Been trying to get a test bench for these speedos working for a while. Your video helped a lot. It's also possible to simply generate the sine wave using an app on a phone, and connecting it to the speedo by a jack cable. :)
@@robertdeptula2003 Interesting point. The speedo I have been testing with, works using an app on my phone. However it’s a later 940 ‘94 speedo, so I am not sure if it works differently. I have a speedo like the one you show in the video, and it does not work in the same setup. Although, I suspect the circuitry is bad.
Well done, sir! Well done! I have a non-working speedo in my 1991 740 wagon. I have electronic skills, but have been hesitant to remove the instrument panel. I assumed that it would require taking much of the dash apart. Your video shows exactly what needs to be done in fine detail. I will have some confidence once I attempt this repair. One question... If I have the instrument panel removed, can the car still be driven? Other than not having gauge functions, is there any harm driving the the panel detached?
Hello, thanks for a good and useful video, I need to do the same work to my -92 940. Did you success repair the second cluster (the fried and overheated one)? Take care and keep it up! 🎉
Not yet, but I have one working with odometer not functioning (step motor must be replaced to fix it), and obviously I will put fresh capacitors in. Good luck with your project!
Hello Robert, thanks for the video! Really helpful. I have a question, followed all your step. Now i have the electronic board out. Your board has a big orange capacitor in de upper left corner (CI3) with a big flat and black component next to it (where the little capacitors are glued on to). I have neither of those 2 on my board. Do you have an answer for that? Side info: the little capacitors that are glued in your video leak also on my board. Hope you understand, greetings from the Netherlands!
Take a look @ 6min 15sec here: th-cam.com/video/ZBpf8dVAPrI/w-d-xo.html Looks like the European market doesn't have this capacitor C13 and the black component. I got my hands on the electric diagram. The capacitor and the black component is an extra feature for the service reminder dash light.
@@robertdeptula2003 That was the first thing I thought of as well, thank you very much for your research! Tomorrow I'm going to resolder en clean the board.
@@robertdeptula2003 The speedo was all the time on 80 kp/h before. I soldered the new capacitors on the board. The speedo is now all the time at 0 kp/h. Note: my sensor in the diff is also broken. But for the replacement of that thing the entire rear axle needs to drop (Volvo 960). Going to do that in a couple of days. I hope the speedo then also comes to life. Going to try the trick with tapping the wires fast against each other to see of the speedo works.
Hi, I replaced the speedometer in my 91 940 turbo with a junk yard one and works great, I believe is a dealer replacement because the last digit on the trip odometer is red are this dealer replacement better than the original or are the same and should I replace the caps? Also my mileage is off by +80k, whats the best way to interchange the mechanical odometer to the good speedometer? Thanks for posting this great information video 🙂👍
I am not the one who can tell you what you should do. But, if I were you I would keep an eye on the speedo behavior and replace the capacitors at the first sign of weird acting to avoid seeping electrolyte to do extensive damage. You can exchange mechanical parts and put the old face plate with mechanical mileage numbers on the "new" electronic board. Good luck with your project!
Wow! this is a nice video, thank you! I'm figuring out how you could calibrate your speedometer (mine is a 1996 940 with Yazaki gauge). I ve mounted big tires on this slighty lifted 940, and have approx 7% fault (100 kmh on gauge is 107 kmh on GPS) I've read somewhere that there is a resistor (about 50 ohms I believe) you can change to calibrate. Do you know which resister that might be?
Check local regulations, your speed inaccuracy can be well within lawful limits. For example in EU the speed indicated must not be less than actual speed, but anything up to 10% more plus 4 km/h is OK. For the resistor question I don't have an answer. Will repositioning the needle do?
@@robertdeptula2003 Thanks. I live in NL, car has passed MOT before with these tires so I don't worry too much about that. I can always place a permanent GPS speedometer thingy from Ali if I need to. Repositioning the needle could be a good simple solution. However, the bigger the speed, the bigger the error. At 50 kmh the speed in the dash is exactly 50kmh on GPS. So from factory the Volvo would be displaying slightly more than the actual speed. Having said that, I could find a solution somewhere in the middle perhaps, so that 80 to 120 kmh is not too much off. Thanks for your tip!
