Can someone help me identify this vintage resistor   - Page 1
Forum section: electronics / repair

author: JuJu504
author_rank: Newbie
timestamp: March 13, 2019, 03:05:50 am
content: I need help identifying this resistor off a 1976 era pcb.

author: Mr.B
author_rank: Unknown
timestamp: March 13, 2019, 03:09:39 am
content: Looks like 47 ohms, 5%, 25ppmhttps://www.electronics-tutorials.ws/resistor/res_2.html

author: JuJu504
author_rank: Newbie
timestamp: March 13, 2019, 03:46:39 am
content: The hardest thing about figuring this out is the fact that it is a 5 band resistor and no 5 band resistor has a 5th band that is yellow. There is no yellow tolerance for the 5th band.

author: DaJMasta
author_rank: Super Contributor
timestamp: March 13, 2019, 03:54:36 am
content: Quote from: JuJu504 on March 13, 2019, 03:46:39 amApparently it was used as an indication of some extra standard, and I've heard the yellow 5th band means it's "high reliability". Maybe somewhat standard of a marking for the time, but now mostly lost to time as the technologies to make and rate them have changed a lot. The carbon resistors from that era are anything but particularly stable, and have often drifted up as much as 10% or so in value.FWIW, I don't think 25ppm is anywhere close to correct, carbon resistors are going to be hundreds, if not a thousand ppm/C drift.

author: MarkF
author_rank: Super Contributor
timestamp: March 13, 2019, 04:00:56 am
content: From this web site:https://www.eeweb.com/tools/5-band-resistor-calculator

author: JuJu504
author_rank: Newbie
timestamp: March 13, 2019, 04:18:56 am
content: Quote from: MarkF on March 13, 2019, 04:00:56 amThanks MarkF that's exactly what I was looking for.

author: JuJu504
author_rank: Newbie
timestamp: March 13, 2019, 05:03:16 am
content: Quote from: MarkF on March 13, 2019, 04:00:56 amany idea of the voltage of that ceramic disc cap in the same photo? This project has been on the shelf for months now due to me not being able to identify the components so that I can replace them. I appreciate the help alot. Thank you

author: TERRA Operative
author_rank: Super Contributor
timestamp: March 13, 2019, 05:18:30 am
content: Probably 50 or 100v. What sort of voltages do you expect in the circuit?No harm in uprating it to be safe amyway.

author: PKTKS
author_rank: Super Contributor
timestamp: March 13, 2019, 12:38:30 pm
content: CRAPPY marked CAP.Z5U = -10C up to 85Cabout 20% tolerance all specsBut by size I would risk at least 400VThe valid codes for this type are messy - crappy fab.Paul

author: ArthurDent
author_rank: Super Contributor
timestamp: March 13, 2019, 12:56:39 pm
content: It appears to be a 47 ohm in series with a .05uF 500V cap that would typically be used across a switched inductive load to absorb spikes. The values would be non-critical and I'd doubt they could be a problem.

author: JuJu504
author_rank: Newbie
timestamp: March 13, 2019, 04:40:06 pm
content: Quote from: ArthurDent on March 13, 2019, 12:56:39 pmthe resistor and capasitor are soldered to a 12vdc relay. This is a circuit board out of a 1976 Mills Bell o matic token vendor slot machine. Here is photos of the whole pcb

author: ArthurDent
author_rank: Super Contributor
timestamp: March 13, 2019, 05:02:51 pm
content: QuoteAcross switch or relay contacts, a typical snubber circuit. It was an afterthought and just soldered on the back of the board. Probably to absorb some noise generated by switching contacts.

author: JuJu504
author_rank: Newbie
timestamp: March 13, 2019, 06:22:26 pm
content: Quote from: ArthurDent on March 13, 2019, 05:02:51 pmthank everyone so much for the help. Now I can finally get my mills slot machine working again!

author: mzacharias
author_rank: Frequent Contributor
timestamp: March 13, 2019, 06:26:27 pm
content: Looks like a really bad solder connection where the resistor meets the cap.

author: JuJu504
author_rank: Newbie
timestamp: March 13, 2019, 07:57:26 pm
content: Quote from: mzacharias on March 13, 2019, 06:26:27 pmthat's actually a photo of the good cap and resistor. The other side is the problem its burned up. See attached photo

author: JuJu504
author_rank: Newbie
timestamp: March 14, 2019, 04:34:53 pm
content: My antique Mills token vendor slot machine is back up and running. My sincerest thanks to everybody who helped out. I appreciate it. I ended up replacing the ceramic disc cap with a NOS mylar 0.5μf 600Volt cap and a 47ohm resistor that I had on hand. Again everybody thank you