Akai m8 reel to reel with a head or switch alignment problem.

[goodswapeh]

I've got a problem with a Akai M8 reel to reel head or switch alignment issue. See the you tube- https://www.youtube.com/watch?v=3Rn-BYr4qXI Any advice wold be most appreciated.

Michael

[cq_tech]

Michael, I'm semi-retired now but I was a VCR/TV technician from around 1980 and whilst I'm not overly familiar with reel-to-reel tape decks, similar principles apply to the early fixed audio head stereo VCRs so I may be able to offer some guidance.

Firstly, FYI, the head on the left is the full-erase head, the one on the right is the record/playback head, and the one at the front is the cross-field bias head. As with most mechanical devices, it is highly unlikely that any of these heads have gone out of alignment of their own accord so no adjustment should be necessary.

Now as you can see from the extract from the Akai M8 Service Manual below, the switching between stereo and mono is actually done by way of a multi-terminal electro-mechanical switch, and it is my best guess that the switch contacts themselves have become gummed-up and dirty with age so the first thing I would be doing is to carefully remove the tape deck from the cabinet so you can gain access to this switch, then either try cleaning the contacts with electrical contact cleaner, or if it's an open type of switch (as most are on these early 1960s machines) you may be able to use a small piece of emery paper to slide between the contacts to remove any built-up or accumulated junk.

It may also be advantageous to apply some light machine oil to the moving parts of the head block mechanism, preferably with a syringe and blunt drawing-up needle so that you don't get any oil where it shouldn't go. These are available from a couple of ebay sellers, or possibly from your local pharmacy. A 3ml to 5ml syringe should be more than adequate for the task.

I must reiterate that if you shouldn't need to adjust any alignment screws for the heads, and if you do, it may be difficult to get them realigned correctly without an 8KHz tone recording and an oscilloscope.

If you need it, you can download a copy of the manual at no cost from http://www.hifi-manuals.com/Akai/M-8-service-manual/download

Good luck, and I hope this does the trick. 🙂

[goodswapeh]

Thanks CQ, I was thinking it was in the switch. I'll give it a good scrub and let you know how it turns out. Thanks so much for taking the time most appreciated.

Michael

[cq_tech]

My pleasure, Michael, and I would be very interested indeed to learn how you get on.

Bill 🙂

[goodswapeh]

Hi Bill, I gave it a clean with contact cleaner but no joy . I've partly dismantaled the switch to get the emery paper in I'll see how that comes up.

Thanks again Michael

[cq_tech]

That's a shame Michael, but I suppose after 50-odd years of little or next to no use, there must be quite a vast buildup of oxide on the switch contacts so physically cleaning them with emery might be the only real solution after such a long time.

I should have asked if it ever worked properly while it was in your possession, just in case someone who didn't know any better tried to adjust the fixed record/playback head, not realising that it's not supposed to move when the selector dial is turned from stereo to mono, although the amount of adjustment available is minimal at best.

It is quite clearly dodgy electrical contacts though, and my only concern is that it would be extremely difficult, if not impossible to obtain a genuine replacement switch so your only option is to repair the existing one. It's a good thing that it's an open-type switch, otherwise you'd have no hope of cleaning it properly.

Just be very patient, very careful not to break anything, and if it needs to be unsoldered and removed completely to gain proper access, then so be it, because you'll only get the one opportunity.

Good luck with it Michael, and my fingers are crossed on your behalf. 🙂

Bill

[goodswapeh]

Thanks Bill,  I picked this thing up from a junk hord and I've never got it to work correctly. What the problem apears to be is- inside the switch it has some small floting contacts one of which has been mangled  . What  it needs is a new switch. One solution I was thinking of was to solder wires across the switch putting it in permanate sterio until I can find a switch replacement(which is what I want anyway)   The only problem being which connections to make??  Michael

[cq_tech]

Sorry to hear that Michael. The chances of getting a genuine replacement are probably zero but I googled "6 pole 3 position rotary switch" and came up with not just a few sources of replacement switches which could be mounted through the front panel where you have a bit of free space, but better still, on the first page of results there is a link to some very useful images and schematic diagrams which would be of immense help in wiring up a replacement switch.

I don't know if you want to go to that much trouble to get the machine working properly though, and as you say, the easiest way would be to simply solder the relevant wires into a permanent stereo position. It should be relatively easy if the wires are colour-coded, but if they're not, then you may have to use a multimeter to figure out which wire goes where, and having the switch-block schematic above should help make that a fairly simple albeit fiddly job.

Keep plodding along with it as I'm interested to learn how you eventually go.

Bill