Brett, Garey, A big old iron has worked the best for me on chassis soldering. The old irons take foreverrrrrrrrrrr to heat up and cool down. Their thermal mass can transfer heat about as long as it took them to heat up. If I use a gun it is a Weller WD250 or larger. But I prefer the iron.
The next time you see an old American Beauty 150 "ugly queen" in reasonable shape for $5 at a hamfest, pick it up for chassis work. About the hardest part is finding new tips. 1/2 inch diameter copper rod is kind of a special item now days :-) But a single decent tip should last a lifetime if you take care of it. Especially if you only use it for chassis or PL259 work. Wire solder/desolder is about a lot of heat fast and get back off just as fast along with a good solder sucker. I use the WD250 when it will fit, otherwise a Weller 8200. Still the insulation in the Drakes wants to run. I don't think there is any way around it. I am still perplexed as to how they soldered it so beautifully in the first place. I suppose solder "work vs rework" has a lot to do with it. 73, Ron WD8SBB --- On Tue, 10/20/09, Garey Barrell <[email protected]> wrote: > From: Garey Barrell <[email protected]> > Subject: Re: [Drakelist] Cap question > To: [email protected] > Date: Tuesday, October 20, 2009, 11:12 AM > Brett - > > Those are what used to be called "Twist-Lok" caps, or at > least that was Mallory's name for them. There are four > tabs around the rim of the mounting end that go through > either slots or a central hole in the chassis. When > slots are used, the tabs were just "twisted" to "Lok" the > cap can to the chassis, or for the mounting method that > Drake used the tabs were just bent out over the edges. > One tab is soldered to ensure a reliable ground connection. > > Soo... Removal is somewhat difficult for a couple of > reasons. > 1. The tab soldered to the chassis requires a LARGE > soldering iron or soldering gun to transfer enough heat to > melt the solder.. > > 2. The wire used by Drake is _extremely_ > heat sensitive, so that even having a large iron nearby is > enough to melt or at least deform the wire insulation. > > The procedure I use is to FIRST make a careful drawing, or > better yet a digital photo of the area to record which > terminal each wire goes to. Once you are satisfied you > can replace each wire to the correct terminal, which are the > + terminals of each capacitor, as close as possible. > > Once the wires are out of the way, look at the brown > phenolic insulator on the bottom of the cap. You'll > see a Triangle, Square and Half Round figure etched in the > phenolic by each of the + terminals. The replacement > cap will have the same figures to identify the > _different_ sections of the capacitor. If you > get your replacement from Tom at > <www.hayseedhamfest.com>, the etched figures will be > in the same order as the original. > > Removing the tab soldered to the chassis is the hardest > part of the process. Push all the wiring as far as > possible from the soldered tab, then apply your LARGE iron > to the tab. When the solder melts, twist the capacitor > can to get the soldered tab away from the solder area on the > chassis and free it. Then bend up the tabs and remove > the can. > > Insert the new can in the hole, carefully orienting the > etched figures exactly like the original. Using your > drawing and/or photo, strip and connect each wire to the > appropriate terminal and solder _carefully_, and with > a big enough iron to heat the terminal, solder quickly and > get off so as not to melt the insulation on the wire. > > As usual, much more difficult to describe than do, but > there are pitfalls along the way, primarily the heat > sensitivity of the wire insulation. If the insulation > DOES pull back in spite of your best efforts, be sure that > the bare wire does not touch anything. The wire is > solid, so it holds it's position pretty well. If you > have some insulation from another piece of hookup wire, slip > it over the bare wire if you can. > > 73, Garey - K4OAH > Glen Allen, VA > > Drake 2-B, 4-B, C-Line & TR-4/C Service Supplement CDs > <www.k4oah.com> > > > > Brett Forehand wrote: > > Ok, I've been told there's no such thing as a stupid > question... so here goes! How do you remove the > canister caps in the R4C? Do they just unplug, do they > come out with a twist and pull, or do you have to unsolder > them from the bottom of the chassis? > > > > Thanks, > > Brett > > > > > > _______________________________________________ > Drakelist mailing list > [email protected] > http://mailman.zerobeat.net/mailman/listinfo/drakelist > __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com _______________________________________________ Drakelist mailing list [email protected] http://mailman.zerobeat.net/mailman/listinfo/drakelist
