Dreamcast PSU Fuse problem

Yeah, those numbers after the logo are date and trace codes. They can be basically anything, and the formats often vary - if it's 3 digits, then it's probably going to be <last digit of year><week in that year>.

 

Oh I see, that makes sense. Thanks a lot for all your help, I've ordered both things on aliexpress, I'll let you know if the Dreamcast finally starts to boot up after replacing those parts. Of course, the hardest part is probably going to be the wait, and considering the time of the year, I fear it's going to take quite a while for them to show up on my doorstep. Thanks so much once again!

 

Both replacement parts have finally arrived, the DF08M came a bit earlier, and just to check I replaced the old one with a new one, and the problem still persists. I got delivery of my 2SK2129 today, and I was going to replace it, but I had a look at the board again and I saw two resistors kind of soldered together. Could this actually be the problem and not any other components? I did have a look at the board multiple times beforehand, but I never noticed this before. I'll wait for a reply before I go about replacing the 2SK2129, perhaps I won't need to expose the board to unnecessary heat? Thank you.

 

No, looks like those parts are connected via the pcb anyway. So having the solder there does no harm.

 

Oh I see, thank you for the advice Bad_Ad84. I did change the 2SK2129, and checking the original piece it was definitely faulty. Unfortunately even after installing the new one, the Dreamcast still has the same fuse blowing problem. Does anyone have any idea what else isn't working properly?

 

I hate to mention it, but is the plastic shield in place underneath the supply?

Otherwise, those boards tend to develop cracks near the spot where the little tab snaps it in to place on the side. Look REALLY closely for hairline cracks on either side of the board around that spot. Wiggle every capacitor on the board as well checking for dry or cracked joints, again paying close attention especially at that same spot.

 

Thanks for your advice squeept, yes the plastic shield is in place underneath the supply, and luckily there are no cracks in the board, or cracked/dry joints. Do you have an idea what else could be going wrong? Thank you!

 

OK, the first thing you should do at this point is see if the replacement 2SK2129 has also been destroyed. If it has, then presumably something else on the PSU is damaged and taking out the switching device. In that case, I suggest you try to find a replacement power supply, since it's a difficult thing to diagnose remotely and we have already tried all the easy solutions.

 

Thank you TriMesh, I had a look and the new 2SK2129 doesn't seem to be damaged so I think another component has quite possibly failed. Do you think it is fairly easy to diagnose and fix the problem, or do you recommend i go for a replacement power supply? Thank you!

 

Sorry to trouble you after all this time, I guess my power supply problems aren't really fixable. Do you still happen to have that spare Dreamcast PSU? I am from the UK, I am hoping you are too!

 

Hey man. Been following the thread in the hope that u solve the mystery. That's bizarre that the fuse is still blowing. Does It blow straight away, are u unable to check components 'downstream' of the fuse while the psu is powered?

I'm in UK. I've got 2 PAL psu, I just need to check them. I'll pm u details.

 

Ah I see, its turned out to be an interesting journey to be honest. Yeah the fuse blows almost instantaneously when I try to switch the Dreamcast on, even after replacing those components. Ah thats swell, thank you very much for your help, hope to hear from you soon!