My First/Last SX-1010
- Thread starter craxx6969
- Start date
Is hum affected by the tone switch?
A. Yes, it creates a lower frequency hum in addition to the normal hum (two hums)
Probe
Signal probe the +/- 24v lines at pins 3(10)+ and 1(12)-, then signal probe on both sides of the 2.2k resistors.
Tape monitor switch is in the down position on the separate receiver.
When the tone switch is in the down position on the 1010 the secondary hum is still present when I probe Pin 5/
Probed pin 3, no difference in hum, no sounds
Probed pin 10, no difference in hum, caused scratchy sounds
Finally signal probe pins 2, 5, 8, 11 grounds.
Probed pin 2 – hum goes down a bit, scratchy noise
Probed pin 5 – hum goes down drastically
Probed pin 8 – no change in hum
Probed pin 11 – no change in hum
Probed Pin side of 2.2K resistor off of pin 1 – no change
Probed non pin side of 2.2 K resistor off of pin 1- no change
Probed Pin side of 2.2K resistor off of pin 10- no change
Probed non pin side of 2.2k resistor off of pin 10- no change
This is strange, no hum or noise on any other functions EXCEPT FM…
A. Yes, it creates a lower frequency hum in addition to the normal hum (two hums)
Probe
Signal probe the +/- 24v lines at pins 3(10)+ and 1(12)-, then signal probe on both sides of the 2.2k resistors.
Tape monitor switch is in the down position on the separate receiver.
When the tone switch is in the down position on the 1010 the secondary hum is still present when I probe Pin 5/
Probed pin 3, no difference in hum, no sounds
Probed pin 10, no difference in hum, caused scratchy sounds
Finally signal probe pins 2, 5, 8, 11 grounds.
Probed pin 2 – hum goes down a bit, scratchy noise
Probed pin 5 – hum goes down drastically
Probed pin 8 – no change in hum
Probed pin 11 – no change in hum
Probed Pin side of 2.2K resistor off of pin 1 – no change
Probed non pin side of 2.2 K resistor off of pin 1- no change
Probed Pin side of 2.2K resistor off of pin 10- no change
Probed non pin side of 2.2k resistor off of pin 10- no change
This is strange, no hum or noise on any other functions EXCEPT FM…
Zebulon,
I based my probe on the exemplar in the photo.. Works decent but as Mark said it is a MONO probe.
See my post above on the results..
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two separate results expected
primary: The sound coming out of the speaker being fed by the signal probe
secondary: any effects/changes the act of probing has upon the unit under test.
note: in probing for hum, especially upon grounds and grounded input humming channels, it may be necessary to hook up the signal probe to the PHONO input, start at zero volume and turn it up until hum is heard and note the relative levels of the hum. Your BASELINE comparison is the hum found when touching the probe to a bare metal chassis point NOT directly in line between the speaker grounds and the power transformer center tap.
BETWEEN two units (one under test, the other the probe's amplifier) a heavy wire should be connected between the two unit's phono ground terminals as well as being plugged into the same outlet. This is applicable when either using the tape monitor input (150mV sensitivity, power amp input (500mV to 2v sensitivity) OR the phono input (2mv sensitivity)
primary: The sound coming out of the speaker being fed by the signal probe
secondary: any effects/changes the act of probing has upon the unit under test.
note: in probing for hum, especially upon grounds and grounded input humming channels, it may be necessary to hook up the signal probe to the PHONO input, start at zero volume and turn it up until hum is heard and note the relative levels of the hum. Your BASELINE comparison is the hum found when touching the probe to a bare metal chassis point NOT directly in line between the speaker grounds and the power transformer center tap.
BETWEEN two units (one under test, the other the probe's amplifier) a heavy wire should be connected between the two unit's phono ground terminals as well as being plugged into the same outlet. This is applicable when either using the tape monitor input (150mV sensitivity, power amp input (500mV to 2v sensitivity) OR the phono input (2mv sensitivity)
I have a solid wire connecting the two receivers phono ground to phono ground. Funny the hum has been transferred to the probing unit(1050) without me even probing the receiver with the hum (1010). That is at minimal volume of the 1050. When I touch the probe to the 1010 at pin 3, the hum on the 1050 stays the same, the hum/buzz lessens on the 1010 and the same for pin 10.
