Vintage Allen Bradley resistor ID

[DaJMasta]

Figured repair forum was good because it's an old part, but I have a package of these resistors and I have no idea what the code means.  Pretty sure they're the mil spec style 1/2W Allen Bradley resistors.

They're 5 band, Orange, White, Gold, Gold, Yellow.... and I've seen somewhere that the last yellow band means they're "high reliability", but that would suggest 3.9 Ohms, 5% tolerance, if I'm reading the code right.... and they all seem to measure 4.30-4.35 Ohms.


Any ideas?

[Stray Electron]

  I still have a couple of sealed packs of AB carbon comp resistors and I poked through the package material (in other words they still haven't been opened) and measured them with a calibrated HP 3468A 4 wire meter and the resistance value is well out of spec.  I have a heap of ex-MIL circuit boards so I went and checked the value of about 15 of the old AB carbon comp yellow band resistors on them and all of them are out of spec.  AB resistors don't seem to hold up well with age.

[DaJMasta]

Haha, so they probably are 3.9 ohm resistors!  Funny so many seem to insist on using them in older hardware... I guess they have the look but if that yellow stripe really means "High reliability", I would not touch a standard one with 10 foot pole.

[Dacke]

Carbon comp resistors tend to drift over time,  usually increasing in value.  The higher the resistance value,  the more they drift.  I have quite a bit still in my inventory,  and probably 70% of them have drifted upwards by 10-15%,  and the brand doesn't really matter.  Allen Bradley, Ohmite, IRC, they all do it.   But yeah,  the only time I see them used anymore is for repairs/restorations to keep something "original".

[Stray Electron]

Haha, so they probably are 3.9 ohm resistors!  Funny so many seem to insist on using them in older hardware...

   High wattage and certain value SB carbon Comp resistors are worth a LOT of money to people that repair old military electronics. The problem for them is that they can't change the component type without reproving the new assembly meets ALL of the original specs including vibration, hot and cold cycling, etc. Pretty much an impossible task once the assembly and test line has been shutdown.  I've seen some of the obsolete component sellers sell high wattage AB resisters for over $100 each. That's actual sales not "asking prices" on E-Greed.  The repair contractors don't mind paying that because (1) it's still cheaper than spending time looking for another cheaper part, (2) the bill gets passed on to .GOV anyway.  AudioPhools have also been known to pay obscene amounts of money for components that they insist "sound" better.  Other than that, I don't know why anyone would want to use these old parts.