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View topic - [FIXED] SMS 2 PAL G - Bad Video and Music issues

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  • Joined: 23 Apr 2022
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[FIXED] SMS 2 PAL G - Bad Video and Music issues
Post Posted: Sun Apr 24, 2022 12:47 pm
Last edited by auxie22 on Mon Apr 25, 2022 1:27 am; edited 1 time in total
Hi All,
This has probably been answered before at some point. I tried to search and only found a thread for the Video issues but they aren't quite the same so I thought I would post a video that includes both the video and audio issues I am having.

The Video has white noise in the background which isn't part of the noise coming from the console.

I have re-capped it and it hasn't made any difference

I also figure that one of the issues is the vram so I have purchased 2 x NEC UPD4168C-15 chips and they will take about a month to get here.

Clocks are all OK

Voltages seem OK on all of the chips

Nothing is getting hot

Thanks in advance for any feedback
SMS 2 Graphics and Sound Issue.mp4 (5.95 MB)
Video of issue

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  • Joined: 14 Aug 2000
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  • Location: Adelaide, Australia
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SMS 2 PAL G - Bad Video and Music issues
Post Posted: Sun Apr 24, 2022 5:23 pm
It looks like there could be an issue with one or more of the data lines going to IC5 where the VDP and PSG is. It could be a broken track on the board, or a dry solder joint, or an issue with the pin on the chip.

Try testing each of the data line for connectivity between the CPU and IC5. For a PAL SMS 2, IC5 is most likely a '315-5246' and D0-D7 connect to pins 1 to 8 respectively.

Good luck.
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  • Joined: 23 Apr 2022
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Post Posted: Sun Apr 24, 2022 8:50 pm
asynchronous wrote
It looks like there could be an issue with one or more of the data lines going to IC5 where the VDP and PSG is. It could be a broken track on the board, or a dry solder joint, or an issue with the pin on the chip.

Try testing each of the data line for connectivity between the CPU and IC5. For a PAL SMS 2, IC5 is most likely a '315-5246' and D0-D7 connect to pins 1 to 8 respectively.

Good luck.


Thanks asynchronous,

I will give that a try and let you know how I go...
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  • Joined: 23 Apr 2022
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Fixed!
Post Posted: Sun Apr 24, 2022 11:54 pm
Hi asynchronous,

Thankyou so much! You have helped revive another SMS 2 console.

D0 had no connectivity between the VDP and Z80

I had to jumper pin 11 of IC3 to Pin 32 of IC4

There looks to be connectivity to the cartridge slot too
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