Re: DC to AC Inverter Test
The measures in ohm scale are (first letter with positive and the second one with negative):
P-U: 4.24 Mohm
P-V: 4.24 Mohm
P-W: 4.24 Mohm
P-N: 7.87 Mohm
N-U: open line
N-V: open line
N-W: open line
N-P: open line
and in diode scale are:
P-U: open line
P-V: open line
P-W: open line
P-N: open line
N-U: 0.435 v
N-V: 0.435 v
N-W: 0.435 v
N-P: 0.797 v
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DC to AC Inverter Test
Hello, I'm having problems with an air conditioning machine. I think that the problem is in the inverter IC. The model of this inverter is PS21245-E.
This IC transforms 320v DC to 20-300v 3-fase AC (and variable frequency).
I have already desoldered one side to see the identification of the IC.
I ask your help in order to check if this inverter IC is working or not.
The datasheet is here: [URL="http://www.ineltron.de/english/mitsubishi-data/IPM/PS21245-E.pdf"]http://www.ineltron.de/english/mitsubishi-data/IPM/PS21245-E.pdf[/URL]...
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Re: Problem with LCD Panel board
The older inverter controller is an OZ9936GN. The new one is an external inverter that I adapted....
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Re: Problem with LCD Panel board
Maybe that's the problem. Now I have the monitor working without brightness control. Thank you all guys.
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Re: Problem with LCD Panel board
Appreciate your help but now I'm trying to adapt an external inveter that I have. As you can read before, I have located both ON/OFF and brightness control but the brightness doesn't seem to work. Later on I would try to reset the logic board....
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Re: Problem with LCD Panel board
It goes from 1.1v approximately to 3.3v. It doesn't get to zero....
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Re: Problem with LCD Panel board
What do you mean by "at the inverter"?. I have checked voltage while connecting the inverter at pin ADJ and the tension is varying but not the brightness.
Maybe it would need more voltage, Right now I'm feeding it with 12v but the Vin says 10-30VLast edited by mokie; 05-24-2014, 05:26 PM.
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Re: Problem with LCD Panel board
ok, thank you for all your help. I have located the brightnes control (next to the ON/OFF wire). When I change the brightness on the screen I can see how change the voltage on this wire.
But, the external inverter doesn't change the brightness at all. This inverter is like this one [url]http://www.ebay.es/itm/390711004363[/url] . It has 4 pins (V+, ground, ADJ, ON/OFF).
I will have to settle with change the contrast only.Re: Problem with LCD Panel board<br ... the brightnes
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Re: Problem with LCD Panel board
Yes, i have desoldered both mosfets and one of them was shorted. I give up.
Now I'm trying to connect an external inverter to power the lamps. I have located the ON/OFF wire coming from the logic board and now I'm looking for the brighness one. Do you know what range of tension have the brightness control?
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Re: Problem with LCD Panel board
oh, this is getting even worse. I have removed R107 and when I turn it on the monitor doesn't do anything. I check with ohmeter and there's continuity between pin 4 and ground. I have removed the OZ and the continutiy persists.
Maybe I should try to link an external inverter which I have over here.
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Re: Problem with LCD Panel board
Voltages are the same than post #12...
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Re: Problem with LCD Panel board
I have checked pins 4 and 5 and they actually "try" to turn on. They go up to 325mV for a short period of time and then they both go to zero.
Resistance between pin 4 and ground: 11.9 Momhs
Resistance between pin 5 and ground: 12.7 Mohms
R104 is 105.5 komhs
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Re: Problem with LCD Panel board
Here are photos of the new OZ9936 replaced. I did the best I could. Yes, pin 3 is connected to ground
In summary, I have checked:
- Secondary of both inverter transfomers. Around 460 ohms.
- I have desoldered all capacitors and their capacity is ok (maybe they have high ESR?)
- I have checked what I think are two fuses for the inverter zone. They are located near the OZ9936 and they are ok.
- I have replaced the two main mosfets for the inverter zone which were opened. They were P609 and I replaced...Last edited by mokie; 05-24-2014, 08:02 AM.
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Re: Problem with LCD Panel board
The voltages are exactly the same as before and the lamps doesn't even flash for a second.
If I light the screen, I can see the image on it.
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Re: Problem with LCD Panel board
I've replaced the OZ9936 and I have the same problem, no backlight at all
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Re: Problem with LCD Panel board
ok ,thank you for all your help. I will be posting the results
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Re: Problem with LCD Panel board
This is what I get. I guess that the OZ is cooked...
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Re: Problem with LCD Panel board
No, actually there aren't shorted. The problem was on the N-channel. If I check between drain and source (negative and positive respectively) I got 0.5 (OK) but if I turn on the gate there's no continuity between drain and source.
Sorry for my bad explanation, I'm not english native.
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Re: Problem with LCD Panel board
- I don't understand well the first question, but when I turn on the monitor there isnt't any signal on the gate pin of any mosfet
- Yes, I get 14.36 volts on both drains (and both mosfets, each mosfet has 2 drains)
- The flashlight doesn't flash at all (with or without the 30 pin plug)
Probably it will be that OZ9936GN. I think this is a good deal [url]http://www.ebay.es/itm/2X-OZ9936GN-OZ9936-Inverter-Controller-ORIGINAL-O2-Micro-F11-/360619504921[/url]
The problem will be the soldering thou...
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Re: Problem with LCD Panel board
look at the picture.
On the bottom, there is an IC with 8 pins. It's a OZ9936GN...Last edited by mokie; 05-03-2014, 01:52 PM.
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