About EEVblog

Check Also

EEVblog #1334 – Mystery Dumpster Teardown

Mystery dumpster teardown time! With the most amazing mechanical mains power switch you’ll ever see! ...


  1. You can’t really complain about the power supply components running too hot when you are operating the equipement with the top cover removed. With it in place, the air would enter through the slots in the side of the case and traverse a specific path, finally passing over the regs in the process. With the cover off, the air likely goes straight through the fan and out the back without any benefit. The fact that the fan speeds up after a short while probably means that there is a temperature sensor remotely located from the fan that is getting no airflow.

  2. It may be interesting to run the unit off 110 or 220, with the power selection appropriately set up and see what effect if any that has on regulator temps. Maybe running it on 240 line voltage just pushes it a little bit too hard.

  3. Since all the voltages seem a bit high, perhaps introducing an additional diode drop on the + and – preregulator rails would be useful.

  4. @circlotron, I guess the point is that if the regulators had been mounted on a sufficiently sized heat sink at the back of the unit (or maybe a heatsink that provides a thermal path to the chassis) the fan would not have been needed at all.

    Funny how otherwise well made equipment is let down by these kinds of things. I guess after solving all the filter maths, there just wasn’t enough energy left to worry about the power supply! 🙂

  5. Did it fix the filter in/out issue?

  6. Someone on the forum posted a photo of what an un-messed-with device looks like. It’s supposed to have a very large metal plate attached to the regulator and transistor that then screws into the transformer where the missing nut is.
    This heatsink shows that the designers id a better job with cooling than what it looks like by looking at Dave’s particular example which was obviously tinkered with a bit.

  7. I wonder if the person who sold it knew who you were and removed the heat sink to see if you could solve the problem!

  8. I think the large heat sink was dismounted because somebody tried to fix the problem with the input filter 😉

  9. I’ll take the easy fixes – every time – lol . . .

Leave a Reply

Your email address will not be published. Required fields are marked *