Buy broken Takasago power supply or not?

[Mr. Scram]

I almost think the internet is a hindrance to learning electronics.  When I learned electronics there was no internet and no one to talk to, I had to read and experiment.  The OP seems to have done is deprive this supply from someone that could use it.  He has just given up at not finding a bad fuse.  Uploading detailed pictures just screams of fix this for me while I sit back. I have no interest in tracing out boards over the internet. I understand that it is easy to look at a mass of parts and think it is just black magic. Diagnosis is an art.  You make a list of what you know and what you don't know about the problem. A power supply is just made up of a bunch of simple blocks. It is a logic chain you work through.  A bad photo tells you enough, look in this section. Don't think the OP has detailed the problem beyond "It's broken."  The OP needs to step up and approach this logically.

The beauty of learning to troubleshoot is that it's a universal skill. If you can troubleshoot one thing, you can troubleshoot another. Though it helps to have specific knowledge on the subject, it's not actually needed to get anywhere.

[CJay]

I almost think the internet is a hindrance to learning electronics.  When I learned electronics there was no internet and no one to talk to, I had to read and experiment.  The OP seems to have done is deprive this supply from someone that could use it.  He has just given up at not finding a bad fuse.  Uploading detailed pictures just screams of fix this for me while I sit back. I have no interest in tracing out boards over the internet. I understand that it is easy to look at a mass of parts and think it is just black magic. Diagnosis is an art.  You make a list of what you know and what you don't know about the problem. A power supply is just made up of a bunch of simple blocks. It is a logic chain you work through.  A bad photo tells you enough, look in this section. Don't think the OP has detailed the problem beyond "It's broken."  The OP needs to step up and approach this logically.

I think it's often used as a quick fix for those who can't be bothered, seen it here a lot, people who want physics to be how they decide it has to be, people who think it's too geeky to learn so they come find the geeks and ask them, then you get the posts where everyone joins in with a dozen different theories which just serve to confuse the OP and cause arguments.

Then there are threads like the 386 motherboard thread or the building my own Z80 SBC thread which are works of beauty, complete end to end solutions (that's not to say there aren't other threads that are, they're just the recent ones I've seen) or other threads where it's obvious almost immediately that the OP is genuinely keen and interested, they all make the time waster threads worth putting up with.

The main barrier to learning electronics is the person who is trying to learn, if they don't want to or just aren't able to learn the subject then they just won't, it doesn't matter how many people try to help them.

[cdev]

These two posts capture the essence of the process for me too. You don't need to know everything there is to know about something.

First you collect information on what is happening when power is applied with your DMM and compare it to what is supposed to happen as laid out in the datasheets for its individual parts. You can also make some additional tools . Since your board is a switching power supply, be careful.

As it has at least one microprocessor on it, you will want to see if the microprocessor(s) has any "heart beat". This may not be as easy without an oscilloscope as it would be with one. Especially, watch out for high voltages. If you plan on doing electronics a lot, try to find a deal on an older scope.

That will give you a good start on it.  Keep in mind the sage advice to doctors. "First do no harm". Don't break anything additional. Use common sense and think when probing the board. Measuring voltages properly is unlikely to cause any damage. Check if voltages that are supposed to power various parts are even there. If they are not, its likely there is your problem.

Even parts that are soldered to a PCB are replaceable. Just watch how Louis Rossman does i in his Youtube videos. (To do that you will need to invest in tools to do it but they are not so super expensive that its difficult. Several tools that work well, either alone or combined with your regular soldering iron are a digital hot plate for preheating, a controlled temperature hot air gun, and ChipQuik: low melting point solder for removing SMD parts, all individually can be quite cheap)

If you fix it - every time you use it you'll get a jolt of satisfaction from having done it.

I understand that it is easy to look at a mass of parts and think it is just black magic. Diagnosis is an art.  You make a list of what you know and what you don't know about the problem. A power supply is just made up of a bunch of simple blocks. It is a logic chain you work through.  A bad photo tells you enough, look in this section. Don't think the OP has detailed the problem beyond "It's broken."  The OP needs to step up and approach this logically.

The beauty of learning to troubleshoot is that it's a universal skill. If you can troubleshoot one thing, you can troubleshoot another. Though it helps to have specific knowledge on the subject, it's not actually needed to get anywhere.

[Asuka]

Hate to see you just give up.

I have not given up. I'll post again in January 2018.

[massivephoton]

I've taken a photo of the main board but didn't attach it yesterday. I had to shrink it to 50% of the size so that it was postable to the forum.

Could that green wire connecting Pin 8 of CN2 to what looks like a smd resistor indicate it was repaired earlier?
If so, this could hint what was wrong.

It's already 2018, time for another try!

[Asuka]

I've taken a photo of the main board but didn't attach it yesterday. I had to shrink it to 50% of the size so that it was postable to the forum.

Could that green wire connecting Pin 8 of CN2 to what looks like a smd resistor indicate it was repaired earlier?
If so, this could hint what was wrong.

It might be that, but I can think of other explanations. For example, this is one of a range of models, so to save manufacturing cost, all the models use the same control circuit board, then they solder a wire between two points after the manufacture of the board to indicate to the board what particular power board it is controlling.

It's already 2018, time for another try!

I'll post something before the end of January, as promised above.