MMA WELDING PRODUCT REPAIR PROCESS OF GYSMI 160P 1/16. Auteur : Alexis Gillet Date : 30/06/2016.

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1 REPAIR PROCESS OF GYSMI 160P 1/16

2 REPAIR PROCESS OF GYSMI 160P Summary 1) Prior analysis and advice ) Safety reminder ) General advice in organizational intervention (Internet home page) ) Useful tips for following diagnosis ) Equipment required ) Structural diagram ) Pre Diagnostic ) Symptoms and failures ) The unit trips the mains breaker switch: a) Control isolation SMI to earth b) Diode bridge control ) The unit starts but not welding ) Repair algorithm : a) Main algorithm b) Secondary algorithm ) Test and control the circuit board : a) Overvoltage protection repair b) Power supply repair c) Check and repair of the control circuit d) Check and repair of the thermal protection ) Product setting procedure ) Detailed structural diagram ) Annexe(s) /16

3 REPAIR PROCESS OF GYSMI 160P 1) Prior analysis and advice 1.1) Safety reminder The repairs must be performed by qualified person(s). Before any intervention in the internal generator, make sure that the set is unplugged. 1.2) General advice in organizational intervention (Internet home page) Read the Overview of Inverters GYSMI. Read the disclaimers GYSMI Guarantee on all models - see the homepage on the Internet. Perform a visual inspection to detect any obvious faults (hot spots, badly crimped terminal, browned diode, burnt transformer, mechanical failure, power module (component(s ) destroyed, burnished zone)). 1.3) Useful tips for following diagnosis The CMS components can become short or open circuit. Verification of resistance with a multimeter in the «ohm» position. Verification of diodes with a multimeter in the «diode» position. For all connections on the board, solder probes on the points of contact indicated. The circuit board is varnished, pay attention to the risk of poor contact due to the isolation created by the varnish, use probes with a sharp tip in order to break the layer of varnish. Check the section with the most common symptoms and failures. Check the procedure step-by-step and make repairs if necessary. 1.4) Equipment required A Multimeter. An oscilloscope and a x10 probe. A 60V power supply isolated from the earth, current limited to 2 amps. Connection cables with crocodile clips. 3/16

4 REPAIR PROCESS OF GYSMI 160P 2) Structural diagram * The values presented are indicative only and may vary from tens of millivolts at the SMI. 4/16

5 3) Pre Diagnostic Faults Causes Remedies The orange light is on, the Thermal protection device does not deliver any circuit was triggered. current. Only the green LED is on but the device does not weld. There are small amounts of static shock when you touch the body of the machine. Poor connection of the earth clamp or electrode holder. Not earth continuity. Check the connections 3 min max. (Orange light off) Check the connections. Multimeter in the «ohms» position. Check the continuity between earth and the mains cable. You should read low resistance (courtcircuit) If OK Check your electric installation by a professionnal. The unit welds poorly. Wrong polarity (+/-). Check the polarity (+/-) advised on the electrode box. 4) Symptoms and failures 4.1) The unit trips the mains breaker switch: 4.1.a) Control isolation SMI to earth Disconnect the plug from the product. Multimeter in «ohms» position. Check the value between the screws of the primary and earth. You should read infinite resistance. Otherwise, the SMI is probably down. Change the power block, réf See procedure to change SMI (annexe). 5/16

6 4.1.b) Diode bridge control Multimeter in «diode» position. Check the value with multimeter. The value should be around 540mV between each diode Otherwise (diode is short-circuited), the SMI is probably down. Change the power block, réf See procedure to change SMI (annexe). 4.2) The unit starts but not welding Check the output voltage of the unit. Connect the unit to the mains. Multimeter in «volt» position. Measure the voltage across the Texas connectors. The value must be : 60V +/-5% Otherwise, check the following items. Check the screws on the Texas connectors (circled in red) If the PCB is burnt. Remove any burn marks/corrosion (Blue arrow). Change the screw réf In some circumstances (faulty circuit) : Cut the card and the degraded areas. Place a cable (10 mm²) between the screw and the Texas connectors as shown below. The must be tightened to 3 N.m. Check the mechanical strength of bolts. Loosen the screws. Test with a rod. Do not push strongly. Check whether one of the bolts (shown on the right) moves. If the bolt moves, the SMI is down. Change the power block, réf See procedure to change SMI (annexe). When the test is complete, tighten the screws. These must be tightened to 2.5 N.m. 6/16

