- Joined: 02 Sep 2023
- Posts: 2
- Location: Australia
|
SMS2 only works with 9v benchtop PSU
 Posted: Sat Sep 02, 2023 12:10 am
|
Found my childhood Sega Master System II, and checked to see if it still works.
It has the original power brick, but it doesn't work with it, only with my benchtop PSU on 9v.
But the power brick doesn't appear to be faulty! It's outputting 13v under no load (which is apparently normal), and then 11v under load coming into the console, and then ~10v going into the voltage regulator, with the appropriate 5v coming out.
What would be the issue, where 9v fixed power supply runs the console, but 9v unregulated PSU doesn't?
Also, the Amp draw from both is the same (~0.330A).
|
- Joined: 14 Aug 2000
- Posts: 742
- Location: Adelaide, Australia
|
SMS2 only works with 9v benchtop PSU
Posted: Sat Sep 02, 2023 2:58 am
|
|
Makes no sense. Have you checked the power brick for voltage ripple on a scope? Maybe the capacitor in the brick has died and there's too much ripple?
|
- Joined: 02 Sep 2023
- Posts: 2
- Location: Australia
|
Posted: Sat Sep 02, 2023 11:15 am
|
|
I know right, doesn't make sense. I don't have an oscilloscope to check. Might be time to crack open the power brick and check for bad cap 🤔
|
- Joined: 10 Aug 2017
- Posts: 31
|
Posted: Wed Sep 06, 2023 4:37 pm
|
The only thing i can say is that the polarity is wrong.
The sms2 uses 9v center negative from minimum of 500ma up to 2A.
So, you can use, for exemple, a mega drive 1 power adaptor, or any generic universal adaptors with 9 to 12V.. but..
center negative, outside positive..
check the polarity with the multimeter... the diode inside the power supply can be faulty.
|
