Jura Z models transformer replacement

はじめに

The transformer can break especially when water drips onto it from above. You should definitely eliminate any leaks at the heaters and at the outlet valve. A typical symptom is when the machine cannot be turned on at all, or it can be turned on, but the solenoid valve clicks loudly multiple times, the brew group does not move, and "Error 8" (brew group not positioned) appears on the display.

必要な工具と部品

手順1 Opening the Jura Z series housing

Jura Z models transformer replacement, Opening the Jura Z series housing: 手順 1、 1の画像 1

Unplug the machine from the power outlet
Remove all attachments: water tank, drip tray, aroma lid

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手順2

Jura Z models transformer replacement: 手順 2、 3の画像 3

Turn the machine so the back is facing toward the front.
The Jura sign must be removed. Turn it a few millimeters counterclickwise.
If this becomes difficult use a suction cup to assist.
Remove the Jura sign.

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手順3

Behind the Jura sign are two screws with an oval head. They have to be removed.
These screws have an oval head that makes them look like rivets (picture 2). You need to use a special bit for their removal. If the right bit is not available, it could be done with a pair of needle nose pliers. Jura wants to keep us out of our own machines!!!!

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手順4

Push the back down a bit and then remove it.

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手順5

Pull the right side panel- as seen looking to the frontpanel - backwards and take it off.
Sometimes it gets a bit stuck and may require a bit more of a pull.

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手順6

Jura Z models transformer replacement: 手順 6、 3の画像 3

In this step, you should remove the screws of the left side panel. The side panel can only be removed after removing the top cover.
Remove the Torx T15 screw on the front wall of the side panel.
In the side part there is a lid over the brew group. The lid is fastened at the top with two oval head screws. Remove those to remove the lid.
With the cover removed the brew group becomes visible

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手順7

Jura Z models transformer replacement: 手順 7、 3の画像 3

This step shows how to remove the top cover
Remove the powder tray and all coffee beans.
The cover is fastened with three Torx T15 screws. Those are easily visible under the covers as well as the small cover on the left back side.
Remove the two Phillips screws on the bean container and remove the bean container.
Lift the cover upwards.
If it is stuck, use a plastic opening tool to carefully pry it open.
The lid of the bean container is held in place by a small, strong magnet that loosely rests. It is either in the green marked recess, or it remains hanging on the bean container. Make sure it is not lost!

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手順8

Pull the left side panel backwards to take it off.
For some repairs it is not necessary to remove the left side panel.

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手順9 Transformer

Jura Z models transformer replacement, Transformer: 手順 9、 2の画像 1

Jura Z models transformer replacement, Transformer: 手順 9、 2の画像 2

The transformer is located on the side between the ceramic valve and the pump. Depending on the model, a bracket may need to be removed.
The pictures depict different models.

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手順10

Jura Z models transformer replacement: 手順 10、 3の画像 3

Unscrew the two low-lying Torx T15 screws from the bracket and remove the bracket.
Lift the transformer out.

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手順11

The transformers are the same in practically all Jura devices.
Disconnect the two red (230 V), the two orange flat connectors (15 V), and two yellow ones (9 V) from the transformer.
To test the transformer, start by measuring the resistances: the 15 V and 9 V terminals (secondary) should read about 1 Ohm, and the 230 V terminals (primary) should read approximately 100 Ohms.
You can also apply an AC voltage of about 20 V to the 230 V (primary) side. You then should measure approximately 1.4 V on the 15 V (secondary) side and around 0.8 V on the 9 V (secondary) side. Never interchange the primary and secondary sides, as it could result in dangerously high voltages.