Tachometers and Speedometers

[Guest arbik]

Greetings,

 

So I've gone into a couple of these beasts, and I have some conclusions that might come in handy for some people.

 

The ITT/ITI instruments, are plain junk. If you can imagine a Veglia, but MUCH crappier...then you've got it.

These things are non-serviceable, and are disposable units.

 

The Veglia instruments, are a bit more serviceable, but not much, and definitely not by the faint of heart.

 

I've opened up a few of them, and I have about a 50% success rate at repairing these units.

Having said that, if anyone has any broken Veglia tachs or speedos that they'd like to give or sell to me, I'd love to have them for parts.

 

Cheers!!

 

-arbi

[Guest gammaguzzi]

my tach recently went on the fritz...cut it open with apipecutter, nice and clean, and i repaired the two fine copper hair wires which came off the coil, but now the tach is reading lower rpms than it should across the board. i may have overlooked something,; does anyone know if and how to adjust the range??thanks gammaguzzi.

[Guest arbik]

Sure.

 

If you have a function generator and a frequency counter, set it up on the tach, with the tach open. There is a trim-pot on the PCB that you can calibrate the gauge with, but its only a rough calibration, as it has to ballance out the spring on the gauge. These things are NOT precision instruments.

 

Cheers!!

 

-arbi

 

my tach recently went on the fritz...cut it open with apipecutter, nice and clean, and i repaired the two fine copper hair wires which came off the coil, but now the tach is reading lower rpms than it should across the board. i may have overlooked something,; does anyone know if and how to adjust the range??thanks gammaguzzi.

[luhbo]

Hi Arbi,

 

great to find an article like that from time to time

Could you ever successfully repair the electronic part of a Veglia? The mechanic things are doable, resolder wires and things, but what if something on the pcb went nuts? I have two of those units. The coil shows a certain resistance, measured at the top of the springs and applying a small voltage makes the coil perfectly moving. Alas, somehow the ecu signal is ignored. The only more complex part on the pcb is a (probably) custom chip of which absolutely no information seems to exist.

 

So, is this the type that makes 50% of the parts that are unrepairable or could you give a hint how to properly deal with those possibly dead pcbs.

 

Hubert

[CFB]

The only more complex part on the pcb is a (probably) custom chip of which absolutely no information seems to exist.

 

Frequency to voltage convertor chips aren't anything exotic, eg. LM2917. I would think the problem is as much that if you scratch build a new circuit on vero board you might struggle to fit the electronics back into the case.

[Guest arbik]

Hi Arbi,

 

great to find an article like that from time to time

Could you ever successfully repair the electronic part of a Veglia? The mechanic things are doable, resolder wires and things, but what if something on the pcb went nuts? I have two of those units. The coil shows a certain resistance, measured at the top of the springs and applying a small voltage makes the coil perfectly moving. Alas, somehow the ecu signal is ignored. The only more complex part on the pcb is a (probably) custom chip of which absolutely no information seems to exist.

 

So, is this the type that makes 50% of the parts that are unrepairable or could you give a hint how to properly deal with those possibly dead pcbs.

 

Hubert

 

There isnt much to destroy on these things...so the electronics are usually pretty robust. Like CFB said, these things are not exotic at all, not by any stretch of the imagination. You can use any Freq. to Voltage converter chip, and use an adapter plate if the pins dont line up. like CFB said, the LM2917 is the current popular F to V converter, and can be had for a couple of bucks from places like DigiKey and Newark electronics among others.

 

The 50% repair rate for me, comes mostly from taking the damn things apart and putting them back together. I dont cut the case, I undo the face bezle and put it back on.

 

There is also some casualty rate, when the springs get tweeked, and you cant get them back in the right shape to have the right spring constant.

 

hope this helps,\

 

-arbi

[docc]

These Veglia clocks . . . they're beautiful (I think), but worrisome, like my Italian woman.

 

I have replaced both my speedo and tach (under warranty), but it worries me what will happen next (100,000 kM).

 

Arbi, where in the world are you??

[Guzzi2Go]

The chip is standard stuff and its data sheet has been posted on the forum. The issue is where to buy the chip. You will not find it @Conrad (Digi-key for you over there).

[gstallons]

These Veglia clocks . . . they're beautiful (I think), but worrisome, like my Italian woman.

 

I have replaced both my speedo and tach (under warranty), but it worries me what will happen next (100,000 kM).

 

Arbi, where in the world are you??

Does your Italian woman read your posts?

[luhbo]

The chip is standard stuff and its data sheet has been posted on the forum...

 

A good mouthfull, honey Could you post it again then? But before that you'd like to count the legs of what you're talking off.

 

Hubert

[Guest arbik]

Arbi, where in the world are you??

 

In all honesty, I wouldnt worry about them breaking.

If they break, you'll figure out how to get them fixed, or replace it with something else...

I'm in Los Angeles, CA by the way.

[Guest arbik]

The chip is standard stuff and its data sheet has been posted on the forum. The issue is where to buy the chip. You will not find it @Conrad (Digi-key for you over there).

 

Standard stuff indeed, and an F to V converter is an F to V converter is an F to V converter.

You can work with anything you can get your hands on...so I dont know why you dont think the LM2917 is good enough to work with in this application.

 

As for the data sheets, here is the site for the LM2917:

 

http://www.national.com/mpf/LM/LM2917.html

[Guzzi2Go]

As requested: http://www.onsemi.com/pub/Collateral/CS8190-D.PDF

[luhbo]

Ok, we had this one and a half year ago already: http://www.v11lemans.com/forums/index.php?...017&hl=tach

 

On the picture you can see (if you can get your eyes off from those beautiful ones of the rideress) a SL494 chip from GPS. First thing is: it's a 14 pin chip. All data available is refering to 16 pin chips. Second thing is: try to google for GPS nowadays

 

Some of you mention just to take this original chip out and put any other F2P (edit: F2V of course, sorry) converter in instead. Well, besides the fact that I never thought electronics could be that easy, should I further follow this bright and easy road and just cut off pins 8 and 9 to make these chips hole compatible?

 

Hubert

[luhbo]

As requested: http://www.onsemi.com/pub/Collateral/CS8190-D.PDF

 

Thanks a lot. This one was new to me. The interesting thing is that they describe in detail how the schematics should be designed.

 

Interesting also as it appears that white Veglias seem to have different internals. I always thought they sell only one version.

 

Hubert