UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - HMV model 2401 "Stereomaster" restoration

dazzlevision · 22nd Feb 2013, 6:50 pm

Hello,

The BRS MA70-A-1 deck fitted in my Stereomaster looks better cosmetically than the spare deck I have, so I will use parts from the spare to restore it.

The first thing needed was to remove the broken off/play/reject knob, which involves removing the plastic trim that is embossed with the control knob functions. This is held in place by several plastic barbs that latch onto the underside of the metal deck plate. Once this was done, a self tapping screw has to be removed in order to free the remains of the off/play/reject knob. The spare was then fitted and the whole thing re-assembled.

I then felt that excessive force was required to operate the off/play/reject knob and this is probably what caused the original knob to break. On the underside of the deck, the knob is coupled in one direction to the on-off switch for the deck motor and the idler wheel (turntable rim drive) engage/disengage mechanism. In another direction, it is coupled to a sliding plate that is part of the complex mechanism that links the tone arm to the trip pawl, etc. I removed the sliding plate, cleaned it and applied some ”Molykote” grease. Now, much less force is needed to operate the off/play/reject knob.

I then removed as much dust and fluff from the mechanism as I could see, re-lubricated the motor bearings with some sintered bearing oil and checked the large die cast gear wheel (I am uncertain as to the correct name for this part) under the turntable that controls the auto-reject system. It was very stiff, due to hardened grease used on the mounting post that is riveted to the deck plate and in the groove in the die cast gear. So, I removed the old grease and applied fresh.

Everything then seemed to operate freely and smoothly, so I refitted the deck into the cabinet. I also refitted the electronic unit and reconnected all the wiring.

Tomorrow, I will apply power and checked for correct operation of all parts. I will also use a jeweller’s loupe to inspect the stylus, to ensure it wasn’t worn excessively. The final step will be to check the deck adjustments: tracking weight, bias force, set down position, etc.

To be continued………..

Dazzlevision

22nd Feb 2013, 6:50 pm	#12
dazzlevision Dekatron Join Date: Sep 2003 Location: Near Swindon, North Wiltshire, UK. Posts: 3,612	Re: HMV model 2401 "Stereomaster" restoration Hello, The BRS MA70-A-1 deck fitted in my Stereomaster looks better cosmetically than the spare deck I have, so I will use parts from the spare to restore it. The first thing needed was to remove the broken off/play/reject knob, which involves removing the plastic trim that is embossed with the control knob functions. This is held in place by several plastic barbs that latch onto the underside of the metal deck plate. Once this was done, a self tapping screw has to be removed in order to free the remains of the off/play/reject knob. The spare was then fitted and the whole thing re-assembled. I then felt that excessive force was required to operate the off/play/reject knob and this is probably what caused the original knob to break. On the underside of the deck, the knob is coupled in one direction to the on-off switch for the deck motor and the idler wheel (turntable rim drive) engage/disengage mechanism. In another direction, it is coupled to a sliding plate that is part of the complex mechanism that links the tone arm to the trip pawl, etc. I removed the sliding plate, cleaned it and applied some ”Molykote” grease. Now, much less force is needed to operate the off/play/reject knob. I then removed as much dust and fluff from the mechanism as I could see, re-lubricated the motor bearings with some sintered bearing oil and checked the large die cast gear wheel (I am uncertain as to the correct name for this part) under the turntable that controls the auto-reject system. It was very stiff, due to hardened grease used on the mounting post that is riveted to the deck plate and in the groove in the die cast gear. So, I removed the old grease and applied fresh. Everything then seemed to operate freely and smoothly, so I refitted the deck into the cabinet. I also refitted the electronic unit and reconnected all the wiring. Tomorrow, I will apply power and checked for correct operation of all parts. I will also use a jeweller’s loupe to inspect the stylus, to ensure it wasn’t worn excessively. The final step will be to check the deck adjustments: tracking weight, bias force, set down position, etc. To be continued……….. Dazzlevision