I added this to another thread, but more people may want to have the data.
While checking out the gauges on my 1966 Duetto and some spare gauges,
I decided to use a precision resistor decade box and calibrated pressure gauge to test some Duetto 105 Jaeger gauges and some sending units.
Meter Movement:
The Jaeger / Veglia gauges have needle movement by using a wafer thin bow tie shaped permanent magnet attached to the needle and using two coils which intersect at 90 degrees to create a field which moves the needle/magnet based on the variable resistance (sending unit).
Test setup:
Test setup for:
Jaeger Water Temperature gauge with 12 v terminal on LEFT side when viewed from rear.
For gauges with 12v terminal on LEFT side, as gauge is held upright (light at top) connect as follows:
1. 12v connected to 12v terminal (Left side)
2. Variable resistance to Signal terminal
3. Gauge body grounded to negative
Test setup for:
Jaeger Water Temperature gauge with 12 v terminal on RIGHT side when viewed from rear, as gauge is held upright (light at top), connect as follows:
For gauges with 12v terminal on RIGHT side, connect as follows:
1. Variable resistance to 12v terminal (I don't know why, but only way it works)
2. 12v connected to Signal terminal (Left Side)
3. Gauge body grounded to negative
It was interesting to note the connection setup needed for proper operation of the gauges with 12v connection on the RIGHT side when viewed from the rear.
Temperature indicated vs Resistance required (matches sending unit)
100F / 40C = 900 - 1000 ohms approx
140F / 60C = 480
180F / 80C = 220
212F / 100C = 120
236F / 115C = 80
260F / 130C = 50
Oil Pressure:
Classic Alfa p/n:EN056 Oil pressure sender Jaeger late and factory Veglia Oil pressure sending unit:
0 psi / 0 bar = 350 - 367 ohms (varies as pressure goes up vs going down – due to mechanical hysteresis)
28.5 psi = 205 - 233
57 psi / 4 bar = 105 - 144
85.5 psi = 46 - 86
114 psi / 8 bar = 22 - 56
The resistance values entered above indicated correctly with some error for either Jaeger gauge when wired per the Water temperature setups.
----------------------------------------------------------
Ground Connection to Gauge Body:
It is very important to have a good hard ground attached to each gauge. It is the only way to have an accurate and reliable reading.
I attach a hard ground to one gauge and daisy chain a wire from gauge to gauge. I use the gauge hold down bolts as the attachment point.
While checking out the gauges on my 1966 Duetto and some spare gauges,
I decided to use a precision resistor decade box and calibrated pressure gauge to test some Duetto 105 Jaeger gauges and some sending units.
Meter Movement:
The Jaeger / Veglia gauges have needle movement by using a wafer thin bow tie shaped permanent magnet attached to the needle and using two coils which intersect at 90 degrees to create a field which moves the needle/magnet based on the variable resistance (sending unit).
Test setup:
Test setup for:
Jaeger Water Temperature gauge with 12 v terminal on LEFT side when viewed from rear.
For gauges with 12v terminal on LEFT side, as gauge is held upright (light at top) connect as follows:
1. 12v connected to 12v terminal (Left side)
2. Variable resistance to Signal terminal
3. Gauge body grounded to negative
Test setup for:
Jaeger Water Temperature gauge with 12 v terminal on RIGHT side when viewed from rear, as gauge is held upright (light at top), connect as follows:
For gauges with 12v terminal on RIGHT side, connect as follows:
1. Variable resistance to 12v terminal (I don't know why, but only way it works)
2. 12v connected to Signal terminal (Left Side)
3. Gauge body grounded to negative
It was interesting to note the connection setup needed for proper operation of the gauges with 12v connection on the RIGHT side when viewed from the rear.
Temperature indicated vs Resistance required (matches sending unit)
100F / 40C = 900 - 1000 ohms approx
140F / 60C = 480
180F / 80C = 220
212F / 100C = 120
236F / 115C = 80
260F / 130C = 50
Oil Pressure:
Classic Alfa p/n:EN056 Oil pressure sender Jaeger late and factory Veglia Oil pressure sending unit:
0 psi / 0 bar = 350 - 367 ohms (varies as pressure goes up vs going down – due to mechanical hysteresis)
28.5 psi = 205 - 233
57 psi / 4 bar = 105 - 144
85.5 psi = 46 - 86
114 psi / 8 bar = 22 - 56
The resistance values entered above indicated correctly with some error for either Jaeger gauge when wired per the Water temperature setups.
----------------------------------------------------------
Ground Connection to Gauge Body:
It is very important to have a good hard ground attached to each gauge. It is the only way to have an accurate and reliable reading.
I attach a hard ground to one gauge and daisy chain a wire from gauge to gauge. I use the gauge hold down bolts as the attachment point.
