I wanted to follow up with you on my little project with the Howard Radio model 418 that I have told you about before. I am pretty proud of myself, even though it isn't perfect. After all, I got it apart, cleaned it up, replaced a couple of parts, and got it back together ... and it works a little better than it used to! That is really something, in my mind.
Anyway, I should clear the air. After I got the chassis out, I made a boo-boo. I was going to take it out to the garage to blow it out, and it was damp outside. I wanted to put a plastic bag over it, so I stood the chassis up on end, thinking that it would stand there for a moment. Well, as soon as I let go of it, two things happened. First, I saw that it was tipping over (the tuning apparatus being so heavy), and it was tweeking the 6K7 tube to one side (I think it is one of the IF tubes, from it's position). Second, I reached out instantly to catch the thing, and my forearm tweeked the rectifier tube, which cracked the base.
The 6K7 is covered by a shield. The end result is that the lead wires were pulled out of the plug. I think, if I could get them all to go back into their proper connectors, I could sweat them back in and glue the base back to the tube glass. I'm not ready to try that yet, so I have replaced the tube in the meanwhile. (It is just that this is one of the original Howard Radio Company tubes, and I wanted to preserve them as long as possible. Oh, well!) As for the 80 rectifier base, I tested it before putting everything back together, so there is no risk of a short -- as long as I don't fool with it any more.
I did not solder the lead on the antenna coil, as you might have expected. The wire felt solid enough, though I didn't give it a lot of tension in testing it. I did get a good indication from my multitester, as well. So, I decided to wait until I had the thing back together to see if it was a problem. It appears not to be, after all.
Whether dust alone can cause the kind of corrosion I have described, I will leave to the experts. I have heard a couple of them discuss the problem, and they seemed sure of themselves. I know from experience, too, that dust is corrosive, but this may have been something more. Someone, thinking they were doing the machine a service, may have used a corrosive chemical to clean the copper, and didn't completely wipe it up afterwards. That seems logical, and it answers another curiosity: The corrosion seems to follow a pattern, like someone wiped the copper off in some areas. Such striations indicate something other than a random effect. Whatever the cause, it may be irreversible. Some of the suggestions I received seem good enough, but it will never be the same.
In the final analysis, I decided that "good enough" is, well, good enough for me. The thing works. I get stations on all three bands. The AM band is quite good, in fact as good as any other radio I have (all modern radios, of course). The SW bands (A is 1.8 to 2.2 MC, and B is 2.2 to 23 MC) do come in. Well, I can get stations if the weather is right, and I use an extender on the antenna (indoor only, of course). Both SW bands have some drift, but that is probably normal. On the A band I get some motorboating right where the traffic is best (around the 48 to 50 meter range), and the B band requires the volume to be way up below about 16 MC (that's MegaCycles, as the dial has it) before I can hear anything. I also have to finagle the band selector switch a bit to get the band to kick in (a dirty multi-position switch I missed, no doubt), but it does work after all. Also, after fixing the dial needle (so that it actually tunes the radio, I mean) it is high by about .5 KC on the AM band (showing 645 when it's receiving 640, for instance), but I figure that dial is probably only intended to give a close approximation of reality anyway.
Maybe an expert would have done a lot more than I did. I did make some mistakes (detailed above), but I don't think I did any more harm than that. The important thing in my mind is that it works. YAHOO! Drift, or not, I really enjoy listening to things like the BBC World Service, or some of the wacky religious people that you find on those bands (did you know that THE END IS NEAR?). Even the Universal Time signal is new to me. What fun!
Many thanks to Norm, Dave, and all those who gave helpful suggestions. The schematic is invaluable, and the information priceless. The novice solutes you.
Later,
RAS
: I wanted to follow up with you on my little project with the Howard Radio model 418 that I have told you about before. I am pretty proud of myself, even though it isn't perfect. After all, I got it apart, cleaned it up, replaced a couple of parts, and got it back together ... and it works a little better than it used to! That is really something, in my mind.
