Magnetic Pickup Problems 2001 Vermeer SC50tx

[a1stump]

I have a 2001 Vermeer SC50tx that has went through about 6 mag pickups in the last 2 years, 3 in the last 3 months. There is grease buildup in the bell housing and flywheel. Will this really take out the mag pickup! Any other suggestions? I tried changing the autosweep computer as well and same result until I changed another mag pickup yesterday, ground stumps for 4-5 hours, load up thinking I was golden and then this morning it did the same thing. Full throttle but not showing lights on the throttle bar and then shut down in 3-5 seconds! HELP!!!

 

[diezelsmoke]

How do you know they are bad? Tell me about the testing you did to determine they are bad.

 

[a1stump]

I have not tested them, just put new one in and then it runs for awhile. I'm gonna bring it to vermeer dealer Monday and he will show me how to test them though.

 

[a1stump]

But why would it work with a new one every time?

 

[diezelsmoke]

My thought is you have a bad wire and everytime you change the pickup you are moving the wiring. Maybe move the wire connector, unplug, etc. and see if it works. To test the pickup use an ohm meter and wave a screw driver past the end and see if your ohm meter changes. The preferred ohm meter too use is the sweeping arm style and not an electronic one.

 

[blades]

Ohm meter - Analog style ( sweeping arm) vs digital, for the purpose of the test indicted above analog meter can be gotten for about $5 or less.

 

[a1stump]

So set the ohm meter to hertz? Then touch the black with the black off the mag pickup and the red with the red off the mag pickup to the ohm meter red/black and then wave a screwdriver in front of the end of the mag pickup to see if the ohms gets a reading, if so it works and wires are bad?

 

[diezelsmoke]

Yep also check circuit board look for green corrosion, etc. at wire connection(s).

 

[blades]

set meter to OHMS not Hertz( frequency) it does not generate a signal but rather varies in resistance which varies the voltage runing though it or allows voltage flow or stops voltage flow depending on design. This is a static check out of circuit . In circuit under power would be a voltage check, but I do not know if you could see the variation on a simple vom. I do not know its parametetrs- on cars 10-11 volts is minimum input for computer

 

[diezelsmoke]

Set to Ohm's sorry about that! If it is a 2 wire sensor it has no power in the system during operation. Basically while the machine is running the ECM is reading fluctuation in resistance of the circuit as the flywheel moves past the sensor. I ment to add previously grease buildup will not be a problem in whether it works or not.

 

[Corytree]

What exactly is the issue with the machine when you have a faulty mag pickup?

I have a sc50tx that is driving me crazy......motor runs perfect, good hydraulic pressure, all new filters (including in tank screen)

Hydraulics will work sometimes and some times no response, now the head will only go up then it falls right back down.

Any advice appreciated, thanks!

 

[blades]

gut reaction says air in system, possible bad bypass/ pressure relief valve ( broken spring?) are these electric over hydro ? then possible intermittent connection to a solenoid or it is sticking- bad ground- broken lead inside insulation jacket-intermittent coil , if plug in relays corroded connections in socket.
Control board -bad or intermittent switch or connections to same and if it is a whole plug in of wires one of the pins could be out of place, printed circuit boards- edge connectors and cold solder joints. Don't forget any safety switch circuits. Pick one area and go through it completely repeat for each. for electrical a Volt/ohm meter is your friend. Ohm section can be used as a continuity checker( provided the component is out of the circuit on things like switches, relays coils, solenoid coils) or simple wire check point a to b. ( disconnect battery though) voltage across contacts looking a rise or fall depending on how it is wired.
basic trouble shooting 101

 

[user 159780]

From Vermeer I ordered mag pickup for my BC1000 chipper, the part received was labeled for the stump grinder. Their parts guy said the Chippers and grinders use the same part.
Anyway, measuring with a DVM it outputs about 10V ac at idle. It increased about 2v with the blades engaged.

The chipper has a electronic controller with LEDs. The LED marked tach is the output for the pickup and should be solid green.
Don't know if the grinder has the same type setup but its worth a look.
If it accumulates crud the output will be weak, cleaning the pickup head should bring it back to life.

 

[iowagold]

I have copies of the manuals here
same thing here dead unit in the shop
out of the manual
disconnect the plug from the harness
on the sensor side of the plugs it should check 1150 ohms + or - 10% or range of 1,035 min ohms to 1,265 max ohms

unit not running for this;
assy of the sensor to the unit turn in the sensor till it contacts the fly wheel back off the sensor 1/2 a turn then hold the sensor with a wrench and tighten down the lock nut
use locktite blue 242 on the lock nut threads

the new part number is
new number 163677052 129.44

while the unit is running and the sensor is connected red wire with the pos fluke 87 meter lead and black meter lead to chassis ground or the lock nut on the sensor
in ac hz setting
you should have 6195 hz + or - 10% or 5,576 hz min to max 6,814 hz

let me know if you need a link for manuals for this unit

 

[iowagold]

From Vermeer I ordered mag pickup for my BC1000 chipper, the part received was labeled for the stump grinder. Their parts guy said the Chippers and grinders use the same part.
Anyway, measuring with a DVM it outputs about 10V ac at idle. It increased about 2v with the blades engaged.

