Re: 2246A--Voltage Self Cal Failure


tom jobe <tomjobe@...>
 

Dave,
I have some of those nice 224x family oscilloscopes, and those six relays are not really a chronic problem with that family of scopes in my experience, plus I don't think I have never changed one.
You might possibly have to change one or two relays... but I would make sure you have not missed something else that makes the problem look like a bad relay.
Playing with the scope to exercise everything a bit might help those 'iffy' relay contacts, and everything else too.
I have two work areas to use, and one has a very nice 2247A on it that I enjoy using.
tom jobe...
PS The 2252 is also in that same family of oscilloscopes, and it seems to just be a 2247A with GPIB capability added (I think?).
Thinking back on the problems I have seen on 224x scopes, I would say a dead main transformer would be the number one problem I've had on eBay purchases of 224x scopes... and you obviously don't have that problem. Of course the replacement of the electrolytic capacitors in the power supply is mandatory on any scope of this vintage.

On 5/11/2018 3:04 PM, dcane4@gmail.com wrote:
Thanks Bob.

I see on the vertical input schematic that both channel 1 and channel 2 each have three relays.

I might just go ahead and replace all of them while the unit is out of its case, but Is the culprit most likely the first relay that receives the volt cal signal from the Voltage Reference Generator?

Dave.


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