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| Congratulations! I forgot that I actually own a set that is similar to your's (electrically). I own the 180 which also has a phonograph. It uses all #27 tubes and no #26 tubes. It is a wonderful set. I don't use it currently because I need to build a power supply for it. I built one with lower B power just for a temporary and haven't gotten around to building the real thing. The original supply is missing. Anyway, great set. If the rubber around the speaker on your set is stiff, you can replace it with suede. Remove the rubber carefully and remove the ring around your speaker cone (or maybe you should remove the ring first). It is attached with screws. Cut out a piece of extremely thin suede (like khaki pants thin). with an inner diameter slightly smaller than the diameter of the paper cone. It should overlap by 3/16 to 1/4 inch. Glue with Elmer's white glue. The outer diameter should be the same as the speaker frame. After glue on cone has dried, place a bead of glue around the frame (thin bead). Press the suede into place and stretch evenly a slight amount until speaker cone is centered. Cone should move in and out without voice coil rubbing. Cone should move freely for good bass response, but tension should be enough to maintain a centered voice coil. Shim voice coil in three evenly spaced places with 3/16 inch wide strips of index card material...perhaps something slightly thinner. Tighten down metal ring over suede with the ring's retainer screws. Allow to dry. Remove shims and test speaker. Bass response should improve dramatically if the original rubber was hard. If you can find a thin rubberized cloth like the original with extremely good flexibility, this will be better than the suede, as suede is organic and changes with humidity. I have used suede successfully many many times, however. I even used it on one of my friend's car speakers. The original foam rubber surround dried out in the hot sun (speaker from 1990). Speaker has been working fine now for 2 years even though car is in both hot sun and sub zero temperatures. You may even be able to find a rubberized cloth surround at a speaker reconing shop, that would fit your speaker. Perhaps you could find an affordable speaker of the same size from say Radio Shack. You could remove this surround from the speaker and use it on your's. This might be more effort than it is worth, though. The glues on modern speakers are tough. A long 70 foot wire should be used with the long wire antenna terminal on the rear of the set. A shorter, say 15 to 25 foot antenna will work for the short antenna terminal. Use which ever length is most practical for you. Run wire in a straight line. Never make turns or bends or have wire fold back on itself. Turns and bends cause inverse waves in the antenna, which cancel out signals and make the antenna inefficient. Suspend the wire outside. Fifteen feet is good. Higher is better, but not necessary. Too high and you attract lightening. The variable coil you see all the way to the left of the schematic is your antenna coil. This coil has a big metal cup that moves over it or away from it, depending upon which way the antenna trimmer control knob is turned on the front of the radio. On my radio this is the right hand knob. You can use this to fine tune stations. You will have to adjust it as you tune over the dial, as it reacts differently for different portions of the dial. If you leave it in one position for one side of the dial, the other side of the dial may be completely dead. Play with this knob before ever suspecting radio frequency alignment issues within the radio--if you haven't alrady played around with it. Once you get acquainted with it, you should find that the radio performs quite well all over the dial. The trimmer condensers on each of the tuning condensers can be tweaked (found in the big barn looking metal structure), but I don't recommend this if your radio functions fine. Your dial is most likely marked from 0 to 100 instead of in frequency markings. If you mess with the trimmers, you can throw things off since you don't really know where stations are supposed to fall. You could lose coverage at the high end of the dial if you tweak the trimmers in the wrong way. If you are having sensitivity issues, though, you can tune to a quiet station around 1400 KC. Align all of the trimmers for maximum loudness and selectivity (ability to differenciate between this and other stations). Thomas |
| Majestic Model 70B | |
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