It has a weird buzz like a blown speaker but it isn't the speakers

Question

Studio Standard by Fisher FM-58

An old stereo/radio system that hooks up to speaker system for surround system

1 질문 전체 보기

Brandon Hammond @bguitar44

평판: 51

2

게시일: 2018년 11월 11일

옵션

It has a weird buzz like a blown speaker but it isn't the speakers

The mixer is broken and a couple other items but that's not my issue..... my issue is as of now an hour ago i turned it on and it started buzzing and i know it's not my speakers because i switched them out for new ones to make sure and the same name came through. It is 40 yrs. old but it hasn’t had any major issues through it’s lifetime. Help!

답변되었습니다! 답변 보기 저도 같은 문제를 겪고 있습니다

좋은 질문 입니까?

예 아니요

점수 0

댓글 10개

It fluctuates with the song currently playing but if i can i will post a audio recording it started this morning after i turned it off for an hour

and i hooked it into an outlet by itself

Brandon Hammond 의 2018년 11월 11일

for example if i'm playing Highway to !&&* by AC/DC the bass works but I can't hear the lyrics and if i can they're very very light like a radio station you get a bad reception for

Brandon Hammond 의 2018년 11월 11일

Following the principal of firstly checking the easily diagnosed and easily fixed things, take the covers off and look for bad electrolytic capacitors. See https://wiki.restarters.net/Basic_electr...

Philip Le Riche 의 2018년 11월 11일

I've looked at it closely and looked for bulging or sideways capacitors and they all look reletivley new keep in mind this one is 40 yrs. old so there is a bit of dust and rust but everything mostly works

Brandon Hammond 의 2018년 11월 11일

I did find a rusty fuse with a deformity but it isn't burned through

Brandon Hammond 의 2018년 11월 11일

댓글 5개 더보기

댓글 달기

답변 1개

선택된 답변

Philip Le Riche @pleriche

평판: 30k

74

27

72

게시일: 2018년 11월 11일

옵션

Is this a mains frequency buzz? If so, I'd suspect a bad electrolytic capacitor in the power supply. If not, perhaps you could make a recording and post it. Is it a constant frequency, loudness and timbre?

해당 답변은 도움이 되었습니까?

예 아니요

점수 3

댓글 2개:

It sounds a bit like a problem I had with a large sound mixer a couple of months ago. At some (low) volume levels the monitor output was distorted, probably clipped. It turned out to be a CMOS analogue switch (type CD4066 I think, or similar) used instead of a multipole mechanical switch to switch the signal path. Someone had removed it and bent one of the pins in reinserting it in its socket, resulting in it not being properly biased.

The preamp stages probably are supplied by both positive and negative rails allowing the signal to rest at 0V when quiet. Possibly one of the rails was failing causing asymetrical power, and if the unit is now completely dead, perhaps that rail has now died completely.

Firstly, check the positive and negative rails, and if they seem ok then identify the ICs, most of which may be operational amplifiers such as TL084 or the older LM741. Find the datasheet online and hence identify which pins are the positive and negative supply. Check the voltages.

Philip Le Riche 의 2018년 11월 12일

In the end, it's still quite likely to be a bad electrolytic capacitor - if it looks good that's no guarantee that it is. The component analyser pictured in the Restarters Wiki article will tell you definitely, or you can just change all the larger ones anyway.

Philip Le Riche 의 2018년 11월 12일

댓글 달기

It fluctuates with the song currently playing but if i can i will post a audio recording it started this morning after i turned it off for an hour

and i hooked it into an outlet by itself — Brandon Hammond
for example if i'm playing Highway to !&&* by AC/DC the bass works but I can't hear the lyrics and if i can they're very very light like a radio station you get a bad reception for — Brandon Hammond
Following the principal of firstly checking the easily diagnosed and easily fixed things, take the covers off and look for bad electrolytic capacitors. See https://wiki.restarters.net/Basic_electr... — Philip Le Riche
I've looked at it closely and looked for bulging or sideways capacitors and they all look reletivley new keep in mind this one is 40 yrs. old so there is a bit of dust and rust but everything mostly works — Brandon Hammond
I did find a rusty fuse with a deformity but it isn't burned through — Brandon Hammond
It sounds a bit like a problem I had with a large sound mixer a couple of months ago. At some (low) volume levels the monitor output was distorted, probably clipped. It turned out to be a CMOS analogue switch (type CD4066 I think, or similar) used instead of a multipole mechanical switch to switch the signal path. Someone had removed it and bent one of the pins in reinserting it in its socket, resulting in it not being properly biased.

The preamp stages probably are supplied by both positive and negative rails allowing the signal to rest at 0V when quiet. Possibly one of the rails was failing causing asymetrical power, and if the unit is now completely dead, perhaps that rail has now died completely.

Firstly, check the positive and negative rails, and if they seem ok then identify the ICs, most of which may be operational amplifiers such as TL084 or the older LM741. Find the datasheet online and hence identify which pins are the positive and negative supply. Check the voltages. — Philip Le Riche
In the end, it's still quite likely to be a bad electrolytic capacitor - if it looks good that's no guarantee that it is. The component analyser pictured in the Restarters Wiki article will tell you definitely, or you can just change all the larger ones anyway. — Philip Le Riche

Studio Standard by Fisher FM-58

It has a weird buzz like a blown speaker but it isn't the speakers

답변 1개

귀하의 답변을 추가하세요