Repair Jura Milk Frosther 72033
Is your Jura Milk Frosther 72033 dead? Not working anymore? Dead? No led lights up? Read on and learn to how to repair the DC/DC converter of the Jura Frosther 72033.
After serval years of usage my Jura Milk Frosther 72033 broke down, it was dead. So, a good reason to take it apart to see if it can be fixed.
Taking apart the Jura 72033
Taking apart the Jura Milk Frosther 72033 is quitte easy. On the bottom you can remove 2 screws and the 2 other screws are behind the 2 plastic feets. These can easily removed by using a pilier. Please note that these 2 screws under there are safety screws, so you have to use a special bit or modify a flat screw driver in order to remove these. After that you can put normal screws back into there.
Once opened, you can remove the main power PCB, by removing the 2 screws and disconnecting the cables. The PCB contains the DC/DC converter, a relay for switching the heater element on and off and some other stuff. An other small PCB, which contains the uprocessor, 3 leds and a switch is located along the side of the using. You can remove this one as well, but it isn't necessary. Please note that if you remove this controller PCB please take care to place it back correctly. This controller PCB is mounted behind the front display, a small flexible tube is mounted behind the display straight to the 2nd LED on the PCB. This tube acts like a light deflector. If you just slide the PCB back into it's mounting place, the tube will bend causing not to guide the light anymore. Solution is to remove the small display cover on the front (secured with 2 clips), remove the small tube from there, place the controller PCB back and slide the tube back in from the front so it fits over the LED correctly.
Repairing the DC/DC Converter of the Jure Milk Frosther
Measuring directly on the PCB was quitte hard because it seemed like that the PCB was covered with some plastic spray. You can remove it with some solvent, resolder all the joints, or measure directly on the component it self (top-side), but the room is quitte tight.
In my case D7 of the DC/DC had a short which caused the DC/DC not to startup. D7 is a SB3100 Schottky Diode 100V/3A which rectifies the voltage on the secondary side of the transformer. You can order these easily on Ebay or AliExpress.
Starting up the DC/DC converter
After D7 was replaced I used a variac, with a current meter, to startup the DC/DC softly. Using the current meter I was able to see that it works or more was damaged resulting in a high current consumption. Once it all was working fine, the Jura Milk Frosther was put back together and was put back in the kitchen in working order.