Looking for an ATX PSU for a VERY HEAVILY EXPANDED A4000 - looking for suggestio

[Reflex]

Hello,

i have a very extremely expanded Amiga 4000 in a full tower case, i added really a lot of boards and all the PSU i tried are not powerful enough on the 5Volt rail.
I mean, using this one: https://www.amazon.it/gp/product/B01AKWVTVQ/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&th=1 i only get 4,3 volt on the CSPPC, i was able to find an old school 350Watt ATX PSU that gives 5,2V with no devices plugged but in my A4000 it gives just 4,5/4,6 volt so it's not enough too.

I have to get 4,8/4,9 volt on the CSPPC in oder to obtain stable operations.

Any suggestions?

[Boing-ball]

Hello,

i have a very extremely expanded Amiga 4000 in a full tower case, i added really a lot of boards and all the PSU i tried are not powerful enough on the 5Volt rail.
I mean, using this one: https://www.amazon.it/gp/product/B01AKWVTVQ/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&th=1 i only get 4,3 volt on the CSPPC, i was able to find an old school 350Watt ATX PSU that gives 5,2V with no devices plugged but in my A4000 it gives just 4,5/4,6 volt so it's not enough too.

I have to get 4,8/4,9 volt on the CSPPC in oder to obtain stable operations.

Any suggestions?

Well funnily enough. I’ve recently built a A4000 Tower using the Amigakit A4000 to ATX kit. I’m using a Corsair RM850 ATX PSU. I always use these in my builds. Have the 450SFX Corsair in a Checkmate A1200 as well as in a A4000D in its original Desktop case. Gives plenty of power. I wouldn’t skimp on a quality PSU.

[Reflex]

i read the specs of the corsair RM850 and it gives just 20A on the 5V line, the ATX i have gives more than 30A on the 5V rail and it's not enough, so it will not solve the problem as i have a VERY expanded A4000 and i'd like to find a solution without unplugging any board

[mechy]

If this wont handle it you likely have some short between +5 and ground somewhere.

https://www.ebay.com/itm/313861638274

Check the motherboard power connector pins,sometimes +5 will spread out and get loose,causing resistance and heat.
Note the Amigakit atx adapters only have a 18ga. +5v wire i believe and this could be limiting. If you are using a mediator that has power to it, the old p8/p9 connector is notorious for the 5v pin failing. Mine actually got hot so i eliminated it and solder 5v direct.
good luck

[Reflex]

yes actually i have a mediator and AmigaKIT ATX adapter, so maybe the problem is there, how can i solve? Is there any other adapter i can use?

[mechy]

There are no other adapters sold i know of. The connectors pins etc. are available from mouser electronics and you can use 2-atx+5v wires to a new crimp pin in your adapter or one heavier gauge wire(16 or 14awg).Did you check all the main power supply and motherboard connectors for bad contact and discoloration from heat? Assuming the A4000 motherboards been recapped and the zorro cards you are using have been recapped(old Tantalum caps can short and draw excessive current). Also address the Cyberstorm PPC card, I just replaced caps on mine,they were physically leaking.
The fast slot can have bad contact with the accelerator also. i install metal standoffs instead of plastic pins to stop the accelerator from creeping out of the slot over time and heat cycles. Deoxit is good for cleaning slot connectors. to be loosing so much voltage on the 5v rail is not normal and something seems to be dragging it down.

[Reflex]

Hese recapped and made an heavy check of the MoBo so it is 100% OK, it's just a matter of Power Supply.
About the CSPPC Stachu100 changed all the Capacitors and upgraded the PPC to a 400mhz.
So the problem is not there.