Monday, November 27, 2006 - 08:02 am, by: Mark Paddick(Sparks)
Backlight tubes are fitted with a tube heater from the factory. This helps them get to operating temperature and uniform brightness quickly. When they fail the tube often strikes normally and the fact that the heaters aren't working goes unnoticed until the tube ages and becomes slow to strike. Often the centre section will be dull or completely black for a few minutes. It comes good eventually and as far as I know does no damage. Even the worst cases are fully bright in 5 mins. The heaters are fragile, easily broken and often deliberately so in a misguided attempt to reduce internal EMV temperatures. This achieves nothing as the heater is thermostatically controlled and so turns off once everything is warm. These heaters cannot be fixed or replaced. Changing a tube for one with the heater intact is likely to damage at least the heater anyway so is not an option. The only cure is a replacement backlight assembly with a working heater and unless you want to pay $5k or so these are not available new. They are getting very rare to find 2nd hand now too. Even the good tubes have o/c heaters. It is possible that reducing the value of the 0.068uF capacitor in the backlight inverter may help an aging tube strike better but it's not worth the risk. Unloaded voltage from the inverter will be higher with the attendant increased risks of insulation breakdown and arcing.
Monday, November 27, 2006 - 10:26 am, by: Harry Lemmens(Wombat)
Probably the best repair option for the future would be to use as many white LED's as you can afford, and build a totally new backlight. As I see it, 100 or so LEDs can be used to replace the backlight tube.
The thing would run cooler than the original. Should also be about the same brightness as the original tube. The colour temperature of the display would also be about the same.
I suspect even the dimming facility for the LED's could be put in place without to much effort.
Most modern displays are switching to LED backlights ... The Sony PSP display uses 7 white LEDS, and is actually BRIGHTER than the EMV display when placed side by side.
I tried several different tubes in an EMV monitor a few years ago. Nothing was as bright, or as white as the original tube.
Monday, November 27, 2006 - 11:31 am, by: Mark Paddick(Sparks)
I've got a working one with LEDs. Whiter and brighter than the original. Differences between individual LCD screens are much more apparent too so a good one is a must. Just connecting the LEDs in series across the input of the inverter transformer works well and the dimmer works too. Unfortunately the best LEDs are still in the $4 each category and cheap ones just won't do the job. I'm looking at SMD LEDs now, as the good ones are brighter and more robust electrically with better diffusion than ordinary LEDs so you can use less of them but still the cost is in the $100 region.
Monday, November 27, 2006 - 11:57 am, by: Mark Paddick(Sparks)
Back light only. The screen is a different matter. I have now convinced every LCD supplier in the known Universe to try to find one to replace the Soarer one. All have failed to supply one. Only Toshiba could supply one and Toyota won't let them. Once Toyota no longer carry the screens as spares then Toshiba may be allowed to sell them. They won't be cheap. Toyota only supply the screen as part of a complete EMV display box for around AU$5k ex Japan so costs on top.
I can do a replacement LCD screen/backlight combination but I haven't worked out the connecting details yet. So far I have a screen and backlight in the EMV with the touch screen fitted and the EMV boards fitted. The screen is still working with it's own electronics via a video input i.e. it's a complete video monitor fitted into the EMV with the EMV electronics as well; the two are yet to be joined. Cost for this will be in the $800 region but you will get a brand new screen and backlight. Providing of course that the particular monitor from which the screen comes is still available, which it isn't, as it's the only screen that will fit and display a full EMV-screen-sized picture without losing any either. These still have a tube type backlight and built in inverter. At least it is all new. Since they are Chinese in origin there are two givens; One, the production spec WILL change between order and delivery Two, anything can be copied and if the original manufacturer can be found possibly very cheaply. Mind you, the major cost is fitting the screen anyway 'cos I ain't doing these cheap!
Monday, November 27, 2006 - 12:00 pm, by: Mark Paddick(Sparks)
I have been asked about screen resolution and stuff. I don't know. It's a generic Chinese monitor so probably not great. I also don't care and it also doesn't matter 'cos it's the only choice in six years of looking and there are no other options aside from hunting down a good 2nd hand one..
Monday, November 27, 2006 - 01:12 pm, by: Harry Lemmens(Wombat)
Find me a screen that is the right size and I will produce a new board for the monitor. (Preferably Automotive grade for the extended temperature range they operate over.)
I have just finished (well almost) an LCD monitor that will find its major use in US cop cars. (And eventually Aussie ones I suppose.)
It works a treat .... In both NTSC and in PAL.
A new monitor board wouldnt need the intervening electronics module currently used to convert PAL to NTSC. ... Still need the sound mod for the tuner though.
Brett ... once a pixel dies on the monitor, that pixel is dead forevermore.
Monday, November 27, 2006 - 01:48 pm, by: Mark Paddick(Sparks)
All I really need to do is pick a video feed out of the EMV main board to feed the monitor. Easy really, just haven't had time to work out where to solder the wire yet. And the PAL/NTSC autoswitching of the monitor does work with a converted TV too but not as well as the dedicated converter I normally use. It's worth having just to clean up the video. Switching it in makes the difference between a watchable picture and garbage even when the monitor will accept the PAL signal unconverted.
If I were going to design a complete driver board for the new screen I'd first try to find a bare screen that was better quality. It should even be possible to have one made at reasonable cost. I'd include all the stuff done by the EMV main board now but leave out that related to driving the backlight inverter and while I'm dreaming add the PAL/NTSC converter too for its' convenience and signal cleaning abilities.. But then, I have a perfect EMV myself so I don't really need to bother
Saturday, September 24, 2011 - 12:30 pm, by: Mark Donovan(Mark_donovan)
Hi Jason - welcome to the forum. Yes, it probably is fixable. Have a look through the Electrical forum and you will find an answer, and who to contact to go about getting it repaired.
Congrats on your Soarer purchase.
Dan McColl Goo Roo Victoria (The Nazi State) Pretty Red Thing and The Black Beast
Saturday, September 24, 2011 - 07:36 pm, by: David Boyle(Amokzar)
Jason, it may not be the back light, when i bought my car i had the exact symptoms you have. I replaced a fuse and 3 capacitors and it fixed it up. (cost me around $5 in parts)
Saturday, September 24, 2011 - 10:02 pm, by: Jason da Silva(Jace228)
thanks guys appreciate the feedback! considering i have no idea about how to do it myself hopefully one of you know where to go to get something like this fixed in Perth?
Sunday, September 25, 2011 - 03:19 pm, by: David Boyle(Amokzar)
Jason, There is plenty of information out there on how to fix these, however, if you contact Damian Ware. He is one of the forums experts on repairing EMV's. Although he is located in Victoria i believe he does fix interstate EMV's. Plenty of tutorials on how to remove the EMV then post it off to him.
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