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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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15th Mar 2016, 12:34 pm | #1 |
Rest in Peace
Join Date: Mar 2006
Location: N.W. Oxfordshire(Chipping Norton)
Posts: 7,306
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'Do not use Metal Cased batteries' in 1960s Radio - Why?
I'm currently in the process of repairing a World radio 'Playmate' 7-transistor portable radio, and have just noticed that, on the label inside the case it states 'Warning'-Do not use Metal Cased Batteries', and the word 'Warning' is in unerlined upper case letters. This is a typical mid 1960s radio, using 3 x AF117, with a 4-transistor amp. made from OC71. 81, and the like. The PCB is mounted on a metal frome, but as the internal cells of any battery are surely insulated from it's case, I'm wondering what problem/fault would be caused by the use of a metal cased PP6. Does anyone know? (I'll post some photos later, btw)
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15th Mar 2016, 12:51 pm | #2 |
Dekatron
Join Date: Jan 2005
Location: Oxford, UK.
Posts: 17,866
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Re: 'Do not use Metal Cased batteries' in 1960s Radio - Why?
As a 5 year-old in the late 1970s, I had a Thomas Salter electronics kit which had a simple AA battery holder made from two strips of plated metal bent into L-shapes, attached to the baseboard with cheesehead screws which also made the electrical connection to hidden leads.
There was no such warning, but when used with a metal-clad Duracell, the screw heads bit through the paint, the cell was short-circuited by its (otherwise isolated) metal case, and became dangerously hot. I wrote a letter to the company, but they didn't even have the courtesy to reply! Could it be that the battery casing could rest against a PCB etc. causing a short circuit? N. |
15th Mar 2016, 2:22 pm | #3 |
Rest in Peace
Join Date: Mar 2006
Location: N.W. Oxfordshire(Chipping Norton)
Posts: 7,306
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Re: 'Do not use Metal Cased batteries' in 1960s Radio - Why?
The radio is built on two PCBs attached to a metal frame, with the Positive line common to the metalwork, so Iguess there's a possibility that a s/c could happen.
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15th Mar 2016, 3:37 pm | #4 |
Nonode
Join Date: Jan 2008
Location: Milton Keynes, Bucks. UK.
Posts: 2,552
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Re: 'Do not use Metal Cased batteries' in 1960s Radio - Why?
Not so long ago I remember a similar s/c problem that could occur when Duracell & other brands of alkaline batteries were used when the toy Star Wars Light Sabre came on the market.
This was due to a sharpish edge along the common part of the battery holder which could cut into the outer wrapping, thus causing the s/c and the battery/s to get hot. As a result, a safety warning was announced, followed by a recall.
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When I die, please don't let my Wife sell my collection for the amount I told her I paid for it! Last edited by camtechman; 15th Mar 2016 at 3:46 pm. |