LCD Module Inop


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satranger
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LCD Module Inop

Post by satranger » Fri Oct 27, 2017 9:55 pm



Have a 93 GL1500SE with a dead LCD Module. Display looks fine, no spot creep at all on it. Its just totally dead, nothing showing. The bike is usually parked under a carport when not being ridden. Its been washed but not ridden in the rain in the last 2 years I've owned it. The LCD was working fine till recently, then it started going off. Sometimes turning the key off and back on would get it working again but now its blank. The lights that lamptest when turn on stay off and the cruise will not set. I've taken the dash apart checking wiring, supply voltages and grounds on the appropriate wires at the connector plugs. Pulled the module out and cleaned the circuit board with contact cleaner even though it was very clean. Only dirt was on the back removable cover. All supply voltages and grounds are good at the connector plugs going to the LCD module. Has anybody ever "bench checked" the LCD module as in hooking to a power supply to power it up? If all voltage and grounds are good, should at least the clock be on the display?



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Erdeniz Umman
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Re: LCD Module Inop

Post by Erdeniz Umman » Sat Oct 28, 2017 1:08 am

Do the side stand light and oil pressure light come on normally?

Have you checked the 6pin white connector behind the cassette player?

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satranger
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Re: LCD Module Inop

Post by satranger » Sat Oct 28, 2017 9:36 am

Yes both the sidestand and oil pressure lights work. They are not associated with the LCD module. I haven't removed the radio 6 pin connector but have wiggled it and the wires going into it with no change to the blank LCD display. The radio works fine just nothing on the LCD Display. Erdeniz, I want to thank you VERY VERY much for posting the GL1500 Color Diagrams. They are easy to follow and excellent help chasing wiring problems! I've started a list of all the connectors on the instrument panel identifying by wire color and circuit each is used for. Listing each circuit end to end with each connector it routes thru. Work in progress as I chase things, but have most identified already.

Useful links
http://www.goldwingfacts.com/forums/2-g ... agram.html
http://vsource.org/VFR-RVF_files/HondaWireColors.htm

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Erdeniz Umman
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Re: LCD Module Inop

Post by Erdeniz Umman » Sat Oct 28, 2017 3:20 pm

satranger wrote:
Sat Oct 28, 2017 9:36 am
Yes both the sidestand and oil pressure lights work. They are not associated with the LCD module. I haven't removed the radio 6 pin connector but have wiggled it and the wires going into it with no change to the blank LCD display. The radio works fine just nothing on the LCD Display. Erdeniz, I want to thank you VERY VERY much for posting the GL1500 Color Diagrams. They are easy to follow and excellent help chasing wiring problems! ....
You are welcome.
I don't know why you thought they were not associated but, here is the picture of the diagram showing their connections. And also the troubleshooting procedure given in the service manual.
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satranger
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Re: LCD Module Inop

Post by satranger » Sat Oct 28, 2017 3:37 pm

The Side Stand and Oil pressure circuits only go to indicator bulbs in the instrument panel with no connection to the LCD circuits. Will pull the radio connectors tomorrow and clean them to see if that helps. Wiggling the plugs and wires didn't change anything. Didn't notice that the clock input was from the radio as mentioned in the troubleshooting chart. Thought those lines were for the radio channel output. Been looking on the schematics for C6 BLK on the back of the instrument panel. It goes to the clock adjust switch but haven't determined where its routed back to. Thinking to the LCD module circuit board.

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Re: LCD Module Inop

Post by Erdeniz Umman » Sat Oct 28, 2017 4:41 pm

satranger wrote:
Sat Oct 28, 2017 3:37 pm
The Side Stand and Oil pressure circuits only go to indicator bulbs in the instrument panel with no connection to the LCD circuits. Will pull the radio connectors tomorrow and clean them to see if that helps. Wiggling the plugs and wires didn't change anything. Didn't notice that the clock input was from the radio as mentioned in the troubleshooting chart. Thought those lines were for the radio channel output. Been looking on the schematics for C6 BLK on the back of the instrument panel. It goes to the clock adjust switch but haven't determined where its routed back to. Thinking to the LCD module circuit board.
The #5 pin in the LCD unit seems sharing the same blk/brn wire with the oil press and side stand lights (G and E).

