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 ---- ----
 +
 +====A2000====
 +
 +===Power Supply===
 +
 +  * motherboard connector is a Molex 2139 KK 3.96MM 14pin
 +  * wire is 18ga 300v from power supply to mobo
 +  * the standard rating is a 200W  power supply
 +  * with no load (mobo or power supply), if you turn on the power supply you should see the fan spin but then stop; with FDD(s) attached the power supply will stay on, along with a constant spinning fan
 +      * can someone test if mobo connector +5V and +12V is actually off with no load?
 +
 +^Pin^Name^Wire Color^Notes^
 +|1|+5V|yellow|total +5V load is 20.5A|
 +|2|+5V|yellow||
 +|3|+5V|yellow||
 +|4|+5V|yellow||
 +|5|GND1|blue||
 +|6|GND2|blue||
 +|7|GND3|blue||
 +|8|GND4|blue||
 +|9|+12V|orange|total +12V load is 8A|
 +|10|KEY|none||
 +|11|-12V|red|total -12V load is .3A|
 +|12|+5V USER|green||
 +|13|-5V|white|total -5V load is .3A|
 +|14|TICK||
 +
 +
 +^Volts^Amps^
 +|+5V|20.50A|
 +|+12V|8.00A|
 +|-5V|0.30A|
 +|-12V|0.30A|
 +
 +  * This system requires a 'tick' circuit which provides a 50/60Hz +/-10% reference signal to the video chipset or motherboard jumper J300.
 +  * Would require a simple linear regulator circuit using a 7905 or equivalent, to generate -5V.
 +  * At motherboard location J300, cover pins 2 and 3 with a jumper to internally generate TICK signal
 +    * from AmigaKit adapter
 +    * is this just their hardware adapter or all atx adapters?
 +
 +====Replacement Power Supplies====
 +
 +Sadly, you can't just substitute any ATX in for the A2000, see below.  There is a small after market for replacement power supplies. See the A500 Power page for an easy Cisco swap. 
 +
 +**Meanwell**
 +
 +Meanwell has become a standard for replacing power supplies for the 8 and 16 bit lines. 
 +
 +  * MPQ-200B
 +    * medical rated, high quality + high cost
 +    * rated for 200W
 +    *  output
 +      * +5V at 15A (vs 20.5A output of A2000 power supply)
 +      * +12V at 7A (vs 8A output of A2000 power supply)
 +      * -5V at 2A (vs .3A output of A2000 power supply)
 +      * -12V at 2A (vs .3A output of A2000 power supply)
 +  * RQ-125B
 +    * only 125W!
 +    *  output
 +      * +5V at 11A (vs 20.5A)
 +      * +12V at 4.5A (vs 8A)
 +      * -5V at 1A (vs .3A)
 +      * -12V at .5A (vs .3A)
 +
 +----
 +
 +====ATX PC Power Supply====
 +
 +Here's the standard PC power supply to compare to Amiga's needs.  Nowadays, there is seldom a -5V power line. If you can find an old AT power supply you're almost guaranteed a -5V. Keep an eye out at yard sales and thrift stores. A quick and easy indicator is if a 5.25" or 3.5" drive is in the PC. This //usually// means it is an old power supply so the -5V may be there.
 +
 +^Pin^Name^Color^Description^
 +|1|3.3V|Orange|+3.3 VDC|
 +|2|3.3V|Orange|+3.3 VDC|
 +|3|COM|Black|Ground|
 +|4|5V|Red|+5 VDC|
 +|5|COM|Black|Ground|
 +|6|5V|Red|+5 VDC|
 +|7|COM|Black|Ground|
 +|8|PWR_OK|Gray|Power Ok is a status signal generated by the power supply to notify the computer that the DC operating voltages are within the ranges required for proper computer operation (+5 VDC when power is Ok)|
 +|9|5VSB|Purple|+5 VDC Standby Voltage (max 10mA, max 2A in ATX 2.2 spec)|
 +|10|12V|Yellow|+12 VDC|
 +|11|12V|Yellow|+12 VDC|
 +|12|3.3V|Orange|+3.3 VDC|
 +|13|3.3V|Orange|+3.3 VDC. ATX V2.3 / EPS12V V2.92 both define that the PSU has to use remote sensing to compensate cable drops on the 3.3V line. Because of this there is an additional brown cable crimped together with the orange cable either to pin 13 (ATX) or pin 1 (EPS12V).
 +|14|-12V|Blue|-12 VDC|
 +|15|COM|Black|Ground|
 +|16|/PS_ON|Green|Power Supply On (active low). Short this pin to GND to switch power supply ON, disconnect from GND to switch OFF.|
 +|17|COM|Black|Ground|
 +|18|COM|Black|Ground|
 +|19|COM|Black|Ground|
 +|20|-5V|White|-5 VDC  (this is optional on newer ATX-2 supplies, it is for use with older AT class expansion cards and can be omitted on newer units)|
 +|21|+5V|Red|+5 VDC|
 +|22|+5V|Red|+5 VDC|
 +|23|+5V|Red|+5 VDC|
 +|24|COM|Black|Ground|
 +
 +  * /PSON activated by pressing and releasing the power button while the power supply is in standby mode. Activating /PSON connects the power supply's /PSON input to ground, thereby switching the power supply to full-on condition.
 +  * 18 AWG is recommended for all wires except pin 11, which should be 22 AWG. For 300W configurations 16 AWG is recommended.
 +
 +
 +
  
Last modified: le 2022/10/26 17:33

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