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I'm sorry if this is the wrong place to ask but I've been having this problem for a couple of days and looking up fixes online didn't quite cut it for me.
I got an untested SMS and like an idiot I plugged an NES power supply into the ac adapter on my SMS, I've since gotten a retro versal universal AC adapter that works with NES/SNES/Genesis (gen 1) and outputs DC 9V/350MA. The NES power supply should've fried my system but my voltage regulator still reads voltages in (+8) and out (+5).
Like the title says, when connecting SMS RF to TV aux using adapter I get a black screen with a white/grey stripe down the middle horizontally but I get the Sega startup sound. So basically I get no video but I do get audio. I've noticed that when running the system that IC5, IC6 and especially IC7 get VERY hot.
I don't think the voltage regulator is the problem. I'm new to working on electronics but I don't think any of the solder joints look bad except for the voltage regulator joints that appear to have some sort of yellowish melted liquid around it. Other than that the system looks very good.
I would really appreciate any insight and opinion you could throw my way. Would love to get this system up and running.

Have you measured some voltages? Voltage regulator input and output, Vcc of IC5..7?

Voltage regulator measures in +8 and out +5. I'm not sure how to check IC5...7

I've also noticed that my reset button doesn't seem to work.

IC5 should have Vcc (+5V) on pins 10/11, IC6/7 on pins 1/26/28.

If these voltages are ok, maybe somethins is short-curcuited?

In case you don't know, there's an official service manual from Sega:

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

Some checks require an oscilloscope, though.

Thank you for your help. I got the following read-outs
IC5: pin 10 - (+2V), pin 11 - (+5V)
IC6: pin 1 - (+5V), pin 26 - (+1V), pin 28 - (+1V)
IC7: pin 1 - (+5V), pin 26 - (0V), pin 28 - (+1V)

I'm sure I'm doing these correctly, using voltage regulator ground as ground for testing.

What SMS do you have exactly? SMS1? SMS2? Name on PCB?

I'm a bit confused about the readings, so perhaps I named some pins incorrectly (some are hard to read in the service manual) or your pinout is different. Vcc should be the same everywhere.

Some even number the ICs differently, so let's double check this, too:

IC5 is the VDP (315-5124 or -5246)
IC6/7 are the VDP-RAM (2x 8KByte 28 pin)

Is the LED still working?
Are some e-caps blown? They tend to do this when connected to reverse polarity.

Does Composite or RGB-Video still work?

By the way: the yellow fluid around the 7805 may be some flux residue, the 7805 get's replaced quite often.

I believe this is the SMS1, name on board is M4 POWERBASE/NTSC
I couldn't find the labeled pins in the manual though. Maybe I'm just blind.

The IC5 says 315-5124
The IC6/7 have 28 pins each and say D4168C-15

I was pretty sure it wasn't the problem but I replaced the voltage regulator with a brand new one, I'm new to soldering and wasn't sure if I did it correctly but I plugged the system back in and the LED came on and I had the same video problem. Audio still works.

Non of the electrolytic capacitors seem damaged. None of them are bloated or anything. Don't have a composite cable, however I just ordered one and will be here on September 2nd.

Thank you for the info. Didn't know that is what flux residue looks like.
Like I said, I'm brand new to working with electronics and I really appreciate your patients and cooperation.

20170831_181009.jpg (3.64 MB)

20170831_180958.jpg (3.89 MB)

20170831_181020.jpg (3.55 MB)

IC5 is VDP, 6 and 7 are VRAM. They should only get slightly warm. Very hot means they're dead...

They get so warm I can't keep my hand on them for long. Could they have gotten fried when I used the NES adapter? Will replacing them fix my problem?

That's a SMS1, the SMS2 looks quite different even from the outside and the card slot is missing as well as the AV-output on the SMS2. I'm sure you've seen a SMS2 before ;).

(Your board's layout looks quite a bit different from the one of my SMS1. But the ICs are named exactly the same.)

I agree with TmEE, I suspect that one ore more of your ICs is damaged (VDP-RAM not working would explain absent video output). Unfortunately it's not the 7805 which could be replaced much easier. The RAM shouldn't get hot, the VDP maybe a little, but the only thing supposed to get hot is the 7805 which has a heat sink.

Hopefully there's no other damage which would lead to the destruction of any part you might change now. But after checking the 7805 only outputs +5V I don't expect this to happen.

Have you any spare parts? I'd begin with IC6/7. Maybe the VDP (IC5) is still working. Desoldering that can be quite tricky.

Without spare parts your SMS may be beyond economical repair (at least from my point of view: here in Europe you get a working PowerBase for 30€ or less, damaged ones even cheaper). And in case the VDP is broken you're lost anyway, because it's a custom chip.

