Sonnet Crescendo 7200 power supply
Sonnet is a 5V card, which requires the additional 3.3V auxiliary power rail. The actual PCI digital logic signalling level is 5V.
The following Mediator models provide the necessary 3.3V power rail:
- Mediator 3000Di
- Mediator 4000Di 3V
- Mediator 4000D 3V
- Mediator 1200TX / 1200TXblack
If your Mediator does not provide the 3.3V rail, Sonnet can still be modded to work, by attaching external source of 3.3V power. This is not recommended, as power from 3.3V lines on Sonnet might be fed back onto the PCI backplane. That being said, this method has been used for a year now with no problems noticed.
The following PCI slot pins are used for 3.3V power:
- site A: 21, 27, 33, 39, 45, 53
- side B: 25, 31, 36, 41, 43, 54
The following picture shows where 3.3V from an external source can be applied to the card:
There is also an empty U8 solder place on the Sonnet. It is possible to install 3.3V regulator there.
This pinout does not look correct.
Pinout for U8 goes (towards C21).
- 3.3V
- Unknown possibly ADJ for regulator NOTE THIS PAD IS NOT CONNECTED TO REGULATOR, the WIRE GOES FROM VRM GND TO THE GND PAD at C21.
- 3.3V
- 5V
- 3.3V
Towards PCI Slot
Tab. 3.3V
