I have special things I print out and

put in a notebook.

This wonderful radio item from you

Neil, will go in there.

Oh, yeah - just like Carl, I never met

a tube I didn't like, either.

Like the first glowing 35W4 I ever saw.  (true!)

Brooce, WLP and the Gnat Network (Owned by

by Dog Radio Corp.) 

a few more times.

Some years ago I was at a local radio

museum - and - there was an operating

radio from 1927.  I don't remember the

manufacturer.  There was a drawer in the

bottom of the radio so one could log the

stations that were heard.  Then they could

be stored in the drawer.  In the drawer were

original loggings from the time - they were

s

still there after all those years.

There are 3 tube radios in my

collection that I really enjoy.  

(I have more tube radios - they

are all in storage in other places.)

Anyway - one radio is a Hammarlund

HQ-140X.  Lots and lots of fun.

I have a great Zenith FM only tube radio

from about 1962.  It's big.  The HIFI is

very good.  It needs a lot of work, though.

Mostly caps, I think.

I also have another Zenith.  It's a portable

vaccum tube radio - AM only - from 1948 or

so.  It has a 90 volt battery and a 1 1/2 volt

battery - I think.  All 3 radios aren't here so

I can't be quite sure.  The vaccum tube portable

can also operate on house 120 VAC.  I think the

radio is called a "Holiday."  Yeah - you go out on

a picnic all day with new batteries at the beginning

of the day.  At the end of the day the batteries are

run down.  You save your $$ for new batteries for 

the next holiday picnic - and then you go out on

that day and run the batteries down again.  Then

you save up your money again - and so it goes.

This radio needs to be recapped. 

I have run my Part 15 AM and FM transmitters

through all of these radios.  It IS a perfect use

for Part 15. 

Brooce

Thank you all for your positive comments regarding my project. Your recollections about similar radios and experiences are interesting.

There are many postings around the web where folks restore old radios and there are sources for many parts and it is good to know that this activity is still pursued by many.

Brooce, I remember the 90 Volt B batteries. My brother was gifted a portable tube radio that used one and at the time I had a state vendor's license and an account at a local parts distributor and could get him batteries at wholesale. They were big, expensive, and didn't last very long.

I visit antique stores around here and have noticed that the stock of antique radios has dwindled in both quantity and quality. A few years ago console radios could be had for about $100 and table sets for about $30 and were in what I judge to be fair condition. Lately the few radios I have seen have been literally junk, do not work, and are priced at $70 or above. Radios in working condition similar to mine are listed on the web for anywhere from $200 to over $500. The value of my radio is not important since I do not plan to part with it.

Years ago I inherited a Philco cathedral style radio which did not work and began troubleshooting to fix it. Philco used multiple caps potted in Bakelite tubs and all of these needed replacement. Using signal injection and tracing I found that the radio was almost working but the signal was blocked in one of the IF transformers. Most likely one of the windings is open but it would be a major effort to remove and repair this part so the project has been on hold for years. Perhaps the next time we are snowed in I will attack it again.

As I recall working on tube radios and TVs back when the failures were seldom due to the tubes. The most common failure was bad capacitors, especially those old style wax dipped paper caps. With experience I could usually tell which was bad by visual inspection and by listening to the set. If others looked suspect I would replace them as well. I can see why tubes got the reputation for being problematic because some of the repair shops around us always managed to find a "bad tube" when radios were brought for repair. This was probably due to the 40 to 50% markup on tubes which were expensive even at wholesale. Most of my business came from folks who had their radios fixed at the local shops and which failed shortly thereafter. They would then take them to "the kid down the street" for repair and I gained a reputation for fixing them right. The repair shop owners took notice and through a friend of my father who was a state tax examiner I learned that one of them had plans to report me to the state for not collecting sales tax. Upon this friend's advice I obtained a vendor's license and collected the tax so I stayed out of trouble. One of the shops went out of business before I moved away.

But, I digress and am still glad that I can dabble in this now and then.

