Reel to reel

Subjects that don't have their own home
User avatar
Mike H
Amstrad Tower of Power
Posts: 19132
Joined: Sat Oct 04, 2008 5:38 pm
Location: The Fens
Contact:

#61 Re: Reel to reel

Post by Mike H »

Apart from that, all looking good. :thumbright:

I am struck how similar it is in general appearance and layout to my Akai, it was obviously a "style" of that decade.
 
"Entrenched convictions cannot be changed by facts." – Dick Francis
Ant
Needs to get out more
Posts: 1726
Joined: Mon Jul 31, 2017 6:45 pm
Location: Yorkshire

#62 Re: Reel to reel

Post by Ant »

As you know, I stumbled upon an Akai 4000ds mkii rtr machine in a local charity shop, less than a week after I sold the Sony to partially fund the new milling machine.
after vacillitating for 10 minutes I bought it, then as mi dads house was closest and I'd have to carry the bloody thing from the shop, I deposited it there.
This is what I got.

ImageCharity shop Akai 4000ds mk2 by anthony cresswell, on Flickr

I then went and did the shopping I was actually supposed to be doing, and came back to collect it.
Before that, we plugged it into mi dads system to see if it worked, and were greeted by a godawful noise which sounded terminal...... not a good start.
there was however, a little chirp of music when the switches were pressed this way and that in random order to try to coax some life out of it, so there was a modicum of hope.

It was a bit cosmetically challenged, but that was the least of the worries.

Fast forward a couple of hours, I pulled the fascia off it to have a look inside.

at this

ImageCharity shop akai 4000ds mk2 by anthony cresswell, on Flickr

Its a bit less complicated than the 377, but similar in design. Interestingly, all the rubber parts were in rather good nick, not all hardened like the equivalent Sony parts. The charity shop lady said it had been her grandads, and had been in the living room as long as she could remember so this may have been due to it being in a centrally heated environment for most of its life rather than a loft since 1985.

I wanted to get at all the pots and switches first, and get them all cleaned out with servisol. Ten minute job, followed by much switch clicking to work the cleaner round them. I couldn't get at the pots from the front, but that could come later as the pots are on the record side, I just wanted to see if it played.

I then screwed it back together and tested it. Lo and behold, it played no problem. Tried the first tape which was full of soul, Marvin Gaye, Otis Redding, plenty of good stuff. Second one was full of Tina Turner.......... Not wanting to be subjected to any more 80's Tina, I didn't play the third one.

I left it alone for a couple of days, and being at a loose end today while waiting for parts for a build came back to it to get at the pots.

The whole mech comes out of the cabinet via 6 bolts, 4 in the back hidden by the feet and 2 in the base. The last one wouldn't come out without being castigated and threatened with the grinder, but I got there with it eventually.

Turns out that for some reason the mech chassis had rusted around where the bolts went through, but peculiarly, not anywhere else or on the inside of the same areas...

ImageCharity shop akai 4000ds mk2 by anthony cresswell, on Flickr

So, access was gained to the rec level pots, (nobles of all things :shock: ) and I could check for bulging caps and inspect the belts.
no dodgy caps in sight, and the belts are fine if a little loose. I'll get some replacements shortly.

Nailed it back together, and that done, I tried to record something.

Oh dear.

There were dropouts all over the place, the levels were up and down like a yoyo, and It came out as a garbled mess.......
So I cleaned the heads with my last bit of isopropyl and tried again. Not quite as bad, but it got as bad if not worse pretty quickly.
I then downloaded the service manual to see what that said, and had a read. Coming back to it half an hour later, I noticed that underneath the machine there was a load of nasty looking flakey dust, and that it was reluctant to rewind. Luckily it was stood on top of my A3 weekly planner which is white paper, otherwise I wouldn't have noticed anything. The tape itself was the problem, it was shedding so badly that there was a tide mark on the heads and a load of dropped oxide after recording a two and a half minute song. It was also stuck up to the eyeballs, which is why it was reluctant to rewind. This was the third tape which I hadn't tried

So I threaded the soul tape, played it through to the end of the recorded stuff and tried again.
recorded no problem .
So, it's fully functional. I also resprayed all the bIts that were flakey and nasty with some etch primer then satin black which has tidied it up no end

ImageCharity shop akai 4000ds mk2 by anthony cresswell, on Flickr

Next jobs are to turn a new aluminium cover for the pinch roller as it has gone walkies and I'm not paying out a fortune for another one, and to sort out the two chunks out of the right hand side of the cabinet.

And to get some more belts, and some more isopropyl to clean the tape path. Then when the belts come I'll fit them and then give the moving parts a good clean, and treat the rubber parts with rubber renue

ImageCharity shop akai 4000ds mk2 by anthony cresswell, on Flickr

Onwards!
Also starring Rex Hamilton as Abraham Lincoln

www.bte-designs.weebly.com
User avatar
andrew Ivimey
Oooo, Roberts Radio's sound nice
Posts: 7375
Joined: Mon Jun 11, 2007 8:33 am
Location: Bedford

#63 Re: Reel to reel

Post by andrew Ivimey »

Epic!
Philosophers have only interpreted the world - the point, however, is to change it. No it isn't ... maybe we should leave it alone for a while.
User avatar
shane
Social outcast
Posts: 3107
Joined: Sun Sep 16, 2007 12:09 pm
Location: Kept in a cool dry place.

#64 Re: Reel to reel

Post by shane »

If you get fed up with it, you’ll find that the motor runs at exactly the right speed to drive the rim of a 30cm turntable platter, using one of the idlers from the tape drive!