@@robertdeptula2003 Not being able to find the info about this secret resistor, I might be able to make a little calibration module with a potentiometer, using an Arduino (-nano). It just has to measure the incoming frequency of the incoming sinus wave, measure the resistance of the potentiometer (on a separate analog input) and output a PWM square wave at a slightly slower frequency. I guess a 3.3V square wave should do the trick too right? (maybe you have the chance to do a quick test for me?) The original speed signal still goes to the ABS module, so if I place my module in between the signal input on the gauge, the square wave is only for the gauge itself..
I will do repair to my other speedo. When at it, I will compare square to sin wave frequency and let you know. But keep in mind, it can take time for me to get my hands on this project.
Hey Thanks for the video! My case: Volvo 940 1995 - Speedometer on 0 km/h and the ABS light is on. Thats means my sensor is damage? I think my cluster is ok because the odometer and the tachometer are working fine.
I'm trying to bench test calibrate a 2 wire electronic speedo with a basic signal generator such as you are using. I can't get it to work. The speedometer works when the vr sensor is driven by a drill motor. What am I doing wrong? thanks for a response.
@@robertdeptula2003 its a electronic speedo from an RX-7. same 2 wire vr sensor type as the volvo . I can't get a signal generator to drive it on the bench. works fine when bench driven with sensor and a drill. But need a fixed speed/frequency to recalibrate the unit before removing needle and reinstalling the needle . I tried 2 different cheap signal generators on sine wave and triangle wave but I get nothing. would you have an idea why that is? There is absolutely no information on youtube or internet search that I can find to get an idea.
Do you have multimeter that can measure frequency or even better an oscilloscope? Then you can determine what kind of signal or frequency is generated by the sensor when driven by the drill.
@@robertdeptula2003 unfortunately I have just a basic multimeter. shop manual shows and states sensor generates a sine wave with pulses of alternating current( with what I assume is a crossing at 0). Not sure what the signal generator is doing. I know from some posts on the RX-7 forum aprox. 150 hz. is about 60mph. I guess without a an oscilloscope I can't confirm.
I've been replace some resistors and capacitors and it works, but only read 0-80kmh or 90degrees movement.. i do replace both IC's and the results are the same.. do you have any suggestion for my problem?
Unfortunately I don't. The curios thing is, that when it goes bad it shows 0, stays at 80 km/h or jumps between 0 and 80. Good luck and report back when you fix it, so others can benefit.
@@robertdeptula2003hey again 😂, i've checked all that you've told me for the controler of an6506 to the air core.. cos + and - also sine + and - are connected to the ic.. and it still didn't makes any different.. i just bought the bench test like yours but i dont know where the 3 output of generator freq is going? Can u help me for wiring that generator into the speedometer? If on the bench test work perfectly, is that possible the sensor is bad for generating signal? I got abs on too
The instrument cluster for 960 is different than 940. But you can take it apart and look for leaky capacitors. Could be same problem and same solution.
Thank you for the professional presentation und detailed description...nicely done
You are welcome!
Wow! Great lesson. I learned a lot more than I thought I needed. Thanks.
You are welcome
Been trying to get a test bench for these speedos working for a while. Your video helped a lot.
It's also possible to simply generate the sine wave using an app on a phone, and connecting it to the speedo by a jack cable. :)
If the app will produce desired voltage then yes.
@@robertdeptula2003 Interesting point. The speedo I have been testing with, works using an app on my phone. However it’s a later 940 ‘94 speedo, so I am not sure if it works differently.
I have a speedo like the one you show in the video, and it does not work in the same setup. Although, I suspect the circuitry is bad.
another banger vid !!!
Well job done thanks
Great job thanks so much
You are welcome
an oscillator from a synth works too, basically the same as a frequency generator.
Can you make a video how you loosen the speedometer alone from the house on the 93-94 years modell yazaki?
Well done, sir! Well done!
