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Posted by D Sherman [72.47.153.24] on Saturday, March 24, 2012 at 15:18:00 :
In Reply to: Good old, much used American tool posted by Bob in North GA [71.30.10.94] on Saturday, March 24, 2012 at 13:01:13 :
The new Wellers look like the old ones but there are three very big differences. The old ones have a Bakelite case and rubber "heater cord" for the power cord. These won't melt if you accidentally touch the hot end of the iron to it, drop solder on it, or use it so long that the two fat electrodes heat up. The new ones have a thermoplastic housing and a vinyl cord, both of which are certain to melt if you use the iron much. The new ones also have aluminum electrodes rather than copper, or at least the cheaper models do, and the screws that attach the heating tip to the electrodes are in a less secure arrangement which makes for poor connections. All I have now are the modern versions, because my old 1950s Weller was in a tool box that got stolen out of my overheating Chevy pickup by some Mexicans at the Ryegrass Flats rest area on I-90. The box also had my great-uncle's 1920s hand drill that I used to use for just about anything and that was way better built than any small hand-drill I've seen since.
The key question is "does the iron still get hot?" If it does, the bulbs are surely burned out. The iron is nothing but a transformer. The trigger controls the AC to the primary, with two taps for "hi" and "lo" depending on how far you squeeze the trigger. The transformer has two secondaries: one very heavy single-turn secondary made out of copper tubing that constitutes the electrodes that you attach the tip to, and another secondary made of a number of turns of small wire that lights the "headlights". The basic arrangement is very similar to a spot welder.
With either the old or new Weller, I've given up trying to keep bulbs in it. The problem is that the voltage to the bulbs fluctuates wildly, with high-voltage surges that tend to burn bulbs out quickly. Also, the bulbs are in series so if one burns out, both are dark. Maybe your bulbs are good because you say the continuity is good, but maybe the filament on one of them is broken at the end and it can wiggle around and sometimes make contact and sometimes not. This would explain your flickering symptoms. Try getting a new pair of bulbs and trying them. I suspect it'll work fine. Then try each of the old bulbs one at a time, with a good new bulb in the other socket and shake the iron around. You'll probably find that one of the old bulbs is still good and the other one is intermittent.
In any case, definitely keep the iron because the new ones, although quite expensive, are built like junk compared to the old ones. Weller is a brand of Cooper Tools nowadays, which doesn't exactly have a reputation for high quality. Cooper is in turn a brand of Danaher, the holding company that bought pretty much all the old-line test and measurement companies except for H.P., including Fluke, Tektronix, and Kiethley. I'm still hoping to find an old Weller 200-watt soldering gun with a Bakelite case, solid copper electrodes, and a rubber cord at an estate sale one of these days. Meanwhile I use the modern version and wish I'd kept a closer eye on my tool box.
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