: Anyway, I should clear the air. After I got the chassis out, I made a boo-boo. I was going to take it out to the garage to blow it out, and it was damp outside. I wanted to put a plastic bag over it, so I stood the chassis up on end, thinking that it would stand there for a moment. Well, as soon as I let go of it, two things happened. First, I saw that it was tipping over (the tuning apparatus being so heavy), and it was tweeking the 6K7 tube to one side (I think it is one of the IF tubes, from it's position). Second, I reached out instantly to catch the thing, and my forearm tweeked the rectifier tube, which cracked the base.
: The 6K7 is covered by a shield. The end result is that the lead wires were pulled out of the plug. I think, if I could get them all to go back into their proper connectors, I could sweat them back in and glue the base back to the tube glass. I'm not ready to try that yet, so I have replaced the tube in the meanwhile. (It is just that this is one of the original Howard Radio Company tubes, and I wanted to preserve them as long as possible. Oh, well!) As for the 80 rectifier base, I tested it before putting everything back together, so there is no risk of a short -- as long as I don't fool with it any more.
: I did not solder the lead on the antenna coil, as you might have expected. The wire felt solid enough, though I didn't give it a lot of tension in testing it. I did get a good indication from my multitester, as well. So, I decided to wait until I had the thing back together to see if it was a problem. It appears not to be, after all.
: Whether dust alone can cause the kind of corrosion I have described, I will leave to the experts. I have heard a couple of them discuss the problem, and they seemed sure of themselves. I know from experience, too, that dust is corrosive, but this may have been something more. Someone, thinking they were doing the machine a service, may have used a corrosive chemical to clean the copper, and didn't completely wipe it up afterwards. That seems logical, and it answers another curiosity: The corrosion seems to follow a pattern, like someone wiped the copper off in some areas. Such striations indicate something other than a random effect. Whatever the cause, it may be irreversible. Some of the suggestions I received seem good enough, but it will never be the same.
: In the final analysis, I decided that "good enough" is, well, good enough for me. The thing works. I get stations on all three bands. The AM band is quite good, in fact as good as any other radio I have (all modern radios, of course). The SW bands (A is 1.8 to 2.2 MC, and B is 2.2 to 23 MC) do come in. Well, I can get stations if the weather is right, and I use an extender on the antenna (indoor only, of course). Both SW bands have some drift, but that is probably normal. On the A band I get some motorboating right where the traffic is best (around the 48 to 50 meter range), and the B band requires the volume to be way up below about 16 MC (that's MegaCycles, as the dial has it) before I can hear anything. I also have to finagle the band selector switch a bit to get the band to kick in (a dirty multi-position switch I missed, no doubt), but it does work after all. Also, after fixing the dial needle (so that it actually tunes the radio, I mean) it is high by about .5 KC on the AM band (showing 645 when it's receiving 640, for instance), but I figure that dial is probably only intended to give a close approximation of reality anyway.
: Maybe an expert would have done a lot more than I did. I did make some mistakes (detailed above), but I don't think I did any more harm than that. The important thing in my mind is that it works. YAHOO! Drift, or not, I really enjoy listening to things like the BBC World Service, or some of the wacky religious people that you find on those bands (did you know that THE END IS NEAR?). Even the Universal Time signal is new to me. What fun!
: Many thanks to Norm, Dave, and all those who gave helpful suggestions. The schematic is invaluable, and the information priceless. The novice solutes you.
: Later,
: RAS
Good job Richard!
Well, most of those things sound about normal for an antique radio..Drift will tend to stablize after a few mins running...heat changes the properties of the occilator circuit..it's best to let that be.
The shortwave stations will fade up and down and also some of the international transmitters out there are shall we say "less than tight"...
There's not a lot on above 16mhz..only during the day.
The antenna you are using may not be broadbanded enough/and or/those contacts need cleaning..SW is a tiny signal (mostly)..
There's a law in antique radio restoration that states something like: 98% working is one price, 99% leads to double the $ and double the time..nothing is perfect. I think that is called the "law of diminishing returns".
Another thing you brought up is overhandling of a chassis when repairing..the more and longer we handle them, the more chance another problem is introduced..
Dont feel bad untill you put your fingers right through a speaker cone!
congratulations!..
Dave
: I wanted to follow up with you on my little project with the Howard Radio model 418 that I have told you about before. I am pretty proud of myself, even though it isn't perfect. After all, I got it apart, cleaned it up, replaced a couple of parts, and got it back together ... and it works a little better than it used to! That is really something, in my mind.
