Quartz Clock Conversion

[wheels78ta]

I've done the quartz conversion to a 1975 and 1978 Trans Am.  The kit I used is part # N-3085 from Instrument Services, Inc.  $90 on ebay.  They say to make sure your clock is a Borg type but I didn't find any kind of markings showing either was a Borg clock.

I think the hardest things about the conversion would be making sure you don't damage the second hand when removing the clock from the tach and soldering.  Other than that it's fairly easy to do.

1.  The kit.  More on the parts inside later.

2.  Unplug the red (positive) and black (negative) wires from their posts.

3.  Unplugged

4.  Remove the 3 screws to remove the back plate.

 

[wheels78ta]

5.  Remove these 2 screws and the clock can be removed from the tach plate. 

6.  Slowly remove the clock section away from the tach making sure you don't catch the second hand on the opening.

7.  Pull it out at an angle and turn it clockwise to remove it from the tach.

    OR.........................

[wheels78ta]

8.  Leave the 2 screws in and remove the hands from the clock while it is still mounted to the tach plate.  Grab the second hand on the sides
     and pull away from the clock.  It doesn't take a lot to remove it.

9.  Second hand removed.

10.  Grab the minute hand on the sides and move it side to side and wiggle it up and out.

11.  Minute hand removed.

12.  Do the same for the hour hand.

[wheels78ta]

13.  Now that the hands are removed you can separate the clock from the tach plate without damaging them.

14, 15, 16, 17.   Remove the 2 screws from the back and the clock will come out.

[wheels78ta]

18.  There are 3 tabs that hold the clock face to the main body.

19.  I used a small set of needle nosed pliers to bend them out just a little bit.

20.  There are 3 tabs that hold the dial plate to the main body.

21.  I used a very small flat head screwdriver and needle nosed pliers to bend them out just enough to remove the dial plate. 

22.  The clock is attached to the dial plate and will pull out as one piece.  The positive (red) wire will keep the unit from coming out all the
       way.  You will un-solder the red wire later.
       

[wheels78ta]

23.  At the bottom of the clock is where you will need to un-solder the positive (red) wire.

24.  Positive (red) wire removed from the clock.  Do not remove the positive wire from the case.

25.  This is just an FYI.  You do not need to do this for the conversion.  These are the contacts that are cleaned if you are going to keep your
       clock original.

 

[wheels78ta]

26.  To remove the dial plate from the clock....you'll need to remove these 3 locking caps.  I used a very small flat head screwdriver to pry up
       and around the locking caps to get them off.

27.   Locking caps removed.  These will be replaced with new ones from the kit.

28.  Separate the dial plate from the front of the clock.

29.   Sometimes, on the back of the dial plate, the cup washers will stick to the grommets.

30.  Just remove the cup washers.  They will be replaced with new ones from the kit.

31.  If the cup washers don't stick to the grommets.....they will be found on the posts of the clock.  You can remove them.



 

[wheels78ta]

32.  This would be a good time to remove the grommets from the dial plate.  They will be replaced with new ones from the kit.

33.  Inside the kit.

34.  According to the instructions.....After 1970 you'll use the 2 black gears.  Before 1970 you use the 2 red gears.  To determine this.....if the
      gear on the set stem has 10 teeth you use the black set.  12 teeth use the red set.

34a.  Set stem gear.  This one has 10 teeth.

[wheels78ta]

35.  Take the negative (small black wire), from the kit, remove 1/8" from the end, and solder to the end of the metal flap.

36.  On the back side of the quartz clock.....there are 2 places that you will solder wires to.  On the left is the 12/24V and the right is GND.

37.  Solder the other end of the negative (black) wire to GND.  Solder the positive (red) wire, the one you un-soldered earlier, to 12/24V.
       Make sure the positive (red) wire is still going through the case.

38.  When everything has cooled down......place the new grommets into the dial plate.  One side of the grommet is wider than the other. 
       Push the small part of the grommet through the back side, that has the gears, of the dial plate.

[wheels78ta]

39.  Time to disassemble the old clock.  Do not let this part scare you.  You're only going to remove 4 pieces.  First remove the very thin
       washer.

40.  Removed

41.  Same pic....different focus.

42.  Remove the Hour Wheel assembly.

43.  Remove the Motion Wheel.

44.  Removed

[wheels78ta]

45.  Remove the Minute Wheel assembly

46.  Removed.

47.  Now for a little bit of reversal.  Take the Minute Wheel assembly, from the old clock, and install it on the new quartz clock.

48.  Minute Wheel assembly installed.

[wheels78ta]

49.  Take the Idler Pinion (black), from the kit, and place it in the opening at the top left of the crescent.

50.  Installing Idler Pinion.

51.  Idler Pinion installed.

52.  New Motion Wheel from the kit (left) and old Motion Wheel (right)



 

[wheels78ta]

53.  Take the new Motion Wheel (black)

54.  And place it on the stud to the left of the Minute Wheel.

55.  New Motion Wheel installed.

56.  Take the Hour Wheel assembly, from the old clock.....

57.  And place it on the Minute Wheel stem.

58.  Hour Wheel installed.

 

[wheels78ta]

59.  Take the very thin washer, from the old clock......

60.  And place it on top of the Hour Wheel assembly.

61.  Thin washer installed.

62.  Place the new cup washers on to the studs.

63.  Cup washers installed.

[wheels78ta]

64.  Put the dial plate and the clock together.  It will only go on one way using the studs of the new clock.  Make sure to put the negative
       (black) wire to the side so that it doesn't interfere with the moving parts.

65.  Push the Dial Plate nuts onto the studs, one at a time.

66.  I used a 1/4" socket to push the Dial Plate nuts down onto the studs to secure the dial plate to the clock assembly.
       
67.  All secured.

68.  ***When bending the metal tabs to secure the dial face to the case.....be careful because the dial face is plastic and over 40 years old.
             It can be brittle and easy to crack.

       Test the clock by putting on the second hand and connecting the leads to either a 12V battery or a power supply with 12V.  The second
       hand should start moving.  Once you have verified that the clock works.....remove the second hand and put the dial plate/clock assembly
       back together.  Install all the clock hands....or install the unit back onto the tach base and then install the hands onto the clock.  Install
       the hands in the 12:00 position and recheck that it works.

[Wallington]

Good one, I'll have a read of this all later!

[gm muscle]

Wow, fantastic job documenting this job!

[Wallington]

You need to send the link to the seller to use as a customer aid, plus commission!

[rkellerjr]

Nice write up! thanks for doing it.

[roadking77]

Yes, very good write up and great step by step detail. Should be very helpful.