Dash Needles

ontheroad1 · January 27, 2007

Ive done a search with lots of ideas on repair and seen the diagrams of the board the tips on the RPM and speedo are just starting to fade could you advise me on which resistors need changing to restore them and the best resistor which lasts longer ( LXY/ KME ).

I can still see them and its only the tips but I guess the needle will soon fail, any help would be greatly appreciated everything else on the dash is great.

dave.

November 1991 LS400 series 1

davepruce · January 29, 2007

Dave

I have had only about a third of my tacho needle for 4 years now, the bit that died went all in one go and has not changed since.

However, if you find out what to change, I would be interested

Cheers

Dave

chris vince · February 7, 2007

Ive done a search with lots of ideas on repair and seen the diagrams of the board the tips on the RPM and speedo are just starting to fade could you advise me on which resistors need changing to restore them and the best resistor which lasts longer ( LXY/ KME ).
I can still see them and its only the tips but I guess the needle will soon fail, any help would be greatly appreciated everything else on the dash is great.

dave.

November 1991 LS400 series 1

Dave,

Do NOT touch anything on the PCB the fault is not there, see the post on top of this page:

Replacing burnt out needles on the dash (or similar title), or LCD Display Problems - Recommended Repairs (on following pages 2 or 3 possibly later)

Regards,

Chris

GoldfingerLS · February 8, 2007

Just out of interest, if its not the needles and its not the PCB, then where does the fault lie ?

This seems to be a very common problem for series 1 and serieies 2 owners.

steve2006 · February 8, 2007

Hi,

From what I remember reading it is the needles that fail due to breakdown of the electro florescent coating on the needles.

There is a "fix" I read somewhere involving an ultra violet light and painting the needles but Chris Vince has a trade secret for repairing them.

I always keep mine at minimum brightness in an effort to minimise wear.

The PCB capacitor replacement is the cure for the blacked out intermittant dash due to leaky capacitors losing their correct value and increased esr within them ( technical jargon as Chris Vince will confirm and Chris can repair the needles)

GoldfingerLS · February 8, 2007

Ah ha, thanks Steve.

When I was doing my homework before buying the LS, I was comparing the differences between the Mk3 and the MK4. I remember reading that one of the improvments of the Mk4 over previous years models was the instrument dash cluster and needles failing.

Apparently, in the past Lexus had used the normal LED technology which had an average life expectancy of 12,000 hours. At the time the MK4 was being designed around 1997, they used the then 'new' cold cathode LED technology in the dash. The cold cathode LED lighting is supposed to be more brighter, clearer and has an average lifetime of 50,000 before failure. I remember reading up on this a few years back. I will try to see if I can dig up the source of the info again.