I sure hope you get this message because I would be very interested in having you repair my KLH radio it was working and then all the sudden it quit hadn’t played it very much at all. Hope you get back to me.
I'm not really a "tube radio guy", I've only fixed a few, and I don't keep the parts stocked for it. You'd be better off finding someone who specializes in tube radios. Good luck!
I wonder if a stack of 15 CR2032's or similar would power the B side for awhile. these are very cheap in quantity, coming in at 20-30 cents each if you buy 20 or so. they could be stacked in a plastic tube to hold them in place.
Fascinating. I never knew about these. Tubes were still being taught in 1965 - 1967 tech school. Transistors were just starting being taught. I hope battery availability remains in place.
Miniature tube radios like this were only sold for a few years in the early-mid 50's, so most people probably haven't heard of them. Odd that they were just starting to teach transistors in 1965, by that point they had largely replaced tubes in "high tech" applications, but tubes were still being widely used in table radios and TVs.
@@50sTransistorRadios It was a time of transition for sure. In the lab portion of our classes we had to build a tube superhet receiver from scratch. The only part premade was a flat chassis with mounting holes already punched out. The instructors were thinking that the next graduating class would be a transistor version but it hadn't been decided by the front office yet. Each bench seating position had permanently mounted 6.3 vac/300 vdc tube power supplies for various experiments. There were only a few low voltage power supplies around for solid state demos. I don't recall building any transistor circuits.
Nice radio with a mellow tube radio tone. I suppose you could wire 4 of those little 12V "N" cell form factor batteries in series to fit in the 45V space but then again with very short battery life. Also looks like each cell of the 45V battery must be thinner than the 9V since 5 of those cell stacks would not come close to fitting inside even after removing the metal shells.
Thanks! I have seen those 12V 23A batteries made into a battery pack for radios like this. I agree that the cells in the original 45V batteries must be quite thin, as there are 30 of them in there.
Wow, little tubes in a little radio...neat. A little cleaning on that speaker with a Dremel and wire wheel or scothbrite ect and touch it up....it would be like new. You may not have much use for it but I keep a product on hand of spray galvanize in a rattle can and you could spray a little on a scrap surface and touch up with a brush. It would have a similar appearance in color to the old plating on that speaker.
Thanks! I may touch it up further at some point, but for now I'm calling that one good. I had no idea you could get "Cold Galvanizing Compound" in a spray can, but that's good to know!
I did some more digging on this one, and found out that "273" is the RMA/EIA code for the "Radio Condenser Company", whose logo is also stamped on the tuning capacitor. While they did put date codes on some of their tuning capacitors, this one doesn't have one unfortunately. As to the battery life, I measured 150 mA of draw on the A cell, and 3-3.5 mA of draw on the B battery. A modern alkaline C cell should power this radio for at least a full 24 hours, which is better than I was expecting.
I really like the colors and styling of these late tube portable radios. You just don't see styles like that anymore. I also like how the tubes start up instantly and it sounds good too. Thanks again for another great video. Cheers!
6 transistors were all that were really needed unless you were to add a tuned RF stage (or it was an AM/FM or multi-band set). Some manufacturers had high transistor counts where some were just connected as diodes and others used transistors that were not even in circuit.
Neat little radio. It would be nice to come up with a 45v battery, perhaps something rechargeable 🤔 I just rebuilt my 1972 Sears 12" B&W tube TV and it works great. I use an external DTV receiver with it.
Thanks, me too! This radio is about as small as you can make a full superheterodyne tube radio with a speaker and built in power supply, without really compromising hard on battery life.
I have a Motorola Pixie as well, and this Hoffman is indeed smaller by a good amount. There might be some miniature Japanese tube radios that are slightly smaller, not sure.
I found this Radio on a flea market some days ago. Very happy with the quality. The timer feature works too. I had to use all the switches for around 20 times until everything worked again. No crackling potentiometers after all these years. The frequency scale is not calibrated correctly. I don't know yet if I will fix this.
