Old style resistors and tolerances - UK Vintage Radio Repair and Restoration Discussion Forum

Nightcruiser · 11th Dec 2015, 7:30 pm

I cant seem to find a great deal of information about these red bodied resistors on the internet or their type.

The values are clearly marked but how does one work out the tolerance?

Herald1360 · 11th Dec 2015, 10:22 pm

Measure a few (lot) and see how close they are to nominal. Do a bar chart with number in each % error band. Depending on how it looks, you can hazard a reasonable guess at the tolerance unless they've all drifted. That would also be fairly obvious from the plot.

Of course if someone recognises them it's lot quicker......

The coloured end seems to be one higher than the three band decade for some reason.

short wave · 12th Dec 2015, 4:39 pm

Hi "Nightcruiser"
some one else has the same problem here (picture 3)

http://prorecordingworkshop.lefora.c...r#.Vmw6yc_tlHw

info i found here may help

http://www.radiomuseum.org/forum/col...g_germany.html
regards S-W

12th Dec 2015, 6:04 pm

A lot of 'posh' resistors were marked like that, posh in quotes is deliberate, they are more than likely a bog standard job. They also look like the E6 series, that is 20%.

stevehertz · 14th Dec 2015, 10:00 am

As they're marked with the value I doubt there's many applications where the tolerance is going to make much difference given the amount of drift usually found in most vintage components, and they generally will work fine. Anything less than 20% is generally fine - to me anyway! What's the actual issue? are you just curious or intending to re-use or check actual value as fitted in a piece of kit?

jonnybear · 14th Dec 2015, 12:29 pm

They look to be of European origin, most of the resistors in vintage radios were 20%. you can always check them with a meter to see how near to the marked value they are.

I would be more concerned about that (awful) wima? capacitor next to them, they used to give untold problems in the Grundig reel to reel tape recorders in the sixties.
John

jjl · 14th Dec 2015, 12:51 pm

This looks like the innards of a Grundig set of the mid '50s. The Grundig 5080 that I had a while ago had this type of resistor, and I found several to be faulty; they would wander about in value when measured with a DMM. Perhaps the end caps were not making good contact with the resistive element. If they need replacing, I'd use modern 2W 1% metal film types; these are a similar size to older resistors and have a suitably high voltage rating.

John is right about the capacitor, German paper dielectric capacitors are just as unreliable as everyone elses.

John

11th Dec 2015, 7:30 pm	#1
Nightcruiser Pentode Join Date: May 2011 Location: Bath, Somerset, UK. Posts: 149	Old style resistors and tolerances I cant seem to find a great deal of information about these red bodied resistors on the internet or their type. The values are clearly marked but how does one work out the tolerance? Attached Thumbnails

11th Dec 2015, 10:22 pm	#2
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,536	Re: Old style resistors and tolerances Measure a few (lot) and see how close they are to nominal. Do a bar chart with number in each % error band. Depending on how it looks, you can hazard a reasonable guess at the tolerance unless they've all drifted. That would also be fairly obvious from the plot. Of course if someone recognises them it's lot quicker...... The coloured end seems to be one higher than the three band decade for some reason. __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

12th Dec 2015, 4:39 pm	#3
short wave Pentode Join Date: Mar 2013 Location: Leeds, West Yorkshire, UK. Posts: 246	Re: Old style resistors and tolerances Hi "Nightcruiser" some one else has the same problem here (picture 3) http://prorecordingworkshop.lefora.c...r#.Vmw6yc_tlHw info i found here may help http://www.radiomuseum.org/forum/col...g_germany.html regards S-W

12th Dec 2015, 6:04 pm	#4
Guest Guest Posts: n/a	Re: Old style resistors and tolerances A lot of 'posh' resistors were marked like that, posh in quotes is deliberate, they are more than likely a bog standard job. They also look like the E6 series, that is 20%.

14th Dec 2015, 10:00 am	#5
stevehertz Dekatron Join Date: Sep 2011 Location: Rugeley, Staffordshire, UK. Posts: 8,833	Re: Old style resistors and tolerances As they're marked with the value I doubt there's many applications where the tolerance is going to make much difference given the amount of drift usually found in most vintage components, and they generally will work fine. Anything less than 20% is generally fine - to me anyway! What's the actual issue? are you just curious or intending to re-use or check actual value as fitted in a piece of kit? __________________ A digital radio is the latest thing, but a vintage wireless is forever..

14th Dec 2015, 12:29 pm	#6
jonnybear Octode Join Date: Nov 2010 Location: Cullompton, Devon, UK. Posts: 1,435	Re: Old style resistors and tolerances They look to be of European origin, most of the resistors in vintage radios were 20%. you can always check them with a meter to see how near to the marked value they are. I would be more concerned about that (awful) wima? capacitor next to them, they used to give untold problems in the Grundig reel to reel tape recorders in the sixties. John

14th Dec 2015, 12:51 pm	#7
jjl Octode Join Date: Jan 2003 Location: Ware, Herts. UK. Posts: 1,082	Re: Old style resistors and tolerances This looks like the innards of a Grundig set of the mid '50s. The Grundig 5080 that I had a while ago had this type of resistor, and I found several to be faulty; they would wander about in value when measured with a DMM. Perhaps the end caps were not making good contact with the resistive element. If they need replacing, I'd use modern 2W 1% metal film types; these are a similar size to older resistors and have a suitably high voltage rating. John is right about the capacitor, German paper dielectric capacitors are just as unreliable as everyone elses. John