Comments on: How To Repair Amplifier No Sound

By: Ross

Ross — Mon, 27 Feb 2023 03:43:39 +0000

In reply to Parasuraman S.

How to find value of burnt resistor if no diagram available.

Likes(1)Dislikes(0)

By: magents

magents — Mon, 11 Feb 2019 09:20:24 +0000

hello! how to find out parts which is not working using multimeter? dont be surprised is for the first time using it.

Likes(0)Dislikes(0)

By: RICHARD ASAMOAH

RICHARD ASAMOAH — Tue, 17 Oct 2017 10:13:01 +0000

please am i had a problem with an amplifier the sound is not coming i check the transitors and it was not good i have change it and i saw that the other transitor too has burn that was C1815 and C2240 i have change all but the sound was not clear it made the main transitors spoiled again thats 2SC2922 AND 2SA1216 the name of the amplifier is HIGH QUALITY STEREO AMPLIFIER TM-812

Likes(1)Dislikes(0)

By: Bafana

Bafana — Thu, 12 Oct 2017 06:05:30 +0000

My ecco amp has sound of great quality in channel B but channel A quality is poor and all controls are not working including volume but there is sound

Likes(1)Dislikes(0)

By: Phil

Phil — Thu, 17 Aug 2017 23:21:12 +0000

Wow!!!, months of looking for someone who has mad skills, man im glad I found you!! Thank you for your intelligence. ?

Likes(2)Dislikes(0)

By: Humberto

Humberto — Thu, 24 Nov 2016 13:02:54 +0000

A great repair Suranga. Congratulations.

Likes(1)Dislikes(0)

By: Raju varghese

Raju varghese — Mon, 21 Nov 2016 05:33:03 +0000

Nice suranga , complicated job
well done.

Likes(0)Dislikes(0)

By: Parasuraman S

Parasuraman S — Fri, 18 Nov 2016 11:42:38 +0000

In reply to Henry.

Another factor that helps in trouble shooting is, if we find + voltage in output, negative rail or biasing is open and vice versa!

Likes(0)Dislikes(0)

By: Henry

Henry — Fri, 18 Nov 2016 01:19:46 +0000

Thank you Parasuraman for that clarification. It helps. I did look at a few on line amplifier circuits and complimentary symmetry arrangements, and now have a bit better understanding. Many of those circuits showed a coupling DC blocking capacitor connected in series right before the speaker output. That should really stop any DC voltage reaching the speaker. However, I guess there are other solutions to the coupling capacitor location. Thanks again.

Likes(1)Dislikes(0)

By: Parasuraman S

Parasuraman S — Thu, 17 Nov 2016 11:14:39 +0000

In reply to Henry.

Depending upon the construction of amplifier, the final output is taken from a push-pull stage many times. Many of us, who involve in Amplifier repair, would have noticed that there are DC blocking capacitors used for coupling. The Transistors are critically biased in such a way, that if there is even slightest variation, the entire array of transistors will stop conducting. This is achieved by a feed back circuit in the output stage, that cuts the biasing circuit entirely. In such a circumstance, DC will be present in the output stage, i.e, speaker outputs. More or less same thing happens, when any or a bunch of transistors fail. While the professional discreet amplifier section is designed for making it noise and distortion free to the maximum extent, any failure or even slightest leakage in a capacitor, can trigger auto cut off of the biasing circuit. Just download a few professional amplifier circuits, complimentary symmetry or push pull type, then you can understand this yourself. But trouble shooting such amplifiers is a pain, no doubt, as we cannot isolate the stages, without temporarily modifying the circuit for the sake of testing!

Likes(3)Dislikes(1)