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Other Vintage Household Electrical or Electromechanical Items For discussions about other vintage (over 25 years old) electrical and electromechanical household items. See the sticky thread for details. |
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19th Sep 2020, 2:12 pm | #1 |
Heptode
Join Date: Apr 2010
Location: West Midlands, UK.
Posts: 663
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What was this Mains Isolator unit used for?
I found this box amongst various junk when looking for a short length of mains cable. As wired it appears to short the mains in the ON position! A DIN speaker socket, switch, transformer and 82 ohm resistor on/in the box.
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19th Sep 2020, 2:16 pm | #2 |
Dekatron
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
Posts: 9,643
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Re: What was this Mains Isolator unit used for?
It says mains, but it's a headphone/speaker accessory for a non-isolated TV set.
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19th Sep 2020, 2:27 pm | #3 |
Heptode
Join Date: Apr 2010
Location: West Midlands, UK.
Posts: 663
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Re: What was this Mains Isolator unit used for?
Presumably mains cable (if original) was used as a convenient 3 way cable. How was it connected to the set, was it permanently wired or was there a plug/socket arrangement?
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19th Sep 2020, 2:42 pm | #4 |
Dekatron
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
Posts: 9,643
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Re: What was this Mains Isolator unit used for?
Not a consumer fit I'd have thought. I've seen it advertised somewhere, it stirred a memory!
Edit: It may have been one of those disposal places in PTV or PW? |
19th Sep 2020, 9:39 pm | #5 | |
Octode
Join Date: Aug 2005
Location: Saltburn-East, Cleveland, UK.
Posts: 1,786
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Re: What was this Mains Isolator unit used for?
Quote:
The switch is wired in series with the "hot" side of the television sound output stage and internal speaker positive the connection to allow the internal television speaker to be muted, the third lead being common ground/speaker negative. The isolating transformer then allows an external speaker or tape recorder/amplifier to be safely connected. I only ever seem to recall seeing one of these units in use back in my "rental' television repair days on either a BRC 3500 or a TX9 chassis, I can't remember which..... Andrew |
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19th Sep 2020, 9:56 pm | #6 | |
Dekatron
Join Date: May 2010
Location: Greater Manchester, UK.
Posts: 18,725
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Re: What was this Mains Isolator unit used for?
Quote:
There was a second box that had a volume control and a 3.5mm jack for the supplied earpiece. The two boxes were connected with a long cable with 2 pin DIN plugs at each end. They were a consession made for our hard-of-hearing subscribers rather than anything else, I think we fitted them FOC
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-- Graham. G3ZVT Last edited by Graham G3ZVT; 19th Sep 2020 at 10:06 pm. |
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19th Sep 2020, 10:02 pm | #7 |
Moderator
Join Date: Dec 2010
Location: Exeter, Devon and Poole, Dorset UK.
Posts: 6,879
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Re: What was this Mains Isolator unit used for?
I made my own for recording from a Sobell TV to my Grundig tape recorder.
I would have been around 14 and it was built into a 2 part Blue and orange slide case with a DYMO title (done at school) Tip of the Pip Toy. I may even still have it although little from this period survives having been dumped by my parents whilst I was in Portsmouth. Yes I used it to record Top of the Pops. The speaker on this set was not isolated by the output transformer. I do still have the tape recorder and some of those recordings. Cheers Mike T
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26th Sep 2020, 6:19 pm | #8 |
Hexode
Join Date: May 2009
Location: Ryde, Isle of Wight, UK.
Posts: 419
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Re: What was this Mains Isolator unit used for?
Looks familiar, fitted by DER or RR to Subscribers who had hearing problems, so they could use Head phones or Earpiece, also we fitted something similar for the Hearing Aid Inductive Loop Systems, I recall.
Ken G6HZG VMARS
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28th Sep 2020, 8:19 am | #9 |
Dekatron
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
Posts: 8,935
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Re: What was this Mains Isolator unit used for?
A lot of these were used to connect an hearing aid when I was at Granada/DER Ltd.
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