mleskovar

I just received and installed the new screen. No lines! All the numbers and characters are well defined, backlight is too bright....not bad, but noticeable. You shouldn't see any backlight other than what shows through for the display. Continued to work well under heat (just park it so the sun hits the instrument cowl). I put a piece of blue acetate between the screen and the backlight and problem almost completely solved. Maybe a shade lighter acetate would be perfect, but it's fine if I can't find that. Interesting side note....the man that looked at my previous screen contacted me saying Sacer helped him figure out the problem with the other screens and how to solve it. He's tested the fix and it works. He didn't elaborate but I think it involves biasing the LCD. When I told him I was trying a different screen vendor he said it would have to be biased as well. I'm interested how the other 'testers' do. I'm guessing all the screens vary slightly and each is biased to match the cluster. The fact that a couple worked well just means those screens (or clusters!) were in the acceptable range. Just a guess.

04mbc230

What is biased? What do you with that? I am not familiar with that term. Well, as for mine, which is the first installed of this product, I didn't do any modification or resistors, other than installing it right from the sealed pouched it came from. It does gets bright, but I think that is how it used to look like when it's new. Perhaps over time, you got used to the screen that slowly died off and got dimmer and dimmer.

It's great to hear that it also work for someone else as well. Now, I need the other 5 testers to give me a review will help.

Can you post some pictures of your working product.

Thanks.

mleskovar

Adjust voltages for optimum display. On this screen it's done by changing/adding/deleting resistance from circuits by changing/adding resistors. We're talking very small changes, +/- .1 volts, and about 6 different voltages.


I've had two screens that both showed better contrast (when cold). They were totally black with only the characters lit.


Taken at night with no flash. Pic #1 is with lights off, #2 is lights on. This is after I added the acetate. My other screens would have no glow around the characters.

04mbc230

Cool. Thanks for the info. Something people would need to know prior to buying either this screen or any other ones in the future.

Perhaps you are right, I did notice the OEM screen is more darker hence why you would put acetate to minimize the glow on the new screen.

As for the resistors, do you think this is needed for this screen or are u suggesting for the sacer product?

mleskovar

Both, unless you're happy with the display. I think my contrast would be better if the screen were biased properly. But I may be happy with what I have, I'll see. If the display is not high enough quality for you then you need to adjust the voltages. Going from not being able to read anything when the sun has heated up the instrument cluster to being readable at any time is great for me now.

04mbc230

So with that in mind, then this problem is similar to the Sacer Product or eventually someone will get the same problem like the Sacer Product.

04mbc230

Well, I will still continue to test for 1 month. When this is complete. Will post the final post and release the info on the supplier. Then's its buy's caveat. Purchase at your own decision and risk.

mleskovar

Perhaps. Or some of them will have similar failures from each vendor. I'm only guessing but I think it's a quality control issue. There's a spec for the screen and the 'biasing' makes up for what's out of spec. The reason a couple of them worked is those particular screens were within spec. When we switched working screens from one cluster to another they worked, so it's not the clusters. Also, the failures were similar for the bad screens but not identical. I bet MB had them tested before installation and only accepted those within a narrow spec. Maybe we're now getting the left overs, or these are new build screens attempting to meet the spec. The difference between Sacer and these screens could only be their control of the processes/calibrations used and they vary slightly. Once again, I'm guessing. I'm curious how the others are doing. Here's what the VDO repair person wrote me: "Basically there is a formula that needs to be applied to the voltage readings and the result is the resistor that is needed to adjust the voltage. It appears that you screen still needs adjustment since the contrast is to high from what you are describing. We should be able to adjust it." I'm going to drive it awhile to see if it bothers me or not.

eesjunin

interesting...

mtnman82

Hmmm, if a screen needs 'biasing' and it's too bright, that means it's drawing too much current. Was the problem with the other screens that they were burning out? Biasing might be as simple as replacing a resistor (putting in a larger value so it draws less current, which will also make it less bright).

