45W PCjr power supply power budget

Hardware questions and modifications

45W PCjr power supply power budget

Postby MattCarp » Sun May 10, 2020 2:15 pm

This is an old topic, but I couldn't find a comment in the forum on this.

The Tech Ref includes specs on the original 33W power supply (short board). It also says that the amount of power on the I/O (sidecar) connector for a fully configured machine with internal features is 400mA at 5V DC.

This would also presume the modem is one of those features. There is no spec published on what the modem consumes, but the 8250a UART is 10 mA on the data sheet. The MK3870 microcontroller on the modem consumes 55 mA. So, we're talking maybe 70 mA max?

I don't know if there was any information published about the 45W power supply. Assuming it's all 5V, that could be as much as another 12W / 5V = 2400 mA.... That's an overall amount of almost 3A.

Does anyone know for sure?
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