# Gaggia D90 electrical questions, switch wiring



## greesha (May 26, 2018)

Would anyone be able to take a photo of their main switch wiring for me?

I recently rebuilt and rewired a 1986 Gaggia d90 2 group.

It was purchased off an auction site in very rough shape, so everything was rebuilt.

I rewired it according to how it was wired when I received it, and have consulted the D90/E90 evolution manual that I was able to download online.

The issue I am having is that only 120V is going from the switch to the control board. My understanding is that it should be 220V.

I think I may have an issue with the switch wiring. Does anyone have a d90 that they could take a photo of the switch for me?

Here is the switch wiring diagram that I have for a d90:









This is the wiring diagram from the control board









This is the switch:









With a little help, we were able to draw a schematic of how the switch works.

It has 18 terming, arranged in 3 rows of 6.

1-6, 7-12, 13-18.









Of the 4 positions:

off: nothing is connected

pos1: (1 and 2) (7 and 8 ) and (13 and 14) are connected, which powers the circuit board.

pos2: also connected are (3 and 4) (9 and 10) (13 and 14), in this position 2 of the 3 heating coils have power.

pos3: also connected are (5 and 6) (11 and 12) (17 and 19), in this position the 3rd heating coil has power.

As the machine came without a plug, and had a 5 wire harness, using a 5 wire setup to the plug to the 220 outlet. 2 live (120v each), 2 neutral and 1 ground.

I wired the switch the same way I received it.

Coming from the outlet:

A live wire is connected to 7 and 4

Neutral is connected to 17 and 13

group is connected to ground point not the frame

2 wires also connected 10 to both 6 and 7.

Going to the control board:

live (black) is connected to 8

neutral (blue) to 14

14 and 8 also had a wires going to a indicator light.

3 wires went from the switch to the pressure stat:

black from 9

red from 3

yellow from 5

My understanding is that since I am only getting 120v going to the circuit board, I am missing a connection between the second 120v coming from the outlet.

If anyone has a d90, and can take a photo of their wired switch, I would greatly appreciate it


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## grumpydaddy (Oct 20, 2014)

Are you in USA?

If so does this help?

https://www.home-barista.com/espresso-machines/can-anyone-help-identify-my-gaggia-model-t27691.html

Sorry but when I magnify those diagrams it is too blurry to read


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## greesha (May 26, 2018)

grumpydaddy said:


> Are you in USA?
> 
> If so does this help?
> 
> ...


Yes I am in the USA.

Is there a better way for me to attach the wiring diagrams?

yes I saw that thread however, there is only one photo of the switch. I see that position 2 is connected to the block that connects wires going from the pressure stat to the coil.

I am also missing a wire connecting to 7, however I cannot see where it is coming from


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## grumpydaddy (Oct 20, 2014)

On closer inspection of those diagrams My question to you is....

What makes you think the control circuit should use 240v?

If you are using the diagram for the 240v delta connection (collegamento a triangolo) and the control circuit for a two group, terminal block 4 clearly shows just black and blue, a live (L1) and a neutral going to the controls

It is normal for any 3 or 2 phase machine to only use the extra phase(s) to power the heating circuit

To get a clearer picture in your mind you need to start thinking about the power from the socket as having:

L1

L2

Neutral (in this case 2 wires, blue and brown are wired to the same terminal)

Earth

L1 and L2 are very distinctly separate circuits/wires so you must always think of them as such

Now go back to your comments about "a live goes to" and specify L1 goes to.... and L2 goes to.... etc

It might also help you to understand if to draw the switch as in fact 3 switches for the 3 positions of said switch

SW1: (1 and 2) (7 and 8 ) and (13 and 14) are connected, which powers the circuit board.

SW2: also connected are (3 and 4) (9 and 10) (13 and 14), in this position 2 of the 3 heating coils have power.

SW3: also connected are (5 and 6) (11 and 12) (17 and 19), in this position the 3rd heating coil has power.

draw in the connections between each switch to better understand what is happening (2 wires also connected 10 to both 6 and 7.)


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## espressotechno (Apr 11, 2011)

Gaggia Italy may be able to supply the wiring colour codes, if you have the serial number etc.


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