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satranger
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Re: LCD Module Inop

Post by satranger » Sat Oct 28, 2017 5:25 pm

The BLK/BRN wire to the two bulbs comes from a tie point with a WHT/BRN wire that eventually makes its way to Relay 3 which is turned on when the ignition switch is on. Its a voltage supply line that runs several places that includes the LCD module.

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Re: LCD Module Inop

Post by Erdeniz Umman » Sat Oct 28, 2017 7:58 pm

satranger wrote:
Sat Oct 28, 2017 5:25 pm
The BLK/BRN wire to the two bulbs comes from a tie point with a WHT/BRN wire that eventually makes its way to Relay 3 which is turned on when the ignition switch is on. Its a voltage supply line that runs several places that includes the LCD module.
Exactly, so you may want to check the continuity of that wire up to LCD unit.

If you have a service manual, you will find the details about the cassette radio deck main wiring harness on page 20-17, 20-18 and 20-19.

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satranger
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Re: LCD Module Inop

Post by satranger » Mon Oct 30, 2017 3:38 pm

Pulled the radio and cleaned the connectors with no change to the blank display. All supply voltages and grounds are good it appears at the connectors going to the LCD module. Continuity check from 6 pin radio plug to the 14P BLK at instrument panel is good. Possibly where the wires connect to the internal circuit board is missing a ground or supply voltage. Took it apart couple days ago and cleaned the circuit board but it looked clean to start with. Can’t tell if those are connectors or soldered connections where the wires attach to the circuit board. May look at the 6 lines from the radio with a scope to see what is on them at the connector to the instrument panel when key is turned on. Anybody ever bench checked the LCD module before?

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Erdeniz Umman
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Re: LCD Module Inop

Post by Erdeniz Umman » Mon Oct 30, 2017 7:48 pm

I replaced the 6pin connector of the radio cassette player last year. There were lots of corrosion and a broken wire at the circuit board where the connectors are attached.
You could open up the rear cover of the radio cassette player and check there.

After checking the continuity of the wires and the availability of the voltages, grounds, and the conditions of the solder joints at the LCD unit, if you can't at least see the clock reading, I am afraid you will have to replace the LCD unit.

I can't remember any repair done on the LCD unit, except replacing the LCD screen and cleaning the circuit board there.

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Re: LCD Module Inop

Post by WingAdmin » Tue Oct 31, 2017 7:45 pm

Does the clock on the LCD appear?

The clock portion of the LCD is driven by the circuit board on the LCD itself, and will still function even if the radio is completely removed from the bike.

So if you're getting absolutely zip on the LCD, you might want to start concentrating on the LCD's circuit board and connectors, rather than the radio connectors.

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satranger
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Re: LCD Module Inop

Post by satranger » Tue Oct 31, 2017 8:53 pm

There is nothing on the LCD display. Been thinking its missing a supply voltage or a ground. As far as I can tell all the supply voltages and grounds are good at the connectors going to the LCD module. Been checking everything else just in case. Had the LCD module out and apart already last week. Cleaned with contact cleaner but didn't notice anything looking bad. About to open it up again and ohm out the wiring to the plugs. Read a post where they thought they found their issue with possible corrosion on a power wire on the circuit board. All mine looked clean but going to take a closer look at them. The points where the wires attach to the circuit board, do you know if those are removable connectors? Kinda look like they are but hard to tell. Have seen similar that were just headers soldered to the board.

Good to know bout the clock display, but everything I've seen so far referenced the radio 6 pin connector making the clock show on the display. Have been wondering if I could power up the LCD module on the bench to see if anything showed on it. Wish there was a circuit description of the module and circuit board. Schematic would be nice too.

