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  • Joined: 05 Mar 2021
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  • Location: UK
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DC Female Power Jack on Sega Mark III
Post Posted: Fri Mar 05, 2021 11:12 pm
I am so sorry to start a new thread if this has already been answered but I am struggling to find the answer here or elsewhere. I typically always do my research, so thank you to @Esrael for their schematics (it didnt help me as I'm useless but it was interesting).

I bought a broken Sega Mark III which appears to actually turn on but only when I hold the power jack at a certain angle, which ends up pushing the female DC connector up. It clearly needs to be replaced before I can rule out any other issues.
However, I cannot find out what part to replace it with. It looks very similar to the Master System DC jack when I opened by SMS1 but I could be wrong.

I have included a photo of the power jack to help. Could anyone point me in the correct direction? I'm in the UK, if anyone knows a place which may sell the part but any info, such as size etc, would be brilliant because if I know what I am looking at, I can certainly source it.
Some parts look similar but they could be a few millimetres off, so not right,

Thanks in advance and despite being a new poster, I'm here to stay. I only just got a Master System (1 and 2) because as kids we could afford them but as adults, life is different and I can relive the days playing on friends systems.
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  • Joined: 16 Dec 2004
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Post Posted: Sat Mar 06, 2021 12:36 am
You might just need to reflow the solder on the connector. A cracked solder joint is very common.
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  • Joined: 05 Mar 2021
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DC Female Power Jack on Sega Mark III
Post Posted: Sat Mar 06, 2021 2:03 am
Raccoon Lad wrote
You might just need to reflow the solder on the connector. A cracked solder joint is very common.


Sadly, in order to get the power light on, the whole jack must move upward when a cable is connected, so I think it needs replacing. I did consider your suggestion but it's the whole assembly which moves and the solder joint is solid.
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Post Posted: Sun Mar 07, 2021 8:22 pm
Looks to me that the DC Jack is the same as my Master system 1, which means it should be easier to find a replacement. I'll get out and buy one, then update you all.

There's an American site which sells a replacement but it doesnt list any details about it, so it might not be as easy as I thought but perhaps I'm over thinking it due to knowing little to nothing about electronics!

Size wise, it appears to be this one.
https://uk.rs-online.com/web/p/dc-power-connectors/1438915/
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Post Posted: Mon Mar 08, 2021 12:32 pm
itdoesntmatter wrote
Looks to me that the DC Jack is the same as my Master system 1, which means it should be easier to find a replacement. I'll get out and buy one, then update you all.

There's an American site which sells a replacement but it doesnt list any details about it, so it might not be as easy as I thought but perhaps I'm over thinking it due to knowing little to nothing about electronics!

Size wise, it appears to be this one.
https://uk.rs-online.com/web/p/dc-power-connectors/1438915/


Hope it works, let us know
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Post Posted: Sat Mar 20, 2021 7:20 pm
Hi again, I have removed the old part (which fell apart on removal) and ordered a new one and it comes next week but I did have a question.

Why is the through hole for the DC connector so brown? A bit of silver came off during the removal to leave a brown section on the PCB board. Is the silver old solder, or part of the PCB?

Should it be silver, or is that brown a copper layer? Sorry if it's a stupid question, I've been trying to do some research on google but I'm not getting the answer I need.

I actually had an issue with the controller port too. After a few reflow attempts, I go all but up working, then on closer inspection found the same browning on the 'UP' through hole. I ended up making the solder a little larger, which (maybe?) connected it to the trace?....that's a guess....

Could anyone offer any advice before I solder next week.
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  • Joined: 05 Nov 2014
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Post Posted: Sat Mar 20, 2021 8:31 pm
The brown is the board material itself. Those boards are made from phenolic and would have been made using a giant punch to knock all the holes and also cut it out all in one hit rather than drilling each hole separately. Its quite a brittle material and the copper will lift off it quite easily, which is whats happened where the silver bits have dissapeared. Try not to keep heat on it for too long and try running your soldering iron a bit cooler which should help
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Post Posted: Sat Mar 20, 2021 8:42 pm
wasup wrote
The brown is the board material itself. Those boards are made from phenolic and would have been made using a giant punch to knock all the holes and also cut it out all in one hit rather than drilling each hole separately. Its quite a brittle material and the copper will lift off it quite easily, which is whats happened where the silver bits have dissapeared. Try not to keep heat on it for too long and try running your soldering iron a bit cooler which should help


You're an absolute star, thanks for responding. I am new to soldering and am using non-lead solder, so turned the temp up. I think I should've invested in some better quality solder, which I will do now!

