Tecnoware FAL501FS12 does not turn on

[CapLeaker]

Re: Tecnoware FAL501FS12 does not turn on

I guess that mystery is solved now.

[falcontech]

Re: Tecnoware FAL501FS12 does not turn on

Hi
I changed the resistances, now the voltage on the large capacitors has stabilized, but the power supply still does not start, I try to change some capacitors and I update you

[falcontech]

Re: Tecnoware FAL501FS12 does not turn on

I replaced all the capacitors, even the small ones under the heatsinks, except one under the heatsink of the secondary that I did not have (220uf 50V) but still not showing signs of life, I checked the schotty diodes and they are good no signs of short, I have always and only 5v standby, what do i do?

[falcontech]

Re: Tecnoware FAL501FS12 does not turn on

on pin 12 of the KA7500 I have 16.5 volts

[R_J]

Re: Tecnoware FAL501FS12 does not turn on

Pin# 12 (vcc) is supplied by the standby transformer, Check the voltage on the driver transformer (arrowed) Also check the voltage on the two transistor bases.
What is the number on the other ic in the secondary?

Use the Secondary Ground to check all voltages on the secondary side (black probe on ground)
This schematic might be close.

[falcontech]

Re: Tecnoware FAL501FS12 does not turn on

Pin# 12 (vcc) is supplied by the standby transformer, Check the voltage on the driver transformer (arrowed) Also check the voltage on the two transistor bases.
What is the number on the other ic in the secondary?

ok, I have to put the black tip on the mass and test with the red one the points you have indicated to me? if I'm not mistaken the second ic is lm339n for safety in a while I look

[falcontech]

Re: Tecnoware FAL501FS12 does not turn on

Pin# 12 (vcc) is supplied by the standby transformer, Check the voltage on the driver transformer (arrowed) Also check the voltage on the two transistor bases.
What is the number on the other ic in the secondary?

Use the Secondary Ground to check all voltages on the secondary side (black probe on ground)
This schematic might be close.

I don't understand what the secondary ground is

[R_J]

Re: Tecnoware FAL501FS12 does not turn on

I don't understand what the secondary ground is

You don't understand the difference between the primary side of the power supply and the secondary?
The primary side is connected to the mains high voltage and could be deadly if you don't know what you are doing.

[falcontech]

Re: Tecnoware FAL501FS12 does not turn on

You don't understand the difference between the primary side of the power supply and the secondary?
The primary side is connected to the mains high voltage and could be deadly if you don't know what you are doing.

absolutely, you did not understand me, I know that well, I want to understand how to manage the tester's test leads on the indications you gave me, as I asked you, should I put the black test lead on the mass and with the red test test the points indicated on the photo? it's a test I've never done

[falcontech]

Re: Tecnoware FAL501FS12 does not turn on

See the picture

[R_J]

Re: Tecnoware FAL501FS12 does not turn on

Yes this is correct placement of the probes, The schematic in post#45 should be closer to your power supply

[falcontech]

Re: Tecnoware FAL501FS12 does not turn on

ok,If it can be useful, the second ics is an lm339ld

[falcontech]

Re: Tecnoware FAL501FS12 does not turn on

Then with the power supply in standby the voltages are these
Driver transformer (yellow arrow) 1,50v
B 2.25v
E 1.50v
B 2,25v
With the power supply running
Driver Transformer (Yellow arrow) 1,85v
B 1.50v
E 1.47v
B 1.52v

[falcontech]

Re: Tecnoware FAL501FS12 does not turn on

what should i check now?

[R_J]

Re: Tecnoware FAL501FS12 does not turn on

That voltage for the driver transformer (arrow) is low, look at the schematic (R12 2.7k) and follow the line on your board, it should have 16v on one side of that resistor. Also check the 2 transistors and the diodes connected to that drive transformer.

[falcontech]

Re: Tecnoware FAL501FS12 does not turn on

Transistors and resistors on the secondary or primary? forgive me but on that scheme I understand very little because it is not structured like my atx, sorry and have patience thanks, if you want I send you a photo without heatsinks

[R_J]

Re: Tecnoware FAL501FS12 does not turn on

A picture without the heatsink would help, The transistors to check are on the secondary (I marked the emitters with a E, and the base with a B and the collectors with a C. The transformer on your board (under the yellow arrow) is T2 on the schematic.
This part of the schematic is closer to your board than you can see.

[falcontech]

Re: Tecnoware FAL501FS12 does not turn on

Okay, now I'll send you a photo without heatsinks

[falcontech]

Re: Tecnoware FAL501FS12 does not turn on

here she is
to the eye it does not seem to me that there are open resistances

[falcontech]

Re: Tecnoware FAL501FS12 does not turn on

I checked the diodes and they are good, the resistances are good too, the transistors are c945, I tried the first one and I have the same value on E and C (i.e. about 618), on the other I noticed a strange thing about C gives me 618 on E 360, what do you say?