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Re: LCD Module Inop

Post by satranger » Tue Nov 14, 2017 11:47 pm

Finally had enough time to work on the LCD Module and tried powering it up on the bench. Connected the two grounds on the connectors to negative and the three 12 volt lines in the connectors to positive on a battery. Never saw any change on the display. No clock or flicker of any sort. Looking like the module is dead. Checked resistance on all the plug contacts to the solder points on the solder side of the PCB. All checked good so no bad solder joints there. The PCB looked clean even before I cleaned it with CRC Contact Cleaner. Wish there was documentation and schematics of the LCD Module. Still thinking lost a ground with all the functions that are not working common to the ground but it should be on the PCB and without information or schematics probably near impossible to troubleshoot. Thinking the PCB behind the LCD Display is probably just drivers to make the display work. Problem there I would think only affects the display and the cruise should still work, mine doesn't, so problem must be on main board since all grounds and voltage lines appear good at the bike harness that plugs into the instrument panel. The voltages and grounds also looked good on the plugs connecting the LCD Module to the panel. Still scratching my head and thinking what else can check on it. Thinking I'll just have to live with it not working till can afford another unit.

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Re: LCD Module Inop

Post by Mh434 » Wed Nov 15, 2017 3:08 pm

Interestingly enough, my LCD display does the same thing when the bike is subjected to cold and damp. As I live in the Pacific Northwest, this is pretty much the case about 8-9 months per year. The LCD goes utterly blank, although the radio continues to function.

It may sound weird, but I use a small, fan-equipped heater, set to a hair above "frost watch", positioned so it blows up from behind the front fender into the space at the back of the dash. The heater comes on 5-6 times per day, and stays on for around 15 to 20 seconds each time. It uses 400 watts per hour on this setting. On warmer/dry days, it doesn't come on at all.

I've been doing this for a couple of years and, as a result, my LCD retains all its functions year-round, the clock continues to keep perfect time, and everything works as it should. When I forget to turn it on, the LCD goes blank after a couple of days & won't come back until the back of the dash gets warm & dry again.

It might seem excessive, but it works. By my calculations, over the winter it uses less than $10.00 of power total at our current hydro rates. That's a small price to pay IMHO, and I worry that if I leave the LCD unheated long enough, the blank screen display would become permanent.

Just my $.02' worth...

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Re: LCD Module Inop

Post by taninauto » Sat Nov 18, 2017 5:21 pm

This will power on the LCD unit and show time. One power, one ground. This should help you narrow down the issue.



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satranger
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Re: LCD Module Inop

Post by satranger » Sat Nov 18, 2017 7:57 pm

Thank you very much for the info on which pins power the clock. Wish there was documentation and/or schematics of the module. Then maybe wouldn't be such a lost cause when the module could be possibly repaired. I tried powering it before but now know which pins to use for sure.

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Re: LCD Module Inop

Post by satranger » Sun Nov 19, 2017 11:15 pm

satranger wrote:
Sat Nov 18, 2017 7:57 pm
Thank you very much for the info on which pins power the clock. Wish there was documentation and/or schematics of the module. Then maybe wouldn't be such a lost cause when the module could be possibly repaired. I tried powering it before but now know which pins to use for sure.
Was good info bout the power pins but did not power up the module. Have to press on troubleshooting the PCB to try identify why it not working. Looking at the PCB components there is a 5 volt regulator which most likely drops the 12 volts to 5 volt powering the other IC chips. First thing to check when I get back to checking the PCB boards. Anybody ever troubleshot the PCB circuits before? Would love to get the info if anybody has it to share.

Anybody got a PCB board out where can look at the IC chips? Need the info off IC4 to tell what type it is. Mine is unreadable.

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Re: LCD Module Inop

Post by taninauto » Mon Nov 20, 2017 10:31 am

We have several if you were interested in purchasing a working board.

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Re: LCD Module Inop

Post by satranger » Mon Nov 20, 2017 10:56 am

taninauto wrote:
Mon Nov 20, 2017 10:31 am
We have several if you were interested in purchasing a working board.


If I can’t repair mine I would be interested in another board. Depends on whether the CPU is bad mostly. Looking at the ones you have, can you tell me the markings on IC4?

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Re: LCD Module Inop

Post by taninauto » Mon Nov 20, 2017 1:26 pm

Can't read on the ones we have either. They could be proprietary IC's made for Honda if they are not standard P/N's.

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Re: LCD Module Inop

Post by WingAdmin » Mon Nov 20, 2017 10:00 pm

taninauto wrote:
Mon Nov 20, 2017 1:26 pm
Can't read on the ones we have either. They could be proprietary IC's made for Honda if they are not standard P/N's.
Very likely they are going to be ASICs that are specific to Honda only and not available anywhere.



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