Hmm... I don't think I have any spare parts to replace vram. If I ever come across another sms, working or not, I'll be sure to get it. I imagine I could buy vram from somewhere though, at least to try out and pray the vdp still works.

I think I found replacement pieces on ebay. Is this the part I need for IC6/7? http://m.ebay.com/itm/282389035448

According to your pictures this is exactly the same chip, yes.

I almost wrote, that for 16$ you almost get a broken SMS1 for replacement parts (including the VDP), but in the US the SMS1 is probably not that cheap as in my region...

Unfortunately it is not. I cannot find even a broken SMS for less than $40.

Update: I've gotten nee vram gor ic6,7 and have replaced the original chips. I am new to soldering and while I don't think it's that difficult I may have done something wrong. I get video output but it's distorted with lines running through the screen. I have attached a picture of the sega default screen so it's progress, but definitely not finished. The new vram doesn't get hot but the vdp is still pretty warm and IC1 is very hot.

20170921_204852.jpg (3.05 MB)

Author	Message
thailey01 Joined: 31 Aug 2017 Posts: 11	Black screen with white stripe through middle on Master System Posted: Thu Aug 31, 2017 2:56 am
thailey01 Joined: 31 Aug 2017 Posts: 11	I'm sorry if this is the wrong place to ask but I've been having this problem for a couple of days and looking up fixes online didn't quite cut it for me. I got an untested SMS and like an idiot I plugged an NES power supply into the ac adapter on my SMS, I've since gotten a retro versal universal AC adapter that works with NES/SNES/Genesis (gen 1) and outputs DC 9V/350MA. The NES power supply should've fried my system but my voltage regulator still reads voltages in (+8) and out (+5). Like the title says, when connecting SMS RF to TV aux using adapter I get a black screen with a white/grey stripe down the middle horizontally but I get the Sega startup sound. So basically I get no video but I do get audio. I've noticed that when running the system that IC5, IC6 and especially IC7 get VERY hot. I don't think the voltage regulator is the problem. I'm new to working on electronics but I don't think any of the solder joints look bad except for the voltage regulator joints that appear to have some sort of yellowish melted liquid around it. Other than that the system looks very good. I would really appreciate any insight and opinion you could throw my way. Would love to get this system up and running.

Knaeckebrot Joined: 03 Aug 2017 Posts: 61 Location: Munich	Posted: Thu Aug 31, 2017 7:16 am
	Have you measured some voltages? Voltage regulator input and output, Vcc of IC5..7?

thailey01 Joined: 31 Aug 2017 Posts: 11	Posted: Thu Aug 31, 2017 8:23 am
thailey01 Joined: 31 Aug 2017 Posts: 11	Voltage regulator measures in +8 and out +5. I'm not sure how to check IC5...7

thailey01 Joined: 31 Aug 2017 Posts: 11	Posted: Thu Aug 31, 2017 8:46 am
thailey01 Joined: 31 Aug 2017 Posts: 11	I've also noticed that my reset button doesn't seem to work.

Knaeckebrot Joined: 03 Aug 2017 Posts: 61 Location: Munich	Posted: Thu Aug 31, 2017 4:13 pm
	IC5 should have Vcc (+5V) on pins 10/11, IC6/7 on pins 1/26/28. If these voltages are ok, maybe somethins is short-curcuited? In case you don't know, there's an official service manual from Sega: http://www.smspower.org/uploads/Development/SegaMasterSystemServiceManual.pdf Some checks require an oscilloscope, though.

thailey01 Joined: 31 Aug 2017 Posts: 11	Posted: Thu Aug 31, 2017 7:47 pm
thailey01 Joined: 31 Aug 2017 Posts: 11	Thank you for your help. I got the following read-outs IC5: pin 10 - (+2V), pin 11 - (+5V) IC6: pin 1 - (+5V), pin 26 - (+1V), pin 28 - (+1V) IC7: pin 1 - (+5V), pin 26 - (0V), pin 28 - (+1V) I'm sure I'm doing these correctly, using voltage regulator ground as ground for testing.

Knaeckebrot Joined: 03 Aug 2017 Posts: 61 Location: Munich	Posted: Thu Aug 31, 2017 9:50 pm
	What SMS do you have exactly? SMS1? SMS2? Name on PCB? I'm a bit confused about the readings, so perhaps I named some pins incorrectly (some are hard to read in the service manual) or your pinout is different. Vcc should be the same everywhere. Some even number the ICs differently, so let's double check this, too: IC5 is the VDP (315-5124 or -5246) IC6/7 are the VDP-RAM (2x 8KByte 28 pin) Is the LED still working? Are some e-caps blown? They tend to do this when connected to reverse polarity. Does Composite or RGB-Video still work? By the way: the yellow fluid around the 7805 may be some flux residue, the 7805 get's replaced quite often.

