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I just read through all 16 pages of this topic, lots of good info. My display comes on at first, but then comes on and off, mostly off. Pulled it out last night to check things out. The capacitors have leaked, diodes 6 and 7 don't look too good, looks like R38 is still good. I'll do some testing and see what I can do with it.
 

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I just read through all 16 pages of this topic, lots of good info. My display comes on at first, but then comes on and off, mostly off. Pulled it out last night to check things out. The capacitors have leaked, diodes 6 and 7 don't look too good, looks like R38 is still good. I'll do some testing and see what I can do with it.
Good luck.
I replaced a lot of stuff on my board and ended up having to just buy another one off ebay. Haven't had problems with the used unit since. It seems like the repairs are really hit or miss.
 

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Does anyone on this board offer the repair service?

There is an $80 one on ebay but I would prefer to deal with someone here. I'm on my 4th display now and have 3 dead ones and a one in the process of dying.

I would do one to have as a backup but if the price is right I would do them all.
 

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Well, the one I replaced a few days ago just died today. I should have hit 88 mph to see if I would have gone to 1985 before the screen went dead. There would be no coming back to 2015 until 1991 when you could walk into a dealership and buy one of these.

https://www.youtube.com/watch?v=NmjTpmm5-Ak
If you decide to go the used route I can send you one with the computer for $55 shipped.
 

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I feel the need for speed
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Bringing this one back from the dead as I'm trying to ressurect 2 dead units. I did the entire component change including TR2 and it lights up but with bright red lines and burns R38. Did anyone figure out what else to change? Both of my previously dark units are doing this since they were "fixed". I'm considering having it fixed via a service to see what else they change lol! At this point I'm considering that the VFD may just be beyond repair but I'd love to be able to crack this problem. Thanks in advance!
 

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I've repaired 6 climate control screens. And here's my results:
2 were fixed 100% and run cool, R38 resistors were not burnt. So if R38 is not burnt, you have a good chance of getting it working properly.
2 work but over-heat. In about 5 minutes TR2 would reach 90C in temp.
2 units I could not get a working display.

On the last four, I've replaced every IC, voltage regulator, transistor, and select resistors and they still did not work properly. I recorded each resistor value, looked up their color codes and also compared it with the other units, and found some bad resistors even though they didn't look burnt. You would think I would get some success, but nope. If R38 is burnt up, it's almost hopeless. On one of the units that overheat, I did a hack job, drilled a large 40cm hole in the plastic case and installed a 12volt fan to keep it cool. Temp stayed below 40C.

Incidentally, when you examine the five group of legs that lead into the VFD, the middle two aren't electrically connected to anything, they're only there for support. You can verify this by taking a bright light source and shine the light through the PCB and you will see there is no circuit traces. This saves you time as you do not have to re-solder them back in.
 

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I feel the need for speed
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Interesting, I guess that confirms that some cannot be fixed no matter what. What's funny is I ressurected the one unit I thought was totally dead just from looking at it. Once I plugged it in I was shocked to see it worked but the display became intermittent and I unplugged it immediately. I changed the Caps which were fixed once before with the wrong ones and it's good so far. I think I'm going to send in my "red line" one for repair to see what else they change and learn the secret lol. I'm surprised no one has figured it out yet. I had a few leads of people who could help but they flaked out on me.

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Note that the aging of the VFD may be the main reason for the failure of R38......in addition to the leaking capacitors.

VF displays "age".....in that their input impedence, over time, drops.......overloading it's supply circuitry.

Soooooo.........after all these years........the problem may not be fixable.

Just a thought....

Kevin
 

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Note that the aging of the VFD may be the main reason for the failure of R38......in addition to the leaking capacitors.

VF displays "age".....in that their input impedence, over time, drops.......overloading it's supply circuitry.

Soooooo.........after all these years........the problem may not be fixable.

Just a thought....

Kevin
I have a VFD that is working and very bright, the resistor is heating up and getting too hot and was burned at one point. I think you may be right. Maybe, I can measure the resistance across the display to verify this issue? My display is so bright, maybe increasing the resistance would dim the display and reduce the heat?
 

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As, I mentioned I have one DCC that heats up R38 but has a display that seems to work. I have another DCC that does not heat up R38 but the display is less than half lit. When I measure the half lit VFD as shown in the picture, I get an open circuit. If I reverse the leads I do get some conduction. So it is acting like a diode. On the display that lights up, I get a small amount of conduction in both directions. I am not sure if this indicates an opening in half lit VFD or or a short in the fully lit VFD. If anyone has a working display that does not heat up please measure the resistance as shown and let me know what results you get. BTW, I have compared both DCC's and they have similar resistance at all points except on the VFD.
285910
 

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3SNY - HondaTurtleFTW
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Note that the aging of the VFD may be the main reason for the failure of R38......in addition to the leaking capacitors.

VF displays "age".....in that their input impedence, over time, drops.......overloading it's supply circuitry.

Soooooo.........after all these years........the problem may not be fixable.

Just a thought....

Kevin
Very old ressurection/quote here, but I figured I'd ask. If the overall impedance of the VFD drops, couldn't one experiment with additional resistors in series to lower the current back within spec, without drastically altering the brightness of the display?

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Is there a go-to guy for repair? I got two units that need a tune up
 

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So, I tried using NTE378 and TIP42C replacement for PNP transistor 2SB1019 (Big green one) . Did a bit of research and the equivalents have differences. I don't really know but it makes sense that the transistor could be the problem since R38 is heating up.

Model Hfe Frequency
2SB1019 Y (120-240) 10
TIP42C (15-76) 3
NTE378 (40) 40
 

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I doubt the transistor alone is the big problem on most of these. It has been a bit since I looked at it since I repaired mine, but if it operates like most SMPS using a TL494, the TL494 drives that transistor which feeds a transformer to up the voltage, which is rectified back to DC by a half or full diode bridge. If TR2 really failed short, the TL494 should almost certainly fail also. TR2 is about the best thermally mounted part on that board. If R38 is failing, the overall circuit is drawing more current than it should. TR2 getting hot is probably more of an effect than a cause unless you use the wrong transistor as a replacement. The VFD or other failing component on the output side of that SMPS is more likely to be the cause.
 

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I doubt the transistor alone is the big problem on most of these. It has been a bit since I looked at it since I repaired mine, but if it operates like most SMPS using a TL494, the TL494 drives that transistor which feeds a transformer to up the voltage, which is rectified back to DC by a half or full diode bridge. If TR2 really failed short, the TL494 should almost certainly fail also. TR2 is about the best thermally mounted part on that board. If R38 is failing, the overall circuit is drawing more current than it should. TR2 getting hot is probably more of an effect than a cause unless you use the wrong transistor as a replacement. The VFD or other failing component on the output side of that SMPS is more likely to be the cause.
Wow, you clearly know a lot about electronics! I recently tried to fix one but kept getting the red lines and overheating R38. Is it true that it's possible it is beyond repair if the VFD goes bad? Information on repairing these is very scarce and sources often have differing information. Thanks!

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