Servicing Akai 4000 DS Mk II - UK Vintage Radio Repair and Restoration Discussion Forum

homophone · 8th May 2006, 5:16 pm

I have an Akai 4000 DS and an Akai 4000 D. I use the 4000 DS to record LPs and the 4000 D to transfer these recordings to my computer hard disk for eventual burning to CDs. To explain my reasons for such a cack-handed way, (1) my stereo setup and the 4000 DS is downstairs and (2) the 4000 D is in my study upstairs where my computer is. However, the problem now is, I have found that when I am recording and monotoring the sound by the Tape/Source switch, the right channel VU is not registering to the same extent as the left channel and the stereo image is deteriorated. As opposed to the source position where the sound is perfect. Whether or not this is a problem with the switch or something more serious, I do not know. Is there anyone on the forum who may have had experience of this problem and able to help with, or suggest, a solution?

DOFFERY · 8th May 2006, 9:59 pm

Without getting too technical to start with , clean the heads thoroughly, then replay a KNOWN good tape, if OK your problem is on the record side.This could be anything from a faulty record pre amp, bias etc.

You are sure it is the right channel? As if a head is suspect it is usually the Left channel that shows up badly, due to head wear.

Try the above first.

Doffery

Markgc · 9th May 2006, 2:18 am

Let me know how you get on. I have the 4000DB model here and I think that I have the factory service manual somewhere around here as well.

Mark

arjoll · 9th May 2006, 8:40 am

Definately give the entire tape path a through clean with 100% (or at least >95%) isopropyl alcohol, and check it with a good tape - some new Quantegy 407 or a known good reel of something like Maxell 35-90B. If you are using Ampex from before 1994 then use something else. Keep cleaning each part of the path until the cotton bud (or Q-tip, not sure what you call them over there) is clean.

Tape from the mid 70s to early 90s can suffer from "sticky shed" - especially Ampex and 3M. I have never heard of Maxell having the problem. Basically the binder in the tape breaks down; I have some un-playable mid 80's 407 and early 90's 456, and recently had a reel of 1/2" 456 from 1993 'baked' so I could transfer the contents into Protools.

The idea of the known good tape is good, but I'd definately give everything a good clean and check with tone on a good tape regardless.

Also clean all the switches - I picked up a GX265D in '04 which would playback in forward direction ok, but loose channels when reversing and randomly not record on one channel. Cleaning everything (with CRC CO dribbled in, not the best but it worked) brought it up as good as new.

Other options are magnetism - although it would more likely affect both channels, or head wear - hopefully not, as you'll then be looking at realignment (MRL tapes aren't cheap) and some coin replacing the heads or getting them relapped.

homophone · 9th May 2006, 5:07 pm

Hi Guys,
Thanks to you all for your posts. Have now changed the tape, cleaned and demagnetized the heads, and generally made the machine 'spick and span'. It seems to have solved my problem but I will still have a look inside to clean the switches. I think the basic problem was the tape - I admit it had been used very many times before but I had not realised it could deteriorate to such an extent. We live and learn.

DOFFERY · 11th May 2006, 9:20 pm

Just to prove the point, try your old tape now you are satisfied with the results after cleaning, you might be surprised!!

Doffery

8th May 2006, 5:16 pm	#1
homophone Retired Dormant Member Join Date: May 2006 Location: Cobham, Surrey Posts: 2	Servicing Akai 4000 DS Mk II I have an Akai 4000 DS and an Akai 4000 D. I use the 4000 DS to record LPs and the 4000 D to transfer these recordings to my computer hard disk for eventual burning to CDs. To explain my reasons for such a cack-handed way, (1) my stereo setup and the 4000 DS is downstairs and (2) the 4000 D is in my study upstairs where my computer is. However, the problem now is, I have found that when I am recording and monotoring the sound by the Tape/Source switch, the right channel VU is not registering to the same extent as the left channel and the stereo image is deteriorated. As opposed to the source position where the sound is perfect. Whether or not this is a problem with the switch or something more serious, I do not know. Is there anyone on the forum who may have had experience of this problem and able to help with, or suggest, a solution?

8th May 2006, 9:59 pm	#2
DOFFERY Retired Dormant Member Join Date: Aug 2004 Location: Blackpool, Lancashire, UK. Posts: 1,488	Re: Servicing Akai 4000 DS Mk II Without getting too technical to start with , clean the heads thoroughly, then replay a KNOWN good tape, if OK your problem is on the record side.This could be anything from a faulty record pre amp, bias etc. You are sure it is the right channel? As if a head is suspect it is usually the Left channel that shows up badly, due to head wear. Try the above first. Doffery

9th May 2006, 2:18 am	#3
Markgc Retired Dormant Member Join Date: May 2006 Location: Raleigh, North Carolina Posts: 3	Re: Servicing Akai 4000 DS Mk II Let me know how you get on. I have the 4000DB model here and I think that I have the factory service manual somewhere around here as well. Mark

9th May 2006, 8:40 am	#4
arjoll Dekatron Join Date: May 2006 Location: Invercargill, New Zealand Posts: 3,457	Re: Servicing Akai 4000 DS Mk II Definately give the entire tape path a through clean with 100% (or at least >95%) isopropyl alcohol, and check it with a good tape - some new Quantegy 407 or a known good reel of something like Maxell 35-90B. If you are using Ampex from before 1994 then use something else. Keep cleaning each part of the path until the cotton bud (or Q-tip, not sure what you call them over there) is clean. Tape from the mid 70s to early 90s can suffer from "sticky shed" - especially Ampex and 3M. I have never heard of Maxell having the problem. Basically the binder in the tape breaks down; I have some un-playable mid 80's 407 and early 90's 456, and recently had a reel of 1/2" 456 from 1993 'baked' so I could transfer the contents into Protools. The idea of the known good tape is good, but I'd definately give everything a good clean and check with tone on a good tape regardless. Also clean all the switches - I picked up a GX265D in '04 which would playback in forward direction ok, but loose channels when reversing and randomly not record on one channel. Cleaning everything (with CRC CO dribbled in, not the best but it worked) brought it up as good as new. Other options are magnetism - although it would more likely affect both channels, or head wear - hopefully not, as you'll then be looking at realignment (MRL tapes aren't cheap) and some coin replacing the heads or getting them relapped.

9th May 2006, 5:07 pm	#5
homophone Retired Dormant Member Join Date: May 2006 Location: Cobham, Surrey Posts: 2	Re: Servicing Akai 4000 DS Mk II Hi Guys, Thanks to you all for your posts. Have now changed the tape, cleaned and demagnetized the heads, and generally made the machine 'spick and span'. It seems to have solved my problem but I will still have a look inside to clean the switches. I think the basic problem was the tape - I admit it had been used very many times before but I had not realised it could deteriorate to such an extent. We live and learn.

11th May 2006, 9:20 pm	#6
DOFFERY Retired Dormant Member Join Date: Aug 2004 Location: Blackpool, Lancashire, UK. Posts: 1,488	Re: Servicing Akai 4000 DS Mk II Just to prove the point, try your old tape now you are satisfied with the results after cleaning, you might be surprised!! Doffery