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Hi !

I have a problem with a SMS 1 (eur, pal, power base VA3, sony cxa1145p chip), it powers up correctly (green led on) but:
- no video
- no sound

Can you tell me how I can find the problem using a multimeter tester ? can you tell me typical voltages for the pin on the ICs pins ?

Thanks

You can try this:

http://www.smspower.org/Development/SegaMasterSystemServiceManual

Maxim wrote

You can try this:

Thanks. I tried yesterday already using that page, but without knowing the correct operating voltage range on each IC pin I cannot discover which is the faulty IC (or the faulty pin or solder)

Is there a page with the typical voltage range of each pin on the ICs on the board ?

It tells you right there. You should have VCC 5 running to all the IC chips. Look at their pinouts for the VCC pin. Connect negative to the ground plane on the board and the positive to the VCC pin.

This is also very typical if you plugged in an AC power supply from an NES.

I had a similar problem with a mastersystem once. It turns out one of the capacitors near the A/V output was loose. I soldered it back in place and it worked.

Author	Message
davdav79 Joined: 27 Sep 2013 Posts: 10 Location: Italy	Faulty Master System 1: power ok,no video, no sound Posted: Fri Sep 27, 2013 2:26 am
davdav79 Joined: 27 Sep 2013 Posts: 10 Location: Italy	Hi ! I have a problem with a SMS 1 (eur, pal, power base VA3, sony cxa1145p chip), it powers up correctly (green led on) but: - no video - no sound Can you tell me how I can find the problem using a multimeter tester ? can you tell me typical voltages for the pin on the ICs pins ? Thanks

Maxim Site Admin Joined: 19 Oct 1999 Posts: 15006 Location: London	Posted: Fri Sep 27, 2013 1:02 pm Last edited by Maxim on Fri Sep 27, 2013 9:26 pm; edited 1 time in total
	You can try this: http://www.smspower.org/Development/SegaMasterSystemServiceManual

davdav79 Joined: 27 Sep 2013 Posts: 10 Location: Italy	Posted: Fri Sep 27, 2013 1:13 pm
davdav79 Joined: 27 Sep 2013 Posts: 10 Location: Italy	Maxim wrote You can try this: Thanks. I tried yesterday already using that page, but without knowing the correct operating voltage range on each IC pin I cannot discover which is the faulty IC (or the faulty pin or solder)

davdav79 Joined: 27 Sep 2013 Posts: 10 Location: Italy	Posted: Fri Sep 27, 2013 8:48 pm
davdav79 Joined: 27 Sep 2013 Posts: 10 Location: Italy	Is there a page with the typical voltage range of each pin on the ICs on the board ?

Maraakate Joined: 05 Jun 2010 Posts: 762 Location: Pennsylvania, USA	Posted: Sat Sep 28, 2013 4:32 am
	It tells you right there. You should have VCC 5 running to all the IC chips. Look at their pinouts for the VCC pin. Connect negative to the ground plane on the board and the positive to the VCC pin. This is also very typical if you plugged in an AC power supply from an NES.

beebogates Joined: 03 Sep 2012 Posts: 44 Location: Egypt	Posted: Sun Oct 13, 2013 11:29 am
beebogates Joined: 03 Sep 2012 Posts: 44 Location: Egypt	I had a similar problem with a mastersystem once. It turns out one of the capacitors near the A/V output was loose. I soldered it back in place and it worked.

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