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Author Topic:   Yamaha LCD Gauges Lose Contrast

jadebluesky posted 06-23-2009 09:11 PM ET (US)
I have a 1995 21-foot Contender with original equipment Yamaha 200-HP outboard. Over the last year, the digital displays on the speed and tachometer gauges have become progressivley harder to read. The displays have become almost too dim to read under most conditions. Do the gauges need to be replaced? Or, is there an adjustment or sensor that will improve performance?
TransAm posted 06-23-2009 09:37 PM ET (US)
Generally speaking, the gauges are not servicable. At service repair rates, it would be cost prohibitive as well. If you are interested, I have a NEW, out of box Yamaha Multifunction Tach I would part with for $150.00. Going rate for new is $340.00. I had a speedo too but just sold it for $175.00; they are over $400 new.
jimh posted 06-24-2009 08:57 AM ET (US)
The Yamaha gauges most likely use liquid crystal display (LCD) devices. The LCD itself does not generate any light, but acts like a shutter to pass or block light. Usually an LCD device employs a source of light behind the LCD, called a backlight. In some cases the backlight may be electrical, but it can also be from ambient light. If the backlight becomes dim, the display will also become dim. The LCD affects the contrast ratio between bright and dark areas on the display. Typically there is an electrical adjustment which controls the display device to vary the contrast ratio. When the display becomes dim and hard to read, the cause could be a loss of light from the back light or loss of contrast in the LCD.
In applications like the Yamaha outboard motor gauge, the display device is probably not easily serviced. The case may be sealed to prevent water entry and hard to open for repair. Obtaining a replacement device may be difficult, and a replacement LCD may be expensive.
My approach to making a repair to a Yamaha LCD gauge would be to attempt to open the housing without damage. If I could open the housing and discover the internal components, I would then make a close visual inspection of them. I would look for a connection between the LCD display device and other circuits in which there might be some corrosion. If I saw any evidence of corrosion, I would try to remove it and clean the connectors. Resistance in a connection due to corrosion might be the cause of the reduced contrast in the display.
TransAm posted 06-24-2009 09:51 AM ET (US)
The older units c. 1994 have a white plastic backing piece that is removable and will enable access to the innards. To what end, it depends how electrically inclined you are. The newer units are all black and are not servicable.
jadebluesky posted 06-24-2009 09:57 AM ET (US)
Thanks, I suspected gauges may need to be replaced. How difficult are gauges to swap out, assuming I can replace with similar gauges. I would be interested in your tach If we can confirm that it is the same gauges/connections as I currently have.
TransAm posted 06-24-2009 01:42 PM ET (US)
jade,
It's pretty much "plug and play" If your Yamaha is a 1995 model year, you are good to go. The change out is pretty straight forward. You have 2 plugs and 4 individual wires out of the back of the tach. The 2 plugs are self explanatory-you cant goof it up. The 4 separate wires are pretty goof proof as well. They tie into the ignition harness which has corresponding, color coded wires. I can send you a wiring diagram if you like. It would be easier just to mark wires you unplug and simply plug the new wires in.
Tohsgib posted 06-24-2009 02:27 PM ET (US)
My Yamagucci gauge was almost impossible to read in the day. At night it worked fine. Somehow the "nightlight" got stuck on so it was too dim in the daylight. I removed the light wire(purple/blue?) and all was good except at night.
TransAm posted 06-24-2009 02:41 PM ET (US)
The illumination wire is blue.
jadebluesky posted 06-24-2009 05:55 PM ET (US)
TransAm, thanks for all the info, if you are sure your tach will work for my Contender (it sounds like it will)how can I buy it from you. Also I think the gauges come in black or white. Mine are black.
jadebluesky posted 06-24-2009 05:58 PM ET (US)
Also is there a part # or other id number on your tach that I can compare with my gauge to confirm they are similar
Thanks
TransAm posted 06-24-2009 06:09 PM ET (US)
jade,
Send me a pic of your gauge, front & back and identify all the wire colors; I should be able to tell from looking. If I'm reasonably certain it will work, I'll send you the gauge; you can install it to confirm it works properly and then send me a check. If for some reason it doesn't work, just send it back. If you keep the gauge and don't send $$$, I have unscrupulous friends in Fla. ;-).
TransAm posted 06-24-2009 06:17 PM ET (US)
Here's a pic of the gauge
http://s299.photobucket.com/albums/mm314/77SETransAm/?action=view& current=EbayGaugesBravoIs021.jpg
jadebluesky posted 06-24-2009 06:52 PM ET (US)
TransAm Thanks, I wish you still had your speedometer as well, the picture of you gauge looks like mine. I left the boat at my place in the FL keys since since I will be going back down there in a couple of weeks for lobster season. I am in St Augustine Fl now. I think I will take a chance with your tach. If you want to send it to me, I will send you a check. If it doesn't work on my boat when I get back to the Keys, hopefully we can work something out. I don't have any unscrupulous contacts up your way, but I am a huge believer in KARMA .
TransAm posted 06-24-2009 07:11 PM ET (US)
Sounds good; drop me an e-mail w/ your address and I'll pop the tach in the mail. jfbetz02@comcast.net
Chuck Tribolet posted 06-26-2009 02:36 PM ET (US)
Low contrast LCDs can be caused by low power supply voltage.
My wristwatch does that to tell me it wants a new battery.

Chuck
jimh posted 06-26-2009 08:33 PM ET (US)
Taking Chuck's suggestion further, and combining it with mine, the low voltage could be due to corrosion of a connection, and the connection could easily be external to the gauge. Check the back of the gauge and its connection posts; also check the 12-volt feed to the gauge.

