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 AWA Radiola 4
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 Return to top of page · Post #: 1 · Written at 8:54:17 AM on 5 September 2017.
Arty41's Gravatar
 Location: Brisbane, QLD
 Member since 18 September 2010
 Member #: 102
 Postcount: 294

Would anyone have any technical information on a AWA Radiola 4 1925? I have one which I'd like to eventually restore but need the voltages and battery connections.


 
 Return to top of page · Post #: 2 · Written at 6:24:00 PM on 6 September 2017.
Garyoz's avatar
 Location: Perth, WA
 Member since 19 November 2008
 Member #: 381
 Postcount: 239

We would love to see some pictures?
Does it look like this?

http://www.radiomuseum.org/r/amalgamate_radiola_iv_4_2.html


 
 Return to top of page · Post #: 3 · Written at 7:26:29 PM on 6 September 2017.
Tallar Carl's avatar
 Location: Latham, ACT
 Member since 21 February 2015
 Member #: 1705
 Postcount: 1574

That is one nice old set. All the valves are the same can someone explain to me as to how this works. Its probably a simple answer but I am interested.


 
 Return to top of page · Post #: 4 · Written at 9:12:17 PM on 6 September 2017.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 4337

There was one in HRSA Action 35 birthday. oz radios.com. Described as Radiola 4 C7/60. Those things follow a fairly common plot. Where there is a "Grid leak" resistor, it's normally out of spec & needs re-coring with a new resistor.

The OP valve will dictate how one sets up a speaker. Most of those were either headphones or a high impedance "Horn Speaker".

Not a lot of complexity. I have a 1924 Gillfilan Bros (USA) set here for repair.

Marc


 
 Return to top of page · Post #: 5 · Written at 7:01:05 AM on 7 September 2017.
JFB's Gravatar
 JFB
 Location: Milton, NSW
 Member since 27 June 2016
 Member #: 1945
 Postcount: 44

The use of a common triode for both RF and AF stages was not uncommon in the 1920's, after all there weren't that many types to choose from. The AWA33 was first manufactured by AWA in 1925 and the museum site lists the radio as being a TRF with regeneration and two AF stages so it was most likely a single RF stage followed by a regenerative detector followed by two audio stages a fairly common arrangement for the time.

The AWA33 was similar to a UV-199 but with a different base.

As Marc noted above the detector is most likely a grid leak type and the resistor is almost always out of spec.

Joe


 
 Return to top of page · Post #: 6 · Written at 9:49:17 AM on 7 September 2017.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 4337

The main traps are polarity and the fact that a lot are top wired and the data sheets show bottom wired (sockets often labelled). I always check all of the caps in those as well, some of the Mica types used in them are indestructible & some not.

Some use different voltages on each stage & generally the "Leaky Grid" (infinite impedance) detector is restricted to below 45V (UX201A) otherwise it needs a "C" battery.

These are not overly complex when affecting repairs. A lot is commonly deteriorated wires, Monkeys that know not what they are doing & Rodents.

Marc


 
 Return to top of page · Post #: 7 · Written at 6:43:13 PM on 8 September 2017.
Garyoz's avatar
 Location: Perth, WA
 Member since 19 November 2008
 Member #: 381
 Postcount: 239

Here is a good explanation of TRF radios.

https://en.wikipedia.org/wiki/Tuned_radio_frequency_receiver


 
 Return to top of page · Post #: 8 · Written at 9:26:01 PM on 8 September 2017.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 4337

TRF is not as complex in its operation as superheterodyne however, if you understand it, that gives a better chance of fixing it. Having a group of tuned RF amps in series, in some cases with TRF's, sees them share an issue with a superheterodyne with a leading RF pre-amplifier.

Some cannot come to grips with the fact that if all of the tuned circuits bringing in signal from the antenna and amplifying it are not on the same frequency it gets blocked, or seriously attenuated. That is common when the previously mentioned Monkey gets at it.


 
 Return to top of page · Post #: 9 · Written at 9:57:54 PM on 23 September 2017.
Robert69's avatar
 Location: Western Victoria, VIC
 Member since 14 November 2009
 Member #: 579
 Postcount: 109

Hi Rudy,

I have one of these sets and a copy of the instruction manual - with circuit and voltages. If you send me a message I will forward it to you. What is the serial number of your set?

Robert


‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
Robert

 
 Return to top of page · Post #: 10 · Written at 10:22:38 PM on 23 September 2017.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6005

I have one of these sets and a copy of the instruction manual - with circuit and voltages

Would you be wiling to have a copy placed on the Radiomuseum site?


 
 Return to top of page · Post #: 11 · Written at 6:37:02 PM on 25 September 2017.
Robert69's avatar
 Location: Western Victoria, VIC
 Member since 14 November 2009
 Member #: 579
 Postcount: 109

Hi GTC,

Yes I'm 100% into sharing info and advice (if useful!). I'm a member of Radiomuseum, so I'll post it there, plus a few pictures of the actual set. I have an AWA 'sealed set' with a slightly smaller cabinet - I'll post some pictures of that as well - just need the time to di it all.

Robert


‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
Robert

 
 Return to top of page · Post #: 12 · Written at 7:37:31 PM on 25 September 2017.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6005

Thanks Robert, that's a great attitude.


 
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