Two Problems

[SHELLDRAKE]

Hello Guys: problem - 1- in September I had new disks and pads fitted to the front of my 400,since then I have noticed on a few occasions there appears to be a reddish powder on the front wheels, is has done 2k+ since then should it be still be doing that or could it be something else?

Problem - 2- On the radio at night the buttons for selecting LW/MW-UKW-TAPE-CD are not lit up but the remainder are,is this normal or has a fuse blown or a bulb.

All information on how to sort things out pleas will be appreciated

Norman.

[ambermarine]

The reddish powder could be brake dust from the pads it is usually black but some pad compounds are coloured with a dye .It could also be rust off the disks which forms very quickly after wet and damp weather conditions.

The light problem is likely to be the array for that section of the pcb is suspect ,could be a bulb in series putting them all out or something more problematic. It is unlikely to be a fuse as all the board would be out.

The only way to determine the state of the bulbs is to remove the centre monitor unit and take it apart and check the bulbs for power.

There are tutorials on Lexusownersclubusa.com that deal with the removal and dismantling of the unit.

[SHELLDRAKE]

Ambermarine: Thanks for that I'll try out what you suggest.

[steve2006]

Good advice from Ambermarine, can't really add to it.

[runsgrateasanut]

Regret reading this thread as its reminded me that I asked a Q. as to the backlighting of my Radio buttons recently.

Now its on my mind Ican't stand things not being right, and I fear I will dwell on the subject until I resolve to do something about it.

Very useful reference by Ambermarine to a thread on the US Club on the subject which I've read with interest. I wonder as all lights are out on my buttons perhaps it is the Resistors rather than the bulbs causing the fault. Not sure if the earlier Pioneer for my Car will be same as the later model Radio which is seen in photo's with the Resistors pointed out.

The Display panel lights up. Would be nice to see the buttons lit but is it worth all the trouble when I can plug in a computer LED flexi light to the Cigar lighter and see the buttons at night?

Darn it, I suspect I won't let it rest!

[Bluesman]

Regret reading this thread as its reminded me that I asked a Q. as to the backlighting of my Radio buttons recently.

Now its on my mind Ican't stand things not being right, and I fear I will dwell on the subject until I resolve to do something about it.

Very useful reference by Ambermarine to a thread on the US Club on the subject which I've read with interest. I wonder as all lights are out on my buttons perhaps it is the Resistors rather than the bulbs causing the fault. Not sure if the earlier Pioneer for my Car will be same as the later model Radio which is seen in photo's with the Resistors pointed out.

The Display panel lights up. Would be nice to see the buttons lit but is it worth all the trouble when I can plug in a computer LED flexi light to the Cigar lighter and see the buttons at night?

Darn it, I suspect I won't let it rest!

I know exactly what you mean it bugs the life out of you when you know it isn't working as it should. You are not on your own. Mike.

[plexus914]

There are 14 soldered on bulbs for the buttons. 4x3 bulbs and 1x2 bulbs are parallel-connected.

 

 

In my case it was the one bulb for the on/off knob.

PS: Does the bulb from that on/off knob still work on your stereo.......?

[soundchaser100]

This is unlikely to be the bulbs. There are 2 Large Transistor Voltage Regulators in the corner of the board. It is highly likely that the Emitter Resistors (1 ohm) have fried on the board causing the print to go open circuit. This is caused by the current demanded by all those bulbs being high ( a few amps ). The cure is to repair the printed circuit board, and then replace all the bulbs with LEDs. You need to fit limiting resistors as well (LEDs don't like 12 volts) which involves cutting the print. The LEDs draw much less current, and so the regulators run much cooler. My LS400 had this problem when I bought it in 2006, so I carried out this modification and the lights still work perfectly.

Paul

[plexus914]

On/off knob lights up again. I changed the soldered in micro bulb. 8V / 0,06A / 0,5watt / bulb head is about 3mm x 5mm

Cheap ones from Fleabay work just fine: 5 - 12 V  / 0,1 A /  3mm x 7mm