I have a non-working speedo in my 1991 740 wagon. I have electronic skills, but have been hesitant to remove the instrument panel. I assumed that it would require taking much of the dash apart. Your video shows exactly what needs to be done in fine detail. I will have some confidence once I attempt this repair.
One question... If I have the instrument panel removed, can the car still be driven? Other than not having gauge functions, is there any harm driving the the panel detached?
I would not do this. First, it is illegal, second, this can trigger error codes for the computer.
I have the R1 resistor damaged on mine. The stripes are discouloured. Any idea what the value is please?
Thank you 🙏🙏
Bless you!
Hello, thanks for a good and useful video, I need to do the same work to my -92 940. Did you success repair the second cluster (the fried and overheated one)? Take care and keep it up! 🎉
Not yet, but I have one working with odometer not functioning (step motor must be replaced to fix it), and obviously I will put fresh capacitors in.
Good luck with your project!
Oh baby this is my kinda content gollyyyyy
Can you make a video how the temp gauge works aswell? And maybe the alarm system volvo has. Cant find online how it works. Great video btw
Sorry, videos I make are about projects at hand. Didn't have a problem with temp gauge and none of my Volvos is equipped with factory alarm system.
Hello Robert, thanks for the video! Really helpful.
I have a question, followed all your step. Now i have the electronic board out.
Your board has a big orange capacitor in de upper left corner (CI3) with a big flat and black component next to it (where the little capacitors are glued on to). I have neither of those 2 on my board. Do you have an answer for that? Side info: the little capacitors that are glued in your video leak also on my board. Hope you understand, greetings from the Netherlands!
It could be different in the European market. The principle is the same. Clean the board and solder in new capacitors. Good luck with your project!
Take a look @ 6min 15sec here: th-cam.com/video/ZBpf8dVAPrI/w-d-xo.html
Looks like the European market doesn't have this capacitor C13 and the black component.
I got my hands on the electric diagram. The capacitor and the black component is an extra feature for the service reminder dash light.
@@robertdeptula2003 That was the first thing I thought of as well, thank you very much for your research! Tomorrow I'm going to resolder en clean the board.
Good luck! Please, report your results.
@@robertdeptula2003 The speedo was all the time on 80 kp/h before. I soldered the new capacitors on the board. The speedo is now all the time at 0 kp/h. Note: my sensor in the diff is also broken. But for the replacement of that thing the entire rear axle needs to drop (Volvo 960). Going to do that in a couple of days. I hope the speedo then also comes to life. Going to try the trick with tapping the wires fast against each other to see of the speedo works.
Hi, I replaced the speedometer in my 91 940 turbo with a junk yard one and works great, I believe is a dealer replacement because the last digit on the trip odometer is red are this dealer replacement better than the original or are the same and should I replace the caps?
Also my mileage is off by +80k, whats the best way to interchange the mechanical odometer to the good speedometer?
Thanks for posting this great information video 🙂👍
I am not the one who can tell you what you should do. But, if I were you I would keep an eye on the speedo behavior and replace the capacitors at the first sign of weird acting to avoid seeping electrolyte to do extensive damage. You can exchange mechanical parts and put the old face plate with mechanical mileage numbers on the "new" electronic board. Good luck with your project!
@@robertdeptula2003 Thank you for your quick response, I woul follow your advice Robert.
Have a great day 👍
Wow! this is a nice video, thank you!
I'm figuring out how you could calibrate your speedometer (mine is a 1996 940 with Yazaki gauge).
I ve mounted big tires on this slighty lifted 940, and have approx 7% fault (100 kmh on gauge is 107 kmh on GPS)
I've read somewhere that there is a resistor (about 50 ohms I believe) you can change to calibrate.
Do you know which resister that might be?
Check local regulations, your speed inaccuracy can be well within lawful limits. For example in EU the speed indicated must not be less than actual speed, but anything up to 10% more plus 4 km/h is OK.
For the resistor question I don't have an answer. Will repositioning the needle do?
@@robertdeptula2003 Thanks. I live in NL, car has passed MOT before with these tires so I don't worry too much about that.
I can always place a permanent GPS speedometer thingy from Ali if I need to.