I'm on hold for my replacement at the moment (the contact is on holiday). I wonder if I should mention this to her before I order ... ?

Edit: can you use the brightness adjust to dim the display a tad and get rid of the problem?

mleskovar

The most common problem is the original LCDs were fading as they became hotter from the sun on the dash. Some had missing lines which showed up as incomplete numbers/characters.

Simpler said than done. First you need to know what the correct voltage(s) should be, then where to find/measure it, then the formula for determining how to correct it by adding/reducing ohms, obtain the part(s) then knowing where to make the change on the board, and last.....doing some micro circuit soldering (you need proper equipment for this or you can wreck a $1200 part). I believe there are 4 or 5 voltages that control the LCD output. Contrast should be one of them.

Not really. That control only works when the lights are on and in my case there wasn't enough range for it to be effective.

All that being said, my replacement screen is readable and doesn't fade with heat. I tried muting the back light but that made it too hard to read during the day. To make it perfect I'll need to have the contrast adjusted. Depends on how picky you are. I'm getting used to it and although it's not perfect it isn't annoying.

04mbc230

Alright guys. I think the sceen works "as is" for me. As for me, i don't know what is off the dealership lot screen looks like. I bought this car with the issues and at times where I can't see the screen at all.

This fix made a total difference from not reading to getting everything. I am happy that I can read what is suppose to be displayed in the cold or heat.

As far with it being too bright, I suppose, but I am not bother by it. I notice that the brightness is from the backlight leds. I did notice this, the leds fails too. Mines somehow goes on and off. Hmmz, I wonder what is the simpliest way to fix this. If the screen is still too bright for you, you can trying putting as suggested earlier, some acetacte.

fookoo303

i had problems with the led's flickering on and off also. usually it happened on the left column. I think its just a bad connection. If you take it apart and put a small amount of solder on the connections, it will fix it. Each column is connected in series so if one of the led connections is bad inside the column than the entire column turns off.

mtnman82

Yup, know the problem with the original screens (I'm on my second one from the dealer) - I was wondering what the problem was with the other replacement screens that were failing? Are they burning out?

Biasing really could be as simple as changing a resistor (or maybe more than one...). If you can figure out which one(s) control the luminocity of the LEDs, you're pretty much there. A little larger resistor will bring the brightness down (using V=IR you should be able to get in the ballpark from where we're starting). Parts (resistors) are easy (Digikey, Mouser, Newark, etc, etc). Micro circuit repair can be tricky, but definitely do-able (I'm actually certified and have some of my own equipment at home).

I went and checked my display after I posted yesterday and you're absolutely correct, the dimmer does not work without the light on. Bummer, as this could have easily solved the issue.

I think I will mention this brightness issue to the gal when I get ahold of her to order and see if they know about it or if they can do something about it. If they can take care of it at their factory, that'd be the easiest solution for all of us. If it is what it is, I might have to do some investigating...

BTW, the contact has been on holiday and she asked me to wait until she got back to order - should be this week sometime. I'm not lagging, just waiting to order.

mleskovar

I've installed 4 of them from Sacer and they all had the same failure.....way, way too bright a background and vertical lines and voids across the whole display. This one from the last vendor had no lines or voids and the background (backlight?) shows through a little bit. After using it for a couple of days I'm thinking I might just leave it as it is. Depends on how much the instrument repair person wants to make it perfect

Glyn M Ruck

My display has always been perfect so I've never pulled it apart. However, there is nothing to a mono colour LCD display.

You have an LCD display of a specific resolution X no of pixels by Y no of pixels, in this case awful, with pixels switchable by a voltage - namely on or of to form a letter, figure or shape.

Then you have a light source - A baby CFL or edge mounted or back mounted LEDs

Your photos show light leak through the closed pixels which means that the backlight is too bright. One would need to reduce voltage to the backlight by insertion of resistors to dim it to your liking.

These are probably Twisted nematic (TN) screens so you could also trim voltages upward to the LCD screen itself to make the black more black by contolling the level of polarisation.

