Amiga 500 Not Powering On – Help with Power Supply Troubleshooting

[idioms]

Hey everyone,

I'm having some trouble with my Amiga 500 and hope someone here can help. The machine was working fine a couple of weeks ago, but recently, it started having power issues. Here’s what’s happening:

• When I turn it on, sometimes the power LED doesn’t light up.

• The machine occasionally won’t boot, and the screen stays black.

• Sometimes I hear a clicking sound from the power supply.

I've tried the following things so far:

• Checked all the connections and made sure everything is plugged in securely.

• Swapped the power supply with a known working one, and the Amiga boots up fine.

• Checked the power cable, and it seems to be okay.

It seems like the power supply is the culprit here. Does anyone know what might be causing these issues? Are there any common fixes I can try before deciding to replace the whole power supply?

Thanks in advance for any help or advice.

Elena

[offog]

That sounds like your power supply is on the edge of failing to start up owing to aging capacitors.

The stock Amiga PSUs are all switch-mode designs - the AC input is rectified to DC, then "chopped" back to AC by an oscillator at a much higher frequency than the original input, before being fed into a transformer. No output voltage and a quiet ticking noise (from the transformer) indicates that the oscillator isn't running.

The most common cause of this is that the electrolytic capacitors in the PSU are worn out. Even good-quality capacitors are designed for a service life of a few thousand hours at the high temperatures found in PSUs, so any well-used Amiga PSU is likely to need new capacitors by now. Modern replacement capacitors are readily available, and the boards are easy to work on if you've got experience repairing PSUs, so if you've got a friendly local electronics repair place then they'd be able to sort it out for you.

(The fancier solution is to replace the board inside the PSU with a modern power supply module - e.g. one from Mean Well - which will be a bit more efficient and have better safely features. But that's a lot more work than just fixing the existing board!)

[Liqourice]

To be honest, most of the work when I replaced my 500 PSU with a Meanwell one was fitting it inside the case. Desoldering the cables and connecting them was a quick and easy job.