W&H LISA 300 Alarm150 solution

This alarm occurs in PR phase(process).The  Internal sterilization chamber temp.

< 134°C / 121°C the steam temperature reading  (internal chamber temperature probe) is below the minimum threshold.

Generally the main CPU board detect the alarm, thanks to evolutiv software and sensors.

This is the description of the alarm. But three conditions that cause it:

1/ Internal chamber temperature probe damaged

2/ Steam leak

3/ Steam generator heating element damaged

The first steep is tracking down the problem by elimination.

The internal Pt sensor is working fine

Remine to check for any leakage.

Door gasket:  I clean the chamber face side and door seal; run a sterilization cycle but the action did not remove the alarm.

To detect the possible internal leackage  we must run a vacuum test. If the test is negative and the alarm 390 occur, that means an electrovalve, a pipe or steam generator damaged.

Effectively, the alarm 390 occurs during the vacuum test, but to determine what component is fault, we must run multi different tests as follows:

1rst test:

Valves EVA/B/C:

 

o Access the components test sub-menu and power EVA, EVB,

and EVC

Listen for an audible click when checking and unchecking

the valves to ensure they are switching properly

o Check if there is steam leaking towards the condenser at any of

the three valves EVA/B/C

drop the condenser flat on the table, initiate a sterilization

cycle, and touch the tube that runs from the EVA/B/C assembly

to the condenser during the PPH phase of the cycle – if the

tube gets very hot during that phase it might indicate a leakage

at any of the three valves; clean or replace valve(s) if necessary.

The result no leackage

2nd test:

Vacuum alarm troubleshooting flow-chart

If…….A390………testB (checks for leaks on:

o 1-way valve (ULKA valve))

This one way valve is working fine, so I proced to testD.

testD checks for leaks on:

o steam generator

 

This test checks if there is a leakage at the one-way valve placed between the water pump and

the steam generator, also called ULKA valve.

 

o chamber interface

o valves EVA/B/C external

 

The 3 valves EVA/B/C are already tested good, the chamber interface is ok too..

The cause is a small crack in the steam generator.

 

The last testE is not necessary.

 

A dead Elbit CRT TV repair. Model EC70-602-CTI

A dead Elbit CRT TV repair. Model EC70-602-CTI
Two of these TV sets came to my shop and both of them had the same problem. Both were dead. When plunging both of them in, I could hear a ticking noise coming from inside the TV. I had to open the back of one TV set to find out what was wrong with it. In this case since both has the same problem, if I am able to fix one of them, there should be no problem fixing the other one. So, let us get started.
When taking the cover off, I scanned with my naked eye for bad electronic component but I could not find anything. From experience, when I hear a ticking noise coming from inside the TV set and the stand by light is not on, one thing comes to mind; the problem is in the high tension area. My focus now is in that area, mainly, the Horizontal Output transistor (Hot).

I measured the output voltages at the secondary section of the power supply and the 145 volts were missing indication a problem either in the way to the Horizontal output transistor or the HOT itself. I went directly to the HOT and measured the voltages there and I was not shocked that I could not read any voltages there. The moment I de soldered the collector leg of that transistor and added a light bulb to the point, the light bulb came on reading a 145 volts and that was a very good sign. Also the ticking noise was gone and I could see the stand by light coming on. The TV set will not come on until you replace that shorted out transistor.

I de soldered the transistor out and checked it with the ohm meter. All three legs on that transistor were shorted out indicating a heavy short in that area. When I asked the customer about that TV set, he informed me that the electricity in his house was going on and off for more than three or four times, causing a heavy load on that transistor and eventually shorted out. The part number of that HOT was BU508A. It was an 8 amp, a 135 watts transistor.

I replaced the transistor and fired up the TV set and it worked fine. Was glad to see that but I was not glad to see another problem in that TV set. The Audio was missing which meant the challenge was not over and I have not won my crown of repair satisfaction yet.

Sound was missing and the most logical answer is to go to the sound IC to make sure it was working fine. Checked the voltages and there was no reading there. That tells me the sound IC is good so far. I need to get these voltages reading back then I will see if the sound will be restored or not. The part number is TDA1521 and the 7th leg is the voltage input on that IC. I traced it backward to the main source which was the main power supply. As I was tracing back, I could see a lot of bad soldering joints and I re soldered every bad joint on that board. I turned the TV set back on and guess what, the sound was restored. The crown of the repair satisfaction was accomplished and I was happy to see that TV set comes back to life.

