TAM - Internal PicoPSU - AUX Power for Expansion Slots

[Trash80toG4]

I've identified available cubic in the TAM for boosting its anemic power budget in the upper right hand corner of the red box:

edit: found a far better pic of available cubic:

A PicoPSU will fit nicely mounted vertically to edge of the ComSlot2 standard riser with hot glue or socketed on a custom repro riser.

Power supplied to the rails of a SATA Connector are a question mark, maybe, maybe not able to drive two PCI Cards off the cable?
ATX connector may be required as source for slots?

PicoPSU in 90W range seem expensive ($100+-) while 150W units seem to be very inexpensive in comparison.

 

[Trash80toG4]

Cooling in a TAM will be the sticky point, don't have one, but tinkering with a FauxProtoMac counterpart.

Maximum Power spec for expansion cards in 6500:

PCI Expansion Slot - PowerMac 5500-6500-DevNote
The main logic board uses the industry-standard peripheral component interconnect
(PCI) bus for an I/O expansion bus. The PCI bus is a 32-bit multiplexed address and
data bus. The PCI expansion slot has a 33.33 MHz system clock.
PCI I/O expansion cards are mounted horizontally in a 90-degree straight-through
adapter board, which is installed in the PCI expansion slot on the main logic board.
A total of 15 watts of power is provided for each of the PCI expansion slots. Both 5 volts
and 3.3 volts are supplied; the total power consumed by both voltages must not exceed
the 15-watt maximum.
The main logic board requires that PCI cards use the 5-volts signaling standard
described in the PCI Local Bus Specification, Revision 2.0.
The enclosures allow for standard 6.88-inch PCI cards as defined by the PCI Local Bus
Specification, Revision 2.0. The cards are required to use the standard ISA fence described
in the specification.
The PCI slots support all the required PCI signals and certain optional PCI signals. The
supported PCI signals are listed in Table 4-3.


PCI Bus Communications Slot Connector - PowerMac 5500-6500-DevNote
The PCI bus communications slot connector is a 112-pin half-height microchannel
connector. A communications card mounts vertically in the connector and its I/O
connector is accessed through the communications port access hole on the right hand
side of the back panel. The size constraints of a communications card are 1.57 inches (40
mm) wide by 6 inches (152 mm) long.
A maximum of 2.5 watts of power is allocated to the communications slot. The
maximum possible current ratings for each power line are
Voltage Current
+5 V 500 mA
+12 V 100 mA
Trickle +5 V 5 mA
–5 V 20 mA

Haven't got the TAM DevNote handy, but we're talking about duplicating or improving upon the 6500 expansion card power budget.

WAG for the time being is that PicoPSU waste heat will be proportional to power drawn by the three expansion cards?
- if so, would it make a difference if 90W or 150W max output PicoPSU is used in terms of cooling requirements?

Dunno, thoughts?

 

[Trash80toG4]

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[Trash80toG4]

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[Trash80toG4]

Lots of activity on the PSU front for 6500 recently and in the far distant past.

Some 14 years ago I was looking into 6500 and Beige G3 ATX conversions. Going for an ersatz TAM/FatBack form factor build now that will be powered entirely by the 250w PicoPSU pictured above.

In his discontinued mAcATX project, blusnowkitty posted his concept for a Q630 version:

That gets me halfway there, 3.3v required for PCI in the 6360 and Gazell machines. I don't need the soft power circuitry as I'll be using a wireless USB KBD/Mouse combo. Hoping to do the conversion in cable by rearranging Molex pins on a 24pin->14pin adapter cabl.for KISS principle adherence. I cannot imagine Apple went with an ATX compatible connection? Assumption would be that a simple ATX PSU startup button switch will suffice? Wondering if such is part of the PicoPSU spec?

This pair of adapter cables are incoming, figuring I'll need wires from the second adapter to do a full 14pin 6360/TAM implementation?

For nearer term project I only need to power the TwinSlot adapter to allow use of a power hungry pair of PCI cards in the TAM. That'll be done on the Dummy CSII riser pictured above. That project will eventually include connections to implement the (ofttimes missing?) standard TAM riser as a bonus feature.

Help definitely needed here. Might a dedicated ATX PSU conversion for these machines topic be better? Anyone have linkage to such things?