Hello from Germany, just found this thread. So the boards are still under production and can be purchased? Need one for a 76' carburettor. Thank's for kind help! Ruedi
Guten Morgen, ich baue hin und wieder Boards wenn ich Zeit habe, kann teilweise etwas dauern. Hast Du die Teilenummer von Deinem Speedo? lg aus Berlin, Adrian
Hallo Adrian, vielen Dank für deine Rückmeldung !!! G1 7309 7G ...ist ein Typ 1 Board. Wenn Du keine Zeit hast, könnte ich mir das Board auch selber bauen. Viele Grüße aus dem südlichsten Bayern Rüdi
Hi Adrian, hast Du eine neue Email Adresse? Die Email [email protected]! The following address failed: [email protected]: multiple delivery attempts failed Gruß Rüdi
I validated that the green wire is getting power and the black one is grounded. So the only other thing to verify is that there is continuity between the sensor on the transmission and the pin with the red/black wires on the speedometer plug?
Is it possible to calibrate with the signal wire not correctly wired? I tested and I have continuity (.611 kOhms) when running a wire from my meter to the wire connecting the sensor on the transmission to the appropriate wire on the instrument cluster, but the speedo shows nothing when the transmission is moving. Should that signal wire show a change in voltage or resistance as the speed changes?)
The onboard calibration is completely independent of the sensor signal, you don't need the sensor being wired up for calibration. You can test the sensor signal with a scope or a Multimeter set to frequency measurement. Check out the "Scope Signals" section here: http://www.dinoplex.org/instruments/vegliaspeedosensor/
I can't seem to figure out why my speedometer won't work. I have checked continuity from the sender all the way to the circuit board and double checked all of the wiring. I don't have a multimeter or scope that will create or create a frequency measurement, but before I bought the new circuit board I bought a new sender and my mechanic assured me he was getting signal at the speedometer. Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
The wiring to the board looks fine to me. If you don't have a scope or a multimeter with frequency/HZ display there is another test you could do: Wire up your multimeter to the black (minus) and black/red (plus) wires on the red connector coming from the Speedo. Turn on the ignition (but don't start) the car, put in the fifth gear and very slowly push the car forward several inches. While the car is moving, the display of the multimeter should change between >3 volts and >8 volts. This would indicate that the sensor receives power and creates an output signal.
Hi Adrian My speedo started jumping around the other day - not stable, and dropping to nothing then jumping back to speed again. It then stabilised. Probably a loose connection, but I'm wondering what the symptoms of a sender or speedo board failure are?
Hi Patrick, sounds like a connection problem (broken wire, oxidized spade connectors) with the sender wiring or a defect of the sender. If the problems start right at the beginning it is rather the wiring, if they start later while the engine compartment heats up then it is more likely the senders circuit board. Would start with checking the connector at the speedo and at the sender and clean them with brake cleaner and then contact cleaner to remove oxidization.
I took the car to a parking lot today and pushed it 5 MPH with the ignition on and a volt-meter attached to the black and red and black wires in the plug that goes to the speedometer. The wires read a steady 12v the entire time.....Not sure what that means?
Having a steady 12V on the black and red wire going to the Speedo would indicate a sensor defect, where the sensor has a defect that passes the +12 supply (sensor yellow or green wire) through to the output (red/black wire). A quick check would be to disconnect the sensor connector in the engine compartment and do the same test again (but without pushing the car, stationary is fine), if you now see 0 volts then there is something wrong with the sensor electronics.
I’ve just found this thread and read though it all. It looks like I have the similar as the above post. I have a ‘79 gt4 with the mph speedo reading double due to a 328 engine/gearbox fitted and the odometer not working. So my guess is I’ll need a type 1 board to fix the odometer, then a modification to that board to halve the speedo reading. (50mph reads 100mph) or I could use an aftermarket speed reducer like they use on motorbikes when changing sprockets? Adrain, great work here and is this something you can help me with? justin,UK
I could do a custom board for displaying 1/2 the pulses to get the right speed. Not sure that an aftermarket speed reducer will work since the signal type and voltage between the sensor and the speedo is a bit special.
Adrian: Is the type I speedometer board still available? (78 GTS US) I went to the dinoplex.org site but didn't see it. The problem I'm having is that the speedometer indicates about 20 mph slow across the board. It just started happening the last time I had the car out. The odometer and trip meter appear to working correctly. The odd thing about it is the speed needle now sits about minus 10 mph rather than plus 10 mph when ignition is off or on. I described the problem in detail here. https://www.ferrarichat.com/forum/threads/yet-another-308-gts-speedometer-question.675557/ Thanks in advance for any input. Barry
Hi, I am reading these threads many years later! Did you ever make the board? I would love to install this fix in my failed speedometer!
You refer to the Type 2/3 board? I did but due to the different design from Marelli it is not really a DIY replacement anymore. It would need someone skilled/instrument workshop to get properly installed due to the additional mechanical work to set this up.
Hi Adrian, my speedo has failed as well. Similar to many others the needle and odo just stopped. The transducer is OK and I can see a square wave on the scope. Ditto the wiring. When the Instrument fitter opened the speedo he could see that BD370C had burned out. As per one of your earlier posts I had him fit BD140 as a replacement (BD370C are hard to come by in these parts). The result of this was that when he powered on (no signal connected) the odo started to spin very fast and the needle went full scale. This is a type 2 for an 85 euro spec 308QV. Rather that to continue on with 40 year old electronics would it be possible to get one of your boards please? Failing that then a layout of the board and a parts list and I can get it made locally. Barry
So just as a followup to this saga. I shipped the speedo and transducer to DinoParts and Service in Germany who have effected it's repair and re-calibration. Special thanks to Alfredo for going the extra yards to ensure a successful outcome. When (and not if) you end up in the same position i did, this was the best way out that I could find.
