Tested Gauge Clusters

[mudnut]

Because of the amount of threads about faulty gauges, lately, I am toying with the idea of buying some GQ gauge clusters and testing/repairing and selling them on an exchange basis on the forum, to trusted members. This would not be a full on business but more of a hobby, to start with. If it is successful, I am thinking of also doing the more technically advanced GU clusters. I have been interested in buying a good oscilloscope and signal generator for a long time, and this is a good reason to do so. To get started, I would need some help to get readings such as differing voltage inputs etc. And even average speed sensor readings for different tyre sizes. I would also need opinions on how much members would shell out for a tested cluster. The exchange would only work if everyone promptly returns their cluster and also I need to find replacement parts. Postage to my location may be a prohibitive cost too. This is only a pie in the sky idea at the moment, but let me know what you think. If I cant find original parts, I might have to retro fit after market ones.

[mudnut]

Any interest at all?

[BigRAWesty]

I was wondering if there was a test sequences for them.. Ie x voltage is half tank, or high oil pressure.

Is there such a thing coz I'd like to test mine to eliminate it from my issues..

[mudnut]

On the early model gauges, most of the input signals can be replicated by a simple voltage and variable resistor and the gauges tested with a multimeter. I want to view, (on an oscilloscope), the average inputs for the tacho and speedos and use a signal generator to produce almost the exact inputs for accurate measurement.

[BillsGU]

Most of them are rated at FSD at a certain current. All you would need to do is build yourself a variable constant current source (using a 7805 or such) and then get the gauge specs. Some gauges have the FSD spec written on them.

[mudnut]

I have the guts out of a few different power supplies left over from some other jobs, so it won't be a problem to build one to test Full scale deflection. But I would like to get some wiring looms and make a plug 'n' play unit. And the "Dearest, I need a an oscilloscope and signal generator" factor is at play here too.:)

[BillsGU]

You won't need much of a signal generator as it would need to be more of a pulse generator. Again a simple kit from Jaycar would do the job. The CRO would also need to be fairly basic as you would not need one with a high frequency response or a large bandwidth. You are mainly looking at pulses at low frequencies.

[mudnut]

I have done a bit of research and found some basic gear for reasonable prices. Brand new portable LCD oscilloscopes have come a long way since the CRO. I have even found one that has an in built sig gen. I also wish to get back into electronics, which has changed so much since the days of my apprenticeship, in the eighties. I have been shopping around for a small second hand metal lathe as well, so I can have the option of fully reconditioning alternator slip rings.

[megatexture]

Drop cuppa a pm incase he has missed this thread as I know his cluster was playing up.

[mudnut]

I'll pm him now, thanks.

[geoffayres]

........I know his cluster was playing up.

He has serious problems.........but, how did you find out??

[Cuppa]

He has serious problems.........but, how did you find out??

Oi, don’t tell everyone ..... it’s personal! :tease:

Seriously though ..... the problem was fixed....... with a little help from my friends & an extra strap.

[BigRAWesty]

@mudnut, a bloke is splitting a gq in Portland.I'll get his number to you if you like.

But if you do something soon I'd like mine tested..

[Yendor]

Mudnut, Do you have a spare GQ instrument cluster or do you know if there is a voltage regulator on the supply feed to the gauges?

I don't think there is but I'm not 100% sure.

[mudnut]

Wow, blokes the Questions are coming thick and fast now! I have spent the last couple of hours researching equipment and variable resistors.

Yes, please, Kallen. PM me his number. I have the cluster, out of my 4wd corolla to do some initial tests on as a guide to what components I will need to replicate gauge readings etc. Finding cheap variable resistors with a good wattage rating is proving to be fun. I may have to parallel some double gangers to cope, so I should get something going in the next few weeks. In the Haynes manual I have, there are some simple tests for the gauges.


Yendor, I haven't got a cluster, but hope to have one soon. I'm hoping all of the Q clusters have the same connectors even though Diesel and petrol models differ. I will scour the manuals and see if there is some sort VR in the circuit.

