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Then swap it out and see what happens
It's certainly bad... can't say for sure the other ones...
Why don't you just buy a 'universal' 12V adaptor from a local electronics/hobby shop?
I don't like to encourage fixing devices that operate on mains
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This one from Sears would seem adequate. Cost is $22.18 plus shipping. There may be others, cheaper. How much is your time worth?
73's de Edd
- Aug 21, 2015
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.
Sir pharaon . . . . . . .
YES . . . that 5.6 ufd unit is the first suspect, with its visible rupturing.
The green one beside it is oriented such that I can't read its capacitance and voltage rating . . .what is it ?
73's de Edd
.
Sir pharaon . . . . . . .
YES . . . that 5.6 ufd unit is the first suspect, with its visible rupturing.
The green one beside it is oriented such that I can't read its capacitance and voltage rating . . .what is it ?
73's de Edd
.
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73's de Edd thanks alot for you help again
and for every one i fix it because it's a hobby and i like to learn alot
and for every one i fix it because it's a hobby and i like to learn alot
i did replace it with another one 10uf and 450v still no output
its 10uf 400v
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That's a great way to learn. And since it's a hobby. it's also a labor of love... no monetary reward expected or desired other than saving the cost of a replacement power supply if you can obtain the capacitors inexpensively. Best wishes for your success!
Check the diodes, and also the mosfet.
I'm not sure if there's an on-board fuse, but the failure of a rectifier diode is something that can cause catastrophic failure of the 400V capacitor -- and this one did not die a slow death. This sort of failure often results in a fuse (sooner or later -- depending on the topology) blowing.
What does that brown rectangular component between the dead cap and the heatsink have printed on it?
And did you remove the MOVs?
I'm not sure if there's an on-board fuse, but the failure of a rectifier diode is something that can cause catastrophic failure of the 400V capacitor -- and this one did not die a slow death. This sort of failure often results in a fuse (sooner or later -- depending on the topology) blowing.
What does that brown rectangular component between the dead cap and the heatsink have printed on it?
And did you remove the MOVs?
73's de Edd
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Sir pharaon . . . . . . .
The MJE13005 is a high voltage, hi speed switching, NPN bipolar transistor .
Looking at the AC power half of the board at at D7 and D8 diodes, over towards the smaller ferrite cored transformer . . . .do I seem some carbonization deposit ?
Also under very bright lighting and magnified examination . . . are there any floating solder ring joints in the power transistor area ?
Seeing the way the 5.6 was used in the units circuitry , I would also suggest subbing in another cap, in place of the mentioned green one.
I see board marked provisions for two unused MOV1 and MOV2, but at the BROWN wire AC line input, isn't there a foam blob covering up your AC line input fuse ?
73's de Edd
The MJE13005 is a high voltage, hi speed switching, NPN bipolar transistor .
Looking at the AC power half of the board at at D7 and D8 diodes, over towards the smaller ferrite cored transformer . . . .do I seem some carbonization deposit ?
Also under very bright lighting and magnified examination . . . are there any floating solder ring joints in the power transistor area ?
Seeing the way the 5.6 was used in the units circuitry , I would also suggest subbing in another cap, in place of the mentioned green one.
I see board marked provisions for two unused MOV1 and MOV2, but at the BROWN wire AC line input, isn't there a foam blob covering up your AC line input fuse ?
73's de Edd
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Attachments
yes i was soldering the capacitor legs to the board
no there is not
you want me to change the green cap" 10uf 400v"?
yes but it's just wire
73's de Edd
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Confirm if 2AL. 250 might be a blown 2A slow blow chemical fuse, since the other was a jumper wire.
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Have you discovered a chemical (acetone, perhaps) that will dissolve the foam material? There are probably zillions of wall-wart power supplies out there in need of repair.
i toke it out of the circuit and open it
that's how it look like..although there's no short between the two legs when i measure with the multimeter
73's de Edd
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Sir pharaon . . . . . . .
Can you "remote" that new PHYSICALLY LARGER electrolytic with leads or use another full leaded length one temporarily.
You have 2 diode leads now pressed right up against its 5 mil insulative film . . .then they are susceptible to making contact with the aluminum outer shell of the electrolytic .
Typically you would suspect those four diodes as being the raw DC power source to that blown cap that you replaced.
Taking out any series fuse . . . . as is being described.
What are the chances of that being some polypropylene "rope" being affixed between the opposing posts and some fusing wire having been routed in its furrows as shown in RED.
Which now has vaporized . . .excepting some possible remaining wire tip blobs.
Since you provide GOOD photos, how about just almost completely filling up a screen with a straight top on and straight bottom on shot of the component and the foil side of that board .
