Update – May 15, 2018: I have almost finished restoring the bottom of the unit (where most of the components are) and expect to have it working in the next week or less!

Bottom of TO6A Half Restored
A mix of old and new parts to replace drifted and/or leaky capacitors and resistors.

Update – May 12, 2018: Here is the Schematic with the parts labeled, this way you can easily see where you are on the schematic while working with only one paper!

Sprague TO-6A Schematic Parts Labeled Hallman Labs

Decided to do what they call a shotgun restore of this unit. I will be replacing all fixed value parts including capacitors, resistors and I already got replacement tubes including one September 1964 JAN Philips 6AB4, one Sylvania USA Oct. 1970 6C4WA, an Amperex USA July 1968 6BL7GTA and finally a Sylvania JAN 6E5 VT-215 “Magic Eye” tube. I already had all the capacitors I needed to replace everything with almost factory identical equivalents including Sprague: Black Beauties, Atoms, etc.

TO_6A Rear 3_sm

Before I start to move/change things I need reference pictures in the chance I lose my spot where I was working, or can’t tell where one leg is meant to go. As you can see, this unit has a lot more going on than my CDE BF-50 cap analyzer.

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I am working with AntiqueRadios.com forums to get my unit back up and working, this way I can finally begin to sell my treble bleeds and individually tested tone caps with a 30 day guarantee.

You can find my thread detailing my progress and the community help here: http://www.antiqueradios.com/forums/viewtopic.php?f=8&t=340116&p=2851870#p2851870

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I hope to have this device working by next weekend, as long as the few parts I did need get here when they say they will.

TO_6A Rear 8_sm
Straight on shot of the rear of the unit.

PS: Does anyone know where to find the 7-27H combination resistance and amperage meter? I can’t find anything like it anywhere without having to buy a 2nd TO-6A. Note: the 7-27 found on the TO-6 will also work.

Forgot to show the bottom side of the unit! Here you go! I have a labeled schematic coming soon.


2 thoughts on “High Res Photos of My New Sprague Tel-Ohmike TO-6A

  • Edward Pittarelli

    I have a TEL-OHMIJE TO-6 A. Is there a place where I could sell it? It seems to be in great condition except for one missing knob.

    • You can get about $250-$300 for them on EBay, especially if they are fully working.

      I had to put my TO-6A project to the side as it was eating too much time with too little progress. I also learned you can do all of the tests the TO-6A does with modern equipment, just not an all in one package like the TO-6A and TO-6 offer.

      Thanks for reading Hallman Labs!

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