The Echorec ‘T7E’ shaded-pole motor is fitted self-lubricating sintered bronze bushings that keep the rotor in position whilst allowing it to spin freely. Although the bushings are self-lubricating types they do eventually dry out over very long periods and most Echorecs are decades old, being manufactured in in the late 1950s to 1970s—the bushings will be dry and this will adversely affect the performance of the machine. As the bushing drys out the rotor speed begins to become erratic and consequently the delay repeat period becomes erratic too. Further, the increased friction between bushing and rotor shaft leads to increased motor noise and ultimately the bushings wear away, permanently ruining the motor (replacement bushings for these old motors are essentially unobtainium).
Oiling the bushings isn’t a difficult task in itself, however gaining access to the bushings could be regarded as laborious, intimidating even, as the mounting plate, rear and bottom panel have to be removed to gain access to the motor. Because the motor is hidden within the Echorec chassis, and difficult access, the task of lubricating them is often never even considered, let alone undertaken. But removing the motor and stripping it down is really not so difficult.
First, the mounting plate has to be removed. This is achieved by unsoldering the screened wires connected to the heads (whilst taking care not to nudge or knock any of them out of alignment!). Next the nuts on the four securing studs at each corner of the mounting plate need to be removed. The plate can then be lifted just a few inches away from the chassis of the ‘T7E’ to gain access to unsolder the earth wire between plate and chassis. The entire plate assembly of drum and heads is then free to be lifted away.
The back and bottom panels of the machine are easily removed by unscrewing a dozen or so self-tapping panel screws. The motor can then be removed by unsoldering four wires connected to the winding and then unscrewing the three retaining bolts that secure it to the chassis. Now is a good opportunity to install new anti-vibration mounts (a.k.a. 5mm rubber grommets) to the three bolts whilst the motor is out. These mounts are normally beginning to disintegrate after 40 years or so of hard life.
Once removed the motor can be disassembled with ease. The motor end bells, housing the bushings, are removed by unscrewing the two long bolts that hold them and the rotor within the stator. Once disassembled the motor can be cleaned using air duster, a small brush and a little isopropyl alcohol for removing dried up grease and grime. Once everything’s been cleaned up the felt pads around the bronze bushing can be lubricated with a few drops of light machine oil.
And that’s pretty much all there is to it. Assembly is the exact reverse of disassembly and it’s prudent to renew the four anti-vibration mounts on the plate too—3mm rubber grommets will do the job.
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