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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

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Old 26th Mar 2023, 12:04 am   #1
DMcMahon
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Default Akai 707S Reel to Reel Checkout

This 2 speed, valve machine is thought to be early to mid 1960's vintage, it is in overal reasonable condition for its age. Its wooden case is rexine covered, some of which needs glueing down.

Externally somewhat similar to the Akai M series stereo machines, it probably pre dates the Akai 3000D and 4000 series machines

Very little information is available, cannot find any user or service manuals, there are a couple of older Forum Threads covering the 707. Do not know what the difference is between the 707 & 707S.

Wonder if the S could be for "Stereo" but it only has one mono amplifier, there is a Head output that possbly could be for connecting to external amplifier for stereo playback. There is a 2 position slide switch above the heads assembly identified as 1 - 2. The 707 (thought to 2 track machine) also has the Head output but no slide switch.

There are two 50/60 Cycle switches on the top panel, I assume the small one near top right corner is an electrical switch to switch the motor run capacitors.

The second cycle switch near the middle of the mechanical chassis should mechancally move the capstan belt but looking at the hole it looks like the hardware is missing ?

The Play/Record control knob is upside down and may not be the original knob.

The Fast Forward/Rewind control knob is totally the wrong type, someone has been inventive and added black Fast Forward/Rewind tape arrows on the chassis. Will replace that with a more approriate knob.

It was sold as a working machine but before I power it up I will have a good look inside to check everything particulary checking for any paper coupling capacitors and the condition of the cams.

At the moment strugging to remove the mechanical chassis, think the top panel has to come off first to access whatever secures the chassis into the wooden case. The top panel appears totally stuck, maybe being held down by the Fast Forward/Rewind control knob, this is fixed to control shaft by a small grub screw but so far cannot budge/loosen the screw.

David
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Last edited by DMcMahon; 26th Mar 2023 at 12:25 am. Reason: Update
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Old 26th Mar 2023, 10:10 am   #2
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Default Re: Akai 707S Reel to Reel Checkout

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Originally Posted by DMcMahon View Post

The second cycle switch near the middle of the mechanical chassis should mechanically move the capstan belt but looking at the hole it looks like the hardware is missing ?

David
This is assuming that this cycle switch is the same/similar to the 4000 Series and other old Akai machines. Looking at several photos of different 700 machines it looks like this should be the same.

Once I get the top panel off all should become clear.

David
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Old 26th Mar 2023, 8:50 pm   #3
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Default Re: Akai 707S Reel to Reel Checkout

Could not get the Fast Forward/Rewind control knob grub screw to loosen, repeated attempts just resulted in the allen key wearing the small hex grub screw and subsequently spinning in the grun screw. Also found a second grub screw which was already worn and the allen key just spun in the grub screw.

Could not budge the 2 grub screws at all so had to remove the knob by sawing it in half.

The top panel still would not move, found that the 2 black rings around the spool holders were holding the top panel down. The Supply one had 2 of the 3 screws screwed down into metal mounting posts (the third screw just screwed into a fixing for the ring). The Take Up ring also had 2 of its screws screwing down into mounting posts, the third screw should also have screwed into a third post, but the screw is too short to reach the post.

With top panel removed then by removing 4 screws that secure the mecahncial chassis to the wooden case then was able to remove the amplifier chassis and the mechancial chassis.

All 4 cams look in good condition, later will strip, clkan and relubricate the associated mechanisms.

I assume some of the capacitors in the amplifier are paper, later will slowly power up and measure the valve control grids voltage to see if any bad coupling capacitors.

Found several bits of horrible black goo that traced to the motor wires, there is a messy lump of black goo that makes a terrible mess even with the lightest of touches, maybe it was a rubber sleeve that the wires went through. Need to clean all this away before doing anything else.

The top 50/60 cycle change switch is an electrical switch which switches the motor run capacitors. The mechanical cycle change switch hardware is totally missing. The capstan belt is around the smaller of the 2 steps on the flywheel, assume this is the 50Hz position.

David
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Last edited by DMcMahon; 26th Mar 2023 at 8:58 pm.
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Old 27th Mar 2023, 8:59 am   #4
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Default Re: Akai 707S Reel to Reel Checkout

I did wonder if the tight knob was original. Online photos mostly showed both knobs as the slimline version not a round knob or had the knob missing. The volume/tone controls are single gang so therefor mono. A similar looking deck (M8) is shown with the amplifier panel duplicated and is stereo.
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Old 27th Mar 2023, 9:39 am   #5
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Default Re: Akai 707S Reel to Reel Checkout

I have a M-8 for spares - I think it may have the knob you need - I'll have a look.
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Old 27th Mar 2023, 11:00 am   #6
DMcMahon
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Default Re: Akai 707S Reel to Reel Checkout

Thankyou Glyn,

I do have 2 control knobs that would do the job, they are fractionally shorter that the one good original and maybe slightly more pointed that the original but not as pointed as the knobs on other 700 images. The dark grey paint is starting to come off those 2 knobs.

David
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Old 4th Apr 2023, 10:55 am   #7
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Default Re: Akai 707S Reel to Reel Checkout

Found that the horrible black rubber goo on the motor cabling had dripped down onto the amplifier chassis and covered one short wire going to the output transformer.

Hell of a job trying to clean the wire so replaced the wire with a new piece, still to clean the motor cabling.

While trying to work out where the coupling capacitors are, using Akai M4 amd M7 schematics as a guide (which should be very similar) I removed the 5 valves to see which valve type was in which position to help locate the coupling capacitors.

On refitting the valves, the valve retaining clip for the 6X4 HT full wave rectifier sprung off and broke the top of the valve !

Hopefully should be able to find a donor from another of my old machines.

David
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Last edited by DMcMahon; 4th Apr 2023 at 11:03 am. Reason: Missing word added
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