thailey01 Joined: 31 Aug 2017 Posts: 11	Posted: Thu Aug 31, 2017 11:25 pm
thailey01 Joined: 31 Aug 2017 Posts: 11	I believe this is the SMS1, name on board is M4 POWERBASE/NTSC I couldn't find the labeled pins in the manual though. Maybe I'm just blind. The IC5 says 315-5124 The IC6/7 have 28 pins each and say D4168C-15 I was pretty sure it wasn't the problem but I replaced the voltage regulator with a brand new one, I'm new to soldering and wasn't sure if I did it correctly but I plugged the system back in and the LED came on and I had the same video problem. Audio still works. Non of the electrolytic capacitors seem damaged. None of them are bloated or anything. Don't have a composite cable, however I just ordered one and will be here on September 2nd. Thank you for the info. Didn't know that is what flux residue looks like. Like I said, I'm brand new to working with electronics and I really appreciate your patients and cooperation. 20170831_181009.jpg (3.64 MB) 20170831_180958.jpg (3.89 MB) 20170831_181020.jpg (3.55 MB)

TmEE Joined: 31 Oct 2007 Posts: 853 Location: Estonia, Rapla city	Posted: Thu Aug 31, 2017 11:31 pm
	IC5 is VDP, 6 and 7 are VRAM. They should only get slightly warm. Very hot means they're dead...

thailey01 Joined: 31 Aug 2017 Posts: 11	Posted: Thu Aug 31, 2017 11:59 pm
thailey01 Joined: 31 Aug 2017 Posts: 11	They get so warm I can't keep my hand on them for long. Could they have gotten fried when I used the NES adapter? Will replacing them fix my problem?

Knaeckebrot Joined: 03 Aug 2017 Posts: 61 Location: Munich	Posted: Fri Sep 01, 2017 1:50 am
	That's a SMS1, the SMS2 looks quite different even from the outside and the card slot is missing as well as the AV-output on the SMS2. I'm sure you've seen a SMS2 before ;). (Your board's layout looks quite a bit different from the one of my SMS1. But the ICs are named exactly the same.) I agree with TmEE, I suspect that one ore more of your ICs is damaged (VDP-RAM not working would explain absent video output). Unfortunately it's not the 7805 which could be replaced much easier. The RAM shouldn't get hot, the VDP maybe a little, but the only thing supposed to get hot is the 7805 which has a heat sink. Hopefully there's no other damage which would lead to the destruction of any part you might change now. But after checking the 7805 only outputs +5V I don't expect this to happen. Have you any spare parts? I'd begin with IC6/7. Maybe the VDP (IC5) is still working. Desoldering that can be quite tricky. Without spare parts your SMS may be beyond economical repair (at least from my point of view: here in Europe you get a working PowerBase for 30€ or less, damaged ones even cheaper). And in case the VDP is broken you're lost anyway, because it's a custom chip.

thailey01 Joined: 31 Aug 2017 Posts: 11	Posted: Fri Sep 01, 2017 2:04 am
thailey01 Joined: 31 Aug 2017 Posts: 11	Hmm... I don't think I have any spare parts to replace vram. If I ever come across another sms, working or not, I'll be sure to get it. I imagine I could buy vram from somewhere though, at least to try out and pray the vdp still works.

thailey01 Joined: 31 Aug 2017 Posts: 11	Posted: Sun Sep 03, 2017 11:29 pm Last edited by thailey01 on Mon Sep 04, 2017 12:23 am; edited 1 time in total
thailey01 Joined: 31 Aug 2017 Posts: 11	I think I found replacement pieces on ebay. Is this the part I need for IC6/7? http://m.ebay.com/itm/282389035448

Knaeckebrot Joined: 03 Aug 2017 Posts: 61 Location: Munich	Posted: Mon Sep 04, 2017 12:19 am
	According to your pictures this is exactly the same chip, yes. I almost wrote, that for 16$ you almost get a broken SMS1 for replacement parts (including the VDP), but in the US the SMS1 is probably not that cheap as in my region...

thailey01 Joined: 31 Aug 2017 Posts: 11	Posted: Mon Sep 04, 2017 12:22 am
thailey01 Joined: 31 Aug 2017 Posts: 11	Unfortunately it is not. I cannot find even a broken SMS for less than $40.

thailey01 Joined: 31 Aug 2017 Posts: 11	Posted: Fri Sep 22, 2017 2:00 am
thailey01 Joined: 31 Aug 2017 Posts: 11	Update: I've gotten nee vram gor ic6,7 and have replaced the original chips. I am new to soldering and while I don't think it's that difficult I may have done something wrong. I get video output but it's distorted with lines running through the screen. I have attached a picture of the sega default screen so it's progress, but definitely not finished. The new vram doesn't get hot but the vdp is still pretty warm and IC1 is very hot. 20170921_204852.jpg (3.05 MB)

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