Siamese system - A2000 project

[cosmicfrog]

wow great thread

Siamese ISA card

ok not essential but u don`t seem to see em often

why u not use the nec2000 has best driver support

love see some nice videos of a Siamese system

 

[ratfink]

@Xanxi - How much control do you have over the pentium cpu caches - can they be disabled in the bios? That would slow it down to 386/486 speeds, extending it's usefulness to earlier games maybe.

 

[Xanxi]

I have to explore the BIOS to see if i can deactivate the cache.
I remember there were some programs to slow down a computer from within widows in the time.


@cosmicfrog:
i'm not well equiped for videos but i will make pictures soon.

 

[ratfink]

yes moslo can slow the machine.

 

[Xanxi]

Ok, i'm angry now.

Windows 95 has once again destroyed itself for no reason, with explorer crashes and registery errors. No way to boot or repair it even in safe mode.
Even for a crap OS, that's not normal behaviour after so few usage.
I blame the Hitachi Microdrive i am using.
Unfortunately, there is no room left anywhere for a real hard drive in this A2000, which is now really heavy to transport.
I don't trust CF but usually have good faith in Microdrives. This proves me wrong.

Now i think i should stop this project now. Besides, i have bought a new GoldenGate bridgeboard that i shall receive soon. It would be nice in this A2000, even if that setup may be redundant with my A4000.

 

[Xanxi]

I took a few pics for Cosmifrog before removing all this stuff and closing this project (until next time).

So, from left to right:
- the SBC with its heatsink fan blowing on the CPU + its Microdrive wrapped in bubbles to avoid shortcut
- DLINK network ISA card
- Yamaha ISA sound card
- ribbon for external LPT and COM port
- Sunrize AD516 zorro 2 audio card
- GVP Spectrum zorro 2/3 card
- Deneb card and fan blowing to the rear of the A2000
- internal USB hub from NZXT and 2 rear USB ports
- Phase 5 Blizzard 2060 card
- PSU and bunch of cables to 2 Amiga floppy drives, one PC floppy drive and USB memory card reader combo, SCSI-IDE adapter and 2,5' IDE drive, front USB ports
- the Indivision ECS is underneath the PSU

The PC and the Amiga were connected through the ISA PC NIC and an USB NIC on Deneb to a switch and to the rest of my home network.

It's sad to stop this project after hours spent to put it up, but actually i have received today this:

I'm fortunate that it seems to be working, and it will be soon upgraded to 486SLC2, FPU and 16 MB, and who knows, Windows 95 might come back

 

[cosmicfrog]

:shhh: :readit: Siamese card frog would be intrested in said card :shhh:

sad u did`t get it working but wow what a good replacement

 

[rkauer]

Corruption in file system might indicate a weak PSU. Are you still using the original one from A2000?

 

[Xanxi]

Yeah that was the original PSU.
However, the label on it reads +5V 20,5A and +12V 8A.

That board needs 8A on +5V and much less on +12V.

Providing the PSU truely delivers that power, it should be ok even with the amiga cards, shouldn't it?

 

[Xanxi]

I've foudn references from Dave Haynie about the A2000 Power Consumption.

According to that, typical consumption of my A2000 without that SBC card should be about 14 A on the +5V line. Indeed, the SBC needs are probably too much for this setup.
Of course, i won't remove amiga boards to lighten the burden on the PSU. The main task of this A2000 is of course to remain an Amiga and not a PC.



B2000 Power Budget By Dave Haynie


A2000/B2000 Power Supply:

All of the specifications herein are suggested. When it comes
right down to it, the machine is being powered by a well-defined supply,
the specifications of which will follow. If you're careful not to exceed
the suggested load for any port, you'll be able to fully load every port.
However, some of the internal ports can supply more than the suggested amount;
for example, an 8 megabyte expansion memory card for the 100 pin bus may
draw more than the suggested 2.0 Amps at +5VDC. The connector is capable
of supplying more without damage, but the extra current must be carefully
worked into a system power budget. Any hardware add-on device that draws
more than the suggested amount must state this clearly, as budgeting will be
required. Some external ports are current limited, thus the numbers for these
ports are representative of the true maximum available.

VOLTAGE SYSTEMWIDE LIMIT DESCRIPTION

+5 VDC 20.0 Amps Main +5 Voltage supply
+5 USER 0.5 Amps Protected +5 for externals
-5 VDC 0.3 Amps Negative 5 Volt supply
+12 VDC 8.0 Amps Main +12 Voltage supply
+12 USER --------- Protected +12 for externals,
derived from main +12
-12 VDC 0.3 Amps Main -12 Voltage supply
-12 USER --------- Protected -12 for externals,
derived from main -12


CONSUMPTION:

Everybody wants power. Here's what can be taken, based on your
particular setup; you get what's left over:

MAIN SYSTEM: +5VDC -5VDC +5USER +12VDC -12VDC

Motherboard 2.5A --- --- 50mA 50mA
Internal 3-1/2" Floppy [1] 250mA --- --- 350mA ---
Internal 5-1/4" Floppy [2] 500mA --- --- 500mA ---
Internal 3-1/2" Hard Disk [2] 750mA --- --- 1.0A ---
Internal 5-1/4" Hard Disk [2] 1.0A --- --- 1.5A ---

EXTERNAL PORTS:

Video Port --- 10mA 100mA 100mA ---
Floppy Port [1] 250mA --- --- 350mA ---
Parallel Port [3] --- --- 10mA --- ---
Serial Port --- --- --- 25mA 25mA
Keyboard Port [4] 250mA --- --- --- ---
Mouse Port [5] --- --- 50mA --- ---

INTERNAL SLOTS:

CoProcessor Slot [6] 2.0A 40mA --- 40mA 35mA
Expansion Slot [6] 2.0A 40mA --- 40mA 35mA
Extra PC Bus Slots [7] 0.5A 10mA --- 40mA 15mA
Video Slot [8] 1.0A 40mA --- 40mA ---


NOTES:
[1] Expected typical consumption. This is very device dependent;
consult the manufacturer's specification for particular floppy
disks. The starting current is expected to be around 400mA
for +12V.
[2] Expected typical consumption. This is very device dependent;
consult the manufacturer's specification for particular disks.
Starting current on the +12V supply for most disk drives can be
as much as twice the operating current.
[3] 47 Ohm Series Resistor limits current.
[4] Expected typical consumption. Current from this port is limited.
[5] Each port.
[6] Each slot. The physical connection can handle 4 Amps; if a 4 Amp
device is used in one slot, other slots cannot supply 2.5 Amps
each, of course; this requires a total system power budget to
be constructed.
[7] Shared PC expansion slots should be considered part of the
100 pin connector that they share. If the 100 pin connector is
unused, the power suggested for that connector can be used
instead by the PC bus. The connectors, like all expansion
connectors, are capable of delievering 4 Amps if proper
whole-system budgeting is done. The specification here is for
both of the non-overlapping PC slots taken together.
[8] Like expansion slots, the video slot is capable of supplying
4 Amps. If a 4 Amp device is used, it must be worked into the
total system power budget.