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Author	Topic: Yamaha LCD Gauges Lose Contrast
jadebluesky	posted 06-23-2009 09:11 PM ET (US) I have a 1995 21-foot Contender with original equipment Yamaha 200-HP outboard. Over the last year, the digital displays on the speed and tachometer gauges have become progressivley harder to read. The displays have become almost too dim to read under most conditions. Do the gauges need to be replaced? Or, is there an adjustment or sensor that will improve performance?
TransAm	posted 06-23-2009 09:37 PM ET (US) Generally speaking, the gauges are not servicable. At service repair rates, it would be cost prohibitive as well. If you are interested, I have a NEW, out of box Yamaha Multifunction Tach I would part with for $150.00. Going rate for new is $340.00. I had a speedo too but just sold it for $175.00; they are over $400 new.
jimh	posted 06-24-2009 08:57 AM ET (US) The Yamaha gauges most likely use liquid crystal display (LCD) devices. The LCD itself does not generate any light, but acts like a shutter to pass or block light. Usually an LCD device employs a source of light behind the LCD, called a backlight. In some cases the backlight may be electrical, but it can also be from ambient light. If the backlight becomes dim, the display will also become dim. The LCD affects the contrast ratio between bright and dark areas on the display. Typically there is an electrical adjustment which controls the display device to vary the contrast ratio. When the display becomes dim and hard to read, the cause could be a loss of light from the back light or loss of contrast in the LCD. In applications like the Yamaha outboard motor gauge, the display device is probably not easily serviced. The case may be sealed to prevent water entry and hard to open for repair. Obtaining a replacement device may be difficult, and a replacement LCD may be expensive. My approach to making a repair to a Yamaha LCD gauge would be to attempt to open the housing without damage. If I could open the housing and discover the internal components, I would then make a close visual inspection of them. I would look for a connection between the LCD display device and other circuits in which there might be some corrosion. If I saw any evidence of corrosion, I would try to remove it and clean the connectors. Resistance in a connection due to corrosion might be the cause of the reduced contrast in the display.
TransAm	posted 06-24-2009 09:51 AM ET (US) The older units c. 1994 have a white plastic backing piece that is removable and will enable access to the innards. To what end, it depends how electrically inclined you are. The newer units are all black and are not servicable.
jadebluesky	posted 06-24-2009 09:57 AM ET (US) Thanks, I suspected gauges may need to be replaced. How difficult are gauges to swap out, assuming I can replace with similar gauges. I would be interested in your tach If we can confirm that it is the same gauges/connections as I currently have.
TransAm	posted 06-24-2009 01:42 PM ET (US) jade, It's pretty much "plug and play" If your Yamaha is a 1995 model year, you are good to go. The change out is pretty straight forward. You have 2 plugs and 4 individual wires out of the back of the tach. The 2 plugs are self explanatory-you cant goof it up. The 4 separate wires are pretty goof proof as well. They tie into the ignition harness which has corresponding, color coded wires. I can send you a wiring diagram if you like. It would be easier just to mark wires you unplug and simply plug the new wires in.
Tohsgib	posted 06-24-2009 02:27 PM ET (US) My Yamagucci gauge was almost impossible to read in the day. At night it worked fine. Somehow the "nightlight" got stuck on so it was too dim in the daylight. I removed the light wire(purple/blue?) and all was good except at night.
TransAm	posted 06-24-2009 02:41 PM ET (US) The illumination wire is blue.
jadebluesky	posted 06-24-2009 05:55 PM ET (US) TransAm, thanks for all the info, if you are sure your tach will work for my Contender (it sounds like it will)how can I buy it from you. Also I think the gauges come in black or white. Mine are black.
jadebluesky	posted 06-24-2009 05:58 PM ET (US) Also is there a part # or other id number on your tach that I can compare with my gauge to confirm they are similar Thanks
TransAm	posted 06-24-2009 06:09 PM ET (US) jade, Send me a pic of your gauge, front & back and identify all the wire colors; I should be able to tell from looking. If I'm reasonably certain it will work, I'll send you the gauge; you can install it to confirm it works properly and then send me a check. If for some reason it doesn't work, just send it back. If you keep the gauge and don't send $$$, I have unscrupulous friends in Fla. ;-).
TransAm	posted 06-24-2009 06:17 PM ET (US) Here's a pic of the gauge http://s299.photobucket.com/albums/mm314/77SETransAm/?action=view& current=EbayGaugesBravoIs021.jpg
jadebluesky	posted 06-24-2009 06:52 PM ET (US) TransAm Thanks, I wish you still had your speedometer as well, the picture of you gauge looks like mine. I left the boat at my place in the FL keys since since I will be going back down there in a couple of weeks for lobster season. I am in St Augustine Fl now. I think I will take a chance with your tach. If you want to send it to me, I will send you a check. If it doesn't work on my boat when I get back to the Keys, hopefully we can work something out. I don't have any unscrupulous contacts up your way, but I am a huge believer in KARMA .
TransAm	posted 06-24-2009 07:11 PM ET (US) Sounds good; drop me an e-mail w/ your address and I'll pop the tach in the mail. jfbetz02@comcast.net
Chuck Tribolet	posted 06-26-2009 02:36 PM ET (US) Low contrast LCDs can be caused by low power supply voltage. My wristwatch does that to tell me it wants a new battery. Chuck
jimh	posted 06-26-2009 08:33 PM ET (US) Taking Chuck's suggestion further, and combining it with mine, the low voltage could be due to corrosion of a connection, and the connection could easily be external to the gauge. Check the back of the gauge and its connection posts; also check the 12-volt feed to the gauge.