As you may have noticed, my SB-600 could use some cleaning.

I did not build this one myself. It used to serve on a club station with a now long decommissioned SB-100. After years in dark and dusty storage it got a new life as a partner to my SB-104A. It is not as stylish as the SB-604 would have been, but appearance wise it was an improvement of the non-boxed speaker element I had been using so far.

To clean it I removed the internal HP-23E power supply that I do not need. It is meant to be used with many tube type transceivers. It’s condition is unknown but I didn’t want to harm it with liquids. Turned out it was secured with only three of the four screws and no washers. Not metric screws of course 🙄

I wanted to remove the speaker element and the wooden plate temporarily for the same reason. However the way it is supported is unclear to me and I couldn’t find a manual online. More precisely, I could find SB-600 manual scans online, but they were all missing the critical pages. Do you have a more complete manual? Another reason I wanted to work on it was that I would want to move the front grid back so that the screws do not protrude outside the front edge. Looking at pictures on the internet, this one seems to be modified.

I noticed it is also lacking rear rubber feet, so I will have to fix that. It could also use a paint job to cover the scratches. Unfortunately Heathkit was not very consistent in the colors used.

Anyway, with some effort (and care) it is much cleaner now.

A cleaner SB-600. In background part of HP-23 supply getting capacitors charged by IP-2728 power supply (center right). Charging current measured by IM-5284 (front right).

And it still makes sound.

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