E116921 Power Supply - Does not work even after parts replaced

Question

I only speak english But I saw this topic in PL language that is very similar to mine: I'd like the same participants to help me on my case. For this reason, I post on the PL forum. I replaced the ZD101 with a 12V zener (1N4742A). But before that, I tested many values only touching, without...

Darek.S · Accepted Answer

Hope I quite accurate describe the problem and solution. I submit aplication of Top . U do bit more cause submit completely diagram of this power supply and i see slight differences. Exactly pins C and F which are connected on diagram and on aplication not.
Try to measure tension of pin C! In my cause I made a mistake and solder zener with wrong value. When I displaced it the tension was 5,6V and power supply went. So I solder 8,2V. There are ISO 101 and ZD102 connected to point C. Check it for shortcut...

Darek.S · Accepted Answer

You already got a proposition. 5,2V on point C is i think too small. I have similar problem but in my case i put the wrong diode with too small Zener voltage. What about ZD102? It could be wrong even without shortcut. I've just ordered a tester wchich can measure Zener Voltage. Earlier a did that with multimetr, resistor and laboratory power supply. Now it should be much easier. Yesterday I bought similar tester But this above is better.

LucasBS · Answer

Hello.
Sorry for the delayed answer. My job allows me to work with this problem only once or twice in a month.

I double checked the supply and the schematics. The C and F are connected.

There is 5.3V on the C pin.
No short circuit was detected on any of the adjacent components.

I will replace the ISO101, since I put a part that I had on my stock that is different than the original.

Meanwhile, what else do you suggest to check ?

LucasBS · Answer

Would you remember the voltage at ZD102 (the voltage when the zener was soldered, and the supply turned on) ? Perhaps you wrote down other voltages, like those on the pins of TOP244 ? If your projector was not yet assembled, could you measure these voltages ? Another noob question: Could it be a capacitor ? If so, is there a way to measure ? I replaced ZD101 with a 6.2V zener: 1N4735A. That is the zener that will stay there.

Darek.S · Answer

Sorry no. My problem was ZD101 and I don't touch ZD102. But what problem to desolder it and measure. There might be some mark on it so You can know what is the value. As I remember on my ZD101 was colour Bar Code...

Dodano po 4 [godziny]:

LucasBS wrote:

If your projector was not yet assembled, could you measure these voltages ?

sorry I gave the device back this time and don't have it tlil this time...

LucasBS · Answer

Bought a new supply. Measured all that I could before sticking it on the projector. Attached I'll stay tuned in case someone has a similar problem. I still have the old board.

E116921 Power Supply - Does not work even after parts replaced

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