Sangean hdr-1 only buzzes no audio - AVS Forum
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post #1 of 8 Old 06-01-2013, 06:31 AM - Thread Starter
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Trying to save a sangean hdr-1 that has a 60 cycle buzz, no audio, no am or fm stations. all functions on the lcd work, volume controls the buzz loudness. also mute works. clock sets fine. filter caps and rectifiers ok. no cold solder connections noted. out of the case with power on, no components getting hot. using headset jack everything is the same. using scan on the tuner it will scan but not stop on a station. manually on a known station no audio detected only buzzing sounds like 60 cycle square wave. Anyone have any ideas?
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post #2 of 8 Old 06-01-2013, 10:57 AM - Thread Starter
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Forgot to mention on the Sangean HDR-1 that buzzes it is a new in the box defective radio from Ebay. I broke all the factory seals when I opened it for repair. Therefore this is a factory defect. I am going to replace the buffer amp njm4580 and the LM358 tuning voltage amplifier. If the problem is not on the main board the radio ultimately may become a door stop.
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post #3 of 8 Old 06-01-2013, 06:55 PM
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60 cycle buzz sounds like the problem could be in the power supply section. If your transformer is good (no leaking from the output leads onto the circuit board) it could be some other part in the power supply section (rectifier) on the board in the back part of the radio. As you know, I have a back part which has a bad transformer for sale. Just let me know. If you need a schematic, send me a private message and I'll send it to you. I hope you get it working as these are nice sounding radios. They really require external AM and FM antennas to work their best...
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post #4 of 8 Old 06-01-2013, 07:34 PM - Thread Starter
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Ohm meter and voltage checks on the power supply revealed nothing defective, at least to my rusty skills. I am curious about your suggestion about "no leaking from the output leads onto the circuit board" , I'm not sure what you mean by leaking leads I was wondering if this is something that happened to your HDR-1? Thank you for your reply,
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post #5 of 8 Old 06-06-2013, 07:33 PM
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Yes, my HDR1 had a bad transformer. I noticed that a black liquid leaked down from the transformer onto the circuit board. I replaced the entire rear circuit board with a know good one (which didn't have the black liquid) and everything is working great now...
Let me know the outcome of your repair...
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post #6 of 8 Old 06-07-2013, 04:42 AM - Thread Starter
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Oh I get it--leaky as in liquid--I thought you were talking about leaky as in leaky capacitor. So I thought you were referring to the leads leaking voltage on the circuit board and that would be rare. I'm still waiting for the OP-Amps to arrive. I don't have much faith in this fix, I will let you know the outcome. I did a better ohmmeter check on the rear circuit board, came up empty on any problems. I'll run the voltage checks again after I solder in the OP-Amps.
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post #7 of 8 Old 06-08-2013, 06:00 AM - Thread Starter
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I am asking Amazon why the Sangean HDR-1 on their site is priced at $891 or is this a misprint. Imagine if the radio were defective and the warranty is no longer valid due to the age of the product. No parts or service is available is what I have been told when I called Sangean support. Anyone have any comments?
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post #8 of 8 Old 06-10-2013, 01:22 PM - Thread Starter
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Well whatever is defective in Sangean HDR-1 is eluding me. I replaced two Op-Amps but nothing changed, the radio has no audio except for a harsh buzzing sound. Using Aux In kills the buzzing but the imported audio never reaches the speakers. The clock sets and I can go through the menu's. It is probably toast.
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