Edit. The electronic manual shows three different gauge clusters, with the what looks like identical sockets.

[mudnut]

Yendor, so far all I have found is the resistor circuit in parallel with the speedo and voltmeter and then in series with warning lamps. This would act a a basic regulator. I suppose they rely on the alternator VR. Please correct me if I am wrong.

I am having trouble finding the expected voltage readings for the tacho in the three manuals I have. I am a bit averse to testing across the terminals with my moving coil meter. An auto elec warned me off doing that many moons ago, but I can't, for the life of me remember the reason behind it.

[Yendor]

Yendor, so far all I have found is the resistor circuit in parallel with the speedo and voltmeter and then in series with warning lamps. This would act a a basic regulator. I suppose they rely on the alternator VR. Please correct me if I am wrong.

I am having trouble finding the expected voltage readings for the tacho in the three manuals I have. I am a bit averse to testing across the terminals with my moving coil meter. An auto elec warned me off doing that many moons ago, but I can't, for the life of me remember the reason behind it.

I didn't think they did have a VR mounted in the instrument cluster.

I'm just thinking if there was, then this is what might be wrong with Kallen's.

A digital multimeter will be fine to use or even better a new scope :wink:

I remember seeing someone posted scope reading, I think for engine RPM and vehicle speed. It was awhile ago......I will see if I can find it later tonight.

[mudnut]

What price would everyone expect to pay for a secondhand cluster and partial wiring loom?

[BillsGU]

Digital meters have a much higher input impedance than moving coil meters (Meg ohms as opposed to kilo ohms in some cases). This means that when you poke a digital meter into a circuit - the meter does not have an effect on the circuit operation (ie the meter does not change the overall resistance of the circuit). Moving coil meters due to their lower input impedance (especially the cheap ones) can do anything from changing the characteristics of a circuit and giving you incorrect readings to adversley affecting a circuit and stopping it from working or even damaging the circut.

[mudnut]

I have a cheap digital multi meter, but it likes to give odd readings sometimes, so the "Dearest, I need a good digital meter too" will come into play when I let her read your post.

[BillsGU]

I have a cheap digital multi meter, but it likes to give odd readings sometimes, so the "Dearest, I need a good digital meter too" will come into play when I let her read your post.

You can get very reasonable digital meters for around $40. Not so many years ago they were many hundreds of dollars - but not any more. Some years ago the average price for our work meters was just under the $1000 mark. Jaycar have a good range of good quality reasonably priced meters. Don't buy a $10 meter. May be OK for an emergency meter in the boot of the car - but not for any serious measurements.

[BillsGU]

One other point when buying a meter - make sure it measures amps in the micro amp range. Some of the current measurements you will be making will be very small. If you buy a meter suitable for an electrician to use you will find they don't measure very small currents. You will need a meter suitable for an electronics tech.

[mudnut]

I remember seeing some lcd screen type meters, by fluke which I think have oscilloscopes in built, if I read the description correctly. I skipped over them thinking that they would be very expensive. I will have another look as someone might make a generic model.

[BigRAWesty]

Pm sent bud

[mudnut]

Thanks, Kallen, I'll get onto him this week, hopefully.

[Yendor]

Heres that link mate

http://www.patrol4x4.com/forum/nissan-patrol-gq-y60-ford-maverick-11/td42-vss-pulse-width-97071/

[mudnut]

That is excellent reading thanks, Yendor. It gives me a starting point. The Q that Kallen put me onto is a TB42 E, so I will have a common gauge to start with, I will see on Monday, what else I can score from the wreck.

[mudnut]

I have got the gauge cluster, blinker and light control assembly, hand throttle and windscreen wiper motor for $50 so I am pretty happy. It was a lwb so all the doors, which looked ok are for sale. The engine is gone, but the auto is still there. The dash looks reasonable too. The clear face of the cluster was cloudy, but I have spent some time polishing it. I want to use armour all on it, but I am wondering if it may go cloudy like some commodores do. Any thoughts?

