Toper by the Italwin Group DC Welder repair. Model ZXP-170

The problem was it does not weld; At least that what the customer told me. Later on I realized, it was a different problem and was very easy to fix.
I took the cover off and turned it on and nothing happens, I was suppose to hear the cooling fan spinning but I did not, instead, I could smell something burning and the smoke was coming out of the cooling fan. I turned it off and looked closer at the fan. I tried to spin it by hand but it did not spin. It was a bad burnt fan.
A bad not spinning fan does not mean the welder is not working. The machine is working fine but the fan is very important in that machine. If the fan was not working and the machine is working, eventually, after a while the machine will go into shut down causing over heating caused by a fan not spinning and cooling off the machine.
It was a 220 volts fan. The motor was completely burnt and the plastic around the motor was melting and it smelled bad. The only problem I was facing in this machine is the ordering of a new fan. It takes about a week or so to get it and the customer was in a hurry to get it fixed. I called so many stores but without any luck. I have to place an order and wait for it.
I remember a while ago, someone brought me a DC welder to be fixed but it was too expensive and the customer did not come by the shop to pick it up. I went to the storage room and found the machine. There were two working fans in that machine. I called the customer and told him if he is interested to sell the DC welder for a cheap price and he said he not need it and offered me to take it for free. That was nice music to my ears; I took the old machine to the shop, took one of the working fans out and installed it in the machine I was working on and the fan worked very nicely.
I took the machine to my brother’s shop next door, connected all the wires needed for the welding process and turned it on. The fan started to spin and my brother tried the machine. It was working fine.
Called the customer to come and pick up his machine. He was so happy that the machine was working fine and was fixed in a very short time. He was happy, I was happy. Case closed.

Electronic DC welding machine repair. Model Zx7-200.

A friend of mine brought an electronic welding machine to my shop. The main problem was, it does not weld. The moment I plugged it in and connected all the welding cables, it did not weld, not even a small spark. The guy told me that he sent this machine to someone else to use it and over loaded the circuitry.
The moment I opened the cover of the welder, I could see a black burn near one of the positive legs of bridge rectifier. This is a high amp bridge rectifier (25 amps) and it is a big part. I soldered out (it was not an easy thing to do due to a lot of soldering joints on both sides of the board). I checked it out with a multi meter and it checked ok. One of the legs that have the burn marks did not have solid connection on the board. I re soldered that part and put the bridge rectifier back on board. I made sure it was soldered in a solid way on four legs and on both side of the board.
I plugged it in and tried the machine again but to my surprise it did not work. Checked the voltages in the machine and they all checked ok. I have the schematic for it and it really helped to have it. I worked on that machine for about four hours and could not find anything wrong with it.
I was really getting frustrated with it. I had to take a break. So I went for lunch break. Played with me son for about an hour or so, then I went back to the shop.
The only way to make it weld is to have the negative side and the positive side working fine. So I checked the connection from the positive side to the coil inside the machine with the LOPT/FBT meter and it gave me a full bar but when I checked the negative terminal, it did not give me a full bar indicating a bad coil or bad connection. I took the coil out and checked it again and this time it gave me a full bar. I checked the wire connection between the coil to the negative terminal and it did not give me a full bar indicating a problem in the wire it self. I traced this wire back and found out that this was the main computer chip feed back to the main computer of the machine. If the machine does not get the feed back to the main chip, it does not work.
I changed the wire with a brand new one and the moment I tried the machine it worked nicely. I was so happy with it.

Zika IK1600 a DC ARC Inverter welding machine repair.

A lot of people come to my shop asking me if I can repair electronic welding machines and I have no clue how to do that, I have no clue how they work therefore I can not fix them. This time I was eager to find out how they work and how I can repair them. A guy who knew my brother came to my shop asking me to repair this electronic welding machine for him.
The moment I turned it on, I could hear the fan running, so I opened the cover and took a look inside to see what I am dealing with. There were about three electronic boards there and components that I am very familiar with. I took it next door to my brother workshop (my brother uses this kind of machines so he is very familiar with it). He hocked up the welding cables and tried to weld with it but it did not work, there was a red LED on board that was on but flickering and the green power led was not on which gave me the indication that there is something wrong with the power supply.
I took it back to my work shop, took the power board off and started testing. I noticed the main capacitor was holding the charge. I discharged it and started testing the component around it. I tested it with a LOPT/FBT meter and it did not give me full bars so I was suspecting some bad component like diodes, main capacitor and MOS N FET some where in the area. After some testing I found a diode that was shorted out in the secondary side of the power supply. It was market with HER 206, so I replace that with HER 203 and tested again with LOPT/FBT and still did not get full bars on it. I noticed that the main capacitor was starting to bulge just a little bit. It was 47uf/400 volts so I replaced that with a new one. When tested with the LOPT/FBT meter, it was not give me full bars yet and when I turn the machine on, the main capacitor was still holding charge. After a deep checking with a strong magnifying lens, I found out that there is a line on the opposite side of the board that connects the main capacitor positive leg to the MOS N FET was not soldered right and I thought that is why the main capacitor was holding the charge.

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