[h2pmr]

going to be a how to thread for the PRND23 bulb replacement from my 87 S4
more use putting it in a new thread, incase someone needs to do it in the future.

inst panel is out on bench, i have new LED's to go in, new PCB plastic foil from Roger and a new speedo gear to go in as well as it must be on its last legs by now and i don't want to be stripping it down again.

not the best job in the world to do as the bulbs are soldered in, but if i can get plenty of good pictures and write a fair explanation of what i am doing it might help someone be able to do it themselves.

might be a few days until the next post but hopefully will be worth the wait.
cheers
Phil

[hernanca]

Looking forward to the pictures. Should be a similar job, if not exactly the same, on my 86.5 auto.

[h2pmr]

rev counter


and noted where the needle sits


having got the rev counter out, need to remove the needle.
best way i found was thin long nose pliers and using the face plate retaining screw as a pivot point for the pliers gently lever the needle off, with plenty of protection on the face plate and keeping a finger on the other side of the round part of the needle to try and keep even pressure on it.


remove the 2 screws and remove just the black face plate, the plastic part the face plate sits on needed a gentle lever to get off and then it looks like this


then remove the 5 wires between this and the main body of the rev counter, note where they plug into and remove the 3 screws picture, the other 2 screws recessed in stay in place


with the base removed its only the 2 green wires soldered to the rev counter that is holding the rev counter to the board so be gentle with it, but can now actually see the little bulbs



usual disclaimer, might be an easier way, don't sue me if it don't work for you etc etc
now for the soldering part, potential for but fingers crossed not.
cheers
Phil

[h2pmr]

to test them first and make sure the wiring is good, the ground point is the brown wire - the middle one of the 3 that joins the circuit board to the body of the rev counter, fit a wire to a 12v battery earth + the earth of a power probe, as pictured below


in the 8 pin connector below pin 1 is the white wire pin 2 is the black wire, pin 3 is the yellow wire etc up to pin 6
P = pin number 4
R= pin number 6
N= pin number 3
D= pin number 2
3= pin number 1
2 = pin number5
so with the power probe connected giving the white wire pin 1 a 12v feed lights up the 3 bulb etc etc
this is an 87 model so wire colours etc might be different for other model years


looking from this side 3 is the farthest right bulb and P is on the left


need to get a magnifying lamp tomorrow for the actual soldering part
if only they were just removable 286 bulbs life would be a lot easier.....
so more to follow
cheers
Phil

[h2pmr]

deleted, thanks Dave

[worf]

if its possible to edit a post the yellow wire is pin number 3, black wire in pin number 2 green in 4 etc

It is:

[h2pmr]

my eyes are still pretty good but it helps to use one of these.


to de solder the original bulb i gently put a small flat screwdriver between bulb housing and circuit board and used the solder iron to heat the pins up and it dropped out


this is the size of them



if using the LED's do not be tempted to cut the long legs off before you have go them through the holes in the circuit board.
-the cutting of the legs squashes the pins so now to big to go through the holes.
and of course LED's are polarity sensitive, they only work if the 12v and earth are the right way round on the pins.
test them to know which pin is 12v and earth.
then when you look at the circuit board you will see one printed line joining into all the bulbs- this is the earth



P LED now soldered and just tested it, picture looks crap but it is a perfect brightness, and very happy with it
P is red
D is going to be green
the rest just std white.


will be next weekend until i get back to this as the day job is beckoning
cheers
Phil

[The Fat Man]

Well done!

I appreciate your work. I will have to do this sooner or later on my 1986.5.

[h2pmr]

just actually noticed there is a spare mounting hole above the P bulb which is wired on the PCB to go to the spare O
bottom right of the picture, and a spare hole in the top housing the actual dial sits on
wonder what Porsche thought they might put in there in the future?
move P to the top hole and have a 5 speed auto?
cheers
Phil

[worf]

Probably for “W” speed.

Good stuff Phil.

[h2pmr]

the actual LED'S i got from a company called Farnell here in the UK, part number from their website of the white one.
LTH3MM12VFR4400 the T1 version
there is a ridge in the legs close to the top, can just be seen below, so when the LED is pulled through the PCB up to this ridge its the exact right place to bend the legs to make the LED in the right position, as pictured below




TEST BEFORE SOLDERING THEM IN, then solder them in, then test again
and as added security i used super glue over both sides of the pins, if they ever need removing will get an apprentice to do it as they are expendable....



D is now green



just a case of putting it all back together and test again before it goes back in the car
cheers
Phil

[h2pmr]

D

[h2pmr]

mainly for UK and Europe residents.
the warning light bulbs 99963130190 are identical to the ones fitted to a Peugeot 205, 309, 405 part number is 611234
and are without the Porsche price mark up
cheers
Phil

[h2pmr]

finally got it all fitted to the car, and working fine
was just a little worried they would be to bright, but they look perfect to me, difficult to show below, but they are the same brightness as the warning lights, but not quite as bright as the main " ! " warning light
crap quality video of them all working
cheers
Phil