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Forum Index : Other Stuff : Picked up a old valve radio
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
As part of my "Get to know your new home town" adventures, I called in to the Toowoomba tip shop to see what they had. They had the usual furniture, scrap iron sheets, etc, and a old valve radio that caught my eye. A quick inspection looked promissing, the internals were still in place and the timber was in good condition, so its been kept dry all these years. They had $200 on it, but I managed to talk them down to $180, squeezed it into the back of the car and drove home. 
Unfortunately someone has painted the cabinate cream at some time in the last 70 odd years. These radios usually have a beautifull vineered timber finish, like this radio from my growing collection. 
So I'll have to strip the paint back and see what condition the timber is in. The back shows the cover still in place, a good sign its been taken care of. 
Cover removed, looks in good condition. All valves are there, and there is very little rust on the chassis. The speaker in these radios forms part of the high voltage filtering circuit, it uses a electromagnet instead of the permanent magnet, and the electromagnet coil acts as a inductor to filter out the AC hum on the DC supply. 
In a few weeks I'll look at restoring the circuit. I've collected and fixed a few old valve radios, its fun to see a old radios working again. The valves are usually fine, but many of the caps need replacing and the whole thing realigned to get it working like new. This one has a original power lead, so that will need replacing. 
Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Barry T Coles Senior Member  Joined: 30/07/2009 Location: AustraliaPosts: 109 |
Hi Glenn They are beautifull old radios, I remember them from a kid. My folks had land not far from Adelaide that wa previously a sand quarry & had a large water hole on it but as the area started to become more suburban people started dumping rubbish there & destroyed it so the old man fenced it off & turned it into dump. We had something like a hundred of these old radios stacked up in the shed all for sale at 5 bob a piece. You mention the speaker in these radios forms part of the high voltage filtering circuit & I learnt very quickly that when it said turn off the unit before connecting/dissconecting the speaker they meant it, I remember not doing it once when I was about 10 & the boot it gave me threw me about 8 foot accross the shed floor & against the wall & my arm was numb for about an hour, did I do it again not on your nelly lesson learned. Hope the new aquisition comes up well, a lot of that old stuff was painted just because gloss paint was the new in thing & wood was old fassioned so there's a good chance the the timber underneath is OK. Ah the good old days. Cheers Barry I need to learn from the mistakes of others. I dont have the time to make them all myself. |
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| VK4AYQ Guru  Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Glenn What a beauty, you will get hours of fun restoring that one, as Barry said the paint has done you a favor to preserve the wood as that usually dies as the old varnish decomposes over time. All the best Bob Foolin Around |
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jimmyjames Newbie  Joined: 06/04/2011 Location: AustraliaPosts: 3 |
G'day Glenn, What a coincidence! I was surfing the net looking for people who service old valve radios in the Toowoomba area and I stumbled across this site. Lo and behold I see your radio purchase from the Toowoomba dump shop. I was seriously considering purchasing this exact radio from the dump shop a few weeks ago! I first saw it about 4 weeks ago and hummed and harred about it, but I felt they were asking too much considering it had been painted. I was out there again 2 weeks later and again seriously thought about it, but decided no. For 100 or even 150 dollars I would have got it. Great to see that you got it and that you are going to lovingly restore it to its former glory. Such a shame it has been painted over, but yes as Barry points out, it has preserved the timber. The pics are great and confirm to me of what I already thought about it coming from a good home. Happy restoring, a lovely purchase. Regards James. PS I hope this msg doesn't turn up twice, this site has been playing up on me. Hi folks, I'm into old valve radios. |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Thanks James, I'll take care of it. I'm also looking for someone in the region who can fix these things. I know the basics, using the fault finding techniques I learned from my past employment, but I would get stuck finding spares or fixing a difficult fault. I was out at the Pioneer Village a few weeks ago and there are a few restored radio's, I'll have to ask them who they belong to. I've started the restoration. Removed the speaker, chassis, speaker cloth and dial glass. 
My brother's a cabinate maker/builder, and he's suggested I do the following. Use paint stripper and a plastic scrapper to remove the majority of the paint. Then metholated spirits and steel wool to remove the remaining. Wash down with water. Its working a treat. There's 3 layers of paint, the white with black trim you see, then a cream with green trim, and finally the original clear laquer. 
The original timber looks in good condition so far, makes you wonder why it was painted, fasion I guess. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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Greenbelt Guru Joined: 11/01/2009 Location: United StatesPosts: 566 |
Hi Glen, I've had much fun playing with old radios. Many of them had short wave bands, Marine band short and long wave, weather and other, I would sometimes change the trim on the Variable Cap. or the slug trimmed Variable Inductor to bring in the highest gain for listening to the 80 Meters Ham radio Band, Lots of fun. Never did get real smart on fixing them but I did get many of them to work when they were given up for Dead. From what I see so far it looks like a choice piece to restore. Here is a link that may be useful A million links to antique Radio Parts. ----Roe Time has proven that I am blind to the Obvious, some of the above may be True? |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Thanks for the link Roe, I'll file that one away. Had some free time today so finished off de-painting the old radio. 
And its first coat of varnish. Tomorrow I'll sand it back, paint the black trim, and add another coat of varnish. Its starting to look good. 
I also re-sprayed the interior flat black. 
