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 Post subject: Re: Radio Restoration Diary 2 ( post photobucket)
PostPosted: Nov Fri 02, 2018 11:46 pm 
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Correct. Wrong dial pointer. The set was missing the pointer and the one I found was pretty close. It sold already anyway, so she's gone.


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 Post subject: Re: Radio Restoration Diary 2 ( post photobucket)
PostPosted: Nov Sat 03, 2018 12:00 am 
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I'm wondering...
Have you ever run across an AM/FM radio with the one-tube "FreMoDyne" FM circuit?

-Steve

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Consoles and floor models, the bigger, the better!


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 Post subject: Re: Radio Restoration Diary 2 ( post photobucket)
PostPosted: Nov Sat 03, 2018 10:39 am 
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Location: Nr London, England, SS1 3PT
Hope the Mods wont mind me busting in on Bob's thread ? It does show that I'm always following along though :)

I have one by Gilfillan, a 68F, which I restored ages ago. Must get it down and see if it still plays :D
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I wrote an article and came up with a 'how it works' for the circuit if anyone is interested.
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This is what I wrote back in 2002:

"AM performance is as good as any small radio of the time and is quite respectable. This can’t be said for the FM band. It can only be described as poor and the quality is worse than the cheapest solid state radio. It is possible that I am still not getting the best from the circuit; I was reluctant to start disconnecting and measuring the ceramic capacitors’ birdnested’ around this stage. However, these did look as good as new with solid encapsulation. US collectors said this performance was about all it was capable of, and some gave a lot of other more disparaging remarks as well! It needs strong signals and careful tuning to minimise distortion and low level background whistles, to which it is prone. It does have reasonable rejection of AM noise, presumably the high gain of the super-regenerator, means it acts as a limiter. "

Gary


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 Post subject: Re: Radio Restoration Diary 2 ( post photobucket)
PostPosted: Nov Sun 04, 2018 4:33 pm 
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Steve,
Not sure what the fm circuit you're referring to, but probably. In fact I picked up a bunch of am/fm sets yesterday, one being a granco fm only set and at first glance it's certainly weird. That one goes to the bench this week, so we'll see what's inside...


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 Post subject: Re: Radio Restoration Diary 2 ( post photobucket)
PostPosted: Nov Sun 04, 2018 5:05 pm 
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Its a radio that has a single tube FM receiver in it like the one Gary posted above.
I have an Olympic and I know Howard made one too. Even Heathkit got in on the act with the FM1

viewtopic.php?f=2&t=348590

The AM/FM models have a normal AM AA5 circuit with the additional tube (often a 12AT7) as the FM receiver.

-Steve

EDIT: Excerpt from Radio Handbook Sixteenth Edition by William I. Orr W6SAI


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_________________
Radio Interests
-Zenith
-Sparton
-Pre-War FM
Consoles and floor models, the bigger, the better!
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 Post subject: Re: Radio Restoration Diary 2 ( post photobucket)
PostPosted: Nov Mon 05, 2018 5:56 pm 
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Steve,
Yes, I worked on a Zenith that had something sort of similar. That was around 3 years ago so I have of course forgotten it.

Anyway, my wife is gone on a business trip for a week and we got in a decent amount of sets to restore Saturday. Since the next show is in 3 weeks and I am short around 15 sets its time to burn rubber this week. The following sets were restored Sunday.... which shows just how amazing my social life is...

1: This really cute little Granco FM only clock radio. The case and chassis are sort of cheaply made. Its about as basic as they come with slug tuning situated right below the 19T8 tube. It was an easy job as the caps were all ceramic and so all that needed replacing was a 80uF cap and a 50uF cap. For such a basic set it works really well on FM. I might keep this to replace the kitchen clock radio we have now, which my wife likes for some reason and I find ugly. If she doesn't like it... might have to take it to the office.

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2:Very generic Sears clock radio with 4 tubes, meaning its actually closer to being a TRF set. Its also got the clock mech that uses an exposed flywheel and those are almost always stuck and need cleaning and oiling to get working again. Amazingly the clock still worked, but I oiled it anyway.

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Someone in the past had very carelessly replaced the caps and just left them dangling loosely inside.
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There's not much going on in there. After recapping it works fine with the addition of another 2 feet of antenna wire for better reception.

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3: Big AM/FM Zenith.
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Zenith used this same chassis design for years over numerous models and cabinet styles. The reason is probably because its a very well engineered chassis with excellent sensitivity on FM with great sound using a large speaker. I believe this is an early rendition of the chassis because in later models most of the paper caps were replaced with ceramics. That and the mesh grill is an "outty" versus the flat mesh grill seen on later models.

