06-10-2012, 02:56 PM
This is my general method for solving problems such as what you describe. It'll need adapting to any specific chassis, model - and the particular job to be done. In a phrase, "How do I get this *^$* thing hot enough?"
If you haven't already done so, remove the tuning capacitor from the chassis, making a note of its wire connections: cut them away from the cap. Usually, removing a tuning cap. means disturbing the drive cord: I usually fix the cord to the various pulleys, etc. with Blue-Tack; perhaps Plasticine will do, or even sticky plastic insulating tape. Now you can put the chassis aside and concentrate on cleaning up the solder connections to the tuning cap. You may find that as it is now out of the chassis, the unwanted heat-sinking effect has gone, enabling you to proceed with the clean-up. Otherwise use a hot-air gun - I use a paint stripper - and heat up the solder joints. Don't apply excessive heat, since that will dry out the tuning cap's. bearings. Then to make the job worthwhile, since the tuning cap. is out of the chassis, give it a good clean using any of the established methods. Finally re-assemble and re-wire.
Of course, a lot of that work can be avoided if you are able - and are prepared to take the risks - of heating the tuning cap. solder lugs with the tuning cap. in situ: all depends on the construction of the particular radio.
The ideal approach - which isn't any help to you right now - is to acquire a 'Metcal' soldering iron: with its 1/4" bit, I can solder direct to 18 s.w.g. steel plate.
Failing that, keep a lookout for a big soldering iron - something like a 200-watt job. Occasionally I've seen those at car boot sales, auctions and house clearance sales: usually they are remarkably cheap: I've got two! But sometimes the heat-gun approach (and a really hot iron) is the only answer - and it's a lot quicker.
Al.
If you haven't already done so, remove the tuning capacitor from the chassis, making a note of its wire connections: cut them away from the cap. Usually, removing a tuning cap. means disturbing the drive cord: I usually fix the cord to the various pulleys, etc. with Blue-Tack; perhaps Plasticine will do, or even sticky plastic insulating tape. Now you can put the chassis aside and concentrate on cleaning up the solder connections to the tuning cap. You may find that as it is now out of the chassis, the unwanted heat-sinking effect has gone, enabling you to proceed with the clean-up. Otherwise use a hot-air gun - I use a paint stripper - and heat up the solder joints. Don't apply excessive heat, since that will dry out the tuning cap's. bearings. Then to make the job worthwhile, since the tuning cap. is out of the chassis, give it a good clean using any of the established methods. Finally re-assemble and re-wire.
Of course, a lot of that work can be avoided if you are able - and are prepared to take the risks - of heating the tuning cap. solder lugs with the tuning cap. in situ: all depends on the construction of the particular radio.
The ideal approach - which isn't any help to you right now - is to acquire a 'Metcal' soldering iron: with its 1/4" bit, I can solder direct to 18 s.w.g. steel plate.
Failing that, keep a lookout for a big soldering iron - something like a 200-watt job. Occasionally I've seen those at car boot sales, auctions and house clearance sales: usually they are remarkably cheap: I've got two! But sometimes the heat-gun approach (and a really hot iron) is the only answer - and it's a lot quicker.Al.