The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Glenn Magic Job, I think you will find reserecting the radio easy after that effort. All the best Bob Foolin Around |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Its alive!!!! Finished off the timber cabinet, 3 coats of gloss varnish. In hindsight, I think a satin/semi-gloss would have looked better. In my first posts I mentioned I thought it was a shame someone had painted it, but looking at the finished product, I think they did the old radio a favour, cause the timber has been well protected over the last several decades. Now to the chassis. First tested the power transformer for open circuit windings or leaks to ground, all OK. Removed all valves, replaced the power cord and powered it up, being very careful, there can be several hundred volts inside these old radios. The transformer outputs measured OK, 6.3vac for the valve heaters, 5vac for the rectifier valve heater, and 600vac across the HT output. Let it run for 5 minutes and turned it off, unplugged the power lead, and then felt the transformer to see if it was getting warm, a sign of shorted windings, all OK. Tested the speaker, remembering is uses an electromagnet so there are 4 wires, all good. Thats the hard to replace bits all tested and working OK. Next I blew out the dust and oiled the dials and switches. You can still source 2nd hand valves for these old radio's, but as a rule, the valves are OK, its the capacitors that need replacing. I replaced about 8 caps with modern day parts, matching the values as close as I could. The main filter caps were 8uF at 600vdc, I ended up connecting two 22uF 450vdc caps in series to get a 11uF 900vdc cap as their replacements. 
Yeah I know, tying a knot in the power lead is not an acceptable method of anchoring the power lead, I will fit a cable clamp, promise I did find one valve, a 6U7, with a tiny crack in its side, about 10mm long. I think the vacuum inside was still intact, so applied some varnish to the crack, fingers crossed the valve is ok, but I dont think it would last long with continued use, the heat/cool cycles would cause the crack to grow and the valve to fail I tested the chassis on the bench, it worked! Needs a bit of a fine tune though, but my cro is packed away, and I dont have a RF signal generator anymore, so I decided to leave it as is for now. Besides I would prefer to replace that 6U7 first. The valve line up was an 80, 75, 6V6 6K8 and a 6U7. Controls on the front were Tone, Tuning, Band and Volume. Next I fitted it back into the cabinet. 
And all finished. 
I'm pretty happy with the way it looks, and it also works, which is a bonus. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Barry T Coles Senior Member Joined: 30/07/2009 Location: AustraliaPosts: 109 |
Looks pretty good to me, now sit back with a beer & enjoy the fruits of your labour. happy listening Barry I need to learn from the mistakes of others. I dont have the time to make them all myself. |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Glen I wonder if any of the wizz bang stuff thats around now would be still working in 70 years or even salvageable any more. If its made in China we are lucky to get one year or even one week. Bob Foolin Around |
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| jimmyjames Newbie Joined: 06/04/2011 Location: AustraliaPosts: 3 |
Hello again Glenn, Even though you've been finished the radio for a while now going by the dates, it's great to see it all ended well. It really is a lovely piece of furniture, and of course a darn good radio. I'm reading with interest at the moment about your experience in getting the caps replaced on this radio, as my Kreisler radiogram decided to start smelling like a burnt sparkler the other night. I pulled the chassis out and everything seemed fine except for one cap that appeared to be leaking a white foamy substance, so my money is on that or it's possible the coils are shorting on the transformer. I found a couple of places around town that do repairs but they get very costly and seem to want to replace all the caps which is a normal thing. I found your reference to the Pioneer Village at Highfields very useful as I might go out and do some more inquiring before I get repairs started. One other thing - whilst looking at the valves and caps in my radio I noticed something very astonishing - they all had 'Made in Australia' on them, where ever do you see that anymore these days. The caps are dated 1966 and according to its former, and only other owner, its only just started to give trouble a couple days short of its 55th birthday, quality has changed so much since then. Hope you enjoy your radio, t'was great to follow the restoration on here. James Hi folks, I'm into old valve radios. |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Hi James Changing all the caps is a common practice, but if the radio is working OK, you really only need to replace the power supply electrolitics. Usually there are one or two of them, 8uF or so, 450v, in a chassis mounted can. If these get a bit leaky they will stress the rectifier valve and the mains transformer, causing them to overheat. The other caps in the radio can affect performance, but if you happy with the radio, leave then in place until they cause a problem. But if you can, make a note of the cap values ( uF and V ). Cockroaches will eat off the capacitor labels given a chance. Its also worth while checking the mains power lead, and making sure the chassis is earthed ( unless its one of those dangerous models with a live chassis ). Ray at the Highfields Village should know of someone who can fix the old radios. Yes its hard to believe, but Australia once had a thriving electronics industry. I think as a isolated country we had no choice, and built everything we needed from scratch to keep up with demand. Once Japan's industry got going after the war, the local electronics manufacturing couldn't compete and died off in the 60's and 70's Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| jimmyjames Newbie Joined: 06/04/2011 Location: AustraliaPosts: 3 |
Hi Glenn, Thankyou very much for taking the time to reply to my email. Cheers for the advice on how to approach the issue of capacitors when it comes to repairing/replacing faulty ones. I have noted all this in my head. The repair shop I enquired to insists on replacing all the capacitors no matter what, so whether they are doing this because it's the common thing to do as you said or they're trying to make some extra money (plus a $40 diagnosis fee) I don't know. I will keep shopping around town for people that fix valve radios and see what I come up with. I will definitely make a trip to Highfields Village. There used to be a place called Simtronics at the old High Street Plaza here in town, the man in there repaired anything and everything, a really good 'old timer' who knew his stuff and no job was too big or too small, but he has since retired prior to the centre getting bulldozed last year. Thanks again for your time, regards, James. Hi folks, I'm into old valve radios. |
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| windhistory Newbie Joined: 14/11/2011 Location: AustraliaPosts: 8 |
Great description of a radio restoration. As a newbie to radio(32 volt) i am interested in all radio but 32v in particular. Most 32v battery banks were charged by lighting plants but some also wind powered. As demand for 32v appliances grew some manufacturers sold radios that could be dynomoter powered or vibrator powered to use 32v . 
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