• 2024
  • Sep
  • 19

The McMurdo Silver “Sparx” Model 905 Signal Tracer - Photos

One of the things I like to do before closing up a device (permanently, or for a while) is to do a good photo retrospective showing layouts, parts, etc. It usually will be submitted to someplace for posterity, and displayed here for your enjoyment. You can also check out Radiomuseum, who accepted a number of pictures for their exhibit on the device.

I had to resize these - they were simply too large and were causing some issues.

The 905 tracer is going on display for the moment, so here are some photos of all the goodies inside:

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The front of the unit. The pilot lamp was not original on this unit, and this one received a nice LED bulb. I pulled the screen out and knocked the dents out as best I could, you can still see a little wrinkling there.

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Here’s the back. Note the big holes for cables at the bottom, this one only has a power cord.

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You can reach in and touch the transformer taps. Designed for those who have some sense.

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This unit has little dimples for the feet, so no crushed rubber.

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The side. It’s…the side.

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The device uses a leather handle. It’s still intact, but I’ve tried not to use it.

Here’s some shots of the chassis:

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The best part - the tubes are all lit up:

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In all, this is a pretty cool device and doesn’t have a lot of things other than it’s basic function of amplifying sound. For now, it’s going to be a showpiece - but eventually it will be used as a small amp in my main room, as I already have a tracer I’m working on rebuilding. I am planning on replacing filters and other electrolytics on this at some point, so stay tuned!

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