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Post by jeremy on Jun 26, 2014 10:00:08 GMT -5
Got a Denon DRA-397 here that has a rather simple problem. Plug it in, turn the master power switch on, red standby LED comes on solid as normal. Pressing the standby power button does nothing to the unit. It just stays in standby.
A factory reset does nothing (it doesn't reset). I've done some checking, and on CP414 I checked the +15v and -15v with ground to chassis, and the -15v gets 350mv, the +15v gets about 100mv. If I turn off the master power switch so the unit has no power whatsoever, those same + and - voltages are 0vdc.
So my assumption is that the receiver is not putting out the 15 volts as it should, thus preventing it from powering on. The standby 5v gets to the faceplate/standby button, and drops to zero v when I push the button so that all appears normal.
I read online that a DRA-685 (similar bigger, but older model) that had the same issue with the standby and voltages were the result of a couple of sensing resistors. Any help is appreciated. I should be able to fix this relatively fast, as I have a physically damaged parts unit here I can take good components from. |
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Post by mastertech on Jun 26, 2014 11:42:20 GMT -5
If you are not hearing the main power relay latching when turning on then the main transformer is not being turned on so you would not have the +/- 15v.
You must find out why the main relay is not being turned on. On the main power board look for CP511. Use pin 14 for neg and pin 12 for pos probes, DMM set on DC voltage and you should see power when you push the Standby/on button.
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Post by mastertech on Jun 26, 2014 11:47:50 GMT -5
Just for verification, press and hold the zone2 and zone3 buttons and while holding down press standby/on button and see if it turns on.
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Post by jeremy on Jun 26, 2014 12:06:57 GMT -5
MT, Checked pins 12 and 14 for voltage, there is nothing at all when pressing the standby/on button. Pressing and holding zone 2 and 3 while pressing standby/on does nothing as well
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Post by mastertech on Jun 26, 2014 12:23:27 GMT -5
Test for 5.6vdc at pin 15 of same connector. If it is there then jump pin 15 to pin 12. When you plug it in and latch the main power switch you should hear the main relay latch. let me know if this happens. If relay does not latch then test pin 15 again with jumper in place and see if you still have the 5.6vdc or if it is less or none.
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Post by jeremy on Jun 26, 2014 12:36:17 GMT -5
Okay, 5.6vdc is on pin 15, I jumped 15 to 12, powered it on with the master power switch, and I did hear the relay latch. Standby/on still does nothing. I tested for 5.6vdc after jumping and it was still there, even when pressing the standby/on, but again still wont come out of standby.
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Post by mastertech on Jun 26, 2014 14:14:26 GMT -5
Go to the CPU board and look for connector CP408. It is probably in the middle of the board with nothing connected. It is a test connector. DMM on DC voltage, neg on pin 5 and pos on pin 2 should have +5v. Let me know.
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Post by jeremy on Jun 26, 2014 15:51:05 GMT -5
Checked for +5vdc on CP408 and it is there on those pins.
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Post by mastertech on Jun 26, 2014 16:16:17 GMT -5
Ok, CPU board, CP406, pin 1 check for +5v. If there then press standby/on button and see if it goes to 0.
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Post by jeremy on Jun 26, 2014 16:21:15 GMT -5
Okay tested pin 1 on CP406, and there is no voltage at all. used the CPU_GND for negative
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Post by mastertech on Jun 26, 2014 16:45:07 GMT -5
I believe CP406 has a harness. Disconnect that harness and again test for +5v (or any voltage) on pin 1 on the CPU board, not the harness. Or just test both.
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Post by jeremy on Jun 26, 2014 17:21:07 GMT -5
Checked it after pulling the front panel ribbon cable out (that's the harness) still the same thing no voltage on pin 1, just can't see the red LED illuminated because of the cable being pulled.
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Post by jeremy on Jun 26, 2014 18:08:58 GMT -5
MT, I took the easy way out because I had a hunch since you had me check the front panel connector on the CPU board. I swapped the CPU board out with my other unit and the receiver is fully working.
What should I be looking for on the CPU board that would keep the 5vdc from getting to the FP?
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Post by mastertech on Jun 26, 2014 21:27:57 GMT -5
I'm curious. Test that pin 1 with the working CPU board and see what you get.
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Post by mastertech on Jun 26, 2014 21:33:38 GMT -5
On the non working CPU board test both sides of D404 for DC voltage. Use gnd from where you were initially testing from. You should have 5.6v on 1 side and around 5v on the other.
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