 

Hemilton CRT TV with vertical problem. Model HEM 433

This is a made in China CRT TV set and was brought to my shop with a vertical deflection problem. Usually a vertical problem is shown on TV screen with a black screen and a line across the screen.
Most of the time, you can turn the TV and you could see the vertical line across the screen but in my case here, the TV was dead. I could not turn it on. The customer told me that a line across the screen came on and then the TV went dead.
I could read the 300 volts on the main capacitor and 124 volts was reaching the horizontal transistor. There was no high tension present and the stand by light was on but the TV was dead. From experience, I have seen it happen so many times that when there is a dead short in the vertical IC itself, it could affect the whole TV and in this case the TV was dead. To confirm my analysis, I checked the 25 volts coming out of the secondary section of the power supply and they were missing. The vertical IC has a dead short in it that it was pulling the 25 voltages down to 1 volts only. How did I know which ACC leg to look for to read the voltages? The only way to know is by checking the specification of the vertical IC online and you will know which leg that is getting the power. In my case, the vertical IC LA78041, leg number two was the power feed to this vertical IC.
The moment I soldered out the vertical IC, power came back to the set and I could see the vertical line across the screen. And I could read the 25 volts on the printed circuit. It is always a good idea to check for bad capacitors around the vertical IC. In my case, I found 6 bad capacitors there. Three capacitors 220uf/35 volts and three capacitors 450uf/16 volts. I replaced all of them.
I replaced the vertical IC and the TV came alive and I could see a picture but there was something wrong with that picture. The blue color was missing in that picture. Usually, there are too things to look for in such a case.
1- The blue color filament in the CRT neck is not working right. Usually there are three light in the neck of the CRT tube. Sometimes you could see them there if you dim the light in the room.
2- The transistor for the blue color in the CRT board is bad.
To my luck, when tested the transistor, it was shorted out. It was BF422. The moment I replaced that transistor, the blue color was restored.
It was lots of work but at the end, I won the challenge and the joy to see that TV come to life was wonderful.

LG microwave oven that does not heat up. LG MS-204H

This microwave oven was brought to my shop for repair and the problem was, it does not heat up. While the customer awaits in my shop, I did a small test. I put some water inside the microwave oven and tried to see if it heats the water or not. When turning on the oven, I could hear a loud noise coming from inside the microwave oven and it did not heat up the water.
From experience, when the microwave oven does not heat up, there is three possibilities:
1- The 220 volts is not reaching the main power transformer
2- The magnetron is shorted out
3- The .70 amp/5000 volts fuse between the 220 volts power transformer and the main capacitor is open causing the magnetron not to work due to the absence of power there.
By testing, I could read 220 volts reaching the main power transformer. The magnetron is not shorted out; This testing is done by testing the ohm reading between the metal body of the magnetron and the two terminals of the magnetron. If you get any reading between the terminals and the magnetron metal body, it is shorted and needed to be replaced. Usually the two terminals are connected together from the inside. It you test these two terminals with a continuity test setting, you will hear a beep. That is very normal.
I checked the fuse that is connecting the transformer to the main capacitor and it was open. this is a common problem in microwaves oven to find an open fuse there. Many repair technicians replace the fuse with higher amp rating causing the magnetron to blown or shorted it on the long run. It is very important to replace it with the same fuse specification to avoid any kind of problem in the microwave oven.
I replaced the fuse and turned the machine on. It worked and the water I put in the microwave oven started to get hot. One more problem remained; that is the loud noise of the oven. It was not suppose to have this loud noise. Usually, this is a problem with the main capacitor in the microwave and I think that is the main reason why the fuse was blown in the first place.
It is a very easy process to replace the capacitors but it is very important to make sure that the old capacitor in the microwave oven is discharged before replacing it. Even if the capacitor is bad, just make sure, it was discharged before replacing it with a new one. Upon replacing the old capacitor with a new one, the noise was gone.
The microwave ovens are very easy to fix and it can generated good income if you know how to do it. Just be careful when dealing with capacitors and magnetrons. Enjoy your repair and be safe.

Hivion digital broadcasting satellite receiver. Model HV9191X

An old man brought this satellite receiver to be fixed. It was a dead receiver. Took the cover off and scanned the power board with my naked eye but could not see anything there.

I powered up the receiver and started to test the voltages in the secondary power supply. All the diodes in the secondary section were not getting any kind of voltages whatsoever. That is an indication of a bad primary power supply. I tested the voltages at the main capacitor and I could read the 300 volts there.

There was a power IC (5L0365R) located near the main capacitor. And the 300 volts were reaching the input on that IC and the out; I could not get any reading which gave me the indication that it is a bad IC. I replaced that with the same exact number part but to my shock, the machine did not work.

It was time for me to start checking the entire component in the primary section of the power supply. Well, my checking lasted only two minutes when I found a bad diode on the same line of that power IC. I took off board and checked it out and found out it was a bad diode. Somehow that bad diode was putting the voltages down on that power IC. The moment I replaced that diode, the receiver came to life and I got a good picture.

I called the guy and he came and got his receiver. He said he did not know how to install it to the TV set at home. I had to go with him to his house and install everything for him. He was using the RF connection to connect the receiver to his TV. That is not the best way to connect it to the TV. I suggested the RCA plugs which provide better picture and an easy way to connect it to the TV inputs without programming the TV.

He gladly agreed and was really happy that the receiver was working and the picture on his TV set was much better than before.