|
Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
|
Thread Tools |
6th Jun 2018, 5:28 pm | #1 |
Heptode
Join Date: Nov 2017
Location: London, UK. Bury, Lancashire quite regularly :)
Posts: 611
|
Murphy A46 Multi-Electrolytic.
Evenin' all.
These receivers use a multi electrolytic HT block, three caps in a beige waxed cardboard container - and are all - as you might imagine - well and truly knackered. I would like to keep the case and re-stuff. Q. What would people suggest to pot the new caps in the (rather large) cardboard case? Something which, ideally, would not be impossible to undo without destroying the case in the future, should it be required. Image attached. |
6th Jun 2018, 5:34 pm | #2 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 14,007
|
Re: Murphy A46 Multi-Electrolytic.
You don't need to 'pot' the caps in anything.
Assuming you're using axial-leaded electrolytics, I'd make up two small squares of PCB: one for each end of the cardboard box. One you leave unetched - it's the one you wire the negative-leads of the electrolytics to. The other you etch in an appropriate pattern to take the separate positive-leads. Then wire the electrolytics between the two, and attach suitable flyleads for the external wiring. (this is a sort-of modern equivalent of what was known to last-century electronics types as a 'cordwood module'). Fit it inside the cardboard. Job done. |
6th Jun 2018, 5:40 pm | #3 |
Dekatron
Join Date: Sep 2007
Location: Oxfordshire, UK.
Posts: 4,311
|
Re: Murphy A46 Multi-Electrolytic.
As G6Tanuki says you don't need to pot it. But if you really want to then Quad used to pot the EHT generator for their electrostatic speakers in beeswax. It could then be melted out for repair.
Cheers, GJ
__________________
http://www.ampregen.com |
6th Jun 2018, 10:27 pm | #4 |
Heptode
Join Date: Nov 2017
Location: London, UK. Bury, Lancashire quite regularly :)
Posts: 611
|
Re: Murphy A46 Multi-Electrolytic.
My initial thoughts wandered around potting compound and silicon sealant, but I discarded these thoughts on the basis that it would likely be a one way street.
I homed in on the wax idea, just a question of which wax and the mechanics (or is it physics) of getting it molten and pouring it in. I confess I hadn't considered using pieces of pcb, in any event I don't have etching facilities, but I suspect this is not an insurmountable objection. I would really prefer not to leave a void in the enclosure though - hence the potting idea. Thanks for your input people. |
7th Jun 2018, 10:05 am | #5 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,536
|
Re: Murphy A46 Multi-Electrolytic.
You can always just use plain FR4 or Paxolin for the wiring end. Drill holes as required and simply wire up with tinned copper wire. (Or just the component leads if they're long enough)
__________________
....__________ ....|____||__|__\_____ .=.| _---\__|__|_---_|. .........O..Chris....O |