When probing pins 1 and 12 the hum/buzz diminishes on the 1010 and the hum remains on the 1050 with no change.
Probed pin 2 – hum/buzz diminishes on the 1010, no change on the 1050
Probed pin 5 – hum/buzz diminishes on the 1010, no change on the 1050
Probed pin 8 – hum/buzz diminishes on the 1010, no change on the 1050
Probed pin 11 - hum/buzz diminishes on the 1010, no change on the 1050
When probing the pin side of the at Pin 1 2.2k resistor there is no change in hum/buzz on either unit. When probing the non pin side, the hum/buzz diminishes on the 101, no change on the 1050. Same exact results for the pin 10 probing.
Tone switch in the down position increase the hum/buzz drastically on the 1010.
Also when I touch the 1010 with the 1050 volume at minimal, not silent, the hum on the 1050 lessens.
Hope this helps.
Check out the number of views for this post!:thmbsp:
We're watchin' it craxx :thmbsp:
It's out of respect for MTF that we're not all jumping in and getting underfoot. What's your main rig while this one's under the knife? Not jacking, just giving it some chatter.
Stranger and stranger. I don't know (MORE problems- damn adobe update has to be UNUPDATED) if this one has a death cap or death resistor - check and see if it's ok.
Using a second receiver as a test probe means both have to be plugged into the same outlet, and the plugs aligned for minimum noise.
I took a fall on Friday, and busted my drivers door window on the way down (it had to be my hand hitting it?) into the mud during the rain. No stitches but zillions of little cuts ALL over. A real gory looking mess. So I now have a car window to replace on top of every OTHER thing that has been stealing my time lately. Granted I am coming up with neat solutions, BUT they NEVER should have NEEDED SOLVING!!!
The political silly season in Illinois is in full swing as well (ostensibly to the end of the month of May), as a further distraction (in fact THAT was the reason I was awkwardly getting into my car in the rain on a Friday night, toting a bundle of newly (they weren't even a DAY old yet!!) minted signs). If anybody wonders where the heck I am...
Using a second receiver as a test probe means both have to be plugged into the same outlet, and the plugs aligned for minimum noise.
I took a fall on Friday, and busted my drivers door window on the way down (it had to be my hand hitting it?) into the mud during the rain. No stitches but zillions of little cuts ALL over. A real gory looking mess. So I now have a car window to replace on top of every OTHER thing that has been stealing my time lately. Granted I am coming up with neat solutions, BUT they NEVER should have NEEDED SOLVING!!!
The political silly season in Illinois is in full swing as well (ostensibly to the end of the month of May), as a further distraction (in fact THAT was the reason I was awkwardly getting into my car in the rain on a Friday night, toting a bundle of newly (they weren't even a DAY old yet!!) minted signs). If anybody wonders where the heck I am...
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MTF, understand about the receivers and how they are set up. I'll check to see if any of the caps are bad that I have installed ( all from our normal place of buying). This beast is not going to beat me.
Sorry to hear about the fall and the car. car is easier than the body. I would use a piece of clear acrylic until you got the window replaced. Check the salvage yards in your area for a good used on. Too bad I wasn't closer as I was a autobody tech in my previous life.
Sorry to hear about the fall and the car. car is easier than the body. I would use a piece of clear acrylic until you got the window replaced. Check the salvage yards in your area for a good used on. Too bad I wasn't closer as I was a autobody tech in my previous life.
My main system is a fully recapped sx-1250 ( by me) pushing a set of one owner (me) AR2ax speakers and a Technics SL Q2 TT. Also I have a one owner (me) set of JBL L112 with the original boxes. Those stay out of site for now.
The suggestion was ONLY aimed at the primary circuits of the power transformer, from the power plug to the transformer primary itself.
We have proved that the power amp is quiet, thus most of the power supply is exonerated.
Poor choice of words on my part. I understand that the power supply is out of the equation. I'll continue to test the circuits.
Thanks
antenna(s)? specifically shared grounds?