I want to confirm either:
Its being either Power oscillator related / or / symmetrical AC power line choke function . . .for that smaller ferrite cored transformer.
Currently . . . . I'm HEAVILY leaning towards it being the latter.
Are you almost ready to get the test ball rolling with the sub in of a 60W incandescent lamp, connected in circuit with use of test leads , to shunt that pulled fuses solder in terminals.
Then do an ac power up test.
Expecting a short dim activation of the lamp on turn on.
And if it was working expect there to be a residual, declining DC voltage at the other half of the boards output section.
Just now noticed your RED CIRCLED diode with its lower forward voltage , don't worry, that is being on the "cold" / AC isolated side of the PCB and is working at HIGH switching speeds . . .thus the use of a Schottkey family of diodes in that application . . . . which have that lower forward voltage characteristic.
73's de Edd
Can you "remote" that new PHYSICALLY LARGER electrolytic with leads or use another full leaded length one temporarily.
You have 2 diode leads now pressed right up against its 5 mil insulative film . . .then they are susceptible to making contact with the aluminum outer shell of the electrolytic .
Typically you would suspect those four diodes as being the raw DC power source to that blown cap that you replaced.
Taking out any series fuse . . . . as is being described.
- THE FUSE:
What are the chances of that being some polypropylene "rope" being affixed between the opposing posts and some fusing wire having been routed in its furrows as shown in RED.
Which now has vaporized . . .excepting some possible remaining wire tip blobs.
Since you provide GOOD photos, how about just almost completely filling up a screen with a straight top on and straight bottom on shot of the component and the foil side of that board .
I want to confirm either:
Its being either Power oscillator related / or / symmetrical AC power line choke function . . .for that smaller ferrite cored transformer.
Currently . . . . I'm HEAVILY leaning towards it being the latter.
Are you almost ready to get the test ball rolling with the sub in of a 60W incandescent lamp, connected in circuit with use of test leads , to shunt that pulled fuses solder in terminals.
Then do an ac power up test.
Expecting a short dim activation of the lamp on turn on.
And if it was working expect there to be a residual, declining DC voltage at the other half of the boards output section.
Just now noticed your RED CIRCLED diode with its lower forward voltage , don't worry, that is being on the "cold" / AC isolated side of the PCB and is working at HIGH switching speeds . . .thus the use of a Schottkey family of diodes in that application . . . . which have that lower forward voltage characteristic.
73's de Edd
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i really didn't get what do you want me to do exactly
didn't get it..you want me to connect 60w lamp to the circuit where the red fuse is connected?
73's de Edd
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Sir pharaon. . . . . . .
The two topics that you were having trouble with were :
<-> When you installed that new capacitor, it was so LARGE that two diode leads carrying 220VAC were pressed into the capacitor.
There was ONLY the very- very thin plastic wrap around the capacitor that was keeping the leads from shorting to the aluminum metal shell of the capacitor . Capacitor go BOOOOM.
<-> On the lamp . . . . I won't say that is a good idea but an EXTREMELY good idea to substitute in a 60 watt incandescent lamp in place of the RED fuse when working with that power supply, after having replaced some critical parts. But you don't know that you have found ALL of the bad parts.
The lamps cold filament is going to initially let a decent amount of AC power into the circuitry.
Then two things are ready to happen :
If things are normal, the circuit will start to try to work by the functioning rectifier diodes starting to charge up the main power supply filter capacitor.
That will show up as a quick slightly dull glow of the lamp and the lamp will then dim because there isn't enough power passing through to fully operate the power switching transistor.
The other possibility is that there is still a bad capacitor shorted diode or power transistor and this heavy power demand will cause the lamp to go to high brightness.
If experiencing the latter situation you go back and see what faults are still there.
Had this last test situation been done with a fuse in circuit, even that short time before the fuse blew could have taken out the same replaced parts or EVEN more parts.
Using your supplied photos for this back / front board markup:
I see you finding 2 of the four diodes used in the main power supplys Full Wave Bridge circuitry as bad units .
In my finding of that situation I always get four of a kind of the same diodes and replace all four . So that they will be matched to each other.
If they are readily available to you, I would use four 1N4007 diodes. Save the two old diodes that are good and you can use them in the future, in circuitry where only one diode is used.
When you test with the lamp in place of the RED fuse there is a good possibility that during that dull red glow of the lamp that enough power activated the power transistor that it started
to generate some voltage for the secondary large filter capacitor. Measure to see if there is still a little charge on that capacitor,whereas there would have been NO voltage on it before.
I would then attempt power up with a conventional 1-2 amp used in place of the special RED fuse .
