31 replies to this topic

[stormintrooper]

point 1 leads to the metallic strip that moves the needle...point 2 goes to the stabiliser (yes i just answered my own question ) id personaly say 3 was the earth to the stabiliser as it touches the stabiliser metal strip when the 2 are connected and 4 being the one for the needle



is number 1 where i should put my multimeter because as far as my logic goes number 2 leads towards the temp sender which then goes to ground neway?

[dklawson]

Stormintrooper, as Dan said, it's hard to tell what's connected where from the picture you posted. Can you try again with photos of both sides and if possible, can you play with the contrast a bit before saving the picture?

All I can say from the first picture is that the area marked #5 is the contact region of the stabilizer. Functionally it should behave and be wired similarly to what is shown in the schematic on page 2 of my stabilizer PDF
http://home.mindspri...eStabilizer.pdf

That is to say, the terminal connected directly to the brass adjusting nut (near 5) should be the "input" of the stabilizer. The resistance wire wrapped around the stabilizer bimetallic element should be connected to the bimetal part on one end. The other end of the resistance wire should have an earth connection. Finally, the bimetallic strip itself should be connected to a terminal. That connection will be the "output" supplying the two gauges.

Please do post more pictures if you can showing the gauge from as many angles as necessary to illustrate each connection.

[stormintrooper]

will do......am i right in assuming that the voltage at the petrol sender end should be 10V when disconnected?..would that be the easiest way to test the voltage?

also would i be better using the VAC measurements on my multimeter due to the fact the voltage rises and drops?

[dklawson]

Thanks. We'll be watching for the pictures.

The disconnected sending unit wire should be 10V as you say. I have never had good luck measuring it with any meter. An analog meter (needle type) is generally better at getting "some" reading than a digital meter. I have always used DC measurements. I'm not sure what you'd find with the meter set to AC.

[stormintrooper]

want to hear something weird? kept adjusting the brass nut for the stabiliser with general lack of any kind of success...then out of agrevation i decided to check it werent just both senders acting up by removing the ground for the stabiliser and in theory...giving the gauges 12V...which i imagined would be better than 3V....anyway..off comes the ground....i check the voltage going to both gauges...what do ya know...hovering between 10.3V and 8.5V

is this just one of those wird moments where im now better off leaving it to work as it is?

and before you ask the 10V reading was with the engine running therefor it should realy be about 13.5V ish and not 12V but still

and i know that the alternator is dishing that out as i checked battery with engine running

[dklawson]

Very curious indeed. I have no explanation for the readings you found.

Since I have never been able to feel comfortable with the voltage measurements from the stabilizer I have resorted to a different method. Go back to the PDF I posted a link to earlier and look at the section dealing with gauge calibration. Basically I have connected a steady 10V supply to a gauge through a 50 Ohm inline resistor and waited for the gauge to reach steady state. Then I put tape on the gauge glass marking exactly where the needle comes to rest. I replace the steady 10V supply with the output of the voltage stabilizer and wait for the gauge to reach steady state again and then tweak the stabilizer adjustments until the needle returns to the position marked by the tape on the gauge face. This has allowed me to calibrate the stabilizer output without any ability to measure the average output voltage from the stabilizer. In theory this would work for the NS stabilizer the same way it worked for the Smiths stabilizer.

What I was wondering about though was... since you have the gauge open and apart... I think you should be able to splice in the solid state 7810 chip effectively bypassing the electromechanical stabilizer.

[stormintrooper]

would be willing to try it as id rather have a definate 10V than a hovering voltage.....thing was with doing the adjusting...it didnt matter if i screwed it in or out the voltage stayed roughly 3V which was useless at any rate so god knows what the hell was going on with it....

id certainly be interested in applying the chip...i wreckon all it would recquire is one or two snips of the wire around the bi-metal...re-solder.....i.e.physicaly remove the smiths style stabiliser...possibly need to cut some of the plastic pcb away from the back...then simply take an ignition live/fused wire to the chip....solder a wire to ground...and then two wires going to each gauge from the output pin?

does that sound about right?

and by the way thumbs up on the pdf its rather impressive

Edited by stormintrooper, 04 January 2010 - 03:45 PM.

[dklawson]

It could be that the points on the NS stabilizer are burned or otherwise damaged. I have seen that with the Smiths parts that have been in service for a long time.

