mondial 8 impulse generator

is there anybody out there in the know that can tell / guide me through a test and repair procedure on the impulse generator on my 81 mondial 8, i have enclosed pictures of it below
this is what i have done so far, stripped the pc board out the housing , found 2 wires at the bottom of unit had come loose , replaced them, still got no ohm reading on the muli meter, more testing revealed a resistor was open, replaced resistor and got an ohm reading through the 2 wires on top of unit. replaced the unit in the car, and with the car on blocks started an ran the car in gear , speedo still not working. disconected the sensor and connected to multi meter , getting the same ohm reading but no pulse when car is running in gear,
have shopped around, found a couple new ones available, however when i change pounds, dollars,or euros into south african currency ....... well i could probaly buy a small car here for that price, so i realy have to fix this thing
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thanks for the reply, i have been on there site and have e mailed them, but like a lot of other spares places around the globe , they do not reply, prehaps you could give me another contact email adress for them,
thanks
george

 

thanks for the replys, my skill level on electronics is very basic, i have enclosed 2 more detailed pics of what i have done, unfortunitly i cant find the resistor i took out, but i replaced it with one that has the same amount of rings and same colour rings as the one that came out. on the pic i have marked it A. ...... B and C are the 2 wires i replaced [ they had come loose of the board ] the bit that has me puzzled is that there is no magnet type coil bit on the board[ not that i can identify ] and there is no magnet in the base of the unit. the board slots into the base of the unit which is plastic,
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thanks for all the input, im begining to get an understanding as to how this works, i got hold of a microscope and had a look at the plastic end capsule that the board slots into, there is what appears to be a disc moulded into the capsule [ it is not picked up with a magnet though ] and looking down the slot on the side of the capsule i can see now that those 2 wires that appeared to have come of the board actualy need to be attached to the disc inside the capsule and not on the board. there appears to be a realy small locating pin in the brass barrel , that will line up and fit into the slot on the plastic capsule , i assume one of the 2 wires that go into the capsule would need to make contact with that locating pin to create an earth. does this make sense or sound like im on the right track, im going to split the capsule carefully [ so that i can rejoin it again, i need to get the disc out to reattach the 2 wires ] the slot on the side of the capsule is only 1mm wide and 5mm deep meaning 2 wires fit into a 1mm slot and they appear to attach 5mm down, what stills concerns me though is that the disc inside there is not atracted to a magnet .

 

ok, i have managed to split the plastic capsule with out any damage, i have enclosed one pic below taken through a magnifing glass,the left unit holds the coil which the 2 wires have to be attached to, the right unit shows the slot which the 2 wires have to go up, one wire appears to go half way up the slot and is fastened to near the outside edge i assume to make contact with the pin in the brass barrel, the other wire appears to go through the slot and connect on a point on the pc board , i dont know on which point it connects to yet, im going to atempt to repair the wires tomorrow, however this stuff is realy small and at this point im not sure im going to win, is there anything else i can replace the part in the pic shown with.
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took the unit to a mate of mine who runs a radio repair shop in a neibouring town , whilst he didnot know how the circuit worked, he managed to put all the wires back as i asked him to [ he got a magnifying glass that makes the unit look like the size of the bottom of a coffee mug and the tools to replace the wires neatly ] before i reassemble the the whole sensor id like to confirm , that small coil in the middle of the unit, would it only have two wires comming of the coil, [ one from the top of coil and one from the bottom of the coil ] would there need to be an earth of some sort to the coil unit,im quite to put it back in the car this weekend an try it out

 

i also just noticed this morning im getting magnetic action on the sensor now, but not the way i expected to see it, when placing a small magnet at the pick up side of sensor it repels , i was expecting it to attract, have i got wires crossed.

 

pic taken through magnifying glass of unit assembled
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before i glued the unit together last night i was running through the whole system with my limmited knowlege on this unit ensuring that i havnt missed anything [ i want to have the best possible chance of this thing working again ] when i reliesed the 2 wires comming up threw the slot on the side from the coil were touching each other, not sure what this may have caused but decided to insulate them with silicon, however at the end of the operation one wire came of the coil, so its back to my mate at the radio shop this comming friday afternoon, what can i use to clear a bit of epoxy of the coil wire to at least get a bit of wire bare to attach the broken wire to, iv scraped it down to the bare wire and can see the complete wire in the epoxy , i somehow need to lift about 3mm of it out the epoxy to ensure a decent connection this time

 

well, after much more headscratching and research , it works

 

hi, the brass body [ housing ] has a lip that is pressed over the white plastic part [ looking at the sensor from the top ] i held the brass body in a lathe and carefully machined the lip away , the next step is very important [ i didnot know what the unit looked like inside and i pulled the white plastic part out from the top and did more damage to the internals then what was already blown ] DO NOT PULL THE WHITE PLASTIC PART OUT FROM THE TOP, push the internals out from the bottom by pressing on the round brown plastic part on the bottom of the unit [ see last pic in above posts . titled pic taken threw magnifying glass of unit assembled the brown part on right hand side is where you need to press on the bottom, there are two very very very small wires that connect the bottom brown part [ which is an inductive magnet ] to the pc board and when they brake of as mine did they are extremly difficult to replace, and they will brake of if you pull the plastic part from the top. the problem i found on mine [ apart from the damage i caused by pulling it out from the top ] was a resistor [ labled A in one of the above pics ] was blown wich i replaced i hope the above helps you
george