[mudnut]

Some initial readings on the gauge cluster plug and play test unit.

The whole dash cluster only uses 1.5 to 2.5 amps with all lamps lit (-ve switched lights. Lamp test and +ve switched lights).

My battery drill only gets the speed sender unit up to 60 kph.

I will have a dig in the shed and find another small variable speed motor to run the unit, until I get a signal generator which will do the tacho input as well.

[BigRAWesty]

Some initial readings on the gauge cluster plug and play test unit.

The whole dash cluster only uses 1.5 to 2.5 amps with all lamps lit (-ve switched lights. Lamp test and +ve switched lights).

My battery drill only gets the speed sender unit up to 60 kph.

I will have a dig in the shed and find another small variable speed motor to run the unit, until I get a signal generator which will do the tacho input as well.

Huh. My spedo is electronic to the cluster. Or did you strip that ti??

[mudnut]

I took the sender off my knackered gearbox, just to see the wave form, current and voltage it produces. I just connected a bit of tough rubber tube between the sender drive shaft and a bit of a bolt in the drills chuck. It works a treat.

[BillsGU]

I took the sender off my knackered gearbox, just to see the wave form, current and voltage it produces. I just connected a bit of tough rubber tube between the sender drive shaft and a bit of a bolt in the drills chuck. It works a treat.

Usually simple = good. Why make it complicated?

[mudnut]

This is the Plug and play gauge cluster test 'bench'. (Don't look at the failed paint job) The speedo signal is at 175 Hz at 60 kph. The power supply drops to 11.9 volts when the cluster is powered up, so this reading isn't accurate. I have to pull the supply apart and check it out. It needs a better voltage regulator and a couple of capacitors fitted to lift it to 13.8 Volts under load. The trip meter and odometer also clocked up 4 ks during the test so that was a bonus.

[mudnut]

The readings on the road for 60 kph with Mrs mudsane driving were 170 hz. Which is very close to the stationary test I did yesterday, but could be her interpretation of what position the needle is at 60.

Anything below 50 was unreadable, but that may have been the way I had set up the oscilloscope.

I tried the scope on my tacho input, but it showed a 9v bias with a minute square wave on the very top. Again, it is probably the way I interpreted the Chinese instructions. I will talk to a mate who does Dyno tuning and get his opinion on what signal to expect.

[BillsGU]

I tried the scope on my tacho input, but it showed a 9v bias with a minute square wave on the very top. Again, it is probably the way I interpreted the Chinese instructions. I will talk to a mate who does Dyno tuning and get his opinion on what signal to expect.

Set the scope to AC coupling. Then turn up the vertical amplitude.

[mudnut]

Thanks, The "toy" only has DC coupling. I have been trying to learn to navigate the device. I have posted the link to the instruction manual in the multimeter thread.

[BillsGU]

Thanks, The "toy" only has DC coupling. I have been trying to learn to navigate the device. I have posted the link to the instruction manual in the multimeter thread.

OK - I have used many scopes and never heard of one without AC coupling. You live and learn.

[threedogs]

http://www.ebay.com.au/itm/291039883238?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

@ Mudnut this any good for you

[mudnut]

Thanks for finding that meter, TD, I have a Jaycar QM1551 meter. You have reminded me to take it back, as the the duty cycle mode is unable to measure square waves correctly.

[mudnut]

To date, I have had trouble finding information regarding the test procedures on tachometers. I took the plug'n'play test bench to a retired electronics tech's place and spent the afternoon running tests and recording results. He is going to draw up a circuit that will amplify the test signal produced by the Oscilloscope. it should be an easy build, which I am looking forward to. And because I'm too tight to pay out for a portable 12v sig gen, I will use a small variable speed 12v motor I have found in the shed, to run the speedo sender up to 110 kph.

[mudnut]

I am enjoying this little hobby and the challenges that have arisen. It has been an eye opener and there is so much to learn.


