Re: [volt-nuts] Update on 720A

2017-08-09 Thread Chuck Harris
Ah, ok. I went for a quick look through the manual, and couldn't find it... It could always be replaced with a concentric shaft pot that has two appropriate sections wired in series. That would lose the "nifty" factor, though. -Chuck David C. Partridge wrote: >> The bridge balance pot may not

Re: [volt-nuts] Update on 720A

2017-08-09 Thread Didier Juges
Maybe a quality Bourns wirewound 10 turns pot would work as a replacement? On Aug 9, 2017 9:22 AM, "David C. Partridge" wrote: > > The bridge balance pot may not be so lucky, though. I don't think it > needs to be anything very special. > > As far as I can tell

Re: [volt-nuts] Update on 720A

2017-08-09 Thread Dan Kemppainen
On 8/9/2017 12:00 PM, volt-nuts-requ...@febo.com wrote: I have trouble believing that the precision WW resistors in the oil bath did go low. I wouldn't presume to argue that you didn't measure them right, but there has to be something other than their value drifting low. WW resistors usually

Re: [volt-nuts] Update on 720A

2017-08-09 Thread David C. Partridge
> I am thinking that the resistor leads have to leave the oil tank some way. > Is it possible that the insulator on whatever sort of feedthru has been > compromised? They are glass (or very similar) feedthroughs, so if that were compromised, I think I'd see oil ... There is no visual sign

Re: [volt-nuts] Update on 720A

2017-08-09 Thread Chuck Harris
Hi David, It is amazing what gets done to equipment in the name of repairing it... I have trouble believing that the precision WW resistors in the oil bath did go low. I wouldn't presume to argue that you didn't measure them right, but there has to be something other than their value drifting

Re: [volt-nuts] Update on 720A

2017-08-09 Thread David C. Partridge
I'm not going to open up oil-bath for a PM (unless someone wants to buy me a replacement 720A). D. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the

Re: [volt-nuts] Update on 720A

2017-08-09 Thread David C. Partridge
> The bridge balance pot may not be so lucky, though. I don't think it needs > to be anything very special. As far as I can tell it is a very special pot wired with two resistance tracks. The coarse track has with two wipers connecting to the fine track which has just one wiper, all driven