It’s a really nicely made motor as well.
Ant
Needs to get out more
Posts: 1726
Joined: Mon Jul 31, 2017 6:45 pm
Location: Yorkshire

#65 Re: Reel to reel

Post by Ant »

Did some more on the akai this morning
Fitted a new set of belts which in this case is the capstan/motor belt and counter belt. While i was at it i stripped and rebuilt the capstan as both it and the motor had to come out to get the belt in.

Had to give the drive surfaces on both a good clean due to surface corrosion. A go round with 600 grit wet and dry, then 1200, then clean off with meths. As the casptan flywheel was out i had a look at the bearing.

The capstan bearing is quite reasonable, it has 2 oilite bushes with a felt wiper in between them which keeps the capstan spindle wet and acts as the oil reservoir. Sprayed some 3 in 1 oil in there to lubricate it.

Also cleaned the motor spindle where the ff/rw idlers contact it and used rubber renue on them.

Also demagged the heads and tape path while i was at it, i managed to pick up a new tonar one for 25 quid so it seemed rude not to.

There is still some pitch instability but its not as bad as it was before. The recordings ive made have been right at the end of a tape. I'll have to dismantle the reel tables, i think its because the back tension is abit intermittent. If its not, next thing will be to look at a pinch roller refurb and an/other capstan sleeve. There are two little nicks in it that ive spotted.

Interestingly, the recordings it makes at 7.5ips sound better if the eq is set to 3.5ips, the top end is better with that eq selected. Its abit dull with 7.5ips selected.
Wonder why...... eq obviously, but why is the 'correct' eq abit dull....
Also starring Rex Hamilton as Abraham Lincoln

www.bte-designs.weebly.com
Ant
Needs to get out more
Posts: 1726
Joined: Mon Jul 31, 2017 6:45 pm
Location: Yorkshire

#66 Re: Reel to reel

Post by Ant »

Last weekend i did abit more work on the charity shop akai.
To try to sort out the pitch instability i took the feed reel table to bits to have a look at the felt clutch arrangement at has, and have a look at the back tension mechanism.

The reel table clutch is fairly simple, comprised of several washers, a couple of spring washers and a conical spring. It can be adjusted by varying the number of washers, this preloads the conical spring to provide x amount of clutch slip to stop the tape being stretched.

The back tension uses a sprung lever with a rubber bush on it that sits against the side of the reel table drum, and is adjusted by preloading the spring to provide more force against the drum..

The reel table was cleaned and put back together as it was, the felt clutch material seemed fine and not contaminated with anything, and the bearing shaft was greased as it was bone dry.

The back tension mechanism was left as it was, the suspect bit was the rubber bush as it appeared to have some deposits on it and was abit crusty.
So the deposits were cleaned with meths then treated with rubber renue.

While i was at it, i had noticed some dings in the pinch roller when i rubber renued it, so i dressed it back to get rid of the dings and get it back to slightly better condition rubber.

These fixes appears to have sorted the problem, i think the major contributor was the nasty rubber bush on the tensioner, it seemed to grip and slip under load.

I didnt have time to test it having had a busy week, so got round to it today.

So the machine now works lovely, all thats left to do with it is to sort out 2 chunks out of the cabinet veneer, and make the replacement ally pinch roller cover.

Its only cost me for a belt set, so its cost me in total about 135 quid, and about 6 hours work. The recordings it makes are better on 7.5ips, with the eq set to the 3.75ips setting, the 7.5ips eq is abit dull with emitape.

It could be rebiased, but sod that its not worth the trouble.

Sound quality isnt quite as good as the sony was, but its not far off, i marginally prefer the sony in this respect. There is abit more hiss from the akai, i can live with that, its not an obnoxious noise like turntable hum.
However, the akai is more compact, and the sockets are on the rear instead if the side making it easier to site somewhere.

Now ive had both of the established 'enty level' r2r machines in very good condition, i can see why they are so popular.
Easy enough to work on, simple enough to understand how the mechanisms work (for me anyway, a little bit of mechanical aptitude is required), they are not hugely difficult to get running satisfactorily.

A recap would probably be adviseable, but as there are no signs of the caps being on the way out in this one, then its just a longevity consideration.

Oh. The meter back light bulb has just gone. Oh well, a new bulb required...

I want another one to play with :mrgreen:
Also starring Rex Hamilton as Abraham Lincoln

www.bte-designs.weebly.com
User avatar
shane
Social outcast
Posts: 3107
Joined: Sun Sep 16, 2007 12:09 pm
Location: Kept in a cool dry place.

#67 Re: Reel to reel

Post by shane »

Next stop Revox?
Ant
Needs to get out more
Posts: 1726
Joined: Mon Jul 31, 2017 6:45 pm
Location: Yorkshire

#68 Re: Reel to reel

Post by Ant »

Got another job completed on the Akai, I made a replacement cap for the pinch roller. Bit of aluminium, more of a pain in the arse than i thought it would be to be honest.

ImageCharity shop akai 4000ds mk2 by anthony cresswell, on Flickr

Had to face the end of the bar then turn the diameter, then cut the recess in it for the plastic part to fit.
Then tried to part it off, which was a hiding to nothing (again) so I had to cut it off, reverse the chuck jaws to grab it, and space it off the jaws so i had just enough stuck out to face it on the side that you can see.

I made a guess as to the dimensions based on some pictures, it looks a little big now its on, but it doesn't really matter. Also the chamfer around the front edge is a bit too small, but the way I had to do it meant that I didn't have enough stuck out past the jaws to make it any bigger.

It's not far off, but at least at a glance it looks original. Better than it did anyway
Also starring Rex Hamilton as Abraham Lincoln

www.bte-designs.weebly.com
Post Reply