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Word to the wise: DO NOT POKE, PROD, BEND, WIGGLE, HEAT, SPRAY, TIGHTEN, LOOSTEN, LICK, or MEASURE the magical can of ohms buried inside. The moment you do anything directly to it (Measuring it by making your connections at the OTHER end of the wires connected to it might be OK.) it will flip its shit. As to the filter caps: Schematic(Parts list) says 4µF, some have found Solar branded 8µF units in theirs, and mine had what appeared to be the factory original in it, which was a dual 10µF @450WVDC, and I replaced it with a pair of 10µF 700V film caps. (Yes I know, overkill all around, but at the time I was rebuilding it, nobody had a straight answer as to how much voltage they actually see, going consensus was 450v rated caps might not be enough, plus film caps are less likely to fail short and take out the delicious 1V rectifier...) These: http://www.mouser.com/Search/Product...1848S61070JP2C Not really expensive when you note that the only suitable electrolytic replacement which is only 450V is only a tad more than half the price... http://www.mouser.com/ProductDetail/...pA4A0AnJua4%3d Look at the load life figures... 100,000 hours on the film cap, and 2,000 on the good electrolytic. Sure there's probably never been a Solar CB-1-60 that's even seen 2,000 hours of operation, but I'll be damned if the next guy who restores it can fault my choice! Here's the schematic and parts list out of the operation booklet for anyone who may need it, linked for table-destroying resolution. (Own hosting obviously.) http://www.funkengine.net/vk-img/201...-Schematic.gif http://www.funkengine.net/vk-img/201...parts-list.jpg Regarding the whole 4/8/10µF thing, looking over the datasheets for the 1V rectifier there's no hazard with 20µF of filter caps hanging off of it. I wouldn't go much higher though. Other tips: Be sure to swap out R12 and R13 on the eye-tube, and also R4 and R5 up by the neon leakage indicator to be sure of getting proper results. If your eye-tube is pretty much all used up and nearly dead, you can move the eye tube's plate/target B+ connection(along with the + side of C7) from the original junction of R9 and R10 (both part of cannedohm unit) over to the junction of R8 and R9.(So one lug further away from the grounded end of the cannedohm) This will increase the voltage on the eye tube by ~40%, so only do this to get the very last drips of use out of an already all but dead tube. I got in on on a few of the Japanese 6E5s produced in the 70s/80s (Nobody knows for sure, but they're of visibly "modern" construction.) and I can actually use mine without difficulty even at 3500+ lux on my workbench. The tube it came with was still quite good, but I pulled it out of service and safely packed it away for future "complete period accurate" uses. My only gripe with the Japanese new-manufacture tubes is that the phosphor used on their target is the standard "ATM screen" grass green instead of the "any non-Tektronix oscilloscope made before 1978 screen" dark green. I'm actually considering splitting R10 into 3 sections and seeing how far down I can turn the wick to extend life via reduced target voltage. Ok, so maybe the original tube was more like "5.5 ouf of 10" in terms of luminance, looking back over the photos... Here's one of the "before" reference shots, the Solar badged dual 10µF electrolytic is dead center... Now looking at the "after" photo I'm ashamed at how terrible it came out... Consider "re-work the Solar to improve mechanical and aesthetic conditions" moved much closer to the top of the "easy evening projects" list... Edit: Quote:
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Well, sometimes it gives you 10µF and the WV of whichever cap out of the two in series isn't dead-shorted. Generally though yes, two caps in series works like two resistors in parallell, if they're the same value you get half the capacity, if they're mismatched values you reach for the nomogram and/or slide-rule. Last edited by NoPegs; 07-22-2015 at 10:43 AM. |
#2
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These schematic links posted here will be tremendously useful! I think the thing to do is look at the tech data and check the existing components for clues as to what may have been going on. Oh, and my box lid does have shellac looking stuff around it, but the interior bottom looks more dirty, oily, waxy......
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"Face piles of trials with smiles, for it riles them to believe that you perceive the web they weave, and keep on thinking free" |
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No problems! Glad to help whenever I'm able to. I went ahead and tossed up the complete operation manual if you or anyone else needs it. I also dug out the best datasheet for the 1V or IV (eye-vee) rectifier tube. It mentions a value of anything 40µF or more needing special design in terms of inrush current limiting. However if you use 10µF caps like most of us are, that's only 10µF directly on the plate, the other 10µF has ~20K ohms in series with it, nothing to worry about there... Drip some ethanol (aka denatured alcohol, not rubbing alcohol though...) on the stain, then daub it with a paper towel after 30 seconds or so. If your paper towel looks like you just wiped up a spill of cola then that's all shellac, and unlikely to be transformer wax... (Ethanol usually won't touch any of the waxes used for potting, it will however pick up carnauba wax to some extent...) |
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Everything on my unit works. Some bridge readings are dead on, then one will be too far off. Nothing is getting hot, but I know the tranny would have been hot quick on the filter caps I yanked with corrosion weeping out of the ends. Basically, I just don't like hearing my transformer to this degree. Are some 30s-40s transformers just louder in general? I wonder because my little Heathkit C2 also is quite noisy. The C3s I have are almost silent. I'm sure that wax in old transformers was in part to provide sound deadening properties & if it's gone perhaps you have what I have described. I'm just sharing and gathering thoughts before I break out my Simpson 260 for current checks.
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"Face piles of trials with smiles, for it riles them to believe that you perceive the web they weave, and keep on thinking free" |
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