You should be able to try the 7810 chip without cutting anything. Place a couple of pieces of electrical tape between the NS contacts that you were adjusting. That will disable the NS stabilizer and remove it from the circuit. The 7810 chip would need three leads soldered to it. (This is discussed in the PDF). The wire on the input to the chip would get soldered to the input terminal for the NS stabilizer. (Without seeing more detailed pictures I don't know for sure... but that SHOULD be the NS terminal electrically connected to the adjusting nut). The output of the 7810 chip should go to the point where the NS bimetallic chip is riveted. Lastly, the earth connection for the chip would be wherever the resistance wire was getting its earth.

With the tape between the NS stabilizer's points and the chip wires connected, the chip alone will be supplying voltage to the gauge circuit. Once you know that the chip works, you probably should find a good earthing point on the gauge housing and rivet/screw the chip down using the hole in its mounting tab. That way the NS gauge parts can act as a heat sink for the chip. Alternatively... you could (I guess) put LONG wires on the chip and mount it OUTSIDE the NS gauge cluster so it will be easy to replace if it ever fails. That way you could mount the chip on the back side of the dash somewhere so the bulkhead acts as a heat sink.

For that matter... once you've identified which screw on the back of the gauge cluster handles input/output from the stabilizer... you could put ring terminals on the 7810 chip's wires and connect the chip to the OUTSIDE of the gauge cluster without any soldering. Frankly, I hope you give that a try. If that method works we will have documented a way for people with the NS gauges to bandage their gauges and keep them working. Until now, all I've ever heard was that the NS gauge system could not be fixed once the stabilizer failed. It would be really nice to have found a fix/work-around.

[stormintrooper]

i was about to say myself if it works il hapily document a procedure for it and hopefully get it (cannot think of the right term) made a permanent thread for all to see with pictures etc..... the only reason i suggested taking a live from elsewhere is that i was worried the live going to the old stabiliser was now 10V...i will check tomorrow when there is some daylight to double check..il completley remove the gauge/stabiliser from the clock set and then measure the voltage....problem with mouting the chip to the inside of the cluster is that the cluster is plastic case...therefore no ground

where can i obtain this 7810 chip?

cannot find a UK seller...we have our own electrical stores known as maplins and they offer a very wide range of voltage regulators.....only thing im worried about is the other one u mentioned required resistors and im worried if going to maplins they may supply me one that requirs add ons

[dklawson]

Being over here I don't know the best place for you to find a 7810 chip. However, you can send a PM to Jupitus through this board. He found a source for them and was selling solid-state stabilizers a while back. I'm sure he can send you a chip or two.

What I had in mind can be seen in the JPG link from my friend Wes:
http://www.adocars.c...mages/v-reg.jpg

Wes sketched this up for the back of center binnacle car speedos. What I'm suggesting is longer wires with ring terminals on each wire. That way you should be able to mount the chip in a convenient location to use the bulkhead as a heat sink. (The chips mounting eye is an earth connection so the black wire on "common" is redundant).

[stormintrooper]

i shall indeed PM jupitus when im done posting this

think i may put bullet connectors between the ring terminals and stabilizer for easier removal (if it was ever needed) to save unscrewing it from the bulkhead...and tomorrow when im scheckin the voltage that goes to the plus of the smiths regulator.....il double check to make sure putting tape between the contact points will suffice..if so only 2/3(if i also use clusters ground point) wires will be needed then all the people on our lovely forum shall know how to sort their gauge problem

[stormintrooper]

i have found this

http://www.maplin.co...?ModuleNo=31737

as they offer one in the 10V range and you can also buy a clip on heat sink from them for a few extra pennies...only thing holding me back is i dont know if its as simple to wire up as the 7810 or if it requires resistors like the other one mentioned in your PDF

[jayare]

Try RS Components for the regulator - they list 'BA17810T' 10v voltage regulators which should be the '7810' chip Doug mentions - RS Search Results
JR

[Dan]

Don't bother with Maplin Stormin, they are frankly useless as electronic component suppliers. They will try to sell you the same TV antenna nomatter where you live in the country for one thing, they simply don't know what they are selling and are a bit of a joke shop to be honest. RS and Farnell are both far superior.

[dklawson]

Stormin, The other issue with the parts you found at Maplin are that they are the 79XX series which will create a -10V output like you would use on a positive earth car. I'm assuming your car is negative earth so these won't work for you. They also did not have a 10V one that I saw, the closest was 9V.

The chip that Jayare found (RS part # 239-2985) sounds ideal. Ask Jupitus how many Amps his chip can support. If Jupitus found a 1.5 Amp chip I would buy one or two from him. If his chip is rated for 1 Amp, that's the same as the RS chip and it will be hard for anyone to beat their price. Buy whichever regulator support more current.