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|    sci.electronics.repair    |    Fixing electronic equipment    |    124,925 messages    |
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|    Message 123,443 of 124,925    |
|    Guy Patterson to ohg...@gmail.com    |
|    Re: Vintage Radio Dial Cord Replacement    |
|    24 Jan 23 07:36:33    |
      From: str00ntz@aol.com              On Tuesday, January 17, 2023 at 9:56:42 AM UTC-5, ohg...@gmail.com wrote:       > On Monday, January 16, 2023 at 6:34:48 PM UTC-5, Cursitor Doom wrote:        > > Anyone successfully done this? If so, what's the secret? I've been        > > f***-arsing around for 4 hours today trying to do one on a 1972        > > Grundig portable FM/AM radio and got nowhere. The design is most of        > > the problem. For some reason, the drive pully is completely smooth and        > > affords no grip to the cord whatsoever, so the thing just slips around        > > such that the pointer only moves when it can get a bit of traction.        > > What a f***ing joke.       > Friction, friction, friction... not at the drive pulley where the dial cord       grabs but everywhere else.        >        > You must eliminate all possible friction from everywhere in the tuning       system. Make sure the tuner's bearings are free of hardened gunk and lubed.       When disconnected, the tuner should only require a very light touch to rotate.        >        > See those little pulley's that handle the string? They absorb all the       string's efforts if they're dragging (and get worse with string tension on       them). If you can remove them, clean and polish the shafts and apply some       graphite. If you can't remove        them (some are staked on), then run some non aggressive solvent into the shaft       and spin by hand until the move with no effort. With a small jeweler's       screwdriver, add some graphite to the hub and tap so the graphite gets inside       the pulley. Don't "poof"        the graphite in as it will probably get on the pulley's surface and transfer       it to the string where it might make it back to the drive pulley shaft.        >        > A lot of guys miss the dial indicator.. they're usually just folded metal       that slide along the metal dial scale. Those things drag like you won't       believe. Sometimes the dial might have a piece of folded fish paper inside as       a bearing, but many don't.        In any case, clean and polish the edge of the dial with an abrasive if need be       to form a highly polished bearing surface. Rub some graphite into the area       right where the dial slides along. Careful not to get graphite on the dial       itself (unsightly).        >        > Before restringing, get a Q-Tip/ISO and clean the drive pulley shaft and all       secondary pulleys of lube or wayward graphite. If you excise all possible       friction, you'll find it will tune with no dragging, jerking, or stopping even       with less turns around        the drive pulley than the diagram calls for (resist the temptation of adding       more turns than it calls for - it only causes windup binding).        >        > I've had people pooh-pooh this advice and end up giving me the radio to       restring because they don't believe that tiny amount of friction will prevent       the dial cord from grabbing.                     Thank you!! After reading this, a light bullb went off and I decided to pull       out a troublesome Philco that has always slipped. I had some guys at Kutztown       restring it about 5 years ago and it worked for a few days and started       slipping again, so I        stopped using it. Nothing more frustrating than trying to change the station       or even tweaking the tuning as it drifts after an hour of use. They put on       some liquid which was probably rosin and it worked great at the table. Too       bad it didn't last. You        were right about the pulleys. With the dial string removed they spun freely       but putting either a little side pressure or up pressure on them where they       might butt up against the peened top made them stiffen right up. That is       probably why the heavier        the spring I tried the worse it got. I used the wide end of a flat toothpick       to tap in a bit of graphite moly powder i had kicking around from Pinewood       derby between the pulleys and the shafts, and now the pulleys spin easily even       when I side load them.         I also found the top rail of the dial binding when I pushed down on it just       like you said. I used a small needle file and dressed the top edge and then       sanded it smooth and rubbed in some graphite with a qtip so I wouldn't get any       on the dial face and        now the dial indicator pushes smooth even when I put pressure on it. The       tuner itself seemed free but I added a couple of drops of light synthetic oil       to the bearings anyway. My Philco now tunes like butter and I can even put my       thumb on the big tuner        pulley and it still pulls the tuner through. I can now tune and fine tune this       radio for the first time ever. Thanks so much. I will do this with every       radio I have from now on.              --- SoupGate-Win32 v1.05        * Origin: you cannot sedate... all the things you hate (1:229/2)    |
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