MX83 tacho modification

[JP]

what I'll be trying with mine is severing the track from the tach input to the black single-row component, and doing the same with the track from pin 14 of the IC to the black single-row piece. Then I'll build a small filtering circuit for the input of IC's pin 14 and feed the tach input to that. I'm fairly confident it will work.

[mr1jz]

Well if you bust the tacho i have a spare one here if you want it.

[JP]

I've got two spares so I'm not afraid to fry one

[mr1jz]

Did you have any luck with this JP. I hate knowing there is an external booster there.

[doommachine]

Did you have any luck with this JP. I hate knowing there is an external booster there.

Prepare for thread necromancy...

Anyway, rather than start a new thread I guess it's reasonable to ask.. has anyone worked out whether or not a simple solution for the mx83 tacho exists as per the 2jz tacho? I really don't want to have a tacho booster. I am tempted to just unsolder the large value resistor near the IC and replace it with a 100 ohm and see what happens.

One thing that would be helpful is if someone has an analog jzx81 dash, the tacho should be the same, right? If they were to take pictures of the board we could compare the two.

[doommachine]

Prepare for thread necromancy...

Anyway, rather than start a new thread I guess it's reasonable to ask.. has anyone worked out whether or not a simple solution for the mx83 tacho exists as per the 2jz tacho? I really don't want to have a tacho booster. I am tempted to just unsolder the large value resistor near the IC and replace it with a 100 ohm and see what happens.

One thing that would be helpful is if someone has an analog jzx81 dash, the tacho should be the same, right? If they were to take pictures of the board we could compare the two.

OK... so now my tacho works with the 1jz Basically I considered what JP had said, and looking at the GX70 tacho driver etc, I figured it can't hurt to try. I broke the track entering pin 14 of the IC, and soldered a 100 ohm half watt resistor between the "P" terminal and pin 14 of the IC. You may not need to break the track for it to work.

So.. I guess its a bit late for many people BUT.. if anyone is doing a JZX83 in the future, at least you won't have to buy a tacho booster. This will probably also work for any other dash using the same IC, ie, 1jz hilux, etc etc.

DSC02119.JPG

[Cressie]

OK... so now my tacho works with the 1jz Basically I considered what JP had said, and looking at the GX70 tacho driver etc, I figured it can't hurt to try. I broke the track entering pin 14 of the IC, and soldered a 100 ohm half watt resistor between the "P" terminal and pin 14 of the IC. You may not need to break the track for it to work.

So.. I guess its a bit late for many people BUT.. if anyone is doing a JZX83 in the future, at least you won't have to buy a tacho booster. This will probably also work for any other dash using the same IC, ie, 1jz hilux, etc etc.

DSC02119.JPG

so I have tried this and still no good.
although believe it or not.. had the signal wire from ecu to tacho out and when holding it in each hand tacho works! as is the resistance between by hands was the right amount to make it work, measured this and its 100x200k ohms?? I have tried adding all sorts of combinations of resistors but still no go but will work straight away when I hold the wires with both hands

[dumbass]

its much easier to add a booster
u don't need to pull the dash out and then the tacho
and ive never had a booster that didn't work on a old school toyota

[red22]

Does anybody have the original pdf saved anywhere? Its disappeared from the entire internet!

[cresslux]

it wont let me upload the image...

but google the pinout for a BA6730B (that's the controller chip).

join a 47k (might be 4.7k, been a while, so try the 47k first) resistor to "P" (the input for the tacho) and solder the other end to anode side 1n4007 diode. solder the cathode side (the side with the line) of the diode to pin 14 on the BA6730B.

that should do the trick

[red22]

Thanks a bunch!

[Slidin23]

did anyone figure out if you can do this with the series 1 mx83?
i put a 1jz into my mx83 series 1 and would like to get the taco working.. im not great with electronics etc though..

cheers Jake

[dnegative]

Yes, same same

[Slidin23]

whats the same. a couple posts up it says it doesnt work?

what do i do exactly to get it working? this thread isnt really very clear no real write up... just people talking about it and im so confused haha

[dnegative]

MX83 tacho booster