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REFRIGERANT RECOVERY RECYCLING AND RECHARGING STATION
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eletmoraes [ 24 апр 2020, 00:17 ]
Заголовок сообщения:  REFRIGERANT RECOVERY RECYCLING AND RECHARGING STATION
Unfortunately I don't know the make and model of the device, the customer took it to the technician to check if it had burnt components. One of the components had exploded, it is the input varistor in addition to two fuses one of 5A and another of 1A.
I will attach photos of the board in question,
The first thing I changed was the blue varistor on the side of two jumpers. Then I put the fuse F1 and fuse F2. When measuring the resistance between points A and B in the electrolytic capacitor 6800uF / 16v I obtained a resistance 0 ohms the same thing about capacitor C32 in points C and D on the side of the integrated U11. Some component is shorted, it can be some integrated or some capacitor. The question is how to know what component it is. This plate is double-sided .



the model of board is : ROBINAIR MODEL: 34700
REFRIGERANT RECOVERY RECYCLING AND RECHARGING STATION

HFC-134a


My idea would be to remove a VR2 MC78L05ACP regulator and apply a voltage of 5v to the pins 2 (gnd) and 3 (vout) of the regulator. NOTE: the resistance shown on these pins is 0 ohms.

This short features about some 100nf decoupling capacitors. There are two MC78L05 regulators where pins 2 and 3 are shorted. The question is whether it would be risky to apply a voltage of 5v using a computer source (desktop)?
dennis85 [ 24 апр 2020, 05:04 ]
Заголовок сообщения:  Re: REFRIGERANT RECOVERY RECYCLING AND RECHARGING STATION
eletmoraes писал(а):
The question is whether it would be risky to apply a voltage of 5v using a computer source (desktop)?

It can provide fatal destraction of some capacitors or microchips, probably, as result - your eyes will have damages. :zvez_ochki:

So for searching shorted components you need current limiting around 1A. Laboratory power supply, or big resistor(for 5V `4.7 Ohms more then 5W power dissipations).
Remove 7805 and put 5V/1A power in to 2-3 pin, then a bit wait and look what a komponents will do heating. :-):
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