Unusual radiogram
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Location: Melbourne, VIC
Member since 26 December 2010
Member #: 794
Postcount: 387
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Hi everyone
I picked up a stereophonic radiogram last week that I'm wanting to restore. There is no branding on it anywhere and I’m hoping someone can assist with info (and potentially a schematic) on it. It’s been suggested on another forum that it could have been built by Classic Radio & TV East Malvern.
Cheers
Scott
Supplimentary photo:-
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Administrator
Location: Naremburn, NSW
Member since 15 November 2005
Member #: 1
Postcount: 7451
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Photos uploaded.
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A valve a day keeps the transistor away...
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Location: Hill Top, NSW
Member since 18 September 2015
Member #: 1801
Postcount: 2115
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9 or 10 valves, nice. No idea what it is though.
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Location: Sydney, NSW
Member since 28 January 2011
Member #: 823
Postcount: 6802
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Location: Melbourne, VIC
Member since 11 July 2012
Member #: 1179
Postcount: 56
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I'm uncertain if the output transformers are original, due to their mounting and perhaps different size, and the marking suggests they were made by AWA. Is the power transformer mounted underneath the chassis?
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Location: Wangaratta, VIC
Member since 21 February 2009
Member #: 438
Postcount: 5472
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What is that metal work which looks like a badge at the front?
Unless there is an indication of the valves and all markings on it, that does not bode well for its ID. It does not look like a common & may be a house brand.
The components in the pan can be a clue. Those are ISO transformers and not overly common in later years. I would expect left of the dial drum:
RF amp (looks like a tube number 6Bxx in front of it); Converter (6AN7) then 1st IF. Between the transformers at the back the rectifier and that may be why ISO as the cans make a heat shield.
It looks like it may have two straight out pentodes for output. so 3 tubes RF ; 1 rectifier; two output tubes (6 tubes so far) possibly two preamps for the out put tubes takes us to 8.
Now that leave one to further speculate on has it got a 2nd IF what is the detector & is one tube impedance matching the turntable?
One may have to learn the time consuming art of reverse engineering.
I have an AutoCAD just for that job. Which should be a hint as to how many times I have done it.
If that turntable is what I think it is, they are an abomination. Look forward to much dry & hardened grease soap which will impede it from working.
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Location: Toongabbie, NSW
Member since 19 November 2015
Member #: 1828
Postcount: 1334
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The colour of the dial backing and the dial pulleys suggest a bit of STC in them?
Agree that the OPT's look like replacements.
A valve line up and photos of the underneath will help a bit.
Its a nice looking piece of furniture with a bit of 60's "style".
Fred.
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Location: Hill Top, NSW
Member since 18 September 2015
Member #: 1801
Postcount: 2115
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On the front, there's a snake symbol followed by a word, but it's too blurry to read.
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Location: Wangaratta, VIC
Member since 21 February 2009
Member #: 438
Postcount: 5472
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Blurry is fixable. You stay in range of the lens & crop out the superfluous later and in this case avoid flash.
I think I may have missed something? One tube is lined up with a hole through to the dial glass / Perspex. That may be a tuning indicator?
If you remove the tubes, watch here you put your fingers, those numbers come off.
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Location: Melbourne, VIC
Member since 26 December 2010
Member #: 794
Postcount: 387
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Hi all,
Finally got the valve lineup.
6AN7, 6BH5, 6N8, 6BR5, EF86, 6BQ5, EF86, 6BQ5, 6CG7 and a separate rectifier with GZ32.
One channel completely dead - both OP transformers test ok and voltages to the OP transformers are ok.
Cheers
Scott
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Location: Sydney, NSW
Member since 28 January 2011
Member #: 823
Postcount: 6802
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Well, that's an odd fish line-up. Can't find anything like it in the usual places.
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Location: Sydney, NSW
Member since 28 January 2011
Member #: 823
Postcount: 6802
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On the front, there's a snake symbol followed by a word, but it's too blurry to read.
I suspect that maybe used to read Stereo-something before some letters fell off.
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Location: Melbourne, VIC
Member since 26 December 2010
Member #: 794
Postcount: 387
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Location: Sydney, NSW
Member since 28 January 2011
Member #: 823
Postcount: 6802
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It's starting to show some of the hallmarks of a locally made house brand unit. We've seen cases where such radios contained unusual valves, presumably because the manufacturer obtained them cheaply as surplus, or something like that.
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Administrator
Location: Naremburn, NSW
Member since 15 November 2005
Member #: 1
Postcount: 7451
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Scott may wish to send a high-res photo of the branding on the front. I've expanded the original image but it is too blurry to decipher.
I agree with Marc on two things:-
1. Stand further back from the radio and use zoom and hold the camera very still. Increase the resolution from 640 x 480. Make sure there's as much natural light as possible.
2. Valve 10 is indeed a tuning indicator. In baseless valves, these indicators were 'side bangers' rather than showing the indicator through the top of the valve like the octals did.
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A valve a day keeps the transistor away...
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