505 - Series 1 - Instrument Cluster - Looking for "Disassembly Instructions" please

[505STI]

Folks,
I have verified the 'Tacho' in my 'Instrument Cluster' is not working.
Was hoping for some information please on 'Disassembly' so as to replace the 'Tacho'.
I can see clips in the rear the same as front but also some screws.
Before I make a mess of it I thought I would ask for help please.
Have had a good look around but unable to find anything.
Will be very grateful for any assistance.
Thanks
Ted

 

[lowpugV2]

I don't have any instructions apart from " beware, the brittle plastics" I once had to pull apart a series 1 instrument cluster to fix a cracked solder. That was easy. Teasing apart the 4(?) Plastic clips holding the PCB was the tense part.

 

[robs]

Hi Ted,

My dashboard came apart pretty easily. I think there was just one screw to undo and you want to release the clips deeper in (towards the front of the car). The other clips only release the lens (I'm pretty sure -- never tried).

1. Start by pulling off the trip odometer knob (I always forget).
2. Undo the screw on the back between the upper speedo and tacho (I think). It connects the dashlight trace between front and back of the dash.
3. Release all the deeper-in clips. Just do them one-by-one, keeping a bit of spreading tension so they don't slip back together again. They look fragile, but mine all handled it ok. Perhaps favour doing it on a warm day rather than a cold one.

I may have forgotten something. It should slide apart very easily. If there's resistance, look for what's getting stretched.

The tacho connector is a pretty silly design. Disconnected, it shorts all its terminals. If you leave it disconnected and run the engine there will be smoke and burnt traces, so make sure to either hook it up to a good tacho or jam a bit of plastic in.

So people know why I've had my dash apart, here's a photo of my latest Megasquirt dashboard installed in the tacho slot:

I've recently picked up some small torx screws which will look a bit better. I'll be fitting them later this week and could do some photos of the dismantly if you like.

Have fun,

Rob.

 

[505STI]

Thanks LowPugV2
Thanks Rob,
Having looked at the challenge of pulling apart 'Instrument Panels' so as to transfer a working "Tacho" over I got a bit worrried.

So I did some more thinking. I have two Series 1 clusters (one good one from a GR and the problematic one on my SR)
One of the three connectors is different (9-Pin vs 6-Pin).
My problematic SR 'Instrument Panel' has CC Connector of 9 pins ( Per Haynes Page 260 Figure 12.9 ) of 6 pins ( 5 wires used)
My good GR 'Instrument Panel has CC Connector of 6 pins ( 4 wires used ).

Rather than pull two instrument clusters apart I looked at changing the wires on the "9-Pin Connector" to a '6-Pin Connector'.

I'll give this a go and see if that works.
I will not have a connection for wire # 47M but don't think that matters.

Thanks very much for your help.

Rob, the 'Megasquirt' display is amazing.

Cheers
Ted

 

[garryw]

I had the same issue with a 505, but some 15 years ago!! I solved the problem by resoldering all the surface mounted devices. If you can do the soldering, then it's about a 15 minute job. If you can't do the soldering, and can't find anybody to do it locally, make contact with me. In fact I'll be in the Castle Hill area tomorrow!!

 

[BP505v6Turbo]

Be careful make sure it's from the same type off dash eg. early 505 1980, had no econoscope and temp gauge and fuel around the other way and pinkers flash like 504s, and there's pj80 0r pj82 make sure same or you'll have dramas, very common series 1 tachos failing.


I like the megasquirt dash
What motor you got the megasquirt on?

Cheers BP

 

[robs]

Ted,
If it's any use to you, you're welcome to my old tacho. It was working fine when I removed it. Includes the econoscope FWIW.

BP505v6Turbo,
It's on a 505 GTI (Douvrin), but I also have one on my 604 (PRV), using a EA Falcon throttle body injector in place of the carby. That was fun and made an amazing difference to the performance. I wrote it up here some years ago (more years than I like to think). Should come up on a search of Megasquirt and 604.

Have fun,

Rob.
[ediit]I did the search: 604 thread

 

[505STI]

Rob,
Having replaced the SR motor and gearbox with a GR motor and gearbox I have just realised the problem with the 'Tacho' is probably related to my reverting not updating the GR 'Points ignition' yet.
I'll change over to the SR Electronic igniton as soon as I can manage it.
In the meantime I changed the 9-Pin Connector wires over to a 6-Pin connector so as to use the earlier GR Instrument Panel with 6-Pin 'CC' connector.
I needed the GR Instrument Panel to have an accurate 'Speedo' reading.
Everything else seems to be working OK on the 'Instrument Panel' after the change.

This is the 6-Pin wiring I used.
Pin Colour Wire#
1
2 Red 25B
3 White 67
4 Yellow 68
5 Blue 30B
6 Green 47A

Rob, Many thanks for the offer but I reckon the 'Tacho' will be OK after the 'Electronic Ignition' is installed.
Thanks all for your assistance.

Ted