the dash would be completely dead most of the time. I was able to fix mine by resoldering a bunch of joints.

The chip I circled is the one that controls the LCD. However, since the pins on that paticular chip are so close together, it is really easy to bridge two pins with solder and completely mess up the display if you try re-soldering it. You might be lucky and the ribbon cable connecting the LCD has become slightly disconnected over the years.

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dikidera · Post by **dikidera** » 29 Nov 2023, 23:47

I already had a similar accident of pin bridging on my HU650 it took me hours to fix it and then triple check with the multimeter. Thing is my odometer was already refurbished once, it is obvious it has been opened already as the needles are not aligned properly and give me lower than normal values.

Post by **vtl** » 30 Nov 2023, 08:13

DIM is commonly a source of endless PIA in those P2 Volvos. Do you have a hot air station? You can try to reflow that chip and some other discrete elements that typically go bad.

yanga001 · Post by **yanga001** » 30 Nov 2023, 08:22

Reflow is your best bet. The enemy of solder joints are heat, vibration, shock, and moisture. We can control for the last one with conformal coating, but the other three will take a toll over the lifetime of the vehicle. Reflowing is fairly easy for non ball grid array devices. Take care not to cook the LCD or other plastics by mistake.

Post by **volvolugnut** » 30 Nov 2023, 08:23

Mercedes cars of 2000 vintage have a problem with ribbon cables to temperature and clock displays. There are ribbon cables available for replacement. You use a flat bar on a soldering iron to CAREFULLY reapply the ribbon cable to the display chip. I got the clock right but messed up the temperature display.
There may be cables for Volvo if this is the same situation.
volvolugnut

Post by **vtl** » 30 Nov 2023, 08:28

yanga001 wrote: ↑30 Nov 2023, 08:22 Reflow is your best bet. The enemy of solder joints are heat, vibration, shock, and moisture. We can control for the last one with conformal coating, but the other three will take a toll over the lifetime of the vehicle. Reflowing is fairly easy for non ball grid array devices. Take care not to cook the LCD or other plastics by mistake.

The worst enemy is lead-free ECO-friendly solder they started to use in the 90s. https://en.wikipedia.org/wiki/Tin_pest

They knew it would happen, so they didn't take the risk of going lead-free in CEM, ECM and TCM, and potentially killing off some customers.

When I reflow something automotive I always add lead solder. Even small amount of lead will stop the tin pest.

Also dikidera add some heat sink to the chip. I had a DIM glitch like 10 years ago, reflowed it with air right over the coating and glued a heat sink permanently.

dikidera · Post by **dikidera** » 30 Nov 2023, 12:08

Thanks for the suggestions guys. Luckily I have everything from lead solder to a hot air station.