SP-600-JX-6, #15182

(Click for full-size picture)	This is an SP-600-JX6, serial number 15182. Standard Frequency range, 540 khz-54 MHz in six bands. The first three bands use single conversion - the upper three use double conversion. BFO range 0-10khz. U.S. Navy model R-274B/FRR, order no. Nobsr-52039 19 October, 1954. Navships manual 91661. I did refinish the front panel. I used a darker grey so the engraving and the dials stand out better. I did repaint most of the black knobs knobs on this one. They were quite dull. The BFO knob was o.k., so I just polished it. I did not try to repaint the meter. I was worried that some paint would get into the mechanism. I applied dial overlays to both the frequency and the vernier dials (originals on the back). I also had to overlay the band readout dial. Large hunks of paint had flaked off. I will warn you that the unit, in person, doesn't look as good as these pictures look. I don't quite know why, but the pictures look great, whereas the actual unit has some nicks and scrapes and rust spots on the chassis. This one had a bit more oxidation and pitting on the chassis than I like. I scrubbed it out as well as I could (no steel wool!). I replaced a lot (not all) of the hardware with stanless - especially on the front panel. Every time I took a screw out, I replaced it with stainless, and every time there was a markedly rusty nut or screw that I could get to, I replaced it. All the controls on this unit operate smoothly and without problem. This one has the smoothest band-change action I have ever experienced. The tuning is quite smooth. The weighted tuning knob spins easily. I did adjust it to drag slightly so it doesn't "walk" on its own. I did go through and replace all the set screws in the knobs with stainless. Maybe they won't freeze up like the originals did..
(Click for full-size picture)	I did wash and scrub the sheet metal with a scrubby sponge. No steel wool was used in the process. De-Oxit was applied to all the tube sockets. The chassis did not need any serious work - it was relatively clean and square. It was apparent that this receiver had not been dropped or otherwise mishandled. There were no bent edges or crushed corners. I replaced the missing tube hold-down clips on V3, V19, and V17.
(Click for full-size picture)	This is where I spent most of my time: the RF deck. All the caps were replaced with 600V ceramic. A number of resistors were replaced as well. I used a lot of shrink-tubing on the leads to prevent shorts but still allow you to get a tool in to align it. A number of wires were replaced. Several out-of-spec resistors were replaced. The caps were dressed to hug the ground plane wherever possible. I replaced the first RF tube with a 6JH6 for added sensitivity.
(Click for full-size picture)	This shows the recapping job on the IF and AF sections. All the orange items are 600V SBE (née Sprague) "Orange-Drop" 716P capacitors. A number of resistors had to be replaced in this area as well. Several capacitors were bad and were replaced. Most of the high-resistance (500K and greater) resistors were wildly out-of-spec and were replaced. I also replaced the (rusted) IF output connector with a new one.
(Click for full-size picture)	This is the rebuilt power section. I replaced the electrolytic with 47-uf, 450-V special high-ripple tolerant, long-life, electrolytics. You should be able to pass this one down to your grand-children.
(Click for full-size picture)	All the miniature tubes have the IERC heat-sheding shields. These are the only tube shields known to actually increase tube life. You will notice that some previous owner cut a large circular hole in the rear panel. He had put an octal socket there that brought out the send/receive switch wires, the audio out, +150V, and the IF out. I think he had wired it to an external SSB converter and maybe a send-receive relay or something so that he hits one switch and both the transmitter and receiver switch. I took all that stuff out. Unfortunately, the hole he left us with is not a standard size, so my normal hole plugs don't fit. Sorry.