More VIC Power Supply Questions

[Victragic]

Okay,

given that there is precious little protection inside a VIC other than a fuse, and I could seriously do some damage here if I do the wrong thing, I need some advice..

I have recently acquired an early (non CR) Vic20, with no power supply. What I THINK I know of the power supply differences between the CR (64-style) and early VIC is this..

1) The early VICs required regulated 9V input at around 2-3A.. though I can't find the Ampere rating anywhere. I believe internally, there is circuitry to 'step down' the voltage to 5v unregulated (according to the schematic at the back of my Programmer's Reference Guide), and most of the current is drawn through this channel.

2) The CR has the same or similar circuitry built into the power supply, ie it supplies 1-1.5(?)A 5v, and several hundred mA of 9v.. both *regulated*.

Thus, can someone tell me if this is correct? Am I right in assuming that I *cannot* use a CR power supply with an early-model VIC?

Cheers
-G

[eslapion]

Ok, I will try my best to provide information here.

1) The early VICs required regulated 9V input at around 2-3A.. though I can't find the Ampere rating anywhere. I believe internally, there is circuitry to 'step down' the voltage to 5v unregulated (according to the schematic at the back of my Programmer's Reference Guide), and most of the current is drawn through this channel.

Early VICs require 9Vac at around 2-3A. AC is ALWAYS UNREGULATED. In other words, the external component of an early VIC's power supply consists almost exclusively of a standard transformer.

The internal circuitry does not only comprise circuitry to step down. It comprises a diode bridge which converts AC to DC, a large capacitor based filter and a linear voltage regulator. The 5V that comes out of these components is REGULATED.

2) The CR has the same or similar circuitry built into the power supply, ie it supplies 1-1.5(?)A 5v, and several hundred mA of 9v.. both *regulated*.

What comes out of a VIC-CR's power supply is 5Vdc REGULATED and 9 VAC which is UNREGULATED.

[Victragic]

Thanks Eslapion..

just as well I didn't start looking for a regulated AC power supply then -- (right next to the flux capacitors in Tandys..!!)

Cheers
-Glen

[Victragic]

Once again, a Commodore 64 comes to the rescue as a cheap source of spare parts for a Vic...

..found I had a C64 power supply lying around unused, so I opened it up and snipped the transformer connections - disabling the circuitry for the 5VDC, and re-routing the 9V AC to a cable that fits the 2-prong socket on the VIC..

..works perfectly!

-G

[idrougge]

I did it the opposite way; adding a DIN connector in parallel with the two-prong connector. The VIC hasn't been exhibiting any problems so far.