devilseye

Hello,
The radio backlight stopped working of my 1999 T/A WS6.

(LCD works, tested by shining a light on the display)

Anyways. i took the radio out... took the bulb out.. and used a voltage meter to check if any current can get through the bulb.. which turned out to be fine.

now what?

i plugged lcd cord back in the radio. and started to measure voltage coming into the board.

at first i measured 1.8volt (on the lines for the light bulb)
after like 15mins. i played with the dimmer switch. and measured 12v when fully dimmed (turned off) and 6or7 volts when i turned the dimmer back on..
ie.. its the opposite? weird


Now what could be the problem? as it obviously getting power

The rest of the radio/steering lights do work properly

Hope you folks understand. my technical english aint that good (i'm dutch)


---
Oh btw, i used the - of the voltage meter on the frame of the unit. and with the + i measured volts on both sides of the lightbulb

VIP1

If the voltage is fine, then the bulb is not. Replace it.

Here are some threads about Monsoon Display issues:
https://ls1tech.com/forums/showthrea...onsoon+display
https://ls1tech.com/forums/showthrea...onsoon+display
https://ls1tech.com/forums/showthrea...onsoon+display
https://ls1tech.com/forums/showthrea...onsoon+display
https://ls1tech.com/forums/showthrea...onsoon+display
https://ls1tech.com/forums/showthrea...ht=monsoon+led
https://ls1tech.com/forums/showthrea...onsoon+display

devilseye

Yes but if you take the bulb out, and put the 2 pins of the voltage meter on both sides of the bulb. and the current can flow through the bulb,
It means the bulb is intact.

correct me if i'm wrong tho

OhOneWS6

iTrader: (11)

1) You can not check a bulb with a volt meter. If a bulb produces voltage it is not a bulb, it is a battery.
2) A bulb is not a circuit completer.
3) You can use a multi-meter to check a bulb if you put it in the ohm position. This is not always a conclusive test (see #2)

When mine burned out I went to Radio Shack, bought a bulb and soldered it into the socket myself. Less than $2. Problem Solved. I don't think I still have the package but I will check. If I do I can get you the part # I used.

Still had the package. 272-1143

http://www.radioshack.com/product/in...ductId=2103786

If you soldering skills are good this is a cheap fix. The bulbs come in a pack of 2 for $1.49

devilseye

Yeah as i said my technical english aint that good
I did it in Ohm position

But anyways.. did another test just now.

Took the bulb out. found some elec wires. and used a normal 1.5v penlite battery.

hooked them unto the bulb. and the bulb worked (of course realy weak due to the 1.5v)
But atleast that means the bulb is ok

After that i put the bulb back in. and set the battery incontact with the contacts for the ribbon on the main board (its connector 3and4 on the board dunno from which side but nvm that.)

Anyways. yet again the bulb went on (weak)..
So what could be the problem :S

As i measure 12volts on the 3rd and 4th cable of the ribbon on the head unit itselfs..., the light should go on!

This is realy strange imo

it just refuses to work.


also put one side of the bulb on the ground surface of the head unit (which is - aka ground), and used a elec wire directly from the 12v contact on the ribbon onto the otherside of the bulb,,
It just doesnt work :S

Only thing i can think of is that something else is broken "somewhere". and i'll just take the + and ground from another source to hook it up directly

VIP1

If you can, follow the traces looking for damage. There must be a bad solder point somewhere or a broken wire or a damaged trace.

OhOneWS6

iTrader: (11)

It seems like in mine the bulb holder showed evidence of getting fairly hot. Just like VIP1 said, I'd look closely at the traces close to where that bulb is installed. It is damn near impossible to troubleshoot a board with components installed. About all you can do is look for a broken trace or bad joint.

Just had another thought. You could run new wire inside the radio chassis to the pin on the connector for the light. You can use This Diag. to figure out which pin it is.

EDIT: Nevermind. Unless you want to add a relay this would only work when the lights are on. There is a circuit in the radio that turns the head unit light on when the dash lights are off and dims it when the dash lights are on. I'm out of ideas for now. Good luck.

ZexGX

iTrader: (28)

Mine burned out. I soldered in a new one into the old socket and it's worked fine ever since. Then I got a newer OEM headunit with a good bulb, except it goes in and out - so I have to take it apart again and fix that one as well. Sigh.

devilseye

did that yesterday.. first i used pin9 and pin7 (from C1)
lights turned off. the lcd light is on (as it should)
city lights on, dimmer off = lcd light on
city lights on, dimmer full = lcd light out, and rest of the panel etc is on..
ie, that strangly works in the opposite direction..

Now i just plugged them on 5 and 7..
only have a lcd light when i turn the city lights on.. thats the only way i can get it to work WITH dimmer

Think i'll just keep an eye on ebay for a new head unit.. atleast i can read the clock/freq again when i want to

OhOneWS6

iTrader: (11)

That is what I expected to happen. You would have to add a relay or use diodes to make it work properly.