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This one took a bit more time because... A: The speaker was blown. I have 4 of these sets now and 2 are parts sets with damaged cases. So I took one from one of the parts sets. B: It has a selenium rectifier and as we all know these things stink like 1,000 rotten eggs when they let go and its mildly toxic, thus not the best thing to stick into someone's hands unless its replaced. So the typical diode and resistor were added to replace it.

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Once fully recapped it worked for about 3 minutes then began to hum loudly. As suspected the 35C5 tube was shorted. I tend to replace those in these sets with 50C5s since those poor 35C5s are driven HARD in these things and the extra 15 volts of filament voltage potential of a 50C5 means a little less stress on the output tube.

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So it works great now. I have another one to do but it can wait.


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 Post subject: Re: Radio Restoration Diary 2 ( post photobucket)
PostPosted: Nov Mon 05, 2018 6:16 pm 
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Location: Nr London, England, SS1 3PT
Good tip on the 35 to 50 tube. With modern high mains input gotta help.

Gary


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 Post subject: Re: Radio Restoration Diary 2 ( post photobucket)
PostPosted: Nov Mon 05, 2018 6:26 pm 
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35C5 tubes at least from my experience are really prone to shorting out. I think because they were driven so hard. That and yes, here in the US we went from having 110 to 125 volts and given that 35C5s were already being redlined they tend to blow much faster.


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 Post subject: Re: Radio Restoration Diary 2 ( post photobucket)
PostPosted: Nov Tue 06, 2018 2:08 am 
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Location: Glendale, CA
Bob,

Thanks for the tips on these Zenith radios. I have four of these radios, the wooden versions. Two of them work perfectly (Y832 and C835) without any humming at all. Another one, a B835, is butt ugly and not working at all. My Zenith H845 works, but has some distortion, so it needs some attention. When you replace the selenium rectifier do you use a 1N4007 diode and a 100 ohm 5 watt resistor? I have never experienced a selenium rectifier going bad....yet. I guess I've been lucky. :-)

Thanks, Tom

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 Post subject: Re: Radio Restoration Diary 2 ( post photobucket)
PostPosted: Nov Tue 06, 2018 3:53 am 
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Tom,
The diode and resistor combo you mentioned is correct. I've had two selenium rectifiers fry on me, granted not one of these zeniths.

I have to replace them because when selling to the public we can't take that chance. Boy do theyys stink when they do.

I started the 2nd of 3 of the same model zeniths today. Both sounded distorted. Amazingly most of this model of zenith seems to always work. But the electrolytic caps are now tired. Replacing these on both sets returned them to excellent sounding sets


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 Post subject: Re: Radio Restoration Diary 2 ( post photobucket)
PostPosted: Nov Tue 06, 2018 9:01 am 
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Bob,

Thanks for the information. You're right, if these capacitors are the originals, they should be replaced.

Tom

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"A challenge to be met, rather than an obstacle to avoid." - Mr. Data


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 Post subject: Re: Radio Restoration Diary 2 ( post photobucket)
PostPosted: Nov Tue 06, 2018 5:57 pm 
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Day 2 of radio-madness week.

1: A NICE looking RCA "Orthophonic" console. I stumbled upon this accidentally while walking to the local bottle shop ( fancy beer) and it was in a store front window. One of these fancy consignment shops. I figured it would be $500-$700 as its the right style, shape, and everything that typical folks who buy up our mid-century modern consoles love. It was $100. It is missing the record player but we have loads of period correct units at the museum. In fact someone donated a almost cherry Duel turntable and it works perfectly and even has a nice teak stand. So I'll later add back the missing shelf and install this in it.
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These are actually really nice sounding sets. I've done 3-4 so far and what always amazes me is that the hardware involved, the speakers, etc, do not look exactly impressive. But RCA must have had some good engineers on this one because the sound is pretty incredible with deep, solid bass and nice crisp highs. They ARE a pain in the ass to overhaul though but as I've done a few so far this one wasn't as terrible.
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The chassis is littered with billions of caps. I find its best to cram the new electrolytics under the wire looms as it keeps them out of the way and also secures them firmly to the chassis. The recap was about a 2 hour deal.
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To my pleasant surprise it worked right away after the shotgun cap replacement job.