Looking at all of your board, and now knowing of some of its failed parts, I think that your power line experienced a lightning strike VERY near to your house and popped these parts.
Hopefully . . . . none of the somewhat more isolated parts on the secondary circuitry were affected .
Your boards F / B markups:
Around your already replaced parts and parts to be replaced:
Can you use some denatured alcohol and a brush to clean the area that you are going to solder on, use a drop of Rosin flux on the joint that you are going to solder and be sure that your soldering iron tip is well tinned and shiny every time before making a solder joint.
Then you use the denatured alcohol again after soldering to immaculately clean up that soldered joint. Then you will have done a PERFECT job.
73's de Edd
The two topics that you were having trouble with were :
<-> When you installed that new capacitor, it was so LARGE that two diode leads carrying 220VAC were pressed into the capacitor.
There was ONLY the very- very thin plastic wrap around the capacitor that was keeping the leads from shorting to the aluminum metal shell of the capacitor . Capacitor go BOOOOM.
<-> On the lamp . . . . I won't say that is a good idea but an EXTREMELY good idea to substitute in a 60 watt incandescent lamp in place of the RED fuse when working with that power supply, after having replaced some critical parts. But you don't know that you have found ALL of the bad parts.
The lamps cold filament is going to initially let a decent amount of AC power into the circuitry.
Then two things are ready to happen :
If things are normal, the circuit will start to try to work by the functioning rectifier diodes starting to charge up the main power supply filter capacitor.
That will show up as a quick slightly dull glow of the lamp and the lamp will then dim because there isn't enough power passing through to fully operate the power switching transistor.
The other possibility is that there is still a bad capacitor shorted diode or power transistor and this heavy power demand will cause the lamp to go to high brightness.
If experiencing the latter situation you go back and see what faults are still there.
Had this last test situation been done with a fuse in circuit, even that short time before the fuse blew could have taken out the same replaced parts or EVEN more parts.
Using your supplied photos for this back / front board markup:
I see you finding 2 of the four diodes used in the main power supplys Full Wave Bridge circuitry as bad units .
In my finding of that situation I always get four of a kind of the same diodes and replace all four . So that they will be matched to each other.
If they are readily available to you, I would use four 1N4007 diodes. Save the two old diodes that are good and you can use them in the future, in circuitry where only one diode is used.
When you test with the lamp in place of the RED fuse there is a good possibility that during that dull red glow of the lamp that enough power activated the power transistor that it started
to generate some voltage for the secondary large filter capacitor. Measure to see if there is still a little charge on that capacitor,whereas there would have been NO voltage on it before.
I would then attempt power up with a conventional 1-2 amp used in place of the special RED fuse .
Looking at all of your board, and now knowing of some of its failed parts, I think that your power line experienced a lightning strike VERY near to your house and popped these parts.
Hopefully . . . . none of the somewhat more isolated parts on the secondary circuitry were affected .
Your boards F / B markups:
Around your already replaced parts and parts to be replaced:
Can you use some denatured alcohol and a brush to clean the area that you are going to solder on, use a drop of Rosin flux on the joint that you are going to solder and be sure that your soldering iron tip is well tinned and shiny every time before making a solder joint.
Then you use the denatured alcohol again after soldering to immaculately clean up that soldered joint. Then you will have done a PERFECT job.
73's de Edd
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sir 73's de Edd
here's what happen
i connect the 100W lamp in the place of the red fuse. the lamp didn't light not even a little. then i connect the multimeter to the output jack of the adapter to see if it's working and when i connect it the multimeter gave me a reading of 12 v as an output. after few seconds of connecting the multimeter to the output jack the "lamp" light a little then went off as you said but then the 10uf 400 v capacitor got so hot and fail as the old one.
what do you think is the cause to make the capacitor failed when i tried to measure to output volte for few seconds
here's what happen
i connect the 100W lamp in the place of the red fuse. the lamp didn't light not even a little. then i connect the multimeter to the output jack of the adapter to see if it's working and when i connect it the multimeter gave me a reading of 12 v as an output. after few seconds of connecting the multimeter to the output jack the "lamp" light a little then went off as you said but then the 10uf 400 v capacitor got so hot and fail as the old one.
what do you think is the cause to make the capacitor failed when i tried to measure to output volte for few seconds
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I would suggest your rectifiers have failed (again).
A 100W bulb is probably too large. I would have started with about 15W.
Ensure your rectifiers are appropriately rated. 400V would be the absolute lowest I would use.
A 100W bulb is probably too large. I would have started with about 15W.
Ensure your rectifiers are appropriately rated. 400V would be the absolute lowest I would use.
so i should use > 400.V Diodes? right
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