mercury pc power supply only 5vsb supply.

[playit]

Re: mercury pc power supply only 5vsb supply.

back with 5vsb ,it was broke positive white wiring,fixed it and back with 5vsb .

[playit]

Re: mercury pc power supply only 5vsb supply.

this time i checked carefully ..the transistor-- the horizontal - black at base- 676- 699
reversed gave- red at base -1749 - 1852
the vertical at base- continuous beep - black at base- continuous beep-value decreases- o-1812
reversed gave - red at base- continuous beep value 0 - 362

[playit]

Re: mercury pc power supply only 5vsb supply.

The diodes D25-D29 are in a different circuit than the diodes near R23.

yes they give readings when read together, but the d9-d10 doesnt give reading like that.. did i fix it wrong... d9 was the one dint give any reading,i removed it and replaced it with ph4148

also could you please compare the old and new R23 areas.. i doubt the jumper/R23/d9 was together soldered ???

[R_J]

Re: mercury pc power supply only 5vsb supply.

The diodes D25-D29 are in a different circuit than the diodes near R23.

[playit]

Re: mercury pc power supply only 5vsb supply.

A 1n4148 is not a zener diode, When checking a transistor or diode with diode test, a silicone junction usually reads about .6xx in diode test. (this number is the voltage drop across the junction) meters with continuity "BEEP" will beep betwen 0 and 150Ω.

oh ok ,thanks.. this psu got my nerves..i just dont want give it up until something very bad has happened to it ..like it just cant be fixed at all! its just we nearly repaired it well but then i spoiled it.. its so not acceptable

[playit]

Re: mercury pc power supply only 5vsb supply.

in the mean time..i will test the diodes ,transistors again,i have an doubt are R23- R32- jumper are connected someway in the middle,i see a little copper head there,
also i want to ask you about this pair 4148 zeners, the pair which is d25,d29. i get reading when i touch negative of d25 and positive of d29 ,as if they working in pairs, but i dont get the same reading for zeners pair near R23 like working in double,but ok when i measure single

[R_J]

Re: mercury pc power supply only 5vsb supply.

A 1n4148 is not a zener diode, When checking a transistor or diode with diode test, a silicone junction usually reads about .6xx in diode test. (this number is the voltage drop across the junction) meters with continuity "BEEP" will beep betwen 0 and 150Ω.

[playit]

Re: mercury pc power supply only 5vsb supply.

oh you replied i dint see it, transmitter game me one continuous beep ,also there is another problem now..the circuit slided and fell 2 times ,then no power came to board,no 5vsb,then i tried to switch on from back,the switch clip was broken loose,now i will get it ,and try again for the voltages.. is there anything else i should try checking again before i list components to be bought ?
also i found one of the 4148 zener diode(in pairs) was dead-no reading ,it was at place of R23. i replaced with ph4148

[playit]

Re: mercury pc power supply only 5vsb supply.

hi RJ this is how it looks now.. i tried my best to put the resistor on R23 and to the jumper ,as no pads are there,they got lifted and teared.. i am sorry i am asking too much.. please do reply when you have time,thanks

[R_J]

Re: mercury pc power supply only 5vsb supply.

How many "beeps" give you a reading of .6xx in diode test?

[playit]

Re: mercury pc power supply only 5vsb supply.

Check the parts with power disconnected. check that none of the parts are shorted.
Check the diodes and transistors using diode test on your meter, The reading is usually around .6xx for a diode one way and open the other way. for the transistors check them from base to collector and base to emitter, then reverse the leads and repeat the test, then check between collector and emitter (this should check open)

i repeated transistor test..i get beep somewhere.. does it mean open? i mean is it bad..its different from before..the result isnt same as before.. should i get new ones? thanks

[playit]

Re: mercury pc power supply only 5vsb supply.

i joined few wires and put the filter capacitors,its the same problem now..i am getting same 5vsb ,and no other voltages.. i get 16v at one side of resistor but not on other side.. which has continuity to jumper..,checked with other resistor too i get the same result.. pls help..i am stuck

[sam_sam_sam]

Re: mercury pc power supply only 5vsb supply.

Just learn how to take your time and not be in a hurry and think about how you are going to complete the task at hand

I have done this before myself and things did not turn out well

Things turn out a lot better when you take your time and do not get frustrated about what you are doing

[playit]

Re: mercury pc power supply only 5vsb supply.

hi R_J i have bought 330uf/200v as i dint get 250v .. i think i fried a capacitor ,a zener diode at R23 place ..i want to use this opportunity to learn with this circuit..i am sorry i have been a bad student here for you.. i am going to fix all those broken caps and try hook up wires on R23 to 1.5k resistor to jumper again..saw some youtube vids ..hope i get to some point.. atleast i will practice these skills.. i felt bad you have been patient and teached me well and i broke it even after it worked ! so i want to make it up and rise once again.

[playit]

Re: mercury pc power supply only 5vsb supply.

hi,sorry for not late reply, i dint find resistor nearby in my stupid place ..thats how my stupid country is. and so i bought online some parts resistors and capacitors ,as you said i put the resistor and it started working and it stopped becoz the solder came out,its too difficult to solder with my big solder point ..
then this time when i tried to solder the whole strip came off teared apart.. i count do anything ,then i got carried away frustrated.. shorted from near by 16volts to other end ,nothing came up ..got angry and threw and broke it .. i lost my cool ..i had much hopes ..but this damm big solder broke it.. by the way thank you so much. i learned so much from you and these days..hope i buy proper tools from now on and practice in my free time.thank you

[R_J]

Re: mercury pc power supply only 5vsb supply.

That cap is only for the standby 5 volts, so it should be ok.

[playit]

Re: mercury pc power supply only 5vsb supply.

this 16v 1000 microfarad capacitor was bulged-- the capacitor you marked in yellow, the center one near the transformer. i wasnt sure if i soldered it in reverse polarity ,as i searched they said reverse polarity capacitor could burst so then i soldered the other capacitor (16v 1000 microfarad ) at correct polarity..then it dint burst .

[R_J]

Re: mercury pc power supply only 5vsb supply.

Which capacitor did you replace that was bulged and that blew up after you replaced it? What was the voltage on the capacitor they gave you?
You should have mentioned this as it might point to other problems

[playit]

Re: mercury pc power supply only 5vsb supply.

thank you ,nice explanation,tomorrow i am gona get the resister and caps too then,if incase needed,by the way.. at first when i opened -- this 16v 1000 microfarad capacitor was bulged ,so i thought to replace it,at shops nearby i dint get the right volts of the same type,so replaced it from a old dead motherboard..
at first i am not sure if mis-soldered the polarity..i swtiched it on-- the capacitor burst !
then i again took other capacitor and placed it..but anyway.as you said i will buy all those caps ,just wanted to let you know if it might help more.

[R_J]

Re: mercury pc power supply only 5vsb supply.

Stop worrying about the Red and brown diodes I marked, They are ok, good, have no problem, are fine, not bad. If they were bad you would not have any 5 volt standby at all.
The diode I marked in pink checks fine also, it is supplying the 16 volts in standby that you measured on the one side of R23
I would replace the three caps (red circle) in the primary and the three in the secondary. this is a minimum, If the power supply works, then I would consider replacing all the small caps and maybe some of the larger ones. The small caps dry out fast and go open and don't usually leak or bulge so the get overlooked.