I need to get good, clear pictures of the front and back of all the different styles and models of the GQ clusters. TB42, TB42E, TD42, RD28, RB30, Turbo, Autos and Manual transmissions etc.

So, If you have a spare cluster, or have a need to remove your cluster for any reason, please take some shots and post them up for me.

Thank you in advance and cheers, mudnut.

[mudnut]

Okay, fellow Patrolians, I have had to wait for the local electronics store ship in an electronic metronome kit. I built the kit, then set about modifying it to run on 14volts and produce a square wave instead of a pulsing beat. I had limited success and the tacho read 3000 rpm until the second hand transistor I used as an input, destroyed itself and the metronome circuit seemed to suffer form some sort of feedback or distortion at above 350/ 400 Hz. I have used a 555 timer instead (From an old egg timer I made in the eighties). From what I can see the tacho on my Old Trol uses an input of 9-10 volts and between 200/ 600 hz and 446 micro amps. I need to order some transistors online and some advice on which type to get would be appreciated.

[BillsGU]

You could use a 2N3055. It is an NPN and should be able to handle the power required. It has a T03 case so it can be bolted to a large heat sink if needed. The transistor in the circuit seems to be used to amplify the output of the 555. You just need ot make sure that the emitter resistor you select limits the current to below the maximum current as per the transistor data sheet. Download a data sheet for the 3055 and it will give you typical values. You may also need a couple of base bias resistors to set up the Q point at the output to give you the swing you want. The idea would be to do some calculations and then bread board it using variable resistors until you get it exactly right.

[mudnut]

Thanks, Bill, your info gives me a starting point. I reckon the transistor I used must have been damaged by heat when I unsoldered it.

[nissannewby]

Mudnut.

Excuse my laziness for not reading back. Do we get a square wave signal at any part of the system?

[mudnut]

Yes, Matt. The tacho input is a very messy square wave with a 9 volt bias. (or so my scope reads that)

[BillsGU]

Yes, Matt. The tacho input is a very messy square wave with a 9 volt bias. (or so my scope reads that)

Do you mean the centre of the square wave is at 9 volts, or the bottom of the square wave is at 9 volts ?

[nissannewby]

Yes, Matt. The tacho input is a very messy square wave with a 9 volt bias. (or so my scope reads that)

Cheers mate. I have an electronic boost controller that can use rpm for boost correction and requires the use of a Square wave signal for its input. I think it's range is 3-12v.

[mudnut]

This is a picture of the tacho signal across the 2k resistor to earth under the bonnet of my RB30, Matt. It shows the approximate voltage of 7.8 volts to earth, a frequency of 332 Hz and the messy square wave. It doesn't show the high spikes with each wave very well, so be aware that they may influence the device you intend to run. The system also draws approximately 440 microamps.

[mudnut]

Do you mean the centre of the square wave is at 9 volts, or the bottom of the square wave is at 9 volts ?

The first couple of times I hooked up the oscilloscope the square wave was about 1.5 -2.0 volts at the top of nine volts dc. That is why I said a 9v bias. Today my scope shows a square wave as just a 7-8 volt wave (peak to peak) to earth. I have no idea why it has done this as I haven't changed the parameters. I am still struggling to understand the chinese instruction manual.:1087:

Edit: Maybe early on, I measured just across the resistor and not from the yellow black to earth??

[BillsGU]

The first couple of times I hooked up the oscilloscope the square wave was about 1.5 -2.0 volts at the top of nine volts dc. That is why I said a 9v bias. Today my scope shows a square wave as just a 7-8 volt wave (peak to peak) to earth. I have no idea why it has done this as I haven't changed the parameters. I am still struggling to understand the chinese instruction manual.:1087:

Edit: Maybe early on, I measured just across the resistor and not from the yellow black to earth??

OK - the second reading makes more sense. You can't use a (normal 240 volt) scope like you use a multi meter. You can't just poke it into a circuit and measure across components because the negative clip is earth. All of your measurements must be wrt earth.

