My First/Last SX-1010
- Thread starter craxx6969
- Start date
Here are the results of the testing based on the information in the link provide by Zebulon:
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That means simply: get two short circuit male rca plugs
plug power cord into wall
connect speakers
be sur pre-out / amp in jumpers cleaned and in place
NOTHING else connected to amp
turn on
put shorting plugs into phono 1, select phono 1, turn up volume, stick ear into speaker, be sure both channels are humming and are they humming equally?
Yes, both channels hum, left louder than the right
repeat all (plugs, select, volume, listen) for phono 2,
Both hum, left louder than the righ.
repeat all (plugs, select, volume, listen) for aux
No hum in aux mode
repeat all (plugs, select, volume, listen) for tuner
This is a receiver, so no tuner option
repeat all (plugs, select, volume, listen) for tape 1 play jacks
When I first turned the unit on, there was static/buzz, after 4-5 seconds the static/buzz went away and there was slight hum. Volume at zero or max did not increase or decrease the amount of hum.
repeat all (plugs, select, volume, listen) for tape 2 play jacks.
When I first turned the unit on, there was static/buzz, after 4-5 seconds the static/buzz went away and there was slight hum. Volume at zero or max did not increase or decrease the amount of hum.
ALSO when I removed the pre in/main out plugs and hooked up my cellphone to power in jack there was NO hum whatsoever.
Thanks,
JT
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It appears this is a grounding issue? I have a red lead on a resistor on the AWR-054 board, resistor #r8 15k and chassis - black lead from dmm. No hum on FM and the tone control does not invoke any hum left or right channel.
Can this be? The ground wire from the AWR-054 board is secured to the ground point. Weird?
the red lead is on the opposite side of pin 12. Just an fyi
Can this be? The ground wire from the AWR-054 board is secured to the ground point. Weird?
the red lead is on the opposite side of pin 12. Just an fyi
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I'll check the continuity between Pin 12 and the multiple ground point. I may have to run a jumper to see if that solves the issue or check the backside of the AWR-054 board for bad traces or cracks, which I did that a long time ago. This unit was not shipped, I drove about 45 minutes to pick it up.
Dang, didn't want to hear that! I'll double check the board looking for those darn cracks.. @j@
Well the board has no cracks in it. I pulled it from the standoffs and redid the solder on the components. I also checked the continuity of that path and it is okay. Based on all the testing it is in the pre-amp section and there is where I am headed next.
Troubleshooting a hum is time consuming. Good job so far!
So no hum when you were checking the resistor (R8) on the power supply? Please explain that a little better.
I have a 1010 here, so if you need a visual reference I can pull it out easily.
So no hum when you were checking the resistor (R8) on the power supply? Please explain that a little better.
I have a 1010 here, so if you need a visual reference I can pull it out easily.
Okay red dmm lead to the R8 resistors lead that is opposite of the #12 pin. Black dmm lead to the chassis. That got rid of the him. After reflowing the pads that set up no longer eliminates the him. If I pull the pre to main bars and run my cellphone into the main jacks, no hum.
So that is as far as got yesterday. I managed to get the flu so I'm not working on it at the moment. It is better to get well then I'll dig into it again.
Flu better?
Try successively shorting backwards the stages at the inputs, if the hum goes away when an input is shorted to it's ground reference, we know from the short forward the chain is blameless. This is what I would do, with a LOT of added study as to the shorting points to interrupt the signal.
Try successively shorting backwards the stages at the inputs, if the hum goes away when an input is shorted to it's ground reference, we know from the short forward the chain is blameless. This is what I would do, with a LOT of added study as to the shorting points to interrupt the signal.
Flu still has me somewhat under the weather. Better but not yet in tip top shape. I'll have to do some heavy studying in order to NOT eff up any of the boards or the output transistors. Once I feel comfortable in shorting the inputs to their own ground I'll have a go at it.
Thanks!
graftdesign
Active Member
Just went through and read this thread. Wow, sounds like a real nightmare! I'm about to rip into mine... and am getting a bit apprehensive about even starting! :0
I would suggest you read as many 1010 threads as you can before you dig into the receiver. Lots of great help on this forum as well. :thmbsp:
tax man here too, for more than myself. plus voting screw-up for tomorrow's election (missing absentee ballot, too late for early voting etc) - the line of pains in my @## grows longer every day. sigh
I feel the pain, I really hate this time of year just because after paying taxes all year long they still want more. :tears: thieves pretending to be your friend. Ha!
