Need help - looking for a explanation on how to test for continuity

[tinkerwalsh]

Hey everyone - been trying to figure out this hum in my AR turntable and im looking to test the continuity measurements between the headshell contacts and the RCA contacts. I just got a multimeter and I am looking to try this test myself. I have never used a multimeter.

Just wonder if anyone could give me step-by-step instructions on how to do this? Starting with what setting on the multimeter I select. I know this is probably very easy to do I just want to do it right.

Thanks for the help!

 

[Nashou66]

What model MM did you get? Just so we can see what setting to use.

Usually there is a continuity test, the symbol is like a sound wave . If you touch the probes together you will hear a beep and the screen should show .000
or something similar.

either this

or this

Nashou

 

[Montycat]

Any of the resistance or Ohm settings will work for continuity. I usually use the 1k (1000) ohm one but it doesn't matter. Some meters will have an audible signal on one setting but many do not. It's nice to have as you sometimes are not easily able to see the meter display but it's not necessary.

On any of the resistance settings, if you touch the probes together you will see the meter read zero, or at least very close to it. If this happens you have continuity. I always touch the probes together as a quick check as I start. You are now ready to go.

Touch one probe to one wire end, say the red wire at the headshell. The other one goes to the tip of the red plug. If you get "zero" or a beep you have a circuit, or continuity. Now touch any of the other rca connections. If you get zero/beep while still touching red, and only red, at the headshell you have a "short circuit" or "short" , for short (couldn't "resist" ). A short is a bad thing.

Test all 4 colours this way:

Red to center tip at RCA red
Green to outer "barrel" of red RCA
White to white RCA tip
Blue to white RCA barrel

Some cables will not use Red and White. They might have grey and black for example. This doesn't matter but what does matter is that one lead at the headshell connects with one and ONLY one of the terminals at the end of the cable.

You can also test from the solder lugs inside the turntable to either the tonearm end or the cable end. This will isolate the connection issue to that area. If it's a problem in the tonearm itself this is a bigger pain as it's trickier to replace the internal wiring than the RCA cable, but it is possible.

 

[NoTransistors]

Also deserves a mention that when on the high setting, if the user is touching the probe ends, the meter will register.
Earth life conducts electricity.

 

[Nashou66]

Any of the resistance or Ohm settings will work for continuity. I usually use the 1k (1000) ohm one but it doesn't matter. Some meters will have an audible signal on one setting but many do not. It's nice to have as you sometimes are not easily able to see the meter display but it's not necessary.

On any of the resistance settings, if you touch the probes together you will see the meter read zero, or at least very close to it. If this happens you have continuity. I always touch the probes together as a quick check as I start. You are now ready to go.

Touch one probe to one wire end, say the red wire at the headshell. The other one goes to the tip of the red plug. If you get "zero" or a beep you have a circuit, or continuity. Now touch any of the other rca connections. If you get zero/beep while still touching red, and only red, at the headshell you have a "short circuit" or "short" , for short (couldn't "resist" ). A short is a bad thing.

Test all 4 colours this way:

Red to center tip at RCA red
Green to outer "barrel" of red RCA
White to white RCA tip
Blue to white RCA barrel

Some cables will not use Red and White. They might have grey and black for example. This doesn't matter but what does matter is that one lead at the headshell connects with one and ONLY one of the terminals at the end of the cable.

You can also test from the solder lugs inside the turntable to either the tonearm end or the cable end. This will isolate the connection issue to that area. If it's a problem in the tonearm itself this is a bigger pain as it's trickier to replace the internal wiring than the RCA cable, but it is possible.

he has an AR XA the color wires are different.

Don't have it on hand at the moment.

Nashou

 

[tinkerwalsh]

Any of the resistance or Ohm settings will work for continuity. I usually use the 1k (1000) ohm one but it doesn't matter. Some meters will have an audible signal on one setting but many do not. It's nice to have as you sometimes are not easily able to see the meter display but it's not necessary.

On any of the resistance settings, if you touch the probes together you will see the meter read zero, or at least very close to it. If this happens you have continuity. I always touch the probes together as a quick check as I start. You are now ready to go.

Touch one probe to one wire end, say the red wire at the headshell. The other one goes to the tip of the red plug. If you get "zero" or a beep you have a circuit, or continuity. Now touch any of the other rca connections. If you get zero/beep while still touching red, and only red, at the headshell you have a "short circuit" or "short" , for short (couldn't "resist" ). A short is a bad thing.

Test all 4 colours this way:

Red to center tip at RCA red
Green to outer "barrel" of red RCA
White to white RCA tip
Blue to white RCA barrel

Some cables will not use Red and White. They might have grey and black for example. This doesn't matter but what does matter is that one lead at the headshell connects with one and ONLY one of the terminals at the end of the cable.

You can also test from the solder lugs inside the turntable to either the tonearm end or the cable end. This will isolate the connection issue to that area. If it's a problem in the tonearm itself this is a bigger pain as it's trickier to replace the internal wiring than the RCA cable, but it is possible.

Awesome thanks for much for the response! I am back home now and gonna attempt this. Ill let you know how it goes.

