[ARC5] Carbon Comp Drift
Phillip Carpenter
carpenterpa at tds.net
Fri Mar 1 20:23:36 EST 2019
Are the resistor binder materials being used today better than the old stuff (I assume they probably are)?
Phillip
WB4PAC
Sent from my iPhone
> On Mar 1, 2019, at 7:49 PM, Robert Eleazer <releazer at earthlink.net> wrote:
>
> I never suspected that resistors could change value without first being overloaded with current, but around 1982 I bought a TS-34 scope at a ham swap meet for $1.00 and found that it worked - but would not focus. I found that all of the 2W resistors, all high resistance value units, had just about opened up. I walked down to the local Layfayette store and bought some replacements; installing them instead of the originals fixed the scope.
>
> I inherited a large number of carbon comp resistors from a friend some years back. I found that many of them now exceed their original tolerances on the high side. In the GRC-9 I found a 230 ohm that went to something like 550 ohm, a 33K that went to 45K, but also a 27K that is still at about 27.5K
>
> I am tempted to ask if there is a vanish or coating that would arrest this process, but the GRC-9 was MFPed in 1950 and that did not help it.
>
> Wayne
> WB5WSV
>
>
> Virus-free. www.avg.com
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