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.
