Vintage Resistors - numbering format, throw away or keep? - Page 1
Forum section: electronics / beginners

author: ra-ma
author_rank: Contributor
timestamp: March 30, 2018, 02:46:00 pm
content: Hello, I got two big cartons of metal-film resistors made by company Rohm probably some decades ago. The values are pretty "interesting" (everything in): 3.48 62.0 64.4 618.0 1.05k 1.6k 2.15k 3.1k 3.4k 3.84k 4.0k 6.4k 6.49k 6.5k 6.65k 6.9k 9.76k 11.3k 51.1k 806.0kIt seems to be series CRB50, CRB25, +/-1% accuracy. Some of the cartons are still full with 1,000 pcs, others are 50% or less full.My questions:1) What does the figure "2" mean between the 4th and 5th color code?2) As I don't need these values/quantities: Is it worthwile spendig effort to sell it somewhere or can I consider it as being trash?Thanks for your help.

author: capt bullshot
author_rank: Super Contributor
timestamp: March 30, 2018, 03:16:18 pm
content: Sometimes I just cut off the wire from a resistor and use the wire for a bodge or similar. Another use is to cut off one wire completely and solder the remainder (wire and resistor body) to a test point onto a PCB to have a nice access for a multimeter or scope probe.So if you don't need a particular value, these resistors can still be useful.

author: Chris-IP5
author_rank: Contributor
timestamp: March 30, 2018, 04:27:11 pm
content: I haven't seen one marked like that before.I've seen reference to a red dot in the 2 position for temperature coefficient. Maybe something like that?Does it say anything revealing on the boxes they came in?I'd love to know what it means

author: james_s
author_rank: Super Contributor
timestamp: March 30, 2018, 05:18:53 pm
content: Surely somebody can use them? If I had a stash like that I'd keep a few hundred of each value and give away most of the rest. Surely you can find lots of applications for values that are close enough? For example 3.4k will probably work in most places where you'd normally select a more common 3.3k.

author: ra-ma
author_rank: Contributor
timestamp: March 30, 2018, 05:22:14 pm
content: I actually found a datasheet for series CRB25 and CRB50. Unfortunately it doesn't tell me a lot.ra-ma.de/media/ebay/DSA2IH00159982.pdf

author: bsudbrink
author_rank: Frequent Contributor
timestamp: March 30, 2018, 05:31:52 pm
content: I work on old through-hole equipment. I happily paypal you a few bucks for 20 of each value, just to have them on hand.

author: Ian.M
author_rank: Super Contributor
timestamp: March 30, 2018, 05:40:31 pm
content: Excellent resistors for anyone breadboarding, from the era before everything got miniaturised and excessively flimsy. If you trash them without making an honest effort to find someone to take them off your hands, you are a nekulturny techno-luddite. At the very least search for hackerspaces in nearby cities and ask if they would be interested in them as a donation.

author: ra-ma
author_rank: Contributor
timestamp: March 30, 2018, 06:07:53 pm
content: Quote from: bsudbrink on March 30, 2018, 05:31:52 pmI'll try out tonight how large/heavy this would be and what it would mean in terms of postal charges. I'll let you know.As I don't want to die as a "nekulturny techno-luddite"- thanks Ian for teaching me new phrases - I'm happy to share.

author: Zero999
author_rank: Super Contributor
timestamp: March 31, 2018, 08:13:46 am
content: Quote from: james_s on March 30, 2018, 05:18:53 pmYes, that's exactly what I did, when I go my hands on a large quantity of resistors like this.

author: SeanB
author_rank: Super Contributor
timestamp: March 31, 2018, 09:50:36 am
content: Just look at the price of some plastic bags that fit a standard padded envelope ( probably a C5 size) and then look at the maximum allowed mass for small packet, or the best value for postage to mass, and simply fill up the padded bags to around 10g short of the mass, using a selection from each box per bag to make things more or less even. that way you can just have a stack of ready made bags, and simply print off an address label, stick it on and go to the post office with all the details already there for a few parcels with little effort per time.

author: Ian.M
author_rank: Super Contributor
timestamp: March 31, 2018, 10:33:06 am
content: Weigh a strip of 100 of the CRB25 type and similarly for the CRB50 type, and you'll have a good enough mass per resistor to work out the postage weight. given the masses, the type and estimated quantity remaining of each value, the mass of your plastic bags and padded envelopes, it would be fairly simple to set up a spreadsheet to tell you how many to cut and pack of each value to come to just under any desired postage weight, without exhausting the stock of any value prematurely.Once you have a packing list, it shouldn't take more than an hour to cut and pack 20 bags, and figure another hour for envelope stuffing, labelling and stamping + whatever time it takes to make a post office run.

author: DC1MC
author_rank: Super Contributor
timestamp: March 31, 2018, 10:55:35 am
content: Quote from: ra-ma on March 30, 2018, 02:46:00 pmThrowing them away will not be a good idea, cheap brand name 1% metal film resistors are hard to find, I will gladly PayPay you for 20x or 50x of each put in padded envelope from Kik. Or even a DHL Päckhen or Packet.Count me in and please let me now when you start shipping.Schütze die Umwelt und verdiene etwas Geld!!!Cheers,DC1MC

author: Edison
author_rank: Frequent Contributor
timestamp: March 31, 2018, 03:35:55 pm
content: I buy 30 from valueprice ?

author: Rog520
author_rank: Regular Contributor
timestamp: March 31, 2018, 05:53:06 pm
content: Quote from: ra-ma on March 30, 2018, 02:46:00 pmBetcha anything that's the tolerance (2%). Normally there'd be a band there, for a total of six, with the first three as significant digits, the fourth as the multiplier, the fifth as the tolerance, and the sixth as the tempco.

author: ra-ma
author_rank: Contributor
timestamp: April 01, 2018, 04:23:27 pm
content: Hi, I got some request already. Please PM me in case of interest (fist come, first serve):- 10 pcs per value 0,04 Euro/piece- 20 pcs per value 0,03 Euro/piece- 50 pcs per value 0,02 Euro/piece- 100 pcs per value 0,015 Euro/pieceInternational shipping 4 EUR for up to 600 pcs. More to be clarified via PM.Still available:3.4862.064.4618.01.05k2.15k3.1k3.4k3.84k4.0k6.4k6.49k6.5k6.65k6.9k9.76k11.3k51.1k806.0k

author: ra-ma
author_rank: Contributor
timestamp: April 02, 2018, 06:26:52 am
content: Thanks for all your feedback. I created a new thread in the right section:https://www.eevblog.com/forum/buysellwanted/(sell)-euglobal-vintage-resistors-from-rohm-several-values/