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AWA 500m low volume
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Return to top of page · Post #: 1 · Written at 9:25:40 AM on 13 March 2023.
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Location: Latham, ACT
Member since 21 February 2015 Member #: 1705 Postcount: 2174 |
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I have checked all caps ( recapped) and resistors. I found a mica ( black AWA ) cap coming off the antenna coil that reads as .05μF! Would this result in low volume. I think it's supposed to be 100pf . I will have to get a photo as I can't remember where the other end terminates ( not to ground ) there are two on the Antenna coil but only one goes to ground. |
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Return to top of page · Post #: 2 · Written at 3:26:38 PM on 13 March 2023.
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Location: Latham, ACT
Member since 21 February 2015 Member #: 1705 Postcount: 2174 |
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Ok I just found out it is actually a .05 but I'm sure I saw uμF printed on it so what's the chance it's turned into a resistor? |
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Return to top of page · Post #: 3 · Written at 7:07:07 PM on 13 March 2023.
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Location: Linton, VIC
Member since 30 December 2016 Member #: 2028 Postcount: 472 |
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0.05μF seems too much capacitance for that end of town. |
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Return to top of page · Post #: 4 · Written at 7:43:28 PM on 13 March 2023.
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Location: Toongabbie, VIC
Member since 1 September 2020 Member #: 2438 Postcount: 138 |
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This sounds like C5. This is the AGC decoupling cap connected to the secondary side of the antenna coil. Leaking here would cause inoperative AGC and possible distortion on strong signals. How are circuit voltages? They perform ok these models but not hot performers by any means. |
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Return to top of page · Post #: 5 · Written at 7:49:04 PM on 13 March 2023.
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Location: Linton, VIC
Member since 30 December 2016 Member #: 2028 Postcount: 472 |
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If it is C5 it will not be a mica cap, probably wax. And it will not be hanging off the antenna coil but the coupling transformer from the antenna coil to the RF amp. |
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Return to top of page · Post #: 6 · Written at 9:08:33 PM on 13 March 2023.
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Location: Latham, ACT
Member since 21 February 2015 Member #: 1705 Postcount: 2174 |
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Its actually C2. I pulled it out and photographed it . Blew it up and it reads 4pf but on the multimeter it read .05.   |
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Return to top of page · Post #: 7 · Written at 9:24:25 PM on 13 March 2023.
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Location: Linton, VIC
Member since 30 December 2016 Member #: 2028 Postcount: 472 |
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Picofarads are more like it for that end of town. |
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Return to top of page · Post #: 8 · Written at 9:44:47 PM on 13 March 2023.
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Location: Toongabbie, VIC
Member since 1 September 2020 Member #: 2438 Postcount: 138 |
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C2 is unlikely to be faulty. You could just remove it and test the radio. It can be difficult testing caps that small. |
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Return to top of page · Post #: 9 · Written at 2:02:53 PM on 18 March 2023.
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Administrator
Location: Naremburn, NSW
Member since 15 November 2005 Member #: 1 Postcount: 7395 |
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Photos uploaded to Post 6. ‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾ A valve a day keeps the transistor away... |
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Return to top of page · Post #: 10 · Written at 8:06:17 PM on 18 March 2023.
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Location: Toongabbie, NSW
Member since 19 November 2015 Member #: 1828 Postcount: 1313 |
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Back in those days the standard units were F(arad), μF and uuF. |
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Return to top of page · Post #: 11 · Written at 8:42:15 PM on 18 March 2023.
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Administrator
Location: Naremburn, NSW
Member since 15 November 2005 Member #: 1 Postcount: 7395 |
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I think you are correct, Fred. The problem here stems from whoever set up the unit for capacitance in the first place and made the unit represent an unrealistic amount of capacitance, which is why the Farad is one of the few units in physics more commonly expressed in millionths (μF), billionths (nF) and trillionths (pF) of Farads instead of just Farads. ‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾ A valve a day keeps the transistor away... |
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Return to top of page · Post #: 12 · Written at 10:40:03 PM on 18 March 2023.
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Location: Latham, ACT
Member since 21 February 2015 Member #: 1705 Postcount: 2174 |
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We found the actual problem today. It was a 40k resistor on the screen that had gone high. Its now a very healthy set |
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