VDO Tachometer- Bulb holder for the instrument lights

[Ian_Edwards]

Conclusion
I finally got around to testing the taco, after getting the pulley diameters from Canada.
The crank pulley diameter is 127.86mm
The alternator pulley diameter is 58mm
Ration of 2.2044 to 1
12 pole alternator, 6 pairs of poles
Pulses per rev= number of pairs of poles x the pulley ratio.
6 x 2.2044 = 13.23 pulse per rev, for reference the standard number of pulses per rev for the original alternator is 10.29
This convert to frequencies of:
220 Hz at 1,000 rpm; 440 HZ at 2,000rpm and 660Hz at 3000 rpm
This is what you need to know to test with a waveform generator.
I programmed the pulses per rev into the taco and it seems to work.


So I now have a working taco with red LED instrument light, all I need now is access to the boat so I can install it and go sailing !

I have written up some notes on the taco, they are in MS Word or .pdf format. If anyone wants a copy please PM me with an email address and I'll forward the notes to you. However, treat them with care, they were written by an amateur for personal use.

 

[zara]

Conclusion
I finally got around to testing the taco, after getting the pulley diameters from Canada.
The crank pulley diameter is 127.86mm
The alternator pulley diameter is 58mm
Ration of 2.2044 to 1
12 pole alternator, 6 pairs of poles
Pulses per rev= number of pairs of poles x the pulley ratio.
6 x 2.2044 = 13.23 pulse per rev, for reference the standard number of pulses per rev for the original alternator is 10.29
This convert to frequencies of:
220 Hz at 1,000 rpm; 440 HZ at 2,000rpm and 660Hz at 3000 rpm
This is what you need to know to test with a waveform generator.
I programmed the pulses per rev into the taco and it seems to work.
View attachment 89413View attachment 89414View attachment 89415

So I now have a working taco with red LED instrument light, all I need now is access to the boat so I can install it and go sailing !

I have written up some notes on the taco, they are in MS Word or .pdf format. If anyone wants a copy please PM me with an email address and I'll forward the notes to you. However, treat them with care, they were written by an amateur for personal use.

Just seen your post I have a dead vdo tacho on my nanni would love a copy of your notes if you still have them my email is body1950@gmail.com

 

[Ian_Edwards]

Just seen your post I have a dead vdo tacho on my nanni would love a copy of your notes if you still have them my email is body1950@gmail.com

I have them, just a matter of finding them. I'll have look this evening and get back to you.

 

[Mistroma]

I have a few manuals showing methods of calibrating VDO tachometers. I found them years ago in case I needed to swap my 80A alternator for 110A spare. Never had to use them but might be useful until you get the notes you want.

VDO Programmable Tach with hour meter
VDO Tachometer Calibration
VDO Tachometer Adjustment

 

[Ian_Edwards]

I hope these help.
I have the data files for the :
Voltage regulator LM 7805
Memory Chip PCF8582C_2
Octal buffer-line driver 74ACT240
and the likely CPU 8XC51_8XC52, but the CPU seems to have a custom Map, specific to the Yanmar.

As I note in the write-up, the basic generic Display seems to have been cleverly designed so that it could be tailored to a wide range of application, by programming the CPU and installing the appropriate chips on the board. The Yamaha seems to have been a custom model, solely for Yamaha, until I realized this I went down quite lot of rabbit holes, looking at altimeter for light aircraft which look just the same, but are electronically different.
P.S.
I've just seem that when I click on the links it ask me to down load the files, that's not what I expected. If it turn out to be a problem, let me know and I'll email them to you.