Question re: PT Terminal 4

[Laudanum]

Manual states :  "Cut a 2" (50mm) piece of black wire, strip both ends back 1/4" (6mm). Attach and solder one end to power transformer terminal 4.  Attach and solder the other end to terminal 22L."

"REVISION 5/6/10:
Making this wire 3" long and connecting it to Terminal 14U instead of terminal 22L may yield more quiet operation."

A couple questions -  first, should terminal 22L show continuity to chassis ground?  Terminal 14 does but 22 doesnt.  That's kinda throwing me off in terms of understanding PT term. 4 jumper connection choices/options.

Second - Terminal 14U is pretty crowded, 14L should provide the same results if I connect jumper from PT 4 to 14L instead of 14U, correct?  (dumb question but I asked anyway just to be sure)

Thanks

 

[Grainger49]

Yes 14U and 14L are electrically the same.  It is possible that further down there are more wires going into 14L, but I don't know.

 

[Laudanum]

Thanks Grainger

14U has, from memory, 3 leads connected not including one of the lugs from the larger electrolytics, so pretty crowded.  I originally had the jumper from PT terminal 4 ready to connect at 14U but moved it to 22 after seeing how crowded 14U was.  I couldnt figure why the manual didnt recommend 14L for connection of the jumper which is why I asked the (dumb) question.  14L is empty but there is supposed to be a sandcast resistor connected to the neighboring lower terminals that would have blocked 14L.  I didnt think about that because I used a Mills which, obviously, is much smaller and leaves some room for the wire.

I think that the jumper from PT 4 should be ideally connected to what would be a grounded terminal (ultimately via chassis ground). And I think that ground integrity would be questionable for terminal 22, especially if the bell housing is painted because it would may be an unreliable contact (because of the paint) of that mounting screw with either the edge of the bell housing mounting hole or contact with the edge of the star washer underneath.  But this is just a guess. 
Id like to know for sure if Im on the right track here.

Thanks

 

[Grainger49]

After building my first Paramour (1) I realized a couple of terminals were crowded.  I pulled out my Dremel tool, chucked up a diamond file (shaft with diamond dust on it) and opened up those terminals from a triangle to a rectangle.  Everything fit in easily for the second one.

Since I'm not near my copy of the Crack manual I will take your word that PT 4 is ground/safety ground.  That means that any grounded terminal, the ones with a screw mounting it to the chassis, would work as well as another terminal. 

I think you are on your way!

 

[Laudanum]

PT 4 is marked 0V.  It connects to the 6080 but also is supposed to have a jumper connected to terminal 22 (which nothing else is connected to).  22 is an end terminal with a mounting leg that one of the transformer mounting screws bolts to (via the thru hole insulators/grommets).  It doesnt show continuity to ground. But it would if the tranny bell housing wasnt painted because the bell housing itself has been grounded through another one of mounting screws. So with a painted bell housing, I think it's possible that 22 could or could not show continuity to ground depending on whether that mounting screw happened to be making decent contact with the unpainted edge of the mounting hole of the bell housing or the star washer underneath the bell housing cover (there are star washers under all 4 mounting holes of the bell housing) ... if any of that makes sense.  So the bell housing itself would be safety grounded but not necessarily making good contact with the mounting screws (with the exception of the one screw that has a star washer on top of the bell housing (penetrates the paint).
Anyway, this is why Im thinking that the instructions were updated to state that connecting to 14 instead of 22 may result in quieter operation.  14 is continuous to ground as I mentioned and 22 may of may not be. I Could probably add a star washer underneath the head of that PT mounting screw that mounts to 22 which would assure better ground contact.

Looking at 14 again, I could probably get the wire in there, it's 12 and 13 that are really crowded.  14 and 15 are workable ... or I could use 14L.

Anyway, I hope my wording made sense.  Id still like to find out for sure if reason for the connection option to 14 instead of 22 is because of a potentially better ground.  Understanding circuits is not my forte by any stretch.


Thanks

 

[Grainger49]

Ok looking at the manual now, and I'm following you. 

Just looking at the mounting instructions for the transformer and terminal strips.  On the top of page 18 there is a wire from the safety ground lug to the top left transformer mounting screw/nut at terminal 16.  This should ground the whole transformer and terminal 22 as well.

The star washers shown on page 14 are supposed to ground the whole bell housing and the other mounting screws.  The point is not to ground all four allowing for eddy currents. 

The bell housing doesn't seem to be painted in the manual, but is on the product page.  You might need to remove the bell housing and remove the paint on the underside of the bell housing at the corners to get continuity to safety ground.

 

[Doc B]

Yes, the teeth on these washers are intended to cut through any coating you may put on the bell in order to create electrical continuity. We moved the wire to 14 to create a better path to ground. Using the lower hole is fine.

 

[Laudanum]

Snugging the screws down usually helps ...duh.

Thanks