SP600 s/n 4596 R-274A s/n 1965
Initial survey was made in 2004.
Both big knobs have broken skirts, not all pcs were in the crate, some broken b4 shipment. S-mtr had no screws holding movement to case, but cks out OK. Phasing shaft & knob gone, 1/4" jack in it's place. No bottom turret cover or 3.5mc osc. can, does have full bottom cover, all tubes present, 8 tube shields missing. The 3 "big tube" hold-downs are present. T-4 & T-5 have been recapped, I did T-2 so all cans OK now. Can see BBOD's inside RF deck, 3 hole plugs missing. All xtal hold-downs on FCU are broken. Both fuses are bypassed - no fusing! A few caps have been replaced under chassis. Some knobs loose on shafts, many hard to remove, burrs on shafts.
Put 60w litebulb under it for 4 days, brought up slowly on variac afterwards. Working in general, but something flakey with AF gain ctrl, it has little or no affect.
Before starting work, May, 2005.
After initial disassembly and cleaning, June, 2005
Closer inspection of panel once removed indicate that it should be stripped and repainted. Gouges around the FCU xtal sel. knob, some in other areas, but not nearly as noticeable. The bottom right corner is slightly bent, not past the rack mount slot, that's a reflection from overhead.
Here are some pix of a cabinet that will fit the SP-600. It has top & bottom covers which are attached with Dzeus fasteners. The side edges of the top fit into a slot on each side, so it is not easily removed. It has been sand-blasted & primed, should be wet sanded before a top coat is applied. The front panel is recessed abt 3/4", overall dim. are 20-1/2 x 20-1/2 x 12 inches, about 2" deeper than necessary for the SP-600. The grayish marks are dirty, not scratches.
Have tried my best to make some progress this week, did make some, but spent one day fixing the shop air conditioner. Glad it waited a day, the previous day tied a record for the hottest. Probably cooled off abt 5 deg. F the day I had to remove it & do some electrical repairs & cleaning. Works fine now.
IF section, done
The capacitors under the selectivity switch, and in the xtal osc. have been changed. This is the almost toughest area to do, the RF deck is more work but it represents almost half of the total recap work time - that and the FCU remain to be done, along with an hour or 2 of recap work still under the chassis..
Another pic of the front panel, with components removed, and the top right area with deep scratches. I flattened out the dent at the bottom right after the pic. I'll get it stripped for painting next week.
--- I was away for 11 days, unexpectedly, took the panel & one other with me in case
I had time to strip & prime, but didn't.
8/12/05 I have been at work this week since getting home late Tues. Took until Thurs. to feel like working, tho'.
The IF section, audio section, bias filter and B+ filter section are done now, all that remains under the chassis is the AC-line replacement/re-wiring and assoc. bypasses (& the turret). The old bathtub for the AC bypasses is still in place, all other bathtubs have been replaced with discrete caps. I think the filter caps on 2 small terminal strips worked out nicely, slightly different than I've done before. The 3 10k decoupling resistors on the bias line were replaced, as well as the 3 associated electrolytic caps, which had been bathtubs. Several out of tolerance resistors were replaced throughout the above work.
Audio secn bias supply B+ filters
Next to the few modules in the turret that have BBOD's, and the FCU. Then the RF deck.
8/16 Replaced the BBOD's in the 6 turret modules, cleaned and replaced the left side panel. Removed the FCU.
8/17 The FCU has been really butchered. The switch is probably unrepairable, several (5 or 6+) wires inside have been cut. I removed the FCU from another rcvr, opened it and found it has been re-capped, and it has all good xtal hold-down clamps. I'll use it in this rcvr, probably will not replace it in the other one, will make it a "plain" SP-600-J, after filling in the holes on the panel. Will clean/replace the rt side panel after getting into the "pod" to replace it's BBOD's, then I think only the RF deck remains, with its 21 +- BBOD's. No pix really show these 2 days' work.
New pix of the cabinet:
The panel is recessed from the front. There are rails front to back in the bottom, to support the chassis and make it easy to slide it in. The tope, bottom, and rear fasteners are Dzeus type. 2 flat-head screws hold a spring clip just inside, across the larger hole, a screw-like fastener fits thru the outside pc, engages the spring in a slot, and 1/4 turn clamps it down. (easier to understand seeing it rather than describing.) I think the "male" pc is captive also.
8/18 I've done the "new" FCU but not installed it yet, will wait until the RF deck is done, it's easier to get the the RF deck connections with the side panel off & FCU out of the way. Have done the "pod" & pulled the RF deck & started on it.
3 days of progress. The RF deck is done (20 BBOD's), the pod was opened up & it's one cap replaced, the RF deck re-installed, the pod closed, the filter chokes re-secured (they must be lowered to get into the pod).
The right side plate, turret top & bottom covers, and pod covers were all cleaned and buffed. The FCU & rt side panel is ready to go back on, as is the front panel, after I solve the problem discovered with the switch that connects the FCU output to the RF deck. The detent ball is missing, and the switch was almost frozen up tight.
The original front panel will not be used now, an identical one which I had powder coated earlier will be used, to save time on this job.
The "Orange Drops" in the RF deck are coupling capacitors between stages, the other 17 are disk ceramic bypasses.
8/22 - 31 The RF Deck is finished, the ant. connector changed out from the 2-pin balanced, to an SO-239. It was re-installed, as was the "new" FCU after recapping it. Buff/polish IF cans, left side panel. Clean knobs, install all items on the front panel & replace it (temporarily, it would need to be moved again). Stainless steel mounting screws and washers used for front panel. The dial bezels are replaced with ones that had been powder coated earlier.
Do complete IF & RF alignment. Dial required repositioning to track properly. Ck FCU operation with 4mc and 11.3mc xtals to cover both single and double conversion bands. It works fine on all positions. Replace limiter switch, the previous owner had installed one that couldn't be mounted properly. Clean & replace all tube shields. Recheck dial freq. alignment, it's OK. Polished hole plugs for RF Deck & Pod and installed. Clean bottom cover and prepare screws for it's installation.
This one's done and ready for delivery. 8/31/05. See you in Shelby.
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