Akai GXC-46D. Noise problem. - UK Vintage Radio Repair and Restoration Discussion Forum

Jocampob · 23rd May 2017, 7:27 pm

Hi I have a Akai GXC46D that has a noise like blank noise but of low frecuency in both channels. I have connected the different stages of the amplifier to gound trying to locate the origin of the noise and the nose is gone except in the 2 first stages. I changed the electrolitycs of one channel (the 2 first stages) with no result. Then I changed the electrolitycs of the power supply with no result. What can be wrong ? The noise is not the typical hum of the 50 hz.

Ted Kendall · 23rd May 2017, 9:25 pm

Could be a magnetised head, which is easy to fix, or noisy transistors. Is it the same on both channels?

Jocampob · 23rd May 2017, 10:58 pm

I have already degmagnetized the heads the noise is the same in both channels

Grubhead · 24th May 2017, 12:58 am

Are there any IC's that have both channels going into them?
If you have the noise in both channels and it's the same noise in both, then you are only looking for something common to both channels. If there are no IC's common to both channels consider a transistor in the power supply, since you have eliminated the caps.

Nickthedentist · 24th May 2017, 7:53 am

Always worth cleaning the record/play switch with Servisol Super 10 or similar before delving deeper.

Jocampob · 24th May 2017, 9:08 am

Quote:

Originally Posted by Grubhead

Are there any IC's that have both channels going into them?

There are no IC's in this deck only transistors. I will try changing the transistors of the power supply and if no result I will change the transistors of the two first stages of the amplifier.

Thank you for your help.

Grubhead · 25th May 2017, 2:08 am

Quote:

Originally Posted by Nickthedentist

Always worth cleaning the record/play switch with Servisol Super 10 or similar before delving deeper.

Pushing it manually should make any noise that would cause go, before spraying it if it is causing it. But I would be surprised if it caused a noise. More likely cut channels off.

Are you thinking feedback hum?

saxmaniac · 25th May 2017, 8:27 am

I got rid of a nasty feedback like noise by checking and tightening mounting screws for amplifier boards as it depends on these for earthing. Worth a look

arjoll · 27th May 2017, 12:40 pm

Have you got the service manual for this deck? It not, zap me a PM with your email address and I can send you a copy.

23rd May 2017, 7:27 pm	#1
Jocampob Retired Dormant Member Join Date: May 2017 Location: Cadiz, Spain Posts: 3	Akai GXC-46D. Noise problem. Hi I have a Akai GXC46D that has a noise like blank noise but of low frecuency in both channels. I have connected the different stages of the amplifier to gound trying to locate the origin of the noise and the nose is gone except in the 2 first stages. I changed the electrolitycs of one channel (the 2 first stages) with no result. Then I changed the electrolitycs of the power supply with no result. What can be wrong ? The noise is not the typical hum of the 50 hz.

23rd May 2017, 9:25 pm	#2
Ted Kendall Dekatron Join Date: Jul 2008 Location: Kington, Herefordshire, UK. Posts: 3,670	Re: Akai GXC-46D. Noise problem. Could be a magnetised head, which is easy to fix, or noisy transistors. Is it the same on both channels?

23rd May 2017, 10:58 pm	#3
Jocampob Retired Dormant Member Join Date: May 2017 Location: Cadiz, Spain Posts: 3	Re: Akai GXC-46D. Noise problem. I have already degmagnetized the heads the noise is the same in both channels

24th May 2017, 12:58 am	#4
Grubhead Heptode Join Date: Dec 2016 Location: Sheffield, South Yorkshire, UK. Posts: 539	Re: Akai GXC-46D. Noise problem. Are there any IC's that have both channels going into them? If you have the noise in both channels and it's the same noise in both, then you are only looking for something common to both channels. If there are no IC's common to both channels consider a transistor in the power supply, since you have eliminated the caps.

24th May 2017, 7:53 am	#5
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,845	Re: Akai GXC-46D. Noise problem. Always worth cleaning the record/play switch with Servisol Super 10 or similar before delving deeper.

25th May 2017, 8:27 am	#8
saxmaniac Heptode Join Date: Oct 2007 Location: Birmingham, West Midlands, UK. Posts: 618	Re: Akai GXC-46D. Noise problem. I got rid of a nasty feedback like noise by checking and tightening mounting screws for amplifier boards as it depends on these for earthing. Worth a look

27th May 2017, 12:40 pm	#9
arjoll Dekatron Join Date: May 2006 Location: Invercargill, New Zealand Posts: 3,457	Re: Akai GXC-46D. Noise problem. Have you got the service manual for this deck? It not, zap me a PM with your email address and I can send you a copy.