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Need a probe for Sencore SC61/3080 part # 39G294

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Posted on October 19, 2011 at 20:23:31
Michael Norona


 
I am trying to locate a 10X low capacitance probe for a Sencore SC61/3080. The SC61 & the SC3080 appear to be very similar, so I am assuming the 39G294 will work in either. The guy I bought my SC61 from sent me a manual for a SC3080. He said the units were essentially the same Thanks!

 

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RE: Need a probe for Sencore SC61/3080 part # 39G294, posted on October 20, 2011 at 07:31:47
Tom Bavis
Audiophile

Posts: 961
Location: Upstate NY
Joined: May 25, 2007
 Good luck as they're unique to Sencore... and there always to be more 'scopes than probes...

You may know this, but it might of interest to others... the probes are special, having two voltage dividers - one for the 'scope input, one for the voltmeter. And they're rated for 2000V... higher than most.

The divider for the 'scope input is the usual 9 megs with compensating cap, giving 10:1 attenuation with the 1 meg input. So any 10:1 probe should work, though it may not have the voltage rating and won't work with the DVM readout. There's also a 13.5 meg resistor connected to the tip which goes to a mini-banana plug for the DVM input. You could make up a series string of five 267K 1% resistors (make sure they're rated for at lest 500V!) and put it inside a regular meter probe for a separate DVM probe.

 

RE: Need a probe for Sencore SC61/3080 part # 39G294, posted on October 20, 2011 at 08:42:07
Michael Norona


 
Tom: I can't thank you enough for the info on the probe itself, that is incredibly helpful. It has become obvious that the Sencore probe is going to be hard to find. There was a guy selling them on e-bay this past June, I think he had 3 or 4 of the probes that were new. I contacted him, but he had sold them all. I am thinking my only option will be to find one that is similar, do you have any suggestion on a company that makes a good probe?

I was getting ready to e-mail Mike Samra for info/specs on the probe because I know he has a SC61.

Are the SC3080 and SC61 similar? As I had said I received a 3080 manual with the 61, and the front panels seem to be identical.

Once again thanks for the info, and advice!

 

RE: Need a probe for Sencore SC61/3080 part # 39G294, posted on October 20, 2011 at 11:25:31
Lew
Audiophile

Posts: 10911
Location: Bethesda, Maryland
Joined: December 11, 2000
 I have two of the 39G294 probes to go with my SC61, but neither came to me with the clip attachment (that screws on to the end of the probe so as to provide a way to attach the probe to the wire being sampled). I have searched high and low for these. I hate to buy a whole new probe just to get the clip attachment. Any ideas?

(39G294 probes do come up on eBay from time to time. I have seen new ones for about $120, and a used one that ended up at about $90. Did not want to pay that much just to get the clip attachment.)

 

Sencore still sells the probe, posted on October 26, 2011 at 20:58:27
Michael Norona


 
I contacted Sencore, and they still sell the probe, $140.00 +. I didn't pay that much for the scope. Looks like this is the best option. Thanks for you help.

 

RE: Need a probe for Sencore SC61/3080 part # 39G294, posted on October 26, 2011 at 21:52:31
ecir38
Audiophile

Posts: 570
Location: LOUISIANA
Joined: May 9, 2007
 just use a short piece of solid core wire leave and strip both ends. Leave one side bare or add a alligator clip. The other side insert the bare wire in and around where the clip went then twist it tightly. This is how I repaired one of mine the the clip was broken on.

Brad

 

RE: Need a probe for Sencore SC61/3080 part # 39G294, posted on October 27, 2011 at 04:35:28
R. Mercure
Audiophile

Posts: 450
Location: Central Appalachian Mountains
Joined: April 25, 2008
 If you need to make up a difficult to source resistor value an old "Ham" trick is to take a reasonably close carbon comp resistor of lower value and while measuring the resistance file a notch in the side with a triangular file until you get the value you're after. Obviously this lowers the power dissipation rating so if you need a 1/2 watter start with a one watter to modify. Seal the notch with something water resistant - the classic was clear nail polish but I've had great luck with superglue. While I don't use this technique much anymore it's still of value and none of the custom resistances I've made have varied over time in any greater manner than a similar carbon comp in the same circuit. With instruments the resistor type isn't critical as long as the voltage, power, and possible lack of inductance are factored - 'scopes are particularly interested in "presence" or "sound stage" or other subjective component classifiers bandies about here.

Rob
"Monoblocks" = "monoblockheads" - it's "monaural amplifier"; "power output tubes" not "power tubes" & "patch cords" not "interconnects!" "Passive preamp(lifier) is oxymoronic!

 

RE: Need a probe for Sencore SC61/3080 part # 39G294, posted on August 23, 2016 at 14:45:52
Michael Samra
Dealer

Posts: 36118
Location: saginaw michigan
Joined: January 30, 2005
 Mike
For the work we do in audio,the generic probes we buy on Ebay are more than adequate and give accurate readings.You do have a capacitance adjustment on the probe that you adjust with the sq wave.These probes also have a times 10 and they are two for 12 to 15 dollars and I use them all the time.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken

 

Here is one more option if the others don't work out, posted on August 23, 2016 at 15:02:59
Michael Samra
Dealer

Posts: 36118
Location: saginaw michigan
Joined: January 30, 2005
 This is a tektronix low capacity probe used for 20 dollars..It will work fine with the SC-61
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken

 

RE: Need a probe for Sencore SC61/3080 part # 39G294, posted on March 16, 2017 at 20:29:04
vica
Audiophile

Posts: 5
Location: Colorado
Joined: August 23, 2016
 I just saw this post. Do you still want Sencore 39G294 probes? I have some.

 

RE: Need a probe for Sencore SC61/3080 part # 39G294, posted on September 13, 2017 at 15:08:49
vica
Audiophile

Posts: 5
Location: Colorado
Joined: August 23, 2016
 The 39G294 probes have been sold.

Thanks,
Vic

 

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