mercury pc power supply only 5vsb supply.

[playit]

Re: mercury pc power supply only 5vsb supply.

oh thers a mistake in my post 19.i misunderstood the both sides wrong and i tested one of r32 which showed 16v, and by the way.. only one side of r23 shows 16v and 0.6 v at other side of r23 which connects with jumper.

[R_J]

Re: mercury pc power supply only 5vsb supply.

Then R23 is open, I don't know what it's value would be, it might be a 1.5k ½watt. I checked a couple schematics and they both used a 1K in that position. Before replacing it, Check the two diodes on the other side of of the board of R23. Also check the two transistors and the 2 diodes that are connected to that drive transformer.

[playit]

Re: mercury pc power supply only 5vsb supply.

what to chek in 2 diodes ,transistors? what reading should i see? volts or continuity?
what points to check in transistors?

[R_J]

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)

[playit]

Re: mercury pc power supply only 5vsb supply.

the red(big) and brown colored big diode you marked gives beep in continuity (50 number at both sides) , pink color diode- gives 450 negative probe to positive probe and reversed gives 1526 .

transistor vertical pins - black probe in middle- 690 and 537 ,reversed gives 1144 at one side and nothing at other side.
transistor horizontal pins- black probe in middle- 600 and 542,reversed gives 1155 at one side and nothing at other side.

[R_J]

Re: mercury pc power supply only 5vsb supply.

All those components are likely ok, I ment to check the diodes I marked green and the transistors on the drive transformer, if those transistor readings were for those transistors, they are likely ok. I would try replacing that R23 with a 1.5K and see what happens.

[playit]

Re: mercury pc power supply only 5vsb supply.

oh ok , will get the resister after few hours here and the diodes reading marked in green-- horizontal zener diode- negative probe to positive- 520 and reversed 1072.
vertical zener diode - -ve to +ve probe- 523 and reversed 1073,are they ok?

[R_J]

Re: mercury pc power supply only 5vsb supply.

There is only one zener diode that I marked, it is ok because you have +5 volts on it. The other diodes I marked are just regular glass diodes, likely 1N4148. there were two next to R23 and two next to the transistors (I marked EBC)

[playit]

Re: mercury pc power supply only 5vsb supply.

i checked three orange diodes around that transistor(zener glass diodes i guess),they all gave readings similar to post #27, and the 2 orange diodes closer to r23 gives reading around 523 only when with negative to positive ,reverse gives no reading.

[playit]

Re: mercury pc power supply only 5vsb supply.

i dint get the resister in my area will have to go 1 hour journey to get that ,is there anything else i would have to buy .. and in post #25 "the red(big) and brown colored big diode you marked gives beep in continuity (50 number at both sides) , pink color diode- gives 450 negative probe to positive probe and reversed gives 1526 "

is it ok for a diode to give same number and beep at both sides?

[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.

[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.

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.

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.

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

[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

[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.

[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.

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

[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