Denon receiver dead - incorrect antenna may have caused this?

Francisco

Francisco

Member
Hadn't turned this one On in a couple of months. Picked it up again, fixed the broken antenna connector...connected an AM loop antenna... worked for 15min and it turned itself off.

The male connector already had the central prong broken when I found this unit in the trash. Today I removed the rest with the Dremel and soldered another prong.

https://i.imgur.com/t31lakm.jpg

https://i.imgur.com/VhnGA92.jpg

I only had an AM loop antenna around but connected it anyway like this:

https://i.imgur.com/nQC5F37.jpg

I dont know if this might have caused the damage or not. The unit worked perfectly for 15min (finally had FM reception) but just shut down and it doesnt turn on anymore.

Havent tested anything with the multimeter yet. I'd just like to ask first if the incorrect use of antennas might have been the problem.

Here is teh service manual:

https://www.google.com/url?sa=t&rct...r1rWjbWi9txosrA&bvm=bv.77161500,d.d2s&cad=rja
https://docs.google.com/file/d/0B6fu025jFteZaHAzZHVndDlWdUk/edit?pli=1
http://www.hifiengine.com/manual_library/denon/dra-345r.shtml
 
Francisco said:
Hadn't turned this one On in a couple of months. Picked it up again, fixed the broken antenna connector...connected an AM loop antenna... worked for 15min and it turned itself off.

The male connector already had the central prong broken when I found this unit in the trash. Today I removed the rest with the Dremel and soldered another prong.

https://i.imgur.com/t31lakm.jpg

https://i.imgur.com/VhnGA92.jpg

I only had an AM loop antenna around but connected it anyway like this:

https://i.imgur.com/nQC5F37.jpg

I dont know if this might have caused the damage or not. The unit worked perfectly for 15min (finally had FM reception) but just shut down and it doesnt turn on anymore.

Havent tested anything with the multimeter yet. I'd just like to ask first if the incorrect use of antennas might have been the problem.

Here is teh service manual:

https://www.google.com/url?sa=t&rct...r1rWjbWi9txosrA&bvm=bv.77161500,d.d2s&cad=rja
https://docs.google.com/file/d/0B6fu025jFteZaHAzZHVndDlWdUk/edit?pli=1
http://www.hifiengine.com/manual_library/denon/dra-345r.shtml
Click to expand...

I can't think of any scenario in which the unit would shut down after fifteen minutes of having an AM loop connected to the 75 ohm FM coax input. I'm not sure of the chronology but could a metal shaving from the dremel have landed inside the receiver?

I once did something careless with my STA-2700. I was shining up the black metal top with shoe polish and some dripped on the circuit through a vent hole. It shut down and stayed down. I left it alone and 24 hours later it worked again. Maybe you could turn the receiver upside down and give it a good shake?
 
Agree, can't think of any reason the problem would be antenna related. More likely is it has some problem that caused it to go in the trash to begin with.
 
Update:

Neither the aerial connections or the AM/FM tuners would affect the amplifier operation since the aerials are not electrically coupled and in any case, the tuners are disconnected from the preamp and main amplifiers when selecting a different input source. There is a block diagram on p13 of the manual that shows how the inter-connections are arranged.

I will proceed to check secondary AC voltages, rectifier outputs, etc, taking in account the circuit diagram in the final pages of the service manual.
 
Dear all

I've got a Denon DRA345R with a blown transformer (the primary on open circuit)
I was trying to find a replacement part but i'm having trouble identifying the secondary circuit characteristics.
Does anyone have the output voltages of these 3 circuits and an idea of the amps being driven by the downstream circuitry ?
Or, does anyone have one of these units and be so kind to take some quick readings on each secondary V AC?
the unit I have is European so it takes 230VAC - 50Hz on the income power line.

Thank you in advance,
 
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