Trin 1 : Check whether the TEC of the handpiece functions normally.
Trin 2 : Check whether the plug pins of the handpiece are in position.
Trin 3 : Open the machine shell as shown in the video to check whether the control board is normal.
Trin 4 : Check whether the circuit between the control board and the handpiece plug is connected properly.
The above steps need to be carried out in order. Only when the check result of this step is normal, proceed to the next.
Trin 1: Check the handpiece.
Switch a multimeter to the diode position.
As shown in the video, we can see the two pins in the upper left corner of the plug facing us. Name the top pin as “Pin 1” and the one below as “Pin 2”.
Touch Pin 1 with the black multimeter probe and Pin 2 with the red one.
If the multimeter rings with “0” or concrete values on the screen, the TEC functions normally. Imidlertid, an “OL” or “1” on the screen shows a broken circuit of the TEC.
Trin 2: Check the plug pins.
Check the two holes in the upper right corner of the socket matched with the handpiece plug( name the top hole as “Hole 1” and the below as “Hole 2”) to see whether the pins are in position.
Check the pins of the handpiece plug. Touch to see whether Pin 1 and Pin 2 are at the same level with others.
Trin 3: Check the control board.
Insert the handpiece plug first and then the power cord. Press the Power button. Switch to the interface shown in the video and set “Skin Cooling” to the maximum.
To measure the voltage of the TEC, switch the multimeter to the direct voltage position over 12V.
In standby mode, touch the red terminal in the upper right corner of the control board with the red multimeter probe, the next blue terminal with the black probe. The multimeter screen shows “0V ” now.
Press the “Ready” button. If the voltage value increases to around 12V, the control board works well; If the value remains “0V” after pressing “Ready”, the control board is damaged and needs replacing.
How to replace the control board:
1. Plug off the power cord for security reasons.
2. To remove the glue, apply 75% medicinal alcohol( available in drugstores) to it and take it off with tweezers a minute later.
3. Unscrew the four corners of the damaged control board.
4. Take each wire off the old board and attach it to the same location on the new one in sequence. Pay attention to the exact position of each wire.
5. Screw the new board. Be careful not to tighten a single screw first. Instead, fix the four screws first and then tighten them together.
The specific replacing process is shown in the video.
Trin 4: Check the circuit between the control board and the handpiece plug.
If the control board works normally and the handpiece TEC still fails in cooling, check whether the circuit between the control board and the handpiece plug is connected properly.
1. Turn off the machine and plug off the handpiece. Switch the multimeter to the on-off position.( Touch one probe with the other. A ringing shows the given position.)
2. Touch the red terminal in the upper right corner of the control board with the red multimeter probe and touch Hole 2 in the upper right corner of the socket with the black one. A ringing shows a good connection; no ringing or “1” on the meter screen shows a broken circuit.
Then change places. Touch the next blue terminal with the red multimeter probe and touch Hole 1 of the socket with the black one. Likewise, a ringing shows a good connection; no ringing or “1” on the meter screen shows a broken circuit.
3. With circuit disconnected, a further inspection is needed to find the break point and reconnect it
Additional Remarks
Functions of each wire:
1. As shown in the video, the two wires in this corner are the power supply ports of the control board. The red is the positive electrode and the blue is the negative one.
2. In the other corner is the control port of the TEC. The red line is the positive terminal of the TEC, and the blue one is negative.
3. The white band leads to the screen interface.
4. On this side, the first white block is the communication interface of the handpiece screen. The second white block is the signal line that controls the laser power supply.
5. On the opposite side, the first white block is the interface of the flow sensor. The second white block is the interface of the handpiece switch. The third white block is the interface of the water tank lamp. The fourth white block is the reserved interface of the 5V signal. And the fifth white block is the interface of the temperature sensor.
For more details, refer to the video: How to Fix the Diode Laser Handpiece Is Not Cooling