7 4.3) Repair algorithm : 4.3.a) Main algorithm 7/16

8 4.3.b) Secondary algorithm 8/16

9 4.4) Test and control the circuit board : For the following test, measurements are performed under restricted Low Voltage 60V 2A. Turn on the 60V supply. Power the card directly to the electrical terminals, as shown. Pay attention to the polarity. Both relays must switch. Consumption Avec SMI Sans SMI Product off 0.045A 0.050A Product on 0.10A 0.053A 4.4.a) Overvoltage protection repair Power on diodes bridge. Change the following components : Transistors : Q41P01 : STD2N ref Q41P02 : MMBTA ref Diodes : D41P09 : ZENER 12V ref D41P11, D41P10 : GS1M ref Resistor : R41P12 : 0Ω ref Varistance : V41P01 : 470Ω ref /16

10 4.4.b) Power supply repair Change the following components : Transformers : TR51X01 ref Transistors : Q51P01 : MMBTA06LT1 ref Q51P10 : ST01NK802T4 ref Diodes : D52P02 : 1N4148W ref D51P02 : ZENER 15V ref Resistors : R51P25 : 47Ω ref R51P33 : 221Ω ref R51P31, R51P32 : 1,3Ω ref R51P21, R51P22, R51P23 : 330kΩ ref Chip : U51P01 : FAN6862R ref c) Check and repair of the control circuit For the following measures, taking HF as the reference on the screws of the diodes bridge as shown. Output signal of the 3845: Capture the control signal at the output pin 6 of the UC3845. Using an oscilloscope probe (see below) Other result is a niche 100KHz 17V signal (see below cons). 10/16

11 If the output signal is absent, check the input signal : The supply voltage of Pin 7, measured voltage 15V The presence and variation of the set of the Pin 1, Voltage Min : 2.36V Voltage Max : 4.16V If the set is not present : Change the following components : Transistors : Q22P01 BSR16 ref Q22P02 2N7002 ref Q22P03 BSS84P ref Chip : U21P ref /16

12 Output signal of the L6386: Keeping the mass on the HT : See higher square wave PWM signal on the screw near power capacitors (below) Signal shown on right Keeping the mass on the HT : See lower square wave PWM signals on the screw near the transformer (below) Signal shown on right If the signals are not present : Change the following components : Resistor : R21P10 : 4,7Ω ref Diodes : D21P01 D21P04 : Zener 16V ref D21P02 D21P03 : BAT42W ref Chips : U21P01 : UC3848B ref U21P02 : L6386 ref /16

13 4.4.d) Check and repair of the thermal protection Thermal protection is triggered by a short circuit using a small flat screwdriver between pins 5 and 6 of the SMI connector. When the thermal protection is triggered, the orange Led lights on. If the thermal protection does not work or is constantly lit : Change the following components : Resistor : R13P12 : 10Ω ref Diode : D13P01 : ZENER 18V ref Chips : U13P01 U13P02 : TL331 ref Transistors : Q13P01 Q13P03 : BSR14 ref ) Product setting procedure This operation is to do each change SMI and change microcontroller. To adjust the product, one can proceed in 2 ways : a. By attaching the product via load bank ref b. By welding with the device. For the welding set, you require two operators for the adjustment operation. An operator welds while the other rotates the potentiometer on the product. Preparation : Connect the product to 230V. Use amperemeter. Amperemeter in position continuous current (A-DC). 1) Setting by load bench. Measure the DC current produced by the product. 2) Setting by welding. Prepare many electrodes Ø4 to weld 2 or 3 minutes. 13/16

14 Product setting : Connect the device to the mains with the potentiometer set to «off». Turn the potentiometer and place it directly in min position, the fan should rotate, green LED off. After one second, the green LED should light. As soon as the green LED lights, weld using an electrode with a diameter of 4mm or to pull a current via a load bank. Gradually turn the potentiometer until there is a current of 160A on the clamp and wait for the fan to cut out. Weld using an electrode with a diameter of 4mm until the unit is in thermal protection, LED lights orange. Once that is on, the setting is stored. If the setting did not work, reset the machine(as shown below) and refer back to this operation Product reset : Turn off the product. Wait 15 seconds. Apply short circuit (weld wire) between pin A and B. Turn on the 60V supply. Wait green light is on (average 10 seconds). Turn off the product. Remove the wire between the pin A and B. The machine is reset and the product setting can be apply. (cf. paragraph 5) 14/16

15 6) Detailed structural diagram 15/16

16 7) Annexe(s) Unscrew the PCB from the power block. Add tin to facilitate the operation. With a big solder and ferrule soldering adapted. Heat the tin on the connector. Wait the tin is completely warm. Remove the circuit. Clean up the circuit connector pads. To make this operation you could use desoldering wick or desoldering pump. Clean up the power block connector of tin; if you want use it again. To make this operation you could use desoldering wick or desoldering pump. Screw before weld the connector when you remove the power block. These must be tightened to 2.5 N.m. Be careful short-circuit between the differents pins of connector. 16/16