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 Post subject: Re: Precision E-200-C Signal Generator
PostPosted: Jan Sun 13, 2019 4:38 am 
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Joined: Jan Tue 16, 2007 7:02 am
Posts: 3128
Location: Lexington, KY USA
Thanks for posting the schematic.

It's likely the Hi-Q brand ceramic caps were used instead of the silver mica ones called out on the parts list. These ceramic parts may be even more stable than silver mica caps.

There may be no silver mica parts at all in this particular unit.

Modern silver mica caps can be used to replace both the Hi-Q ceramic parts, and the mica capacitors. NP0 / C0G ceramic caps can also be used, and may be easier to find and less expensive. Again, there may be no actual need to replace any of these. Best left alone unless shown to be defective.

Ted


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 Post subject: Re: Precision E-200-C Signal Generator
PostPosted: Jan Mon 14, 2019 12:38 am 
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Joined: Nov Wed 28, 2018 2:29 pm
Posts: 16
Usually Lurking wrote:
Thanks for posting the schematic.

It's likely the Hi-Q brand ceramic caps were used instead of the silver mica ones called out on the parts list. These ceramic parts may be even more stable than silver mica caps.

There may be no silver mica parts at all in this particular unit.

Modern silver mica caps can be used to replace both the Hi-Q ceramic parts, and the mica capacitors. NP0 / C0G ceramic caps can also be used, and may be easier to find and less expensive. Again, there may be no actual need to replace any of these. Best left alone unless shown to be defective.

Ted


Thanks Ted; I’m going to leave ‘em alone! I didn’t know the difference between silver mica, and ceramic!
Simon


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 Post subject: Re: Precision E-200-C Signal Generator
PostPosted: Jan Mon 14, 2019 12:51 am 
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Joined: Nov Wed 28, 2018 2:29 pm
Posts: 16
Doc Holliday wrote:
I just restored one of these of the same vintage. As mentioned above, there are modern equivalents of everything you would need to restore this unit. I doubt you will find one much better unless you buy a restored one (which will have the same components you will install). This is a great generator and easy to calibrate. I also restored an e200d and an e400 to go along with it. I use it with a Precision 98VTVM. I really like the Precision instruments. Don't give up on them to quickly. I've restored some instruments that looked like they were ready for the scrap heap and they turned out working perfectly. When I get to that frustration point, I just let them sit a few days and come back to them. BTW, when you get it on a scope don't be put off by the ugly wave forms. These units produce harmonics by design. Good luck. Doc


Thanks Doc for the encouragement; I’ve never owned or used a sig generator before, or ‘fixed’ an old radio; but not too late to learn! I only own a VTVM, and VOM, so no scope or anything yet. But, I have recapped and replaced resisters on 3 simple tube radios (wood cabinets) so far, and 2 of them work now! The other had a resistor cord, but will circle back to that one some day. My son likes to restore the cabinets. He is pretty darn good.
I might need a little help with alignment and usage, and I appreciate the ones on here that have experience!!
Simon


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