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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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24th Dec 2017, 2:14 am | #21 |
Dekatron
Join Date: Apr 2012
Location: Worksop, Nottinghamshire, UK.
Posts: 5,553
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Re: Magic Eye on Precision Aneroid Barometer stopped working
Those blue display calculators that were every ware at one time had one in them.
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24th Dec 2017, 7:28 am | #22 | |
Dekatron
Join Date: Jun 2015
Location: Biggin Hill, London, UK.
Posts: 5,208
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Re: Magic Eye on Precision Aneroid Barometer stopped working
Quote:
I am not sure what the law says about using it to de-pot encapsulated electronics, but who is to know |
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24th Dec 2017, 7:31 am | #23 | |
Dekatron
Join Date: Jun 2015
Location: Biggin Hill, London, UK.
Posts: 5,208
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Re: Magic Eye on Precision Aneroid Barometer stopped working
Quote:
Incidentally, some of those old calculators are of interest to collectors so it would be a good idea to check what you've got (particularly if it has more than the standard 4 functions) before stripping it. |
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24th Dec 2017, 11:08 am | #24 |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
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Re: Magic Eye on Precision Aneroid Barometer stopped working
In the instructions, the change in the length of the display between Pattern A and Pattern B doesn't look a lot so I wonder if the grid bias needed for Pattern B is by contact potential bias, eg: no separate -ve grid bias supply?
A resistance measurement between the grid and supply -ve might give a clue? Lawrence. Last edited by ms660; 24th Dec 2017 at 11:26 am. |
30th Dec 2017, 1:06 pm | #25 | |
Hexode
Join Date: Oct 2010
Location: Sandiway, Cheshire, UK.
Posts: 326
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Re: Magic Eye on Precision Aneroid Barometer stopped working
Quote:
I may have an original potted inverter that will fit your Baromec. From memory two different types were used but the one I have is 24x30x60mm with yellow/blue 1.5V input wires and red/black for the 120VDC output. Somewhere I may have the small pcb with the DM71 on it as well as some other Baromec parts. Ian |
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3rd Nov 2023, 3:15 pm | #26 |
Triode
Join Date: Mar 2009
Location: Exeter, Devon, UK.
Posts: 36
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Aneroid barometer Magic Eye update...
Thank you all for your comments. I used 5 x A27 12 volt batteries for the HT. They needed replacing for the first time this week.
The plastic holders were a bit weak for the springs and they had all split. This time round I used bakelite discs and penny washers to keep them together. All set for a few years and looking forward to the next low pressure system! Last edited by Station X; 3rd Nov 2023 at 3:24 pm. Reason: Threads merged. |
4th Nov 2023, 5:41 pm | #27 |
Octode
Join Date: Jul 2006
Location: Willand, Devon, UK.
Posts: 1,023
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Re: Magic Eye on Precision Aneroid Barometer stopped working
Good to see you have kept it running!
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5th Nov 2023, 9:54 am | #28 |
Hexode
Join Date: Dec 2019
Location: Hohenroda, Eastern Hesse, Germany
Posts: 460
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Re: Magic Eye on Precision Aneroid Barometer stopped working
As a former user of several precision and sometimes "ancient" barometers I can say every service effort was followed by a sometimes time and cost intensive re-calibrating laboratory process. Often some tiny corrosion on contact surface caused malfunction. A close look was rewarding. DM 70 or DM 71 (just different in wiring) are still available, so I would prefer to get it back to original. These instruments are made much better than any today's stuff.
If it was mine I'd want to contact the Met office and ask who does calibration/certification. These folks will know who can repair it - if they do not offer that service, too. Over here in Germany I'd contact DMT Exam, TÜV West. Got to admit I have been out of this for many years now. Joe |
5th Nov 2023, 11:45 pm | #29 |
Tetrode
Join Date: Dec 2011
Location: Cheshire, UK.
Posts: 89
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Re: Magic Eye on Precision Aneroid Barometer stopped working
I picked up one of those barometers in one of Chas Miller's Radiophile ferreting boxes. Made by mechanism Ltd. Mine is a bit different, probably older. I used 6 12 v fob batteries in series giving 72v. & s 1 1/2 v D cell. The switch contacts inside short a 1 meg grid resistor so display is either fully open or closed. Easy to set to local air pressure, I set mine against a Fortin mercury barometer. If memory serves, you just remove the knob, slacken the screw in middle of shaft, and adjust the inner shaft relative to the outer till the contacts open at the desired reading. Nip the screw back up & refit the knob. Note they read from low to high, i.e when contacts open, not closing. It was reading 954 mb on sat, never seen my barometers so low.
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5th Mar 2024, 10:12 am | #30 |
Moderator
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 21,288
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Re: Magic Eye on Precision Aneroid Barometer stopped working
__________________
Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. |