Use for audio transformer - Page 1
Forum section: electronics / beginners

author: fixit7
author_rank: Regular Contributor
timestamp: June 26, 2019, 10:59:55 pm
content: I had this in my trash, but thought it might be worth keeping for some future use.Not sure what that might be. I inherited the pack rat behavior from my father.https://imgur.com/a/TKLTuuz

author: james_s
author_rank: Super Contributor
timestamp: June 26, 2019, 11:06:48 pm
content: That's not an audio transformer, that's a power transformer which likely came from an audio amplifier. Audio transformers are used for impedance matching the audio signal itself.

author: fixit7
author_rank: Regular Contributor
timestamp: June 26, 2019, 11:14:42 pm
content: Quote from: james_s on June 26, 2019, 11:06:48 pmThanks.Out of the blue, for about 15 seconds, it made a sound vaguely resembling a buzzing sound.Strange, as it has not had been powered up or anything else since I removed it from the radio which came out of a dumpster ?

author: Electro Detective
author_rank: Super Contributor
timestamp: June 27, 2019, 12:01:03 am
content: Looks like an old school decent made YamahaIf working ok, might be worth something on Ebay,or some useful voltages for DIY projectsEither way, it's not bin worthy unless it's fried,in which case the metal scrap yard will take it

author: fixit7
author_rank: Regular Contributor
timestamp: June 27, 2019, 12:31:39 am
content: I forgot how heavy it was, 9 lbs, and pulled a muscle pulling it out of my trash.

author: fixit7
author_rank: Regular Contributor
timestamp: June 27, 2019, 02:31:30 am
content: I plan on trying to sell it on Ebay. I have a box rated at 29 lbs/inch for Edge Crush Test.Do you think that is strong enough for a 9 lb item?If that is dropped, there may be a broken foot etc.Thanks,Andy

author: Electro Detective
author_rank: Super Contributor
timestamp: June 27, 2019, 09:41:25 am
content: Buffer the inside with stiff carton cornering and then string up the cartonso butterfingered potential droppers have something to grab on to

author: Old Printer
author_rank: Frequent Contributor
timestamp: June 27, 2019, 12:18:49 pm
content: Value would go up if you knew it's specs and better yet what products it was used in. Best money would be from someone looking for that particular transformer to repair their whatever unit. That followed by you being able to list the different input and output voltages and demonstrate it was still in good working order.

author: james_s
author_rank: Super Contributor
timestamp: June 27, 2019, 07:23:34 pm
content: Quote from: fixit7 on June 26, 2019, 11:14:42 pmYou must be mistaken. There is nothing in that transformer to make a noise and it has no ability to store energy when not powered up.

author: Zero999
author_rank: Super Contributor
timestamp: June 27, 2019, 07:31:45 pm
content: Quote from: james_s on June 27, 2019, 07:23:34 pmThe only plausible explanation I can think of is, there was some moisture which had absorbed into the transformer. When water evaporates from within something it can make a noise, as the gasses permeate. When it was turned on it got warm, causing evaporation, which continued as it was cooling down, after it was turned off.Other than that, it's more likely it was something else which was making the noise.

author: schmitt trigger
author_rank: Super Contributor
timestamp: June 27, 2019, 07:34:17 pm
content: It is a shielded power transformer.With a DMM, locate the pair of terminals with the highest resistance. Apply there the AC voltage via a Variac, increasing the voltage slowly.When the nominal voltage is reached, measure the voltage across all other terminals. Sketch a schematic.That step will significantly increase its resale value.

author: fixit7
author_rank: Regular Contributor
timestamp: June 27, 2019, 11:04:41 pm
content: Quote from: schmitt trigger on June 27, 2019, 07:34:17 pmI have a meter, but no variac.What terminals are you talking about, ?There are 9 terminals on one side and four on the other.https://imgur.com/a/TKLTuuz

author: schmitt trigger
author_rank: Super Contributor
timestamp: June 28, 2019, 12:27:20 am
content: You will have to figure out the primary wire pairs by trial and error with a DMM, as described above.No Variac, no problem.Put a 40 or 60 watt INCANDESCENT lamp in series with the suspect primary. If the lamp lights-up dimly or not at all, congratulations you have found the primary.Now with the DMM figure out all of the secondary voltages and its relationships.I.e. a secondary may be center tapped.As others have mentioned, if you show that information in your sale listing, chances will increase exponentially that someone will become interested and make a reasonable offer.

author: fixit7
author_rank: Regular Contributor
timestamp: June 28, 2019, 01:17:47 am
content: Quote from: james_s on June 27, 2019, 07:23:34 pmIt was my fitbit watch sounding an alarm.It had no visual flashing and it was sitting next to the transformer.

author: Electro Detective
author_rank: Super Contributor
timestamp: June 28, 2019, 11:11:08 pm
content: Glad it's sorted, the last possibility left for comment was'ghosts in the machine'