[mudnut]

Got the tacho signal working today. I can adjust the TB42E tacho from around 1000 up to about 5800 rpm. I have been a bit slack with setting up the speedo properly as I have decided to make the unit detachable so that it can be fitted to the sender under the car as well.

[NissanGQ4.2]

Not sure if your interested: https://www.facebook.com/photo.php?fbid=10152481833884281&set=gm.603088916472719&type=1&theater

[mudnut]

Thanks, I don't have FB, so I'll get Mrs mudsane to check it out.

[mudnut]

Nearly finished. I still haven't completed the speedo drive unit as such, but I have all the gauges working. All that is needed to drive the tacho is a 555 timer with a couple of pots to balance the voltages to get a wide range of output frequencies with out being limited to fixed frequencies from just switching different capacitors. The whole unit looks shoddy as I have expanded on the original idea. Hopefully, I'll bring it to the next meet up and I can test a heap of clusters.

[Bloodyaussie]

Nearly finished. I still haven't finished the speedo drive unit as such, but I have all the gauges working. All that is needed to drive the tacho is a 555 timer with a couple of pots to balance the voltages to get a wide range of output frequencies with out being limited to fixed frequencies from just switching different capacitors. The whole unit looks shoddy as I have expanded on the original idea. Hopefully, I'll bring it to the next meet up and I can test a heap of clusters.

Looking good !!!!

[mudnut]

Came across some simple circuits to produce low voltage AC sine waves to run the speedo. Had time to have a bit of a play with another 555 timer chip on the bread board and got a low voltage output that runs the speedo up about 40kph. After about 116Hz, the Variable Resistor/ capacitor circuit freaks out and the chips output drops enough to be unable to drive the speedo. Have tried a few different capacitors , but none work too well. I have found a more robust circuit, and will order some more components this week.

[mudnut]

I spent some time mucking around with a 555 timer and a couple of small transistors on the breadboard today, and have finally got a simple signal generator working. The signal is able to be easily adjusted, then fine tuned, so I am very happy with it. I have decided to remove the tacho signal box from the test bench. I will combine it with the speedo output in a small box, powered by a 9 volt battery. That way I can throw the unit in the Patrol, for any meet ups.

[mudnut]

I've been a bit slack, but I had a bit of time inside, because of the rain, so I finished off the speedo signal generator.

I had to remove from the tacho generator from the box as the AC speedo signal was feeding back through the -ve wire.

I will make a separate unit for the tacho. All I need to do is extend the cable so it plugs in, under the vehicle. I will also make some leads that plug in behind the dash.

My 'third arm' is also shown in the picture. I used the base and flexible arm from an old desk lamp. I will replace the G clamp with a spring loaded clip, when I get around to it

[NissanGQ4.2]

I need to get good, clear pictures of the front and back of all the different styles and models of the GQ clusters. TB42, TB42E, TD42, RD28, RB30, Turbo, Autos and Manual transmissions etc.

So, If you have a spare cluster, or have a need to remove your cluster for any reason, please take some shots and post them up for me.



Do you still need pics mate?

When I get a chance I have a TB42E Auto cluster I can pull out

[mudnut]

Yes, thank you. There are three types of clusters A, B and C. I welcome any photos to give me an idea of how to set up for each type.

[NissanGQ4.2]

Yes, thank you. There are three types of clusters A, B and C. I welcome any photos to give me an idea of how to set up for each type.

No worries, probably won't get a chance for a few weeks 2 pull it out but will get it done for you.

[mudnut]

Cool, I hope others follow your lead. I am thinking of making portable units for each type.

[mudnut]

All done except for making leads and installing speaker output ports on the Tacho signal box, to hold the meter alligator clips. I will now go in search of some stuffed gauges to learn how to repair them and for spares. It is interesting to note that the tacho is spot on 150 Hertz at 3000 rpm.