Repositioning the needle could be a good simple solution. However, the bigger the speed, the bigger the error. At 50 kmh the speed in the dash is exactly 50kmh on GPS. So from factory the Volvo would be displaying slightly more than the actual speed. Having said that, I could find a solution somewhere in the middle perhaps, so that 80 to 120 kmh is not too much off.
Thanks for your tip!
You are welcome. Let's keep them rolling.
@@robertdeptula2003 Not being able to find the info about this secret resistor, I might be able to make a little calibration module with a potentiometer, using an Arduino (-nano). It just has to measure the incoming frequency of the incoming sinus wave, measure the resistance of the potentiometer (on a separate analog input) and output a PWM square wave at a slightly slower frequency. I guess a 3.3V square wave should do the trick too right? (maybe you have the chance to do a quick test for me?)
The original speed signal still goes to the ABS module, so if I place my module in between the signal input on the gauge, the square wave is only for the gauge itself..
I will do repair to my other speedo. When at it, I will compare square to sin wave frequency and let you know. But keep in mind, it can take time for me to get my hands on this project.
great video! do you take in repairs?
Where are you located?
@@robertdeptula2003 hi,thanks for response.bridgewater, ct
It will be pricey to send package US-Canada-US.
Hey Thanks for the video!
My case: Volvo 940 1995 - Speedometer on 0 km/h and the ABS light is on. Thats means my sensor is damage?
I think my cluster is ok because the odometer and the tachometer are working fine.
Check wires @ the differential sensor.
@@robertdeptula2003 thanks a lot.
I'm trying to bench test calibrate a 2 wire electronic speedo with a basic signal generator such as you are using. I can't get it to work. The speedometer works when the vr sensor is driven by a drill motor. What am I doing wrong? thanks for a response.
What car is it?
@@robertdeptula2003 its a electronic speedo from an RX-7. same 2 wire vr sensor type as the volvo . I can't get a signal generator to drive it on the bench. works fine when bench driven with sensor and a drill. But need a fixed speed/frequency to recalibrate the unit before removing needle and reinstalling the needle . I tried 2 different cheap signal generators on sine wave and triangle wave but I get nothing. would you have an idea why that is? There is absolutely no information on youtube or internet search that I can find to get an idea.
Do you have multimeter that can measure frequency or even better an oscilloscope? Then you can determine what kind of signal or frequency is generated by the sensor when driven by the drill.
@@robertdeptula2003 unfortunately I have just a basic multimeter. shop manual shows and states sensor generates a sine wave with pulses of alternating current( with what I assume is a crossing at 0). Not sure what the signal generator is doing. I know from some posts on the RX-7 forum aprox. 150 hz. is about 60mph. I guess without a an oscilloscope I can't confirm.
Then it should work.
I've been replace some resistors and capacitors and it works, but only read 0-80kmh or 90degrees movement.. i do replace both IC's and the results are the same.. do you have any suggestion for my problem?
Unfortunately I don't. The curios thing is, that when it goes bad it shows 0, stays at 80 km/h or jumps between 0 and 80. Good luck and report back when you fix it, so others can benefit.
@@robertdeptula2003 did u know which components that controlling current frequency into the sin cos air core?
Sin+ goes to leg nr 17 in AN6505, sin- goes to 16, cos+ to 12 and cos- to 13.
@@robertdeptula2003hey again 😂, i've checked all that you've told me for the controler of an6506 to the air core.. cos + and - also sine + and - are connected to the ic.. and it still didn't makes any different.. i just bought the bench test like yours but i dont know where the 3 output of generator freq is going? Can u help me for wiring that generator into the speedometer? If on the bench test work perfectly, is that possible the sensor is bad for generating signal? I got abs on too
@@robertdeptula2003 i just start frustating on it but i dont wanna give up 😂
Is it the same for a Volvo 960 1991 3.0L? (my speedometer works sometimes and sometimes not)
Swedish specs.
The instrument cluster for 960 is different than 940. But you can take it apart and look for leaky capacitors. Could be same problem and same solution.
Good luck!
Do you offer repair on an 87 740?
Where are you?
@@robertdeptula2003 california, USA