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Old 01-13-2021, 03:31 PM   #1
budwich
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Default onkyo 919 Receiver... hum problem but...

I have an onyko 919. It has a hum problem at cold start which eventually dies / goes quiet. I have been "chasing" it for a while. Tightening ground screws and checking a few places. Basically, the problem is in the "back half" of the unit.... that is, if I take the sound out of the "pre-out" and feed it to a stand alone amp, it is good. If I feed in a signal at the external decoder input and play thru the back end of the onkyo, it has the hum.

Anyway, along the way (the chase), a number of components (resistors, capacitors, etc) on the main board and the DSP board are loose and appear to have "cold solder joints" or equivalent (ie. poor solder connections). These may be contributing the problem... maybe. Some are addressable with the boards in place BUT the DSP board is at the back of the front panel and the board itself needs to be removed. :-(

To get the board out, I have been fighting with "damn onkyo ribbon connectors". The individual wires of the "ribbon" are "ribbed" and each appear to push into the body of the connector. I have ruined on connector that I have included a picture of. It has 5 wires / pins. As you can see the wires are somewhat "ribbed" making it very hard to pull them out of the holder. As you can see, the entire body of the connector pulled away from the board... :-( I think I have figured out how to remove the wires "normally" by pushing down on the "top holder cover" of the connector. My question is: Does anyone know what the name of the connector is referred to as and can they be found anywhere for sale?

To get at the board, I need to release about 5 others and am hoping not to "crunch" any others.

Thanks for any help / direction.
Attached Images
File Type: jpg Onkyo 919 cable clamp.jpg (426.7 KB, 10 views)

Last edited by budwich; 01-13-2021 at 03:44 PM..
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Old 01-13-2021, 07:15 PM   #2
budwich
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Default Re: onkyo 919 Receiver... hum problem but...

closer look at the dsp board with the "wiggling" components. The pads of those components have come "dislodged" from the board substrate. The component, itself, is still soldered / connected electrically thru to the subtending track. Perhaps a bit of crazy glue to give some "solidness" to the area to prevent possible fracture of the track????
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Old 01-13-2021, 08:47 PM   #3
redwire
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Default Re: onkyo 919 Receiver... hum problem but...

The ribbon cable connectors have a release latch. If you don't undo the latch- you will trash the connector. I thought it's a bar that you poke with a small screwdriver that pushes back the spring on all pins.
edit: I think you pop up the top plate

Last edited by redwire; 01-13-2021 at 08:51 PM..
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Old 01-14-2021, 07:12 AM   #4
budwich
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Default Re: onkyo 919 Receiver... hum problem but...

thanks... yep... one tab on one side of the "cover" broke off and then continual pulling caused the whole connector to become detached. Yes, pushing on the top helps release the grip but it still seems very difficult to pull up on the ribbon wire as it appears that the "release tab" in the underside doesn't have enough "drive" in to the fingers to spread them to release the wire. I have not found any such connectors in my search so far so it is unlikely I will find a replacement. I hope I can make do with the existing connector "remains".

On a side note, I found an electrolytic cap (vertical mount, thru the hole) that has its outside "can" able to rotate / turn. Strange, never come across that before. The "legs" are still soldered / attached properly to the boards. Its a likely candidate for replacement and potentially the "root cause" of the noise... I am hoping.

edit: out of circuit test on the cap indicates 368uf as opposed to the 100uf value. fingers crossed.

Last edited by budwich; 01-14-2021 at 07:56 AM..
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