Thursday, September 03, 2015

Bush VHF81 Chassis restoration

The electronic restoration of the VHF81 chassis was pretty straightforward. With the chassis removed from the cabinet everything is easy to get to.


Everything looked original, with just five wax paper and two Hunts capacitors to be replaced, including one connected directly across the switched AC input. This was replaced with a X2 type rated at 275V AC. Any other faulty components will be found when the set is powered up again.


The original power cable was replaced with a piece of modern white two core flex. I would usually have used black, but in this case white will fit in nicely with my planned colour scheme. As this is an AC/DC radio, I did a quick check with a DVM to confirm that the neutral was connected to the chassis, and not the live!


The mechanical problems were a bit more difficult. Replacing the broken dial cord took a while. Fitting the cord was reasonably straightforward, although the diagram on the 'Trader' service sheet helped a lot. Getting the tension right was much more difficult, especially when on the third or fourth attempt the tension spring flew off and disappeared somewhere under the bench! Fortunately I had something similar in my junk box, and after a cup of coffee it all came together OK.


The sub-chassis carrying the VHF tuner is attached to the main chassis via anti-vibration mounts; basically rubber grommets with brass bushes through the middle.  The old crumbling rubber bits were replaced with modern plastic grommets. Putting these in boiling water for a few seconds made them just pliable enough to be squeezed, with some difficulty, into the holes in the chassis.



Keep listening!

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