The chipper has a electronic controller with LEDs. The LED marked tach is the output for the pickup and should be solid green.
Don't know if the grinder has the same type setup but its worth a look.
If it accumulates crud the output will be weak, cleaning the pickup head should bring it back to life.

hey hemi
what kind of crud are you seeing???
is it picking up magnetic junk??

I have one here in the shop today.
the coil is open.
and when replacing when the part arrives yes I will check the slots in the flywheel pulse generator.

 

[user 159780]

hey hemi
what kind of crud are you seeing???
is it picking up magnetic junk??

I have one here in the shop today.
the coil is open.
and when replacing when the part arrives yes I will check the slots in the flywheel pulse generator.

Looked like rust particles. The coil was not open, the resistance of the new pickup was not even close to the original part.

 

[iowagold]

I was looking for any oem markings or part numbers .
some of these simple pulse pickups are low cost off the shelf items if you know the exact specs..

let me know if there are any numbers on the metal part of the pickup on any of yours.

there could be an over current issue on the computer due to maybe a bad shorted isolation capacitor.
after all the electrolytic caps have acid in them.. they go bad over time.
just for fun I might price the modules...

they did have an issue with the rubber potting material letting moisture in the computers...
even a tech bulletin or "tsb"
it was showing a recall for back in the day to pot over the old material with epoxy...

the heck of it is that epoxy would not seal as good as better rtv...
and some of that softer potting material is conductive over time...

Kenwood ham radio's suffered that in the 1980's through 2010's
as well as GM Delphi and Delco and ford Motocraft radios..

so maybe it is too much load on the super small coil wires in the pickup?

or the seals on the pickup are letting soap from car wash in and corrosion sets in and opens up the pickup coil..
or in the computer..

so if you go get a new unit look at the seal on the pickup to output wire..
if it is soft rubber like material like on my old ones.
use some good gray rtv for oil to help seal this..
as well as on the place where they trim the out side jacket on the cable to expose the 2 small wires..
this stuff works well

Permatex Gear Oil RTV Gasket Maker
Part # 81182 Line: PER
https://www.oreillyauto.com/detail/...l-rtv-gasket-maker/81182/4610249?q=rtv&pos=23

and it will seal out the oils as well..
use good non chlorinated brake clean first to remove any oils..

O'Reilly Brake Parts Cleaner
Part # 72408 Line: ORC
https://www.oreillyauto.com/detail/...s-cleaner/72408/4600013?q=brake+cleaner&pos=2

or the green can of crc brake clean
CRC Industries Brakleen Brake Parts Cleaner
Part # 5088 Line: CRC
https://www.oreillyauto.com/detail/...kleen-brake-parts-cleaner/05088/4176069?pos=5

just watch what you spray with that stuff as it will eat plastic.
and use this thread locker on the lock nut after you are tight

Permatex 36ml Threadlock
Part # 24240 Line: PER
https://www.oreillyauto.com/detail/...threadlock/24240/4610162?q=permatex+242&pos=2

I will use the brake cleaner and a stiff air hose on the flywheel generator teeth to make sure it is super clean..
if you do remove the bell housing for another repair.
take care with the sensor!!

they do not like to be bumped!!

 

[user 159780]

I spent considerable time searching for an alternate source. No OEM markings on that part. Since the 3.3L Cummins diesel engine is actually mfg. by Komatsu I searched that route as well, no luck. The pickup is not listed in the Cummins parts book.
The chipper controller was $600, its potted so no peaking inside.
Another thread mentioned the controller taking out the pickup. The Vermeer Tech replaced both at the same time.

 

[iowagold]

hey guys I spent 3 hours yesterday and 2 today with engineering.
direct contact me for details!!
good stuff not for publication yet!
I have the new part here different part number!
and have addressed the other issues.
waiting for rtv to setup on the part seal.
I should know some thing maybe Friday late.
stay tuned as they say... this is going to be good!!

 

[iowagold]

yup the numbers are different on the new coil they are using now.
1950ohms so the range should be 1,755 ohms min to 2145 ohms max..

yea I have mine on now!! and it works!!
just a tip on the installation.
clean all of the teeth with brake clean and blow dry with an air wand.
and make sure the threads are perfect clean as well! no oil!!
use a big pry bar and center a tooth on the middle of the hole.
trust me this is where most fail!!
carefully screw in till it touches the tooth, then back out 180 deg.
use permatex blue 242 locktite on the nut and hold the sensor perfectly still and tighten down the nut.

and there is an update for the polarity on the sensor as well.
on the little grinder the white on the sensor connects to the red on the machine side!
that is flipped from the old oem sensor's polarity!!
mine started right up and settles down after it learned where it needed to be on idle.

all machine functions came back as well.

i still have a drive glitch in the right joy stick or a valve sticking at times.
that will be tomorrows job...
it could be the joy is out of adjustment for center.
yea first things first see what the leds say on the controller..
then if they are saying the comands are right it has to be a valve issue.

kinda surprised they do not have a set of zerks on the track slide tubes...
it was stuck as the previous owner gave up on the machine and it sat for 4 years..
they had smashed the sensor in to the teeth on the reluctor or starter ring gear teeth.
it was a good find with the ohm meter for sure!!
a real smoking gun bad part!!

more later