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View topic - Help with MS2 from thrift store

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  • Joined: 25 Jun 2019
  • Posts: 4
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Help with MS2 from thrift store
Post Posted: Tue Jun 25, 2019 8:37 pm
I bought a master system model 2 today with a mega drive plug and I couldn't get video out. I looked at the back of it and saw some kind of mod but I can't identify it. Can anyone tell me if this is salvageable or what is wrong with it?
20190625_223649.jpg (3.63 MB)
Back of motherboard, maybe a composite mod
20190625_223649.jpg

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  • Joined: 05 Nov 2014
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  • Location: Auckland - NZ
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Post Posted: Tue Jun 25, 2019 11:39 pm
Looks like a not so great attempt at composite video.. and that red wire possibly audio. It looks like they have tried to remove the rf modulator too. If you resolder the 3 pins on the rf modulator and get rid of the added in red wire and the coax cable it may work again on rf.
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  • Joined: 25 Jun 2019
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Post Posted: Wed Jun 26, 2019 7:05 am
That red wire looks like the 60hz If I remember right is it going to the chip 315-5246 , pin 57

Its difficult to see where the green wire is soldered to in your pic, but it appears to be composite video - cxa1145 pin 20.

This looks like a bad composite mod.

No picture, might just need a 220uf cap to buffer the video.

There is RGB right there on that chip

______

Does this mean anything to you? Someone suggested this to me
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  • Joined: 08 Sep 2018
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Post Posted: Thu Jun 27, 2019 3:24 pm
Its definitely a really bad composite video mod. I agree with wasup, just desolder the red wire and the big coax cable and solder the modulator back in and test it out. If you want RGB there are some mod boards thatll do the trick and look cleaner. you could also wire it up to a mini din port like the ones the Sega Mega Drive has.
wz3g53xv.jpg (1.7 MB)
My suggestion
wz3g53xv.jpg

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  • Joined: 25 Jun 2019
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Power supply
Post Posted: Sun Jun 30, 2019 11:26 am
could the problem be the power brick?
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  • Joined: 25 Jun 2019
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Post Posted: Sun Jun 30, 2019 11:28 am
here's a picture
11111111.JPG (120.38 KB)
11111111.JPG

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  • Joined: 08 Sep 2018
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Post Posted: Sun Jun 30, 2019 4:32 pm
10v 1.2 amps
compared to
9v 0.5 amps
I could be wrong but that adapter may have killed this thing...
The original North American SMS power rating is 9v 0.85 amps same as the SEGA CD. I dont know the tolerances of the system but Ive heard bad things about mixing power supplies.
On the other hand, the Original MegaDrive/Genesis supply is credited for being great on a wide range of systems like the SEGA CD, TurboGrafx16, and the front loading NES.
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  • Joined: 19 Oct 1999
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Post Posted: Sun Jun 30, 2019 8:27 pm
More amps doesn't matter - but using a power supply capable of too few may cause trouble.

One extra volt doesn't matter because it all goes into a voltage regulator. Those things low quality higher voltages into high quality 5V. Modern ones typically take up to 35V, an old one will be fine with 10V.
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