It got a bluetooth adapter that feeds into the tape input. That leaves the phono input reserved for the player I'll install later. Plus there is a power outlet for it too. So just some basic carpentry work to secure the replacement player and the future owner will have AM, FM, bluetooth, and a record player. I will look around for a companion speaker to allow for full stereo function.
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2: This cute lil' RCA. I can tell by its overall design and the type of fonts and stuff that its from the same era as the Orthophonic unit. I generally despise working on these but its a nice looking piece. Luckily someone had already overhauled it. So all I did was polish the case with Novus so its good to go

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 Post subject: Re: Radio Restoration Diary 2 ( post photobucket)
PostPosted: Nov Thu 08, 2018 5:51 pm 
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Another batch of Zeniths. Boy this week has been the same deal for all three Zeniths: BAD speakers.

1: The somewhat dumbed-down version of Zenith's higher end AM/FM sets with a smaller speaker.
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Upon testing it worked but sounded really awful. Upon opening it up I found why: Someone in the past, in a lame attempt to offset a blown speaker stuffed the whole speaker with fiberglass insulation.
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So off to the speaker parts bin at the museum where I actually found the correct speaker for it. That solved that. Other then that... full recap, cleaning of the case with plastic polish, new diode and compensating resistor to replace the selenium rect, and a new 19T8 since the old one was marginal. This improved FM reception dramatically.
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2: Zenith "race track" radio. YES... I know the knobs are wrong but I couldn't find any after digging in boxes full of knobs. I found a set that at least looks decent. Interesting that this one has the "Console-tone" markings up front. Who was Zenith kidding? It came with a plain-jane boring ole' 4.5" speaker. False advertising in my opinion. The old speaker was perforated with big holes... too large to patch. So I dug out a spare I had sitting around.

Someone has recapped it in the past and it was a decent job. I reconstructed the back which was in pieces and also polished the case. This radio has been floating around the museum for awhile. It had been donated some years ago but was missing the knobs and the large metal piece up front. And then one day while cleaning out some bins I found the piece and was able to reunite the two.
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 Post subject: Re: Radio Restoration Diary 2 ( post photobucket)
PostPosted: Nov Tue 13, 2018 5:35 pm 
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Here's the latest. This time a true "FrankenZenith". I had a Zenith case missing the chassis and a Zenith chassis missing a case. The chassis is AM/FM and the case is for a AM only chassis. The chassis had a bad speaker, of which I harvested from a parts chassis. New holes were drilled for the chassis to fit and the holes for the knobs made slightly larger. The case was completely faded and lacking any shine. So it was cleaned and painted.

The chassis was in pretty bad shape. The electrolytic can had exploded at some point. 35C5 was completely shorted... as in fused inside. Replaced with 50C5. caps replaced, selenium rectifier replaced with diode and resistor, new dial cord, replaced very marginal 12BA6. The dial pointer's shaft was not long enough to reach through the plastic grill, so a piece of copper pipe was added to the back, which extended it long enough.

So there you go. Literally 3 junk radios turned into one.
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 Post subject: Re: Radio Restoration Diary 2 ( post photobucket)
PostPosted: Nov Thu 15, 2018 5:41 pm 
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I spent the last several evening overhauling a larger Gilfillan chassis with chrome plating for a person who dropped it off as the museum last week.
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It must have been one of their upper end models due to the large quantity of tubes and the aforementioned chrome plating. It had been partially restored sometime in the past, as in maybe the 70's. It was not easy to get down into the chassis to get at some of the parts. Anyway, its up and running now. Great sounding set.

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 Post subject: Re: Radio Restoration Diary 2 ( post photobucket)
PostPosted: Nov Fri 16, 2018 10:27 am 
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Impressive lot of radios you have ready.

Could you tell us this time how many sell out of the total?

thanks Gary


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 Post subject: Re: Radio Restoration Diary 2 ( post photobucket)
PostPosted: Nov Fri 16, 2018 5:43 pm 
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Well, At least around here in the Bay Area we seem to be doing better than we used to. I used to take around 20 sets per show and would be lucky to sell 5. But after a few years with experimenting it seems that the ticket is to add audio inputs and if there's a plain brown or white set, giving them a interesting paint job helps. So in order to not run out by the end of the day we have to take at least 50 at a time. We're selling these for around $50 a piece on average for the table tops so its not exactly huge amounts of money but over the years it adds up and at least helps pay for the cost of heating and lighting the museum. Plus it is a solution for keeping the volume of radios down from storage.

