Retro: Philips 1542 DC power supply

RE: Retro: Philips 1542 DC power supply

Wintitech — Mon, 28 Jul 2025 09:28:52 GMT

Hi Jan,

I have actually repaired the same power supply - the main capacitors were dried and made interal short circuit.

One open issue I have, but not sure if its immanent in the powersupply: When you turn the Current limiting knob (0-3A) of the 5V output down to zero, the voltage will be cut off.

But when you turn the powersupply off and then on again, there will be a 5V output given for about a half of a second, before it returns to zero again.

Do you have the same effect on your Powersupply?

Kind regards

Andy

RE: Retro: Philips 1542 DC power supply

kkazem — Wed, 01 Jul 2020 03:29:46 GMT

A nice, beefy linear power supply. Just look at those 2N3055s (TO-3 transistors). You don't see much of that package anymore. They do have certain advantages, like low Rthj-c and they're usually hermetic.

RE: Retro: Philips 1542 DC power supply

Jan Cumps — Sat, 13 Jun 2020 20:45:54 GMT

I'm digging in deeper:

[View:/resized-image/__size/620x333/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-947ea096-5eed-4215-9fee-b6fc88084362/4530.contentimage_5F00_191478.png:620:333]

[View:/resized-image/__size/477x777/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-947ea096-5eed-4215-9fee-b6fc88084362/1881.contentimage_5F00_191479.png:477:777]

[View:/resized-image/__size/620x249/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-947ea096-5eed-4215-9fee-b6fc88084362/3060.contentimage_5F00_191480.png:620:249]

[View:/resized-image/__size/620x341/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-947ea096-5eed-4215-9fee-b6fc88084362/6082.contentimage_5F00_191481.png:620:341]

RE: Retro: Philips 1542 DC power supply

Jan Cumps — Sat, 13 Jun 2020 10:05:12 GMT

A view inside the switches:

[View:/resized-image/__size/272x473/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-947ea096-5eed-4215-9fee-b6fc88084362/1803.contentimage_5F00_191476.png:272:473][View:/resized-image/__size/394x470/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-947ea096-5eed-4215-9fee-b6fc88084362/0825.contentimage_5F00_191477.png:394:470]

Channel A end C work as expected now. Channel B seems to have other issues in current mode...

RE: Retro: Philips 1542 DC power supply

balearicdynamics — Sat, 13 Jun 2020 05:27:27 GMT

It is a great device, I saw it live, and it is really nice [View:/resized-image/__size/16x16/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-947ea096-5eed-4215-9fee-b6fc88084362/contentimage_5F00_1.png:16:16]

RE: Retro: Philips 1542 DC power supply

Andrew J — Fri, 12 Jun 2020 21:33:47 GMT

That’s some heat sinking going on there, no wonder there’s no fan. Looks good for its age, really dust free - I guess there’s no case holes.

RE: Retro: Philips 1542 DC power supply

Jan Cumps — Fri, 12 Jun 2020 19:53:32 GMT

Little preview of the repair:

[View:https://www.youtube.com/watch?v=7bqMBzcRQcg:1110:699]

RE: Retro: Philips 1542 DC power supply

genebren — Fri, 12 Jun 2020 18:15:47 GMT

Very clean package. Nice to see vintage test equipment.

RE: Retro: Philips 1542 DC power supply

Jan Cumps — Fri, 12 Jun 2020 17:44:59 GMT

I'm opening it up to fix the volt / amp switches. I'm filming the exercise, and have taken some pictures.

Video is for later, when the project is finished.

[View:/resized-image/__size/512x780/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-947ea096-5eed-4215-9fee-b6fc88084362/6180.contentimage_5F00_191472.png:512:780][View:/resized-image/__size/466x771/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-947ea096-5eed-4215-9fee-b6fc88084362/3463.contentimage_5F00_191473.png:466:771]

RE: Retro: Philips 1542 DC power supply

geralds — Thu, 11 Jun 2020 19:49:09 GMT

[View:/resized-image/__size/16x16/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-947ea096-5eed-4215-9fee-b6fc88084362/contentimage_5F00_930.png:16:16] It is a typical µA723 power supply. "... hmmm ..." sweet "! - the scent of pertinax.