Sat Nav Type C Display Repair

[jonsowman]

After looking at this thread, I'm wanting to have a go at repairing one of these. I've a fair amount of experience in reflow and surface mount soldering.

So question is, has anyone got a broken one lying around?

I couldn't offer to pay much, but since they'd otherwise be thrown away...

[GingerMagic]

Hi mate, I have one. It has quite a few lines but it is still readable, just.

I was going to keep it as a spare but it will probably rot before I need it. If you like I can bring it to Haynes.

No payment required, but I may keep just the surround to use as a project one day.

[jonsowman]

That would be great if you could bring it to Haynes, thanks a lot! By all means keep the surrounds and trim etc

Anyone else got one? I could do with a few for my experimenting

[FarmerPug]

I sent one to some place called ribbontrade ltd
http://pixelfix.net/eng/
that fixed saab displays they seem to break in the same way and replacement ribbons are offered, but the display for the 406 is much rarer that it wouldnt be economical for them to make a ribbon.

Their explanation at the time:

Normally, the Z axis conductive adhesive dries over time, but in case of Peugeot 407 and 607 my experience is that replacing the ribbon and the adhesive does not help. The problem is caused by some sort of short caused by oxides that grow between the plumbum oxide pads / traces. This short overloads the driver IC and makes it malfunction if it heats up.

So I'd say the glass and the cable should both be replaced to get these units fixed properly...

Having said that, i still think the hot bar reflowing technique is promising, id happily send you a type c display but ribbontrade never sent mine back, the one in my car is starting to intermittently loose horizontal lines

[jonsowman]

I've got several things I want to try with these, including hot air reflowing and anisotropic conductive film (ACF). I've got a decent soldering iron and hot air reflow kit, so I should have what I need!

If the driver IC is is stuffed that'll be annoying, but LCD drivers are often all fairly similar, so finding a pin compatible replacement might not be beyond the realms of possibility.

[GingerMagic]

I do not understand a word of that

[rwb]

There are two issues: the missing lines (both vertical and horizontal) and the fading when hot.

If in PP2000 you run the screen test on a hot screen that's faded, it displays perfectly (other than any missing lines).

[jonsowman]

I'm pretty sure the missing lines will be failed bonding on the cable, and that's usually at the PCB end (not the glass end). So I plan to remove the cable at the PCB end and clean it up. If it's in particularly poor condition, I'll trim the end of the cable off and remove some of the insulation to provide clean contacts.

The re-bonding is usually the difficult thing with repairing LCDs, because it requires even heat and pressure. However there's this ACF (anisotropic conductive film) available now for repairing LCDs, which I have some of. Basically it conducts in the y and z axes, but not the x axis. So I can do the rebonding by just sticking some ACF to the PCB, then attaching the ribbon (with careful alignment).

As for the fading, I'm not so sure how to solve this. Some good heatsinking might go a reasonable way to sorting it out!

[rwb]

I believe the later 407 displays do have a fan in them.

On the coupe club article the lines are reported as re-appearing soon afterwards. Nevertheless, it's very impressive. It will be really cool if you can advance this.

[Doggy]

I'm pretty sure the missing lines will be failed bonding on the cable, and that's usually at the PCB end (not the glass end). So I plan to remove the cable at the PCB end and clean it up. If it's in particularly poor condition, I'll trim the end of the cable off and remove some of the insulation to provide clean contacts.

The re-bonding is usually the difficult thing with repairing LCDs, because it requires even heat and pressure. However there's this ACF (anisotropic conductive film) available now for repairing LCDs, which I have some of. Basically it conducts in the y and z axes, but not the x axis. So I can do the rebonding by just sticking some ACF to the PCB, then attaching the ribbon (with careful alignment).

As for the fading, I'm not so sure how to solve this. Some good heatsinking might go a reasonable way to sorting it out!

I do not understand a word of that

I was doing OK, until I tried to visualise selective conduction in 3 axes, (how does it know)?

FWIW, mine works perfectly at comfy temperatures, but sulks if too hot or too cold. I have concluded it's female.

[steve_earwig]

I was doing OK, until I tried to visualise selective conduction in 3 axes, (how does it know)?

The unbonded film is slightly tacky at room temperature and consists of a thermosetting epoxy/acrylate adhesive matrix randomly loaded with conductive particles. These particles allow interconnection of circuit lines through the adhesive thickness, but are spaced far enough apart for the product to be electrically insulating in the plane of the adhesive.

Better?

[jonsowman]

I was doing OK, until I tried to visualise selective conduction in 3 axes, (how does it know)?

Weird isn't it! But there are quite a few examples of repairing LCD ribbons with this stuff, and it certainly seems to provide a more resilient bonding than reflowing. Anyway I have some of it (this one specifically), and it can't hurt to give it a go on a practically dead display.

I'm really hoping I can find a reliable way of fixing these; I'd happily do it for other people

[FarmerPug]

Any luck repairing the screens?

The screen i have in my car lost quite a few more lines than normal after sitting dormant for a week, i got back into the car and most of the trip computer side and some horizontal lines disappeared, although once the heater got up to temperature the lines slowly came back.

[jasper5]

I was doing OK, until I tried to visualise selective conduction in 3 axes, (how does it know)?

Weird isn't it! But there are quite a few examples of repairing LCD ribbons with this stuff, and it certainly seems to provide a more resilient bonding than reflowing. Anyway I have some of it (this one specifically), and it can't hurt to give it a go on a practically dead display.

I'm really hoping I can find a reliable way of fixing these; I'd happily do it for other people

I still have my old 407 display if you want to have a play with that....the screen is perfect until the cabin warms up when it goes black.

Let know if you want it and send me your address so I can post it to you.

[jonsowman]

Any luck repairing the screens?

The screen i have in my car lost quite a few more lines than normal after sitting dormant for a week, i got back into the car and most of the trip computer side and some horizontal lines disappeared, although once the heater got up to temperature the lines slowly came back.

I just haven't had time to give it a go yet, been very busy the past couple of weeks with moving to uni and starting a new course etc. I will definitely give it a go soon though.

The anisotropic film needs clamping for around 24 hours after application to ensure a decent electrical connection, to I need to construct a device to do this. This is not as easy as it sounds since I can't lift the cable away from the PCB by more than about 5mm, otherwise the joints at the other end start to break. Once this happens, the thing is scrap since the driver IC fails to work.

I've been using GingerMagic's donated display (thank you!) in my car to see how it performs, and have noticed the same effect. Missing lines when very cold, but reappear as it warms up. This is really odd and quite unexpected really, but I suppose there's no way to know what the dodgy joints are doing.