[mudnut]

G'day all. If anyone has an old gauge cluster or gauges that are faulty, I am willing to work on them, gratis at the moment, but you will have to pay the postage and parts.

[Bloodyaussie]

Craig I am working on an issue with my speedo not working and am trouble shooting the problem from the gearbox back... it may comr to the point that I will need the clocks tested.

[mudnut]

No worries, BA. It is easy to test the sender by spinning it by hand, or using a battery drill on the drive. You can get someone to test the voltage at the back of the speedo while you are testing the sender. Are you able to get someone's spare speedo if needed?

[Bloodyaussie]

Ok Craig I checked the worm drive in the gearbox and I have replaced the sensor as that was seized but still no joy so I pulled the clocks out and plugged in my old set and ta daa !!!

Now the clocks I plugged in I have sold so I cannot use them for parts, what would be the next step???

At least I know the problem and now its a matter of fixing them.

[Bloodyaussie]

Update... I have sorted it, there are 4 screws holding the speedo in place and one was missing and one was not factory and looked to not be touching the ribbon so I took 2 out of the clocks I have sold and will replace later.

I have not gone for a drive as yet but with the power drill all was good.

Cheers...

[mudnut]

It is really easy to take the speedo module out of the cluster. Check ALL of the solder joints. If there is no problem, then there was a cluster for sale, on this forum, earlier this year.

Or if there is a kind-hearted member, maybe you could get a loan of a cluster. Send the stuffed cluster to me. I will have a go a repairing them.

As a matter of interest, how much did you flog your other set for BA?

The problem is at the moment, is I only have a TB42E cluster in really good order, as a spare and I am using it as a a reference.

[mudnut]

Hey, BA, does your Odometer still run?

[Bloodyaussie]

I think you missed the post Craig... I fixed them and they are working fine.

The only issue is the speedo is out by a fair bit?

[mudnut]

Silly me. That's great, that you fixed it. Have you changed to a TD42 cluster, or are you still running the TB42 unit? It is easy to drill a hole so you you can adjust the speed reading without having to take the speedo out. I use the small screw caps from the old style power points to seal the hole, but a piece of tape should do.

[Bloodyaussie]

I have td clocks series 2.. can you adjust the reading for the speedo?

[mudnut]

How many kilometres out is it? GQtank's thread should help you, BA.

http://www.nissanpatrol.com.au/forums/showthread.php?23540-Gq-Speedo-adjustment-to-read-correct-speed&highlight=speedo+adjustment

[mudnut]

Ok, Folks. I haven't done a great deal with the gauge cluster as I spiked my little oscilloscope while I was testing a late model diesel injector pulser circuit I am designing.

Unfortunately I threw some cash away on an Allsun EM125 scopemeter. Using it is like trying to eat lunch with a pitch fork.

It wont read frequency within an acceptable scale for speedo calibration and the high voltage is reliant on a x10 switch on the probe, so 240 volts shows up as 23.5volts, which is just bloody dangerous.

I have my eye on a few other scope meters but they are $400 upwards, so I am saving up for one.

I am also having fun and games trying to source stuffed gauge clusters for spares at a reasonable price.

Last time I checked, there is another bloke in central Vic advertising reco cluster for a price I can't match.

If anyone has any stuffed/ spare clusters let me know. Cheers.

[gf0012-aust]

have you looked at the 4.19mhz oscillator? its the thing that invariably gets replaced by instrument repairers

[mudnut]

have you looked at the 4.19mhz oscillator? its the thing that invariably gets replaced by instrument repairers

Yeah, that and high resistant solder joints. That is a 4.19 crystal. GQ Tank has found the closest available locally is a 4.097mhz crystal from RS electronics, which seems to work fine.

[gf0012-aust]

you can get the actual proper speed oscillator - I bought half a dozen from a US elec component seller. approx $20 got the lot incl delivery

just checked and now cheaper to buy out of germany

US seller has over 15,000 in stock. German seller just lists 10+

[mudnut]

Cool, gotta link for those?