 

[tinkerwalsh]

he has an AR XA the color wires are different.

Don't have it on hand at the moment.

Nashou

thanks for reminding me of that I remember marcmorin explaining that to me. ill look around for the headshell wiring.

 

[Montycat]

he has an AR XA the color wires are different.

Don't have it on hand at the moment.

Nashou

Yes, I know though I don't recall AR wire colours either. I mentioned that they are not all the same and described how to work around that. One to ONLY one is the key.

 

[tinkerwalsh]

Yes, I know though I don't recall AR wire colours either. I mentioned that they are not all the same and described how to work around that. One to ONLY one is the key.

Okay so I was able to get this set up and figured out - I think.

I also gave the RCAs a very good cleaning before hand. They looked very clean but I was surprised how much oxidation came off!

I checked my head shell wiring:

red wire to red pin beep - no beep to other points
white wire to white pin beep - no beep to other points
green wire to white shield - no beep to other points
blue wire to red shield - no beep to other points

i checked the solder lugs with the same results.

I will say that come of the 'Beeps' from the multimeter sounded a little scratchy at times. Not sure if thats a issue.

should i be checking for ground loops as well?

might try and and hook this baby up and see what happens!

 

[Nashou66]

Okay so I was able to get this set up and figured out - I think.

I also gave the RCAs a very good cleaning before hand. They looked very clean but I was surprised how much oxidation came off!

I checked my head shell wiring:

red wire to red pin beep - no beep to other points
white wire to white pin beep - no beep to other points
green wire to white shield - no beep to other points
blue wire to red shield - no beep to other points

i checked the solder lugs with the same results.

I will say that come of the 'Beeps' from the multimeter sounded a little scratchy at times. Not sure if thats a issue.

should i be checking for ground loops as well?

might try and and hook this baby up and see what happens!

You didn't say if these had continuity or not ....was there a beep for them?

Athanasios

 

[Marksj]

Someone have the diagram someone kindly hand drew about a month ago? Just wondering he said a him issue and has to make sure all grounds are summed. The diagram helps some understand it better. I don't know if you have original interconnects but might be a good time to change them out if they are original.

 

[Nashou66]

Someone have the diagram someone kindly hand drew about a month ago? Just wondering he said a him issue and has to make sure all grounds are summed. The diagram helps some understand it better. I don't know if you have original interconnects but might be a good time to change them out if they are original.

was it me?

 

[tinkerwalsh]

was it me?

Someone have the diagram someone kindly hand drew about a month ago? Just wondering he said a him issue and has to make sure all grounds are summed. The diagram helps some understand it better. I don't know if you have original interconnects but might be a good time to change them out if they are original.

Thanks fellas for this. I plugged in the AR last night and it sounded good but still a small hum at a very high level of volume. you cant hear it at normal listening levels.

how to i got about testing to make sure all the grounds are summed?

again thanks so much for the help. really love this old turntable!

 

[tinkerwalsh]

You didn't say if these had continuity or not ....was there a beep for them?

Athanasios

yes the beep means there is continuity

 

[Marksj]

That looks like it to me! Gonna screenshot it ,so I won't forget it?

 

[Marksj]

There are more experts than me here. You need to block it up properly and flip it over and check it or reattach wires as noted in the drawing. Out of all the threads I have read about humming it relates to a poor connection at headshell or ground wiring under Neath. Are you using the original connected interconnects? If so those are old!!Good place to start, replace them. Most people replace them with female connectors attached to the back. Then you can use any length of interconnects you chose. Good time to clean up wiring underneath. I don't have the ability to solder that small wire, but you might. Like I said earlier unless it's been worked on tonearm wire and connections have some age too them.

 

[Montycat]

Thanks fellas for this. I plugged in the AR last night and it sounded good but still a small hum at a very high level of volume. you cant hear it at normal listening levels.

how to i got about testing to make sure all the grounds are summed?

again thanks so much for the help. really love this old turntable!

When you say hum at "high level of volume" do you mean with no music playing? If so this is pretty normal. Nothing is ever completely without some level of noise but Phono stages due to the high levels of amplification of extremely low voltages are more likely to have a bit. If you can't hear it, great.

 

[tinkerwalsh]

When you say hum at "high level of volume" do you mean with no music playing? If so this is pretty normal. Nothing is ever completely without some level of noise but Phono stages due to the high levels of amplification of extremely low voltages are more likely to have a bit. If you can't hear it, great.

Yah before I cleaned the RCA's I could hear the hum in the music. Now after cleaning it seems like the issue has been solved!!

 

[markshan]

Yah before I cleaned the RCA's I could hear the hum in the music. Now after cleaning it seems like the issue has been solved!!

Hopefully it is that easy. More likely the "scratchy beeps" may have represented an intermittent short in one of the RCAs. If you have any more issues I would just solder on new wires. It's likely due anyway.

 

[tinkerwalsh]

Hopefully it is that easy. More likely the "scratchy beeps" may have represented an intermittent short in one of the RCAs. If you have any more issues I would just solder on new wires. It's likely due anyway.

awesome thanks for that reply. might be a good time to order some RCAs and get that done since work is slowing down.