How To Fix Tacho, R33 (maybe)

[Black4DR]

I removed the tacho in my R33. Then went around the circut board with a soldering iron and resoldered all connections ( they looked fine before hand )

Problem solved.

[owtaman]

Hi, 

My car is a year 1996 ECR33 S2, just got it replaced with a S1 cluster due to RPM gauge drop to zero occasionally, now my Speedo is running lower speed than usual, seems like doing around 60 km/h instead of the actual 100 km/h(I gauge it by RPM needle at 3000), any idea what could be the problem ? Does S1 and S2 meter use the same signal voltage ? 

Please note I am not too sure if my S2 comes originally with a S1 or S2 meter cluster, I can't tell which is which.. 

[RANDY]

1 hour ago, owtaman said:

Hi, 

My car is a year 1996 ECR33 S2, just got it replaced with a S1 cluster due to RPM gauge drop to zero occasionally, now my Speedo is running lower speed than usual, seems like doing around 60 km/h instead of the actual 100 km/h(I gauge it by RPM needle at 3000), any idea what could be the problem ? Does S1 and S2 meter use the same signal voltage ? 

Please note I am not too sure if my S2 comes originally with a S1 or S2 meter cluster, I can't tell which is which.. 

So at 3k you're doing 60 in 5th when previously it would be 100? Sounds like the cluster was modified for MPH or something? I was pretty sure the signals were the same and you can just swap the tacho into your S2 cluster to fix the RPM problem if that solves the problem for you.

[stewart1]

I just pulled mine out after it started flicking all over the place then sulking down at 6 o'clock for days...I resoldered the chip on the back of the tacho too but honestly it looked ok and if I hadn't had a degree in electronics I would have stuffed it for all time...the pins and solder pads are very small even with a desolder machine and magnifier I struggled.

I reckon looking at it it was more likely to be the screws that tighten on to the flexible plastic printed circuit board I gave them all a light tighten and It worked perfect when I put it back in and has stayed good for a week now.

Worst part apart from the chip was getting the plugs out to remove the cluster I made myself a tool to grab both sides and pull they are almost impossible by hand.

 

 

Edited July 18, 2017 by stewart1

[RANDY]

38 minutes ago, stewart1 said:

I just pulled mine out after it started flicking all over the place then sulking down at 6 o'clock for days...I resoldered the chip on the back of the tacho too but honestly it looked ok and if I hadn't had a degree in electronics I would have stuffed it for all time...the pins and solder pads are very small even with a desolder machine and magnifier I struggled.

I reckon looking at it it was more likely to be the screws that tighten on to the flexible plastic printed circuit board I gave them all a light tighten and It worked perfect when I put it back in and has stayed good for a week now.

Worst part apart from the chip was getting the plugs out to remove the cluster I made myself a tool to grab both sides and pull they are almost impossible by hand.

 

 

Ah the first time you do it... I remember. It's TIGHT. I've had mine out probably a dozen or more times now for various things and it takes me a minute to undo them.

I also tried the screws, as they seem to pass power to the gauge but it didn't help me. The second hand one I put in years ago now is still working perfectly.

[EeLeYe]

Sorry to bring up an old thread but just wanted to say that I fixed my tacho this morning by resoldering all the bits on the PCB board, even the main chip

I have zero soldering experience and get it working… after TEN years of having the broken tacho!  

Thanks for the instructions!

[RANDY]

21 hours ago, EeLeYe said:

Sorry to bring up an old thread but just wanted to say that I fixed my tacho this morning by resoldering all the bits on the PCB board, even the main chip

I have zero soldering experience and get it working… after TEN years of having the broken tacho!  

Thanks for the instructions!

Funnily enough, two weeks ago my replacement tacho is now doing the same thing. I'll solder everything and see what happens. It makes sense that it's a dry solder joint since it's a sudden yet intermittent fault.

[JasonMate]

Iv finnaly fixed mine after a year. Soldered 12v feed, neutral and signal directly to tacho. I bypassed the screw contacts basically. Good as gold. 🤟

[RANDY]

16 hours ago, JasonMate said:

Iv finnaly fixed mine after a year. Soldered 12v feed, neutral and signal directly to tacho. I bypassed the screw contacts basically. Good as gold. 🤟

Thanks for the update. I never got round to fixing the second cluster/tacho so I might try this method. Did you use some jumper wires or something for the direct connection? You'd have to scrape away at the trace and tack a conductor onto it yeah?

[stewart1]

Here is the before and after of the scraping/sanding of the IC pads on the tachometer board for the fix mentioned in this thread.

And yes it worked fine after.

Just a note if you change any components on the board the tach calibration can be wrong showing the wrong idle etc...only problem is once it is installed back in the cluster you can't get to it to adjust...ouch!

My fix was to cut out the calibration pot (the blue one) from the board and run it with two wires to the fuse panel under the dash where I could adjust the idle calibration once everything was installed.

And yes I soldered everything up again including the half soldered components either side of the IC in my photos

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Edited March 11 by stewart1

[RANDY]

I still haven't gotten around to fixing mine. Now the blend actuator has broken AGAIN. Twice in 20 years. tsk tsk.