Bench testing the Gicar auto refill controller

Equipment doesn't work? Troubleshooting? If you're handy, members can help.

#1: Post by black85vette »

In my thread on rebuilding my Quick Mill Andreja I asked about how to test the Gicar auto refill controller on the bench rather than in the machine. Here is some information I have gathered and some learned on my bench.

This box has two rows of pins that are numbered on the case. Pins 1 thru 10 on one side and 11 thru 20 on the other. They count positions with no connector showing. Starting with pin 1 and 2 is the AC 120 volt mains input. For the Quick Mill Andreja pin 3 which is labeled for the heating element and has the highest amperage rating is not connected. Pins 4 and 5 go to the pump and refill solenoid valve. 6 is not present and 7 while labeled EVRRUPPO is controlling the heating element. Skip to pin 18 on the other side which is a common ground for the tank sensor and reservoir switch. Pin 19 connects to the lower reservoir sensor and pin 20 connects to the boiler water level sensor on top of the boiler. Finally there is a 4 pin connector on the controller. The two pins closest to pins 18 - 20 are the upper reservoir sensor. The other two pins I believe are an LED output but my machine does not use them so I did not test them.

To verify operation you need to set up the controller so it thinks it has water in the tank and boiler so place a jumper from 20 to 18, 19 to 18 and across the two pins used in the 4 pin connector. Apply 110 volts to pins 1 and 2. For testing I removed the jumper on top of the Gicar to enable the beeper to work.

Apply 110 volts to pins 1 and 2. Pin 7 will have 110 volts referenced to the AC return pin 1. This provides voltage to enable the heater to work.

First test is to remove the jumper on the 2 pins in the 4 pin connector. This will simulate water below the top reservoir sensor and the controller will beep intermittently but the heater stays on.

Second is to remove the jumper from 19 to 18. Now the controller will beep continuously and pin 7 will no longer have 110 volts on it. The heater is shut down when the reservoir drops below the lower switch.

Third is to replace both sets of jumpers and remove the jumper from 20 to 18. This will simulate a low water condition in the boiler. The voltage on pin 7 drops to shut down the heater but pins 4 and 5 now have 110 volts on them to run the pump and refill valve. Place the jumper back on after a few seconds and the heater comes back on but the pump and valve shut down. NOTE: if you leave the jumper from pin 20 disconnected for more than about a minute the controller goes into a fault, sounds the alarms and shuts down everything. This is a good thing because it thought it was filling the boiler but did not detect the water level reaching the sensor so a pump, valve or line could be bad. Shut down power to the controller to reset it otherwise it appears to be dead.

Checking a controller that does not work. There are a couple of preliminary checks you can make. 110 volts on pins 1 and 2 should be verified with a meter. There is a 12 volt power supply on the controller board fed by a transformer. There is a 4 leg rectifier that should have two "S" markings which are the AC sinewave input to it. There should be about 20 volts AC on these two pins from the transformer. The other two pins are the DC output of the rectifier and should have about 20 volts DC on them. The actual voltage is not critical. Next is a 3 leg 7812 regulator that has a 12 volt stable output. This needs to be very close to 12 volts. Also near this is a 35 volt 330 uf capacitor. There is not a simple test for these but my experience over the years is that they are very cheap and not worth testing anyway. I replace every filter capacitor I see if it is more than a year or two old. These are polarized and the negative lead goes to the inside of the board. Also on the board is a smaller surface mount 7805 3 legged regulator that outputs 5 volts DC for the microprocessor / logic. If you have all the jumpers on and have all the voltages verified you should hear a relay click and have 110 volts on pins 3 and 7. If the relay does not energize the controller may be dead.

These are the quick checks to verify a Gicar is working before you start troubleshooting the rest of the machine. I can't even start to go into how to troubleshoot a dead Gicar.

DISCLAIMER!!! I have 40 plus years in electronics and high voltage equipment. I am very comfortable working with pins with exposed 110 volts on them. If you do not understand how to do this safely please find someone to do it for you. These voltages can be lethal. I believe this information to be correct but I am working with a controller that I have not verified in a working machine so do not take my observations as the final word. If I have made any errors I will edit and correct them.

Hope this is helpful to someone.

12 volt supply and filter capacitor

5 volt 7805 regulator

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#2: Post by Nunas »

Nice job!