S/Line Restoration Project
Apr 5, 2008Public
Photo: The 75S-3B Receiver as purchased (5 April 2008). It's a "transitional" unit, built as they changed from the winged emblem to the round one. This front panel was originally made for the winged emblem. The remnant mounting holes are filled in with little countersunk phillips screws painted to match the front panel. (To follow additional description of the restoration process, go to http://www.w2pa.com and click on "Articles".)
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Photo: Inside the 75S-3B receiver. This rig has probably had cigarette smoke blown at it for about 35 years. There is a layer of brownish gunk coating everything. At the very top of the photo you can see a dark brown patch of convection-enhanced smoke staining which will wash away. The styrofoam "peanuts" are left over from it being shipped to the previous owner after repair - someone decided to fill the inside with these things. Ugh.
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Photo: The 32S-3 Transmitter as purchased.  Not to worry - that big blue '6' is only a sticker.
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Photo: Inside the 32S-3 transmitter.
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Photo: Front of the cabinet housing the 516F-2 power supply.  It's not actually a 312B-3 speaker, but rather is a 5165F-2 cabinet to which a speaker has been added.  The modification is professionally made and meant for this cabinet.  I don't know its origin (Collins or otherwise) but they seem to be fairly common.
Photo: Rear of the Power supply inside the speaker cabinet.
Photo: Maxi-Tuner, encased to match the S-Line.  These were made in the 1970s in either Collins or Heathkit colors.  I've seen them  with and without the meter circuit.
Photo: Interior of the Maxi-Tuner
Photo: Rear panel
Photo: Inside of the Maxi-Tuner
Photo: 75S-3B underside chassis - except for some styrofoam pieces, it looks fairly clean, as undersides usually are.  But it will get a cleaning anyway.
Photo: The receiver's top chassis with tubes, crystals and filter cover removed.  Notice the clean shadows left by the crystals on the blue crystal board.  The filters are, left to right, 200Hz, 500Hz, and 2.1kHz.  The spare position can be wired into the circuit if an AM filter is installed.  As-is from the factory it's unwired.
Photo: ...and with filters removed
Photo: Detail showing part of the preselector slug rail, a portion of which, at right, has been test cleaned using a dry Q-tip.  Looks promising!
Photo: After removing the tuning dial escutcheon (with drive shaft) and tuning dial.  The complete procedure is described in Collins service bulletin ASAB 1007, 1011 or 1014 – they’re basically the same.  They are downloadable from the CCA web site (http://www.collinsradio.org/Archives/Collins_Radio_Equipment_Manuals.aspx)
Photo: Rear view after removing dial and escutcheon.  Note illumination bracket, also removed, is to the left near the meter opening
Photo: The fiducial dial marker after removal.  Unfortunately I cracked it near the pivot hole while trying to remove it from the plastic pivot hub that is mounted on the front panel.  It should be easy to repair and will be hidden from view anyway when reassembled.  It will not affect the operation at all but I'm kicking myself nonetheless.
Photo: The removed, yucky looking main tuning dial
Photo: The back of the dial
Photo: Three screws hold the metal hub onto the dial assembly and hold the entire assembly together under compression, between the metal hub on the back, and the black ring in the front.  The kHz dial is fixed to the hub while the numbers dial turns independently.