Hi Fabio, the DB877 is a nice box and is still available from IET Labs. See http://www.ietlabs.com/sitesearch?q=db877 The manual is here http://www.ietlabs.com/sitesearch?q=db877
They will sell you parts but they are not cheap. You won't find a compact 8 decade box with it's accuracy very easily. Even with standard 0.1% resistors subsituted it's a nice unit. Robert G8RPI ________________________________ From: Fabio Eboli <[email protected]> To: Discussion of precise voltage measurement <[email protected]> Sent: Tuesday, 19 June 2012, 19:04 Subject: Re: [volt-nuts] Wanted wirewound precision resistors and ESI DB877 Here I put some photos of the decade: http://www.eevblog.com/forum/product-reviews-photos-and-discussion/db877-teardown/ Frank Stellmach <[email protected]> ha scritto: > I think, you should better measure the resistance by a high resolution DMM, > on its normal OHM range. > Thats much more stable and less power is dissipated. A comparison between two > of them is also much easier. Yes I'm using a pair of multimeters: the keithley 2015 and a solartron 7061, the keithley should be not far from real values, but has a maximum count of 1200000, the solartron is "zeroed" against the keithley, has a maximum count of 21000000, permitting to compare the 1M and 2M resistors without changing range and resolution. I used the fluke to try to test for leackage, I tought that if there was some leackage, the current would have been higher than V/R ratio and not proportional to the voltage. > ingresses between the windings. I assume, your resistors are tubular ones, > with plastiv caps around, and they are not hermetically tight, therefore they > cant be filled completely for corrosion protection and thermal conductivity, > like in the Vishay metal foil VHP type. See the link, there is a pic of the resistor, it's open, no protection at all. > > Besides electrical measurement (on OHM range!), I 'd recommen optical > inspection of the case, and if its possible, of the windings for > burnt/overheated areas. Corrosion may be easily identified, also by slightly > stained parts of the wire. yes, the low valued resistors (10/20 ohm) seem a little corroded. The intermediate valued ones seem ok. Is the wire used (manganin?) prone to corrosion? Fabio. ---------------------------------------------------------------- This message was sent using IMP, the Internet Messaging Program. _______________________________________________ volt-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. _______________________________________________ volt-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
