Bush DAC90 - loose main adjustment tags

[Voxophone]

Does anyone have a reliable method for repairing the mains adjustment tags on a Bush DAC90?

The top two tags where the wire connections are soldered were originally compressed against the paxolin strip by rivets, ensuring an electrical connection. On my set however the strip has broken in half and although I can screw it back in place the tags (especially the top one to the heater chain) are rather loose. The radio does work, but the multimeter suggests an intermittent connection between these tags and the brass barrels on the dropper resistor which can’t be a good thing.

I considered making a new paxolin strip however there would be no way to fit it over the rivets. Soldering the tags direct to the barrels might also work, however the join would need to withstand some serious heat! The only other method I can think of would be wander plugs in the sockets themselves to replace the soldered connections.

Is there a tried and tested method of dealing with this? I want to keep the dropper in place for the winter months…

Cheers

Liam

[Station X]

Would it be possible to drill out the rivets and replace them with brass cheese head screws, washers and nuts?

[Tim]

I would certainly consider small nuts and bolts/screws. I have done many similar things before, and not had any problems. I would think about a method to ensure they can't come undone. Small locknuts maybe difficult to find so a dab of nail varnish or even Tippex( other correction fluids are available) would probably be wise. If you are feeling brave you could try pop rivets, but I would'nt on Paxolin type stuff.

[Voxophone]

Thanks for the suggestions. I agree that screws would be the ideal solution. The problem I think is that there is nowhere to screw them into except into the sockets of the brass barrels. I suppose I would have to cut a thread into these?

Alternatively, perhaps I could remove the two relevant barrels altogether and run bare wire jumpers from the tags on the resistor to the screws on the adjustment strip. The problem here would be that the top of the resistor would be unsupported.

[60 oldjohn]

One solution that I used, is an auto transformer as detailed at the end of the DAC90 manufactures service sheet. Much safer, greatly reduced heat, no asbestos, easy to buy scale bulbs. Effectively an AC90. TX are available from forum member Ed Dining. I agree not every one would want to do this, but I am able to use this daily radio in the house without the risks.

John.

[Tractionist]

Mmmm .............

I seem to recall spending a lot of time on mine i.e. a) neutralising/stabilising the dropper 'chimney' asbestos with a few coats of dilute PVA [after complete removal of same] b) removing the dropper and isolating/insulating some pins with heat shrink c) reinforcing parts of the paxolin strip with additional sections super-glued on, and ........ d) tightening-up the mains 'in' female brass pins [which are screwed to the dropper tapping clamps].

I recall tightening the latter up by placing the whole lot 'ends on' [whilst off the dropper but still obviously on the paxolin strip] on a hard surface and re-peening the female/banana plug ends very carefully with a small ball peen hammer. I also worked them around a bit whilst doing so - in order to ensure a good clean contact with the entrapped washer and associated tag.

No problems so far .................