[gf0012-aust]

http://www.ebay.com.au/itm/CSA4-19MG-MURATA-CERAMIC-RESONATOR-30PF-0-5-4-1900MHZ-CMOS-2-PIN-RADIAL-/111649253264?hash=item19fed06790:g:P~oAAOSwEeFVMXL s

http://www.ebay.com.au/itm/MURATA-CERAMIC-RESONATOR-4-19MHz-30Ohm-10-Stuck-/360591059569?hash=item53f4e6ea71:g:M1UAAOSwQJ5URk2 T

US seller is easy to do business with.

note, these are Murata's as well - the recommended replacement

[mudnut]

Good to have the right stuff to work with,

Cheers.

[mudnut]

I haven't done much of late, but I have finally made a small table which fits on my work bench so I can work with better posture.

I have settled on and built this Variable speed circuit to run the old battery drill to drive speedo senders.

[mudnut]

Finally made the battery drill run off the cigarette lighter, with the above circuit. It now runs from zero to around 60kph, which should be ample for testing but not calibration.

After experimenting with the drills gearbox, by locking one stage, to get it to go up to 110 kph, I found the drill's motor dragged too many amps and nearly cooked the electronics..

I have made a threaded attachment that is glued to the torque setting ring on the drill. The speedo sender is screwed into modified PVC pipe extension which is then locked onto the drill using a nut.

[mudnut]

After a long break, I've had a couple of days mucking around with the cluster that Rossco sent me. I unfortunately found that removing the needle off the tacho, destroys the bearings.

Bugger! They have designed the collar to protrude under the hub of the needle, so there is no way of removing it, without the whole spindle sliding out.

This will make it a lot harder to conduct repairs on the PC boards of both the speedos and tachos.

So, if anyone has had success in removing the needle please let me know how you did it.

I have also found that the TD42 diesel cluster loom sockets aren't compatible with the RB30 and TB42 clusters. so I will have to find a way to make adaptors for the test bench. I'm guessing the RD28 is different again.

On a positive note, I redesigned the electronic speedo signal generator to produce a stronger, smoother output. I also found that a 10k ohm resistor across the output kills any feedback voltages from either the sig gen or from the speedo, which is a bonus.

[MudRunnerTD]

After a long break, I've had a couple of days mucking around with the cluster that Rossco sent me. I unfortunately found that removing the needle off the tacho, destroys the bearings.

Bugger! They have designed the collar to protrude under the hub of the needle, so there is no way of removing it, without the whole spindle sliding out.

This will make it a lot harder to conduct repairs on the PC boards of both the speedos and tachos.

So, if anyone has had success in removing the needle please let me know how you did it.

I have also found that the TD42 diesel cluster loom sockets aren't compatible with the RB30 and TB42 clusters. so I will have to find a way to make adaptors for the test bench. I'm guessing the RD28 is different again.

On a positive note, I redesigned the electronic speedo signal generator to produce a stronger, smoother output. I also found that a 10k ohm resistor across the output kills any feedback voltages from either the sig gen or from the speedo, which is a bonus.

liftlid you might find this thread of interest mate. I have that cluster out and sitting on the camper for you to pickup mate. The Speedo is all but Gone but the Tacho and other gauges are there and the cluster is a TD cluster.

mudnut, yes i went through this when i did my ground up build and also failed to get the needle off damn it. I was though able to correct the speedo calibration (needle position at 100km/h) by simply driving with the face cover off and man handling the needle and spinning it on the shaft. I was able to do this by spinning the needle past full speed and took a 5degree spin on the shaft or so. L then let the needle go and was able to do this in either direction to get it bang on at 100kms running 35s.

[mudnut]

MudRunnerTD. You were very lucky that you didn't break the return springs, doing that but, hey it worked!

I wonder if heating the hub will release the needle. If that fails, the moving coil unit must be non serviceable.

Since stuffing the tacho up I have found that it is very easy to un-solder the unit from PC board, to gain access to the other components.