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I picked up a master system mk1 at a carboot sale, i have opened it, although it fires up it just shows solid colours. Its getting power, how would i further diagnose it

I have cleaned it all to no avail, the caps look ok, but i havent replaced them.

I have noticed when i do touch the sony cxa1145, pins on the chip which connect to the av out, the colours change could this be faulty?

I have checked traces and they all seem fine.

I really want to get this system working, i only had a mk2 growing up. This seems a bonus having av out, i have a multimeter but am not a expert at diagnosing, any help will be much appreciated.

20230910_150928.jpg (2.45 MB)

20230910_150925.jpg (2.54 MB)

Welcome @masterturk!

I'm not an expert on failure modes, so hopefully someone with a bit more hands on experience can chime in if they recognise what's going on from your picture, but at a guess I would say what you're seeing is some kind of loss of sync issue within the video generation.

Are you using RF out or AV, and if the latter, how are you connecting it to your TV exactly?

Although the caps look fine, it is common to recap these units as a matter of course since degraded capacitors are not always obvious and do cause "mysterious" issues when they fail in different combinations so in most cases it's easier to replace them all than trying to pinpoint which ones have gone bad.

If you're looking for a quicker fix and suspect the cxa device you could try just reflowing the pins with a soldering iron but tbh I doubt this will do any good. I suspect when you are touching the pins it changes the picture simply because you're affecting the circuit with your skin and it doesn't necessarily mean the part is at fault.

Are games running and responding to inputs from the controllers based on what you can hear in the audio?

I havent heard any audio coming through on the tv. I havent plugged in controllers to try test it further, thanks will try that

asynchronous wrote

Are games running and responding to inputs from the controllers based on what you can hear in the audio?

Are you using RF out or AV, and if the latter, how are you connecting it to your TV exactly?

I am using both rf and the av out, i think it may be something to do with the tv not liking the signal. I will test it with another to rule if its the actual tv not liking it, or the console

Author	Message
masterturk Joined: 11 Sep 2023 Posts: 3	Need help with mk1 master system va3 board Posted: Fri Sep 15, 2023 9:30 pm
masterturk Joined: 11 Sep 2023 Posts: 3	I picked up a master system mk1 at a carboot sale, i have opened it, although it fires up it just shows solid colours. Its getting power, how would i further diagnose it I have cleaned it all to no avail, the caps look ok, but i havent replaced them. I have noticed when i do touch the sony cxa1145, pins on the chip which connect to the av out, the colours change could this be faulty? I have checked traces and they all seem fine. I really want to get this system working, i only had a mk2 growing up. This seems a bonus having av out, i have a multimeter but am not a expert at diagnosing, any help will be much appreciated. 20230910_150928.jpg (2.45 MB) 20230910_150925.jpg (2.54 MB)

willbritton Joined: 06 Mar 2022 Posts: 671 Location: London, UK	Posted: Sun Sep 17, 2023 8:35 am
	Welcome @masterturk! I'm not an expert on failure modes, so hopefully someone with a bit more hands on experience can chime in if they recognise what's going on from your picture, but at a guess I would say what you're seeing is some kind of loss of sync issue within the video generation. Are you using RF out or AV, and if the latter, how are you connecting it to your TV exactly? Although the caps look fine, it is common to recap these units as a matter of course since degraded capacitors are not always obvious and do cause "mysterious" issues when they fail in different combinations so in most cases it's easier to replace them all than trying to pinpoint which ones have gone bad. If you're looking for a quicker fix and suspect the cxa device you could try just reflowing the pins with a soldering iron but tbh I doubt this will do any good. I suspect when you are touching the pins it changes the picture simply because you're affecting the circuit with your skin and it doesn't necessarily mean the part is at fault.

asynchronous Joined: 14 Aug 2000 Posts: 742 Location: Adelaide, Australia	Need help with mk1 master system va3 board Posted: Mon Sep 18, 2023 11:32 am
	Are games running and responding to inputs from the controllers based on what you can hear in the audio?

masterturk Joined: 11 Sep 2023 Posts: 3	Posted: Sat Sep 23, 2023 2:35 pm
masterturk Joined: 11 Sep 2023 Posts: 3	I havent heard any audio coming through on the tv. I havent plugged in controllers to try test it further, thanks will try that asynchronous wrote Are games running and responding to inputs from the controllers based on what you can hear in the audio?

masterturk Joined: 11 Sep 2023 Posts: 3	Posted: Sat Sep 23, 2023 2:38 pm
masterturk Joined: 11 Sep 2023 Posts: 3	Are you using RF out or AV, and if the latter, how are you connecting it to your TV exactly? I am using both rf and the av out, i think it may be something to do with the tv not liking the signal. I will test it with another to rule if its the actual tv not liking it, or the console

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