Anyway... Here's the latest. I forgot to take before pics of this one because I assumed it wasn't salvageable. Its a smaller sized "Radiola" set. I assume a cheaper RCA because it lacks a pilot lamp for example. This one was cracked almost in half and the dial glass was missing. But one day I got bored, glued it back together and used a can of dark blue spray paint that has been sitting around for years because what else did I have to lose?

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I dug through the parts bin and found a large sized dial glass from an RCA. It was too big, but I used to cut glass for windows years ago and so I decided to see if I could cut the glass to fit this radio. I was able to do so and it looks pretty believable. Otherwise the radio was overhauled, new plug, new output tube, and she works. Yes- the blue it entirely inaccurate but it actually to me looks somewhat OK.
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 Post subject: Re: Radio Restoration Diary 2 ( post photobucket)
PostPosted: Nov Sun 18, 2018 2:04 am 
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Hey Bob,

I heard on the radio that, due to the fires, the air is really dirty in the San Francisco area. I assume that means you, too. I hope you're hanging in there.

Tom

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 Post subject: Re: Radio Restoration Diary 2 ( post photobucket)
PostPosted: Nov Mon 19, 2018 5:38 pm 
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The air quality has been rated between "Unhealthy" and " Very unhealthy" for almost a week. So I bought a huge air purifier. The whole Bay Area has turned into a mini-apocalypse with few people going outside and if they do, wearing a respirator. So I've been holed up in the house or the office now for a week and getting cabin fever.

So that means finding stuff to do inside. As we are now all set for the next antiques show I decided to work on a stereo system I sort of accidentally won at an auction during the summer.

Its a Tanberg Huldra stereo.
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The name "Huldra" or "Hulder" refers to a female forest spirit. Human in appearance with a tail. In folklore they are known to be friendly with charcoal burners, watching over their charcoal kilns as they sleep, waking them if there are issues with the fires.

The Huldra stereo here is from 1965 and uses a hybrid chassis of 5 tubes and 4 output transistors ( SE4010 X4 ).
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Whats nice is that the chassis is housed in a square frame that allows you to flip it over without worrying about crushing stuff, which is the direct opposite of most other sets, especially Germans stuff where delicate bits are mounted way up top.

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As far as 60's era audio this was about as high a quality as one could get and as seen, most of the original components are still there since almost all of it still tested as perfectly fine. Lots of Swiss, Norwegian and German parts inside.
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I installed an audio input line so that I can run my phone or other devices through it.
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Unfortunately its missing 2 knobs and a button. The knobs were made out of some kind of plastic that disintegrated. As they were plain black I'll dig around and find something similar.

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Overall its one of the best sounding systems I've heard in some time. I'm likely not going to keep it but its nice to work on something this fine of quality.
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Next up, well you all saw this before, but its the RCA "Orthophonic" system from a few weeks ago. Whoever had owned it before had unfortunately removed the record player along with the shelf it had sat on. Our buyers tend to LOVE record players, so returning that feature was sort of necessary.

A few months ago a member donated a nice Dual turntable that he had painstakingly restored. If you've ever worked on one they are damned near impossible to get right, but he knew what he was doing and all worked perfectly. The problem was that its a newer unit with a magnetic pickup versus the original crystal pickup that the stereo came with.

So I got lucky on 2 counts:

A: A utterly ruined console that had been taken apart yielded a piece of veneered wood that was the same color as the RCA. So it was cut to fit the shelf area on the RCA.

B: I randomly found a Fisher pre amp sitting on a shelf. That was overhauled and installed.

So now the shelf has been added back and the future owner will have a nice and highly respectable turntable, plus bluetooth.
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 Post subject: Re: Radio Restoration Diary 2 ( post photobucket)
PostPosted: Nov Wed 21, 2018 5:22 pm 
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Another one, just in time for Thanksgiving, the infamous Philco "Junior" or model 80. The model has an interesting history. It was priced under $20, which was unheard of at that time. Philco's plan for the model was to draw people into dealers at which point buyers could be shown more feature-packed, more expensive models. Given this was in 1932 at the height of the depression these sold in massive numbers.
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Someone had been in there before me and replaced all of the caps in the bakelite blocks. But the work was really shoddy and I wound up redoing all of it. The electrolytics were dangling precariously too so those too were replaced.

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When tested the set would come on and then start a horrible pop-pop-poping sound, clearly a short. After poking and prodding it was the socket of the 42 tube. There was a dry joint for one of the pins that needed re-soldering.

The finish is original and cleaned up decently. Some of the wood supports inside were coming loose and were re-glued.


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