Kit set i need I.D on.
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Location: Wangaratta, VIC
Member since 21 February 2009
Member #: 438
Postcount: 5461
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It is rare for the transformer to take out a rectifier. It is more common for a rectifier and a transformer to be taken out by a short. One exception to destroying a rectifier tube, is running #80 / 5y3 side ways.
I note the IF can looks like its had a whack on the top and if its a top trimmer and the top is staved in enough that can short the trimmers. That can could have its former broken as well and that can short.
Check pin 1 of 6K8 as it is a metal and some have a bad habit of using that as a terminal of convenience that can cause all sorts of issues. It should ground.
At this point powering is not an option; its assessment. Very odd for the Henderson type transformer to have a short on the terminal board, but we don't know who's been at it. Any rubber & frayed "push" wire it s to be treated with suspicion.
Never, overlook heater & filament windings for shorts.
The usual suspects apply, bad wax caps & Electrolytic ones anywhere. Transformers often rattle or growl if shorted. I will, on a set like that disconnect / isolate all windings (CT only on filament rectifier.) tube out. Then insulation test all windings to ground and between other windings.
Interesting set with history. I will check the paper warfare, I may have a circuit?
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Location: Latham, ACT
Member since 21 February 2015
Member #: 1705
Postcount: 2192
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MARCC THE 83 is gassy. It heats up but no filement.
But as I have found it had no short and was good to go.
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Location: Latham, ACT
Member since 21 February 2015
Member #: 1705
Postcount: 2192
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This is a intriguing little set.
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Location: Hill Top, NSW
Member since 18 September 2015
Member #: 1801
Postcount: 2109
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Robbert would you have a 6B7S as I dont have a good one.
I had a look and found one, but it looks gassy and I have nothing to test it in.
Unfortunately these pre-octal types are rapidly dying of gas...
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Location: Sydney, NSW
Member since 28 January 2011
Member #: 823
Postcount: 6797
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was there not a Doug Walters who wrote radio articles for R&H?
Not as far as I know ( ... but he did score a lot of runs for Australia).
The various Little General articles in R&H and RT&H were penned by John Moyle, Neville Williams, Raymond Howe, Philip Watson and Alan Nutt.
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Location: Latham, ACT
Member since 21 February 2015
Member #: 1705
Postcount: 2192
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GTC that Doug Walters didn't die in 1950 though.
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Location: Wangaratta, VIC
Member since 21 February 2009
Member #: 438
Postcount: 5461
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How do you know #83 is gassy? It does not look very gassy in the picture. How does one of the hottest tubes in the radio heat up if the filament is dead: Totally illogical. Gassy tubes also tend to see the Getter go white. There may be a filament to Plate short.
The two big pins 1& 4 are the filament check with ohm meter. A gassy, or overloaded rectifier will usually have a light blue halo around the outside of the tube plates, not an electric blue on the inside. If you are determined to run it and risk killing the transformer.
Put a voltmeter on "B" Make sure its not an #83-V: And if it fails to start producing volts shut it off and don't power it again.
The stepped & protected voltage capacitor reformer here, was deliberately made to power a "B" rail (set not powered) suspected of having a shorting cap, or other short. That saves cooking things.
There are two Tube testers here 1938 VCT and a Knight 600.
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Location: Latham, ACT
Member since 21 February 2015
Member #: 1705
Postcount: 2192
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Marcc I should say the 83V has lost its vacuum.
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Location: Sydney, NSW
Member since 28 January 2011
Member #: 823
Postcount: 6797
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GTC that Doug Walters didn't die in 1950 though.
As Graham Kennedy used to say: That was a joke, Joyce.
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Location: Latham, ACT
Member since 21 February 2015
Member #: 1705
Postcount: 2192
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I do have a friend that loves doing up these old cases so I'm thinking of sending it to him to get it done properly. I will be trying to source a 5 or 6 inch field coil or permanent mag speaker for it.
I have a good old valve tech close by that might asses the chassis for me but other than that I may just send it away to get done properly.
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Location: Wangaratta, VIC
Member since 21 February 2009
Member #: 438
Postcount: 5461
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#83 and #83-v are different. Like 5V4 , 83V has a cathode sleeve an is a slow heater. #80 is a 5Y3 and Silicon diodes and a fast heater and these will create a voltage surge prior to the heater heater tubes coming into conduction.
If the set was not designed for a non sleeved rectifier it is liable to have underrated filter caps and they will punch through. The other trap for sets not run for ages, is that those filter caps will have lost form (polarity) and can / and have presented as a short circuit, taking out the rectifier & sometimes the transformer.
"Gassy" is a common term for a tube which has lost vacuum. That tube is of a construction I have seen used in early 6X4's and they (which were designed for car radios) were notorious for going short heater to cathode. I am not yet convinced the tube is gassy: I am more of the suspicion that the filament has warped & shorted to one of the plates or its being overdriven by another short, which may make it look like its gassy.
The American Forum is a prime example of different fixers with different experiences, having different ideas on fixing & fault finding. That's healthy as it presents a range of ideas: It basically comes down to .."Whatever works for you".
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Location: Latham, ACT
Member since 21 February 2015
Member #: 1705
Postcount: 2192
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Now I will say that the only two things that has been changed on this is the power cord ( maybe a wire was dislodged) and the speaker from a field coil to a permanent mag speaker ( which looks crappy ). All of the original work is highly professional. The 83v glass is very loose and maybe one of the issues.
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Location: Sydney, NSW
Member since 28 January 2011
Member #: 823
Postcount: 6797
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That tube is of a construction I have seen used in early 6X4's and they (which were designed for car radios) were notorious for going short heater to cathode.
Did you mean to say 6X5's?
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Location: Toongabbie, NSW
Member since 19 November 2015
Member #: 1828
Postcount: 1331
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Bugger!
GTC is correct, DOUG was pretty good at hitting cricket balls, but,
It was CALVIN Walters that wrote for R&H.
I just flicked through a RH and checked.
Note to myself: do research BEFORE opening mouth!!
Fred.
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Location: Latham, ACT
Member since 21 February 2015
Member #: 1705
Postcount: 2192
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Fred
Calvin and Doug may have been brothers lol. The fact that Douglas was a technician at 2GB still gives this little set some provinence. I will try and take clear photos of the underside and send them. His work was really neat.
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