Akai 4000D Still Recording Badly..

[alunhart]

My Akai 4000D still seems to be playing up. I cleaned all the switches and things seemed okay but the problem (patchy recording on the left channel) has returned and it's very irritating.

Am I simply going to have to have it repaired by an expensive pro or is there a simple cure?

Alun

[TIMTAPE]

It was mentioned in previous thread but... have you THOROUGHLY cleaned the record/play head?
The reason I say that is because you mention "patchy' audio which could be poor tape to head contact, and also that you said it's the LEFT channel.
The left channel head gap is right at the top edge of the tape path and once the head gets a wear groove in it, it's easy for tape gunk to collect in this little crevice and can be very hard to remove. Sometimes the only way is with a sharpened piece of softwood like pine, a match, popstick etc.

Modern reel to reel tapes such as from about '75 to some time years later could go very sticky and deposit all sorts of muck on heads very quickly.
This may also be a cause. If so look up "sticky shed" on Google, especially Eddie Ciletti's site.

Cheers, Tim

[Top Cap]

Originally Posted by alunhart

I cleaned all the switches and things seemed okay but the problem (patchy recording on the left channel) has returned and it's very irritating.

Thinks you may have cleared the problem and then it came back, I doubt if the switches would give this problem after such a short time from being cleaned. I would now suspect tape shed on the heads as suggested by Tim. Try using another tape brand such as 3M or Maxell and see how it goes.
Les

[Skywave]

Please bear with me if I start by asking an obvious Q.: Are you sure that it's the recording process that's "weak" - or is it "weak" on playback? I ask this simply because if the recording path has a problem, then obviously the playback will be weak also.

That aside, hopefully some useful stuff! -
I had one of these many moons ago, and had similar problems: I am going to try to recall from memory what it was all about, but the earlier comments on "muckite" on ALL heads was quite a common problem. Prior to every recording, I used to clean the heads with IPA - and often prior to replay as well. I did find that some of my really older 7 1/2" tapes started to shed oxide - so they went in the bin, el pronto!

As this is a stereo machine with a fault on one channel, I took the approach of feeding a mono source to L and R channels and using a 'scope, compared the record path L to R through the machine up to the heads. (At this point, you really need a very sensitive 'scope - or some way of "pre-amplifying" the signals so that you can see them). When I looked at the bias record chain, I found that the level was low on the offending channel feed to the head.
Since all the heads were a bit worn, I replaced all three. This itself is a bit tricky, since you have to get the alignment and azimuth just right. And setting up the bias / erase level. I also replaced the capstan that the pinch wheel grips: there was a sizeable dent in it where it had been left (mechanically) switched to FF - with the power off - for an embarrassingly long time!
Followed by the usual prev. maint. with switch cleaner on the pots / switches, and testing with a brand new good quality tape, it worked fine.
Soon after this, I selected only those recordings I wanted to keep, transferred them to cassette and scrapped any 7 1/2" tapes that I was doubful about. At this point, it gradually fell out of use and was eventually "pensioned off".

Overall, though, I was pleased with the relaibility and performance that this machine had given me over many years.

Hope this helps.

Al / G8DLH