Adding heatsink to the A4000 voltage regulator

I’ll show you how to add a heatsink to the A4000 voltage regulator without soldering.

 

Background

A voltage regulator like the 7905 shown in this guide delivers -5v out even if you have an input of -10v. As with almost all things in the physical world excessive energy will be transformed into heat, so will the excessive voltage from -10 to -5 volt, that means the regulator becomes hot. I haven’t checked the input voltage on the Amiga 4000 but looking at the print beneath the regulator shows it gets really hot.

On some pieces of electronics you can see the PCB will be used as a heatsink around the regulator, this is done by attaching the regulator to the PCB with a screw. This is ok when it doesn’t become too hot and the engineers have done a good job designing it.

You can also attach a heatsink to the regulator, which is what I’ll show in a few.

 

Getting ready

Tools needed:

  • Thermal compound (optional but recommended)
  • Screw and a bolt
  • A screwdriver that fits the screw
  • A pair of tweezers or similar (optional), or a hexagonal top that’ll fit the nut

I couldn’t get a flat bolt, but the triangular headed screw can do the job. I cut the screw to a shorter size with a dremel.

I bought a few heatsinks on the internet, the silver ones were priced around €0.50 each

The dimensions of the medium sized one is 13.3 * 19.1 * 12.7mm

The black one is way too large, the small and medium ones are good choices. I could use the smallest one as the A4000 didn’t come with any at all, but I might as well use the medium one.

 

The mentioned voltage regulator

Ready to work

Add some compound on the heatsink, not much is required. The cut down screw with nut

I gently lifted the regulator to an upright position so it was easier to attach the screw with the screwdriver. The screw is preferably inserted from the bottom, it was a little troublesome to attach the nut when you don’t have a hexagonal top, but I managed.

The screw doesn’t need to be tightened with force, just enough when you feel a resistance and the heatsink is firmly attached.

 

The finished result from 2 angles

The regulator cannot be bent down vertically again, if you want this, you need to do some soldering.

 

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