Will it be okay to solder the DC jack back over that section, or do I need to consider a repair to that part first?

Also, just noticed you're a Kiwi. Some of my family live in the Dairy Flats and I visited them last year, just before covid hit. I'm missing good quality pies. People in the UK think we do a good pie but they havent a clue until they head to NZ.
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Post Posted: Sat Mar 20, 2021 9:09 pm
Yea.. lead free solder will need to be a hit hotter.

Solder the new socket in, it should be fine. The solder will add more than enough material to make up for the missing copper.

Yea, our pies are good! You have to get them fresh from a bakery though, the frozen ones the supermarkets sell are a bit crap. I think bakerys are a nz thing too though.
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Post Posted: Sat Mar 20, 2021 9:26 pm
wasup wrote
Yea.. lead free solder will need to be a hit hotter.

Solder the new socket in, it should be fine. The solder will add more than enough material to make up for the missing copper.

Yea, our pies are good! You have to get them fresh from a bakery though, the frozen ones the supermarkets sell are a bit crap. I think bakerys are a nz thing too though.


Amazing. I will take all that on board and hopefully you'll help others too.

Yeah, your frozen ones are the one most people in the UK eat while on the go....basically, crap!

I think bakeries for pies are a NZ thing, not a UK thing. We have some nice pies in restaurants but we don't have the bakery approach you do. I've been to NZ twice and I eat at least 2 pies a day because quite frankly, you're pie legends. When I arrived last time, I forced my auntie to stop at 2 on the way home. Ha.
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DC Female Power Jack on Sega Mark III
Post Posted: Sun Mar 21, 2021 11:00 am
Before you solder, cover the pcb pads and the pins of the DC power jack with flux paste. Buy some if you don't have some already. When you solder, the flux will clean the metal and the molten solder will be drawn to it like magic.

Also apply the heat to both the pin and the pad to be soldered.

I know these 2 points sound trivial, but with soldering, the devil is in the details.
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Post Posted: Sun Mar 21, 2021 3:02 pm
asynchronous wrote
Before you solder, cover the pcb pads and the pins of the DC power jack with flux paste. Buy some if you don't have some already. When you solder, the flux will clean the metal and the molten solder will be drawn to it like magic.

Also apply the heat to both the pin and the pad to be soldered.

I know these 2 points sound trivial, but with soldering, the devil is in the details.


Thanks for the advice. I'm always nervous about touching the pad (which means I end up trying to be precise & so often ending up reflowing my work), so from now on, I'll be a little more confident.

Gotcha about flux, I bought some a few weeks back and use it liberally but perhaps I might invest in some better stuff and some better solder too. I bought flux/solder (non leaded) for a Famicom Mod, assuming I'd mess it up and give up soldering but it worked and so it inspired some confidence.
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Post Posted: Wed Mar 24, 2021 7:02 pm
All done and it now works beautifully. Though I am sure the screen appears a little darker but I think that happened during testing when I first got it, so I may have to recap it? I did reflow the RGB port pins for good measure but no luck.

I'm missing the reset switch and some original pads (also, I actually dont have any games, ha) but for £33 and a bit of soldering education, I'm pretty happy that I have a Mark III.

For those needing replacement power jacks, the ones I bought were Lumberg NEB21R and I paid £5 for 2 on ebay.
They fit very well and I used some tape to anchor the plug while I put the solder on. I also used multicore with the flux and it's so much easier to work with than lead free.

Just for some general info, I brushed the solder a little to ensure I covered where the board was showing but only on the side pad because after some continuity testing, it appears to me that the pin at the back is just an anchor.

I also looked back at my photo and there appears to be some solder which bridges the front on left through hole. I didnt know if that should be there but it came up when I was soldering, so I assume not!

Anyway, hopefully this thread helps somebody, I now have a 3D adapter to recap as it's not working and I can see some gunk coming out of one of the capacitors....wish me luck; again!

Huge thanks to asynchronous, wasup, Segamaster and Racoon Lad for responding and your guidance.
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