Gaggia G90 electrical question, switch wiring

greesha

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Aug 5, 2018
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Hello,

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:

The first is the wiring going from the control board
Screen Shot 2018-08-05 at 1.53.40 PM.png

The second is the high power side, so the wiring going to the switch:
Screen Shot 2018-08-05 at 1.55.04 PM.png
 

greesha

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Aug 5, 2018
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With a little help, we were able to draw a schematic of how the switch works.
This is the switch.
It has 18 terming, arranged in 3 rows of 6.
1-6, 7-12, 13-18.

1319066.jpg
IMG_0186.JPG

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
 
Last edited:

Rustlen

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Dec 9, 2020
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Cwmbran
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Why don’t you find a specialist to help you with this task? It is not very hard to make it yourself, but a specialist could help you a lot. Still, if you want to do it, you have to understand how a transformer works, and only after that will you be able to make gaggia g90 work perfectly. I am not a professional to give you a piece of advice, but I think it would work if you change the switch wiring, it could be damaged because of its age. Anyway, good luck to you, and I hope you’ll manage to make it work.
You are totally right
 
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