According to the script, the radio belongs to Mr Howell, his company even made the batteries, he had the means to have it modded, Mrs Howell probably picked the color. A friend of mine that bought surplus movie equipment knew where the original was, people kept dropping and breaking them, at the time it was a low cost radio and plentiful. Imagine having to replace a transoceanic every week😮
I have one! Not only is the sound quality terrific due to the ingeniously placed, big vertical speaker but the selectivity and reception is outstanding. If you find one, grab it.
Very interesting video. With the display driver issue and missing segment, I’ve found that this is not uncommon on LED calculators. Occasionally it’s the driver chip, but on testing it’s often just a dry joint, and reflowing the solder can resolve. Mind you the build quality of some of the later 70s calculators; I came across one where the leg of the chip for the missing segment hadn’t been soldered at all. I doubt it ever worked as the calculator was pristine. Interesting about the neon displays and light. I noticed that one of my neon calculators displayed really quickly when tested out of case after I just replaced the capacitors, but that once back in the case it takes time (as do my others). Was this always an issue with these type of displays? I hope you’ve managed to solve the segment issue with the clock. They’re lovely clocks.
Thanks! Both of them were working okay by the end of the video, they just have some glitches on startup due to the early MM5314 ICs, and maybe interference from the displays. Speaking of the displays, yes, it's typical for Panaplex displays to have some trouble starting in low light and/or low temperatures, as the gas inside needs to be ionized a bit to start conducting.
I have an R-310Y with broken missing jammed sections. Call the outer tube #1. Tubes #2 and #3 were totally stuck inside #1 - their ends were totally free. I was able to get #3 out by working #4 out so half the brass clips were exposed where I could get pliers on them to forcibly rotate #3 which broke it free. I attempted same to get #2 out, but when I started to expose #3 clips, one was cockeyed maybe 20 degrees. I believe if I tried to work it out more, I would break something. Another tube had a guy take a thin pointy Xacto knife and undo the curl at the end of a tube to allow the inner tube clips to come out easily - this might be a good way to remove #3 with the tilted clip. Sort of a lost cause because I'm missing all tubes >#4. The diameter of the antenna is 10mm and it has a female screw thread in it. Hard to find on eBay or Aliexpress since no one puts dimension in titles (!) Go figure!
I found from experience that getting the EXACT right antenna for a given radio often requires finding a parts radio of the same model, as there seems to be little standardization of antennas. I've had mixed luck with repairing separated antennas, I think you need whatever crimping tool the factories used to really get them reattached properly.
@@50sTransistorRadios One fellow cuts the bottom off and disassembles all the sections out the bottom. (You have to get the tip off which hopefully is screwed). I think the trick is to cut the bottom just above the crimp so there is some plug exposed to master the main section when it is soldered back. (of course this method is good especially if the main seciton is inside the radio.) It would be possible to roll or possibly burnish the lip on the section tops on a lathe. If you have the antenna removed, this should be possible on a lathe - the body of the antenna would go thru the spindle hole so the section to be rolled would be very close to the chuck.
@@NoferTrunions I can see that technique working, though I unfortunately don't have a lathe to try it for myself. As to the tips being screwed on, that's the case maybe half of the time. I suppose you could cut the tip off, then later drill a hole in it and re-attach it.
@@50sTransistorRadios I tested the resistors in circuit, not Ideal but it worked. They were all OK apart from the one in the bottom left which read zero ohms. I think that's part of the timing circuitry though. The holes in the board are smaller than atoms so I think I damaged the zif socket, other than that I think the soldering is OK although some joints could do with a bit more solder. Thanks for the input.
I bought this one in 1986/87 - it's actually of better quality than it looks - the tape deck isn't bad at all for a boom box of that price range and the analog radio is okay as well
It should run with a 6 VAC adapter BUT I believe the clock gets its timing from the 60hz AC line frequency, so it would run slow on 50hz. I don't have the manual to know for sure.
This was my first sw radio and I had all the coils . I do not know what happened to the radio, i guess we wore it out. I listened to hams on 40 m and 80m , back then everything was am it was before ssb era. Good radio , I enjoyed it and one of the things that made it really work was a earth ground and a 50 foot bare wire long antenna.
@@50sTransistorRadios Now all I get is static wit a long antenna. I have a friend that has a telescope he can look at the sun with and the turbulence and activity on the sun is unreal. I believe that is making the shortwave bands where you can barely hear on them.
