vboost servo motor

[schudaddie]

while testing my servo motor prior to install, the motor works fine doing the test in the manual but, when checking the resistance, the check between terminals 3-4 shows high 10.6. It's supposed to be 7.5 +- 30%. terminals 1-3 is 7.44 and 1-2 is 7.45. The manual says replace but I'm not sure since it operates fine. what exactly is this resistance test telling me.
thanks in advance, Bill

 

[naughtyG]

while testing my servo motor prior to install, the motor works fine doing the test in the manual but, when checking the resistance, the check between terminals 3-4 shows high 10.6. It's supposed to be 7.5 +- 30%. terminals 1-3 is 7.44 and 1-2 is 7.45. The manual says replace but I'm not sure since it operates fine. what exactly is this resistance test telling me.
thanks in advance, Bill

7.5 + 30% is just under 10, so you're just slightly over. It may simply be a dirty connector, or something that hasn't moved for a while and built up resistance. I would give it a try, if it needs replacing it's not all that hard - just gotta remove the carbs rack to get to it if I remember right. :confused2:

 

[bazwell]

I'm at work and don't have the info I need in front of me, but something sounds wrong in what you are measuring.

From memory terminals 1, 2 and 3 are the potentiometer, and between 1 and 3 needs to be about 7.5 - 10k. Terminals 4 and 5 are the motor, I can't remember what they are supposed to be.

But, even so, I think that you are probably OK. Those readings don't sound too far off in any case.

 

[schudaddie]

I'm at work and don't have the info I need in front of me, but something sounds wrong in what you are measuring.

From memory terminals 1, 2 and 3 are the potentiometer, and between 1 and 3 needs to be about 7.5 - 10k. Terminals 4 and 5 are the motor, I can't remember what they are supposed to be.

But, even so, I think that you are probably OK. Those readings don't sound too far off in any case.

oops, typo on my part. I meant to say 10.6 on terminals 2/3.
anyway got everything hooked up, turned on key, got the fuel pump clicking and the v-boost servo pulled forward / on and stayed there. guess the servo unit will have to come out. Is there anything inside of the servo that can be repaired or is it the control unit that's screwed up? I did go thru the control unit and resoldered all the wire connections to the circuit board. one other question. on the bottom of the air box I believe there are supposed to be 2 vent hoses. mine only had the larger one at the rear and I can't seem to see where the front one is supposed to be attached to the engine.
any help on this would be greatly appreciated, bill

 

[dingy]

Terminals 1-3 should be 7.5K ohms +/- 30%. There is a misprint in the manual referring to terminal 4. Also theyused numbers 1 & 2 in top and bottom diagrams which is not good practice.

The motor coil is across what is shown as terminals 1 & 2 in top diagram on page attached below. This reading is about 14.5 ohms. I have measured this on good test equipment for another related project. See top diagram in attached picture.

1-3 read the entire potentiometer resistance, from 1-2 & 2-3 will vary depending on position of potentiometer. But the 2 of them should equal 1-3 reading. See bottom diagram in attached picture.

1st picture shows motor with cover removed.

2nd is cut from manual.

1 set of the ohm readings you posted should have been in K (1000) ohms. Ate you using a digital meter? If so, the display will have a K on it when reading this range I think. Other pair may be close to zero it potentiometer at max or min travel.

Gary

 

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Only one hose connects to the bottom of the air box. It goes to the rear. The front hole does not get a hose.

 

[schudaddie]

Yes I am using a multi meter and it does have the K. That misprint was confusing at first but I've seen plenty of others in this manual. so what is telling the motor to go on to the open position then reverse to the closed position when turning on the key? the control unit? if so mine must be bad.... Oh Sean got one of those lying around?
later,bill

 

[88Vmax]

I know this is an old thread but I can't find a 7.5k ohm potentiometer, can I use a 10k? Or even a 5k. I figured with the 5k the potentiometer will either be full open or partially closed. And with a 10k the potentiometer will probably open fully at the 7.5 mark which will be 75% of the 10k then stay open the remainder of the 2500k. Make sense?
Or if I used a 10k and put 7.5k resistors on pins 1 and 3 so it dont go over the 10 to vboost controller.

 

[thor_eyerdhal]

Just find an old servomotor, open it and take the potentiometer, you can take the motor too.
I taked parts from an old YPVS servo, same parts except gears (different ratio)