Not all 4H dials are the same.

[Greg G.]

I swapped out the dial on my 151AL and discovered the new 4H dial is different from the old.  I can't tell from looking at the wiring diagram where the wires are supposed to go because the colors aren't the same as what's listed on the diagram.

[poplar1]

The dials have the same terminals, just not all in the same position. Notice that when the "old dial" was converted, the former W terminal was restamped R, and W is now next to the governor. In the bottom picture, the terminals are arranged as in a 5H dial.'

Try this:
1. Move the yellow line cord wire from Y on dial to B-Y terminal (put it with the blue harness wire).
2. Move the double blue harness wire from W on the dial to BB on the dial.
3. Strap BB and R on the dial.

What is the blue wire on the RR terminal, just an unused wire in the line cord?

[poplar1]

There is one error on the diagram: there is no "Y-BK" terminal for connecting the black line cord wire to the black harness wire. This terminal exists only on the apparatus blank, which is not used when you have a dial. The black wire from the subset goes directly to BK on the dial.

[poplar1]

The diagram shows a 2A dial. If you are using a 2H, 4H, 5H or 6A instead, you will have 5 terminals instead of 4. The "extra" terminal is labeled R. Just strap the BB and R terminals with a small piece of wire and the newer dial will be equivalent to the 2A.

[Greg G.]

What is the blue wire on the RR terminal, just an unused wire in the line cord?

I'm not sure, but it's hooked up to the hook switch. 

[poplar1]

What is the blue wire on the RR terminal, just an unused wire in the line cord?

I'm not sure, but it's hooked up to the hook switch. 

I was talking about the brown wire with blue traces that is on RR. Is that going from RR in the phone to the black condenser wire in the subset? If so, it needs to move to BK on the dial. There should not be any wires on RR.

[poplar1]

I may be looking at the wrong picture. The moves I was talking about earlier were for the phone with all the wires going somewhere.

In any case, they look right on the hookswitch. So just be sure that the  wire on BB of the hookswitch goes to BB on the dial, the wire on R of the hookswitch goes to the R terminal near the cord entrance in the base (not to R on the dial), the yellow wire from the hookswitch to the B-Y terminal and the black harness wire from BK on the dial to the transmitter.

[Greg G.]

What is the blue wire on the RR terminal, just an unused wire in the line cord?

I'm not sure, but it's hooked up to the hook switch. 

I was talking about the brown wire with blue traces that is on RR. Is that going from RR in the phone to the black condenser wire in the subset? If so, it needs to move to BK on the dial. There should not be any wires on RR.

The phone's not hooked up to a subset just yet, there's no line cord on it.  I think the line cord will be easy enough, I just need to know how to hook up the dial I swapped.  I deleted the picture of the old dial.

[poplar1]

Yellow wire (from Y on hook switch) to Y on dial
Black wire from transmitter to BK on dial
Black wire from subset to BK on dial
Double blue or brown-blue wire (from BB on hook switch) to BB on dial
White receiver wire to W on dial
Strap BB and R on dial
Don't connect any wires to R on dial.

http://www.classicrotaryphones.com/forum/index.php?topic=8465.0

[Greg G.]

Mine doesn't have those same colors, that's where I'm confused.

[poplar1]

"Purple"=blue
"Yellow"=yellow
These are the 2 wires that are wrapped around the D3B dial cord

"Greenish"=Black
"Diff shade of Greenish"= Double blue
Red=Red
These are the 3 wires of the D3B cord

"Brown with white fleks"= White
This is the receiver cord