SmashTV SID and C64 optimized PSU, dobule Voltage Regulator?

MIDIbox SID
1

I budling a core8 + sid module and LCD. I bouth everything from smashTV and going to use a C64 psu (brown).

In the instructions i read to bridge the 7805 on the CORE module:

http://www.ucapps.de/mbhp/mbhp_8xsid_c64_psu_optimized.pdf

But my SID-module also contains a voltage regulator, should this also be bridged?

http://www.midibox-shop.com/mbhp_SIDR3a.html

2

no, because the two output voltages of the C64 psu are added to about 14V and the 7809 / 78L09 on the sid module regulates this down again.

3

no, because the two output voltages of the C64 psu are added to about 14V and the 7809 / 78L09 on the sid module regulates this down again.

I missed that text on the connector 14VDC, I thought 7809 always delivered 9V. But now its 5+9V?

Thanks anyway…

4

As far as i know the C64 PSU delivers 9V AC, which are, after the bridge rectifier ca 9V * 1.4 or 12V, which are then fed into the 7809. But this may well be wrong :slight_smile:

Bye,

Peter

5

Nope, that 12V to 9VDC transformation sounds about right. The trick is that one of the PSU setup variants lifts the virtual ground of the 7809 with +5VDC to obtain 14V. That’s referred to as PSU option B if referring to the MB6582. If you’re rolling your own baseboard you could still nick a few ideas from there. 14V would only be needed from 6581 chips anyway.

6

Interesting. Thanks! You never stop to learn :slight_smile: