jamespond24

iTrader: (13)

I got 5volt going into both lm1815 chip but doesn't get any voltage to the CAS wire. I was told the lm1815 chip might be bad. Also if the MS box not grounded could it cause static to fried the chip?

Aaron Cake

iTrader: (1)

It is actually quite hard to fry something with static.

I assume you have checked your wiring several times to verify that the circuit is set up correctly?

It could be a bad LM1815. Check with a voltmeter to make sure that 5V is on the appropriate pins. If you have a scope, scope the input of the LM1815 to make sure you are seeing a sine wave from the CAS as it is spun. Then check the output for a square wave. If you get the sine wave but no square, the chip is wired wrong or bad. If you get a square wave, then the circuit is operating as it should.

jamespond24

iTrader: (13)

Sorry for the poor picture but if you know about the msns DB v2.0 this is where the 5 volt is coming from the main board to both of the lm1815 chip. My question is where does it comes out of on the lm1815 chip ( looking for the Ne+ and G+ on the chip).

jamespond24

iTrader: (13)

No 5 volt on either pin 2&4 (which is Ne+ & G+)


This is where I track the pin 2 &4 (which suppose to be the Ne+ & G+) so if I don't get voltage from the pin on the lm1815 than that means chip is bad?

jamespond24

iTrader: (13)

This one is coming from the lm1815 to a resistor that goes to the 2 & 4 plug on the CAS.

pmrobert

The CAS is NOT fed 5 volts. The CAS wires are simply conductors for the CAS' output from each of the two VR sensors, which are basically small generators - they have a magnet and a coil firmly mounted in the sensor itself and take advantage of the fact that a magnetic fields' characteristics change if a piece of steel enters that field. If the steel is moving, the magnetic flux from the biasing magnet changes thus creating current in the coil of many turns of fine wire that precisely follows the changing magnetic flux. The VR sensor output can generate up into the near 100 volt range at very high RPMs and only a couple of volts at crank. The LM1815 will emit a pulse on it's output pin in response to the input it gets from the VR sensor - the inputs are your Ne & G pairs of wires. I'll try and call you later today and will attempt to find the schematic for the board you have so we can get this thing troubleshot.

-Mike

Aaron Cake

iTrader: (1)

Oh, you are looking for 5V at the CAS wires? Yeah, that's never going to happen in the way you think it is.

Check for 5V at the power pins of the LM1815s, and then follow my instructions to make sure the VR circuits are working as they should.

muythaibxr

Yeah, the 5v does 2 things for the lm1815:

1) powers the lm1815 itself
2) in combination with a pullup resistor, provides the +5v square wave to the ms1/ms2 chip.

Ken

jamespond24

iTrader: (13)

I assuming you saying that the lm1815 provide 5v to the cpu chip on the main board? So does this mean if I wire one wire to the chip and crank the motor I can vertify the lm1815 is working? Thanks for being patience with me I'm use to the PFC, Microtech,aem,haltech, which I dont have to open the box and try to figure out what does what. I'm really interested in the MS and hopefully if I get everything down I would like to built myself one.

BTW: I notice that the diagram I looked at on the lm1815 is for the 2.25 so does anybody have a diagram for the v 2.0?

jamespond24

iTrader: (13)

Could there be 2 lm1815 at one time? So the 2 wire that goes from the daughter board to the main which one one on the 11pin on the cpu and the other goes on another chip that is a 6six pin should get a 5v pulse reading when the motor is cranked?

jamespond24

iTrader: (13)

Sorry I type without looking, my question is could there be 2 bad lm1815 chip at one time? Is it rare to have both going out at the same time?

Aaron Cake

iTrader: (1)

The LM1815 does not provide 5V to the main board. The LM1815 turns the sine wave from the CAS into a square wave for the CPU.

I gave you some testing procedures for the VR circuit earlier in this thread.

It is of course possible to have a bad chip (or two) but you can only determine this through testing.

jamespond24

iTrader: (13)

[QUOTE=Aaron Cake;9118916]The LM1815 does not provide 5V to the main board. The LM1815 turns the sine wave from the CAS into a square wave for the CPU.

I gave you some testing procedures for the VR circuit earlier in this thread.



I don't have a scope or access to one. The only thing I have is a multimeter.

Aaron Cake

iTrader: (1)

I think you'll have a very hard time testing with a basic multimeter. Google for "sound card oscilloscope". There is software out there that lets you use your laptops sound card as a scope. You just need to make a set of probes.