Model PC2258USLC-3NO (either zero or letter O) hard to tell from pic SN 30704 There is also a long Product Identification Code if needed. Problem is simply that the LCD on the operator control panel is dead, no display at all. The backlight works, but nothing shows on the display. I removed the display LCD element itself and it appears to have been subjected to heat. In my experience with these, they should be semi-transparent so that the backlight can shine through to provide better contrast to the glass. They are built out of two layers of glass with a very fine wire matrix embedded usually in some adhesive, but some are actually liquid filled. This one appears to be one that is adhesive filled, and there is no evidence of any leakage. Holding the LCD up to the light, the center area is much lighter in tint than around the edges. This can come from several reasons. One, the icons and values displayed are mostly centered on the display, thus it sees voltage more often and for long periods of time virtually continuously. Another cause of this is simply extended exposure to the sun. UV is hard on LCD panels. Also an enemy is heat buildup. On this example, since there is absolutely no information displayed, my only real question is about testing the input to this entire display module. It does communicate with the main ECM of course, and any other control processors on the machine. It uses, I would guess RS232 or similar. Even with no incoming signal, I would expect to see something in the way of a warning, probably related to a communication error. But all I have is the backlight, which only proves the HV power supply is working. This display module is a pair of double sided PCB's loaded with SMD's. Nothing obvious wrong with it, nor does is smell of hot electronics. Anyone had to deal with this before? Suggestions? I can replace it for less than $500, so that's my initial recommendation unless someone has a better idea. I can only guess that there is a data port elsewhere that would carry the same signal, and perhaps the dealer could verify that indeed the signals are all there to drive this display, but otherwise, I'm temped to assume they are. The machine starts and runs, operates normally, you just can't see any gauges like fuel, voltage, oil pressure, etc. As far as functions, there is a push button array below this LCD, and I can turn on and off the wipers, but I can't tell what else may be working under the control of this module. One Thumb
I show your machine as a 2008 model PC228USLC-3. I have never found out what the NO letters at the end mean. They were built from 2001 to 2010 and yours is a 2008 model. The earlier machines with the liquid crystal display had the UV problem. The display would turn a maroon color and the digits could no longer be discerned. The only repair was to replace the entire panel which was expensive. I have heard rumors that someone found a display that could be retrofitted but have never been able to run that down. There is another issue to go with what you have. Komatsu started putting different monitor panels in different models of machines and the reduced tail swing machines is where I saw that the most. A photo of the panel would help in running down what you have. Komatsu doesn't use connections to the system for monitoring or troubleshooting their machines. All the diagnostics are in the machine and accessed through the monitor panel. They like to keep secrets as much as any other manufacture so someone might have the secret hand shake that may bring up the hidden pathway into the system. From my view point of experience, I'm thinking that replacing the panel might be your only way to a repair. Maybe there is another machine somewhere near by that you can swap a known working one in long enough to check operations. Good Luck!
Thanks John. Here are a couple of pictures The cover, with the overlay, I don't have here at the shop. I left it in the machine cab. Amazon shows to have one for $2600 or so, but ebay has some they claim as new for less than $500. I'm going ahead and ordering one, unless there are other options anyone knows of.
Thanks for the photos. I had not seen one taken apart with that kind of screen.
You're most welcome. That enclosure is quite full when assembled. There are two double sided boards (might even be multi layer, but I don't believe so). The actual LCD sit on top of the white rectangle where you can see the two leads that drive the fluorescent backlight. There is a ribbon cable connecting the LCD panel to the top board, and two ribbon cables between the two boards. I'll spread it out a bit more so you can see the rest. The array of push buttons align with the keyboard overlay with plastic pins that actuate each switch. Sort off a fiddly affair IMO. I'd rather have a membrane switch and connecting cable. I've ordered one from ebay, says it is new and all the numbers match. They do have a return policy, 30 days. I probably won't see it until next week though, so I'll get those pics up then wait until I get the part in and see if it works on this machine.
Did you make sure that the one you ordered matched up with your serial number? The only reason I ask is because I dealt with this issue about a year ago on a 2005 pc200 lc-7. I finally ended up with one that most everything works as it should. The only issue I have with the screen I currently have in there now is that I have to push the button that shuts off the auto idle function to get the machine to run full throttle. I assumed as long as the screen fit and plugged in correctly that it would be fine but that is not the case evidently.
The part number and application match, so I'm hoping. I could not get a specific build sheet qualification. Worst case, provided the driver boards are functional, I can likely just swap in the LCD panel. But if it doesn't give me full function, I can send it back. I don't know what other matching could be done. I hate to do that, it seems the cost wouldn't be reasonable to pay nearly $500 for just the glass, but It would tell me if the control was functional. It's no big deal to swap the panel in temporarily if I end up needing to try that. I'm not replacing just the screen anyway, I'm putting in the entire module. I think I'll be ok. Thanks for mentioning that though. I assume you mean a specific match with the machine sn. The module/display has a serial number, but it will be unique to that module.
Success. All functions normal. This was a Chinese copy of a Japanese OEM, but seems to work fine. Only complaint is lost service hours. I plan to go back to the previous owners and see if they had a display when they serviced the machine and tag this machine as having those hours plus what accumulates on this new module. Thanks for the comments! On to the Crambo....