Author Topic: Are those really massive MOVs in the B+K 2709B?  (Read 2867 times)

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Offline tom66

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Are those really massive MOVs in the B+K 2709B?
« on: August 02, 2011, 07:53:02 pm »
I opened my 2709B up today... then I looked at the MOVs. Or supposedly they are. They have the component ID "C##", for capacitor. And the markings on them seem to suggest they are capacitors. The other protection on the board seems to consist of a PTC and a small 1W input resistor. This is very disappointing if it is true, since I paid almost $135 to get it to the UK plus 20% tax (probably the largest amount of money I have spent on any test equipment), and have been using it in potentially dangerous situations with regard to the CAT rating and the massive MOVs which Dave indicated in his video.

First question, are these really caps or are the mislabeled? To the credit of B+K, they are massive for capacitors. And they are in exactly the right spot to look like MOVs so it is easy to get them confused. If that's deliberate I do not know.

Second question, would this meter have ever met its specifications? (CAT III 600Vac/dc & CAT II 1kVdc/750Vac)

Third question is the meter actually designed by B+K? I notice several odd markings on the PCB and no reference to B+K throughout the whole meter, except on the front name plate. It could be that B+K are buying meters cheap from Taiwan and rebadging them. If it's a Mastech, call me pissed. Mastech make okay meters for low voltage circuits but I would never trust them on anything high power like I have been trusting this one.
 

Offline lowimpedance

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Re: Are those really massive MOVs in the B+K 2709B?
« Reply #1 on: August 03, 2011, 12:03:06 am »
Some pictures of your actual unit would be useful.
The odd multimeter or 2 or 3 or 4...or........can't remember !.
 

Offline tom66

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Re: Are those really massive MOVs in the B+K 2709B?
« Reply #2 on: August 03, 2011, 12:28:38 am »
I'll try to post pics tomorrow, when I find my camera. But Dave's meter is the same... see video. 25:00 onwards.

 

Offline EEVblog

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Re: Are those really massive MOVs in the B+K 2709B?
« Reply #3 on: August 03, 2011, 12:33:00 am »
They are MOV's
10S112K

Dave.
 

Offline tom66

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Re: Are those really massive MOVs in the B+K 2709B?
« Reply #4 on: August 03, 2011, 12:40:50 am »
They are MOV's
10S112K

Dave.

Good to know - now I was annoyed because they are marked C... but why? Just a mistake, I guess? I will have to look at in more depth tomorrow.
 

Offline EEVblog

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Re: Are those really massive MOVs in the B+K 2709B?
« Reply #5 on: August 03, 2011, 01:04:18 am »
They are MOV's
10S112K

Dave.

Good to know - now I was annoyed because they are marked C... but why? Just a mistake, I guess? I will have to look at in more depth tomorrow.

The layout/schematic person decided to use that designation for some reason.
I guess they are closer to capacitors in terms of usage than anything else.
Not the first time I've seen it.

Dave.
 


Offline mikeselectricstuff

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Re: Are those really massive MOVs in the B+K 2709B?
« Reply #7 on: August 03, 2011, 09:43:31 am »
They are MOV's
10S112K

Dave.

Good to know - now I was annoyed because they are marked C... but why? Just a mistake, I guess? I will have to look at in more depth tomorrow.
They probably used a library footprint for a capacitor and couldn't be bothered to change the "C" that came with it.
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