Tecnoware FAL501FS12 does not turn on

[falcontech]

Re: Tecnoware FAL501FS12 does not turn on

Yes ok

[CapLeaker]

Re: Tecnoware FAL501FS12 does not turn on

check Q3 and Q4 plus the components in that area

[falcontech]

Re: Tecnoware FAL501FS12 does not turn on

Ok thank you

[CapLeaker]

Re: Tecnoware FAL501FS12 does not turn on

basically pin 8 and 13 are driving Q3 and Q4. Then it goes through tranformer t2 and drive the big transistors Q1 and Q2. It continues through transformer T1 and then all gets rectified on the secondary (low voltage side).

[falcontech]

Re: Tecnoware FAL501FS12 does not turn on

ok thanks tomorrow i try

[falcontech]

Re: Tecnoware FAL501FS12 does not turn on

I looked at the circuit, q3 and q4 are the transistors that I have already replaced so they are new I saw that nearby there are capacitors that I have already replaced and diodes but they are all good, the visible resistances are good

[CapLeaker]

Re: Tecnoware FAL501FS12 does not turn on

r11 and r12 are good too? check the winding on the transformer and if all checks out ok, we have to go to the next stage.

[falcontech]

Re: Tecnoware FAL501FS12 does not turn on

please if you can tell me what these resistances are on my photo, I have a little trouble understanding that scheme thanks

[CapLeaker]

Re: Tecnoware FAL501FS12 does not turn on

check again Vcc on pin 12 on the KA7500, and then measure each voltage rail, while turning the PSU on and off again on each rail. I am looking to see if the PSU actually tries to come on but is getting held back or something is open. I am looking for minimal voltages on any of the output rails -12V, +12V, -5V, +5V and 3.3V.

[falcontech]

Re: Tecnoware FAL501FS12 does not turn on

ok tomorrow i will try what you asked me now i am not in front of the psu

[falcontech]

Re: Tecnoware FAL501FS12 does not turn on

I did the tests you asked me, I have no output voltage except for the 5v standby, nothing on -12 +12 -5 +5 +3.3, on pin 12 I always have about 16.50, I have a equal power supply working and I saw that on pin 12 we have more than 18 volts

[falcontech]

Re: Tecnoware FAL501FS12 does not turn on

In a while I try to invert the two heatsinks with all the components even if they don't give me any short problem. I also eliminate this doubt.

[CapLeaker]

Re: Tecnoware FAL501FS12 does not turn on

those 18V on pin 12... is with the PSU on. What do you get with the PSU off?

[falcontech]

Re: Tecnoware FAL501FS12 does not turn on

Hi Caps I solved, it was those two resistances that I highlighted on the photo, looking at the working power supply I noticed that they were different, someone before me had replaced them by mistaking the value ... all ok thanks now I have to repair another one, there we hear on another thread THANK YOU

[CapLeaker]

Re: Tecnoware FAL501FS12 does not turn on

Very good find! We would not be able to find it, like you did. It's always harder to repair something that someone else had worked on before. You are getting good at it and soon be helping rather asking for help!

[falcontech]

Re: Tecnoware FAL501FS12 does not turn on

thanks my friend to you for your patience, however I opened another thread for another atx more or less the same, I explained them all the tests already done, I'll wait for your valuable advice