Teac A-450 cassette recorder & player

Pre-purchase photograph

This handsome beast was a 1973 attempt at perfection for home recording market as an alternative to reel to reel recorders popular at the same time. Although the sound reproduction only reaches a high of 16 kilo hertz, this is at the top end of the average persons hearing response. The way it achieved this was the build quality and attention to detail. It used just one motor for all functions, but this motor is quite large and gives off a large amount of heat and is near almost silent in use.

Circuit showing power supply on US version, UK has a multi-tapped mains transformer with a selector switch/ also timer mains SW (not shown here)

The repairs
I purchased this unit second hand on-line for £15. The 1973 cost in the UK would have been around £187, this relates to about £1400 at today's cost of living. ($350 US)

First thing is to take lots of pre photo's (good for checking later for where things went) then remove all sides to gain access to the machine. Remove the cassette box on top with 4 screws, then remove steel cover and cassette loading door. I always put the screws in a small plastic box, so you don't lose then. The unit was going dead when you moved it accompanied by a puff of smoke, this turned out to be a broken mains cable at the point where it entered the back, All 4 rubber belts had 'lost the will to live' and the main large thick capstan belt had long turned into dust. Belt kits are available on-line from the States but with postage would cost to the UK around £40, so this was to me not an option. For the main drive belt, around 15 cm long and 5 mm wide I used a BSR turntable belt (found in my loft) that I reduced in size by cutting the rubber to the new length and Super glued the shortened belt together.

Front removed, new bulbs fitted to right VU and Dolby SW

If you make the cut with a sharp knife do it with the belt overlay-ed so the angle is the same a both both ends. The other belts I sourced using China kits of about 30 differing lengths. The take-up reel was still struggling to move and this turned out to be drag caused by the feet counter mechanism needing some oil. Several jockey wheels needed to be cleaned with 70 % alcohol, they are underneath the capstan drum that is easily removed by a bar plate that holds it in place. Take care not the loose the 'c' clips that hold the small jockey wheels on the spindles, if you do, use wire from a 1/4 watt resistor wrapped around to hold in place.

Main belts and jockey wheels

The right hand VU meter light bulb had gone. To fix this, after the aluminium front has been removed you can pull off the plastic cover to the VU meter, but remove the black tape that surrounds it as it holds it tight in place.
The reason for the tape being there is to stop bleeding light from the meters leaking to the feet counter tape movement display that also houses a bulb. The bulb can then be un-soldered and a new one fitted, it's a 5.5 V bulb (I used a 3 V model railway bulb with an 82 ohm resistor in series to give a matching brightness the the other VU meter. The Dolby light was also faulty and the same type of bulb was used here. I found the circuit diagram on-line and unfortunately this wasn't totally correct for the UK model that has a few extra components wired in to the mains input. A timer switch on the front also caused me a lot of grief  because if this is left on the power is removed from the mains input wiring that somehow comes back when you press play button, but will disable the FF & RW functions, nightmare, lol
Sewing machine oil is needed around all mechanical moving parts, switch cleaner also on spayed into the six slider volume controls, bias switches, head switch (found left side of player above) and the two record switches on right-hand signal panel (under cassette box) Small drop of oil to pinch roller spindle and clean ferrite heads with alcohol cloth and the rubber roller to remove all brown tape residue.

Capstan drum with belt removed and + end of tape cut-off solenoid

Cabinet repairs
As with any 46-year-old unit, time creates damage. A label on the rear suggest the last repair was in 1993, but my guess is that  was an estimate and the machine was scrapped then.
The main cosmetic issue is rust corrosion showing through the paint on the top, I used a bronze brush followed with a wire wool treatment, this left the surface smoother but still pitted. I found I needed about 5 coats of spay matt black paint, and even then some discoloration still showed up. The wood chip veneered ends were dented and a piece had broken off at the rear. This was treated with wood filler and then touched-up with wood Finnish coloured felt tip pens, the wood grain can be added with a pencil to match existing lines.

The restored machine being tested