: Anyway, I should clear the air. After I got the chassis out, I made a boo-boo. I was going to take it out to the garage to blow it out, and it was damp outside. I wanted to put a plastic bag over it, so I stood the chassis up on end, thinking that it would stand there for a moment. Well, as soon as I let go of it, two things happened. First, I saw that it was tipping over (the tuning apparatus being so heavy), and it was tweeking the 6K7 tube to one side (I think it is one of the IF tubes, from it's position). Second, I reached out instantly to catch the thing, and my forearm tweeked the rectifier tube, which cracked the base.
: The 6K7 is covered by a shield. The end result is that the lead wires were pulled out of the plug. I think, if I could get them all to go back into their proper connectors, I could sweat them back in and glue the base back to the tube glass. I'm not ready to try that yet, so I have replaced the tube in the meanwhile. (It is just that this is one of the original Howard Radio Company tubes, and I wanted to preserve them as long as possible. Oh, well!) As for the 80 rectifier base, I tested it before putting everything back together, so there is no risk of a short -- as long as I don't fool with it any more.
: I did not solder the lead on the antenna coil, as you might have expected. The wire felt solid enough, though I didn't give it a lot of tension in testing it. I did get a good indication from my multitester, as well. So, I decided to wait until I had the thing back together to see if it was a problem. It appears not to be, after all.
: Whether dust alone can cause the kind of corrosion I have described, I will leave to the experts. I have heard a couple of them discuss the problem, and they seemed sure of themselves. I know from experience, too, that dust is corrosive, but this may have been something more. Someone, thinking they were doing the machine a service, may have used a corrosive chemical to clean the copper, and didn't completely wipe it up afterwards. That seems logical, and it answers another curiosity: The corrosion seems to follow a pattern, like someone wiped the copper off in some areas. Such striations indicate something other than a random effect. Whatever the cause, it may be irreversible. Some of the suggestions I received seem good enough, but it will never be the same.
: In the final analysis, I decided that "good enough" is, well, good enough for me. The thing works. I get stations on all three bands. The AM band is quite good, in fact as good as any other radio I have (all modern radios, of course). The SW bands (A is 1.8 to 2.2 MC, and B is 2.2 to 23 MC) do come in. Well, I can get stations if the weather is right, and I use an extender on the antenna (indoor only, of course). Both SW bands have some drift, but that is probably normal. On the A band I get some motorboating right where the traffic is best (around the 48 to 50 meter range), and the B band requires the volume to be way up below about 16 MC (that's MegaCycles, as the dial has it) before I can hear anything. I also have to finagle the band selector switch a bit to get the band to kick in (a dirty multi-position switch I missed, no doubt), but it does work after all. Also, after fixing the dial needle (so that it actually tunes the radio, I mean) it is high by about .5 KC on the AM band (showing 645 when it's receiving 640, for instance), but I figure that dial is probably only intended to give a close approximation of reality anyway.
: Maybe an expert would have done a lot more than I did. I did make some mistakes (detailed above), but I don't think I did any more harm than that. The important thing in my mind is that it works. YAHOO! Drift, or not, I really enjoy listening to things like the BBC World Service, or some of the wacky religious people that you find on those bands (did you know that THE END IS NEAR?). Even the Universal Time signal is new to me. What fun!
: Many thanks to Norm, Dave, and all those who gave helpful suggestions. The schematic is invaluable, and the information priceless. The novice solutes you.
: Later,
: RAS
Hello Richard,
Congratulations on getting your radio to work so well. it's terrific when you put all that effort in and it sings. I also understand the sinking feeling when an accident occurs like that. It happens to all of us, thankfully it sounds like the damage wasn't too bad. You should be able to replace the tube base. Melt the solder in each pin in turn and suck it out with a solder sucker if you have one, otherwise, bump the base down on the bench and the molten solder will shake out. Protect the bench and yourself from hot solder, newspaper is good. If the leads have broken short, extend them with fine fuse wire, twisted and soldered to the stubs, poke them back into the pins and resolder. Use a glue like epoxy to fix the base. you will have to examine the tube to identify which wire is which. Good luck and happy listening. Don.