Neil

In the tangle of memory I think an electronics pal once told me that capacitors got heavier when they went bad. Since then I have always tried to sense the "heavier" caps as the first step in troubleshooting.

Is there any truth to it?

My Grandma had one and when I went to her house I could pick up FM stations 100's of miles away.  It picked up stations better than any transistor FM Radio made today and the sound was SWEET.  I loved that Radio even though it was Mono.  I seen one one day at a pawn store but didn't know if it actually worked.  If it would have and I had the big money I'd would have bought the Radio just because you could really DX with that Zenith Radio.  Yes Tube stereo's and Radio's sound better and perform way better when you have all the tubes renewed and all the caps replaced and everything is in line.  The German one that was white and tube worked about the same way and was HUGE.  It had AM SW and FM.  The FM on that Radio was amazing.  It used the electric cord as an antenna and had screws in the back to connect both an AM or FM antenna to, but just with the built in antenna it would pick up the same as if you had an outside antenna on your Stereo and that was back in 1983.  That is why I feel the FCC needs to go after the makers of receivers and improve that.  I bet a part 15 (Legal) FM station would have almost went a mile on those Radio's and part 15 AM may have went 2-3 miles on those Radio's.  Yup if we could only pass that we could use 250 uV/m @ 3 meters and be more than happy with the results lol.

Carl,

I have never heard the "fact" that bad caps are heavy but it might have some truth in it. The wax dipped cap's failure mode is the wax dries out and becomes brittle. This allows moisture to enter and be absorbed by the paper dielectric which could explain a weight gain. The few removed caps which I was able to measure had values much higher than their nominals. Water has a very high dielectric constant and I suppose absorbed moisture could explain this.

The Legacy,

I recall that the FM tuners produced in the 60s and 70s were generally high quality. Tuners, by definition, were intended to be connected to other audio equipment such as hi-fi and stereo systems so they had to sound good to induce someone to purchase one. Since there were not many FM stations back then the tuners had to be sensitive enough to pick up non-local stations. It was common for listeners to install an outdoor antenna just for FM or to use a splitter on their TV antenna leadins. I have a FM turnstile antenna which I installed on my parents' house back in the early 60 and still use it for my home entertainment receiver. Back then, using an Eico HFT-90 tuner we could receive stations full quieting from 50 miles away. The attraction back then to FM was that the stations had few commercials and played mostly music.

The introduction of stereo broadcasting gave a big boost to the popularity of FM over AM and the industry response was to try to maximize profits by increasing the number of stations and by selling more commercials. FM became what AM was.

It seems that as FM programming became more commercial and abundant and emulated AM that the need for quality receivers gave way to poor performing portables and table top radios. Gone was the need for quality audio and sensitivity since the band became filled with stations. Personally, I don't want to be shouted at by some shrill huckster in full fidelity stereo (or on AM for that matter) so I seldom listen anymore.

Neil

I'll be back.

Brooce

Neil: I thought "B" batteries were 45 Volts?

John,

My understanding of the designations is this. The early tube receivers were powered by batteries and these served three different functions powering the filaments, the plate circuits, and the bias circuits. They were designated A, B, and C respectively by function rather than by voltage.

I have encountered B batteries of 9, 22.5, 45, and 90 Volts and there are probably a lot more but these used to be common.

Neil

Notice the relationship among 22.5, 45 and 90 volts.  It's kinda like the origins of 6.3 volt filaments. 🙂

Talking of valve receivers, i previously owned a Murphy B40 receiver.
This was a Navy communications receiver, and was VERY heavy!
It used 10 rf, and 10 if valve stages, the sensitivity was amazing.
Here in the UK, i had no problem picking up WWV on practically all frequencies, 20 mhz being the most variable.

Other unusual car receivers i have used, when i was a kid, had a vibrating can that chopped the 12v supply to supply ht, and another very unusual car radio was a valve model that had no ht voltage at all, and used special low voltage type valves.

Paul.