04mbc230

Glyn. I don't think the backlight has anything to do with this. That is OEM. We are just replacing the glass. The glass does not control the backlight. So I don't think it is related. I did notice that the screen is orange. I did a check because I had a problem with the blacklight leds goes on an off. Was investigating how come and notice that the screen had orange letter to start with. I guess the backlight enhance the orange letters.

Once again, I think the other poster said use acetate to darnken the backlight and it should do.

I am planning to release the supplier info next week. I think it's conclusive that my install is similar to mleskvor's install. His active pictures is similar to mine. So the only problem is perhaps it too bright. If biasing fix this, then that is the resolution. As for me I am happy with mine, being bright. I am happy that I can read the screen more than bother by it being bright.

I don't think I want to play with resistors, since I am everyone is not a electrican by nature and playing with the solder means a possible of no return if one breaks it.

I guess at this time, the only way to get 100% is with the stealership replace the whole cluster. Getting 98% at this time, is very satisfying for me. Well, I consider it being 100% since I never knew how a off the lot screen looks like. I inherit the issue when I bought the car lately.

So what do you guys think. Just let the flood gates open and put a caveat that it's 98% close to OEM. But for sure you can read your screen again.

04mbc230

From my investigation, I think there is no way we can achieve white color screen like the 05+. The letters on the screen is made orange to start with. So even with white blacklight, it will come out either a different color or stays orange.

So unless we can ensure the letter on the glass screen is white, I doubt it would be acheivable.

Glyn M Ruck

The orange screen is an LCD. With voltage applied selectively it goes black & just allows light through the open pixels which will always be orange. Backlight intensity will effect how bright the orange is & LCD voltage will effect how black the black is. If the backlight is too bright it will cause light leak through the black. Achieving pitch black has always been an issue with LCDs - Which is why top active matrix LCD TVs like the Sony XBR8 use dynamic local dimming LEDs behind the LCD panel to achieve high contrast & decent blacks.

mleskovar

I removed the acetate because it reduced it too much in the daylight. We're not talking a huge leak, but enough to notice. More importantly the characters are easily readable.

04mbc230

Hmmz.. You are right.

What do i know. hhaha. I am just a mercedes c230 for 1 month. hahah Wow, how time flies.

04mbc230

Okay.. I can confirm that is how the oem looks like regardless. It leaks orange color. See picture. That is way before I found the supplier info and such. At the time, I didn't even know if there was a fix.

That picture is right after I bought the car on the second day and after I had it clean and waxed.

So... Since OEM is like that. Then why are we so concern about this supplier when it looks the same as the OEM.

Notice my edge are darken. It gets worst when it hits 78 degree and driving. hahaha. As for now, after the fix, I read everything all the time. So to me. It's done, but for the picky, good luck and please seek help! Life is too short.

04mbc230

Oh.. Btw, for those who wants to fix this and is in Northern California. Perhaps I can help you install your Replacement Screen.

I think I have trained myself enough to do this comfortablely.

Oh of course, bring some COLD green tea with honey, you know that tall drink as compensation would work (Installation work that is). You have to buy your own screens first.

mleskovar

Agree, not that big a deal if you aren't looking for the same as original. I have an original screen to compare it with and there is no background visible at all. Livable/usable yes. For comparison look at your radio and HVAC LCD panels. The other screens I tried weren't usable at all.

04mbc230

Awww... You have a point there. You got me there.

I guess we go back to the is it a big deal kinda thing. If so, they should head to the stealership and pay $$$ to get exactly OEM.

As for a 98% fix, I guess it will do.

I guess for those who chase perfection, then yea, proceed forward with finding it. But then again, if perfection is the case, won't it be easier by just forking up the $$$ and go with the dealership?

Just my 2 cents. But mleskovar, thanks for all your input. As it is very valuable for those who read this and for them to make their decision.

Thanks again and please give yourself a pat in the back for me.