Astro city PSU not getting more than 4.8V

[kernelchagi]

Hello. My NAC PSU is not able to get more than 4.8v and is fluctuating a lot between 4.4 and 4.8v. It is receiving 115v of AC and is just recently full recapped.
The model is JQ10011.
Any ideas? Maybe the potentiometer regulating the voltage?

[kernelchagi]

Changed the voltage potentiometer, same problem. The psu had a 13k ohm, in the shop i went they only had 10k ohm and 20k ohm, with the 10k ohm im only getting 2.6v and with the 20k ohm im getting no more than 4.7v (like with the 13k "original" one).
Chacked the IC3 for continuity and it doesnt have. So should i suppose this is working correct?

[kernelchagi]

Okay replaced the IC with no result. I decided to give it a try and measure voltage with a PGM plug in... The result ks that i got 5.25v exactly and no variation...
But when i plug a raspberry pi 4 with a jamma to pi i start to get the voltage up and down from 2v to 4.5v like non sense. Any idea?

[grantspain]

someone else had this issue, i think they used an external psu to run the pi
it must draw more power than the psu is happy with

[kernelchagi]

someone else had this issue, i think they used an external psu to run the pi
it must draw more power than the psu is happy with

Thanks for the answer. It is little strange since this PSU should be able to output 5V and 7A and the raspberry only requires 5v and 3A...
Anyway do you think it is normal that the output voltage varies so much while unloaded? I have no clue about this.

[grantspain]

i worked on a astro psu this week, i did not see any fluctuation on 5v with no load attached
I do not know why the PI has issues on this psu but I know this psu has issues with alot of games that draw a bit of power - probably the reason a meatier psu was released for this cab

[nem]

it must draw more power than the psu is happy with

It's the opposite, it doesn't draw enough. It's less than 1A.

[grantspain]

it must draw more power than the psu is happy with

It's the opposite, it doesn't draw enough. It's less than 1A.

so its basically not sensing any load at all?

[nem]

Exactly.

[gamezer0]

Same thing is happening to me with a Raspberry Pi 4 (with RGB Pi Jamma hat), any other board I plug works fine (NeoGeo, CPS1, Mistercade…) I don’t have the PSU model at hand, but it only happens in one of my two Astros (they have different PSU model)

[nem]

Shouldn't be too hard to add some cement resistors on the jamma hat.