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Vintage Test Gear and Workshop Equipment For discussions about vintage test gear and workshop equipment such as coil winders. |
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18th Nov 2022, 8:56 pm | #1 |
Nonode
Join Date: Aug 2007
Location: Walsall Wood, Aldridge, Walsall, UK.
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Marconi TF1041 Meter glass refixing, and large deflection when stood up
Can anybody recommend a suitable adhesive for fixing the front glass of the meter movement from a Marconi TF1041B valve voltmeter please?
As well as this, when I stand the instrument vertically with the knobs facing the front the pointer swings to about ⅓ f.s.d! Has the movement been damaged in transit or is this normal for this instrument? – I was wondering if this is why Marconi provided a zero control that swings the meter over it's full f.s.d. range! (I did see a picture of one of these on a Spanish website and it showed a similar deflection of the meter to what mine has when stood up vertically!) I'll re–post in the appropriate thread if it looks like the movement will need attention from someone with better eyes than me, or a replacement movement! Chris Williams
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It's an enigma, that's what it is! This thing's not fixed because it doesn't want to be fixed! Last edited by Chris55000; 18th Nov 2022 at 9:25 pm. |
19th Nov 2022, 10:01 am | #2 |
Moderator
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Re: Marconi TF1041 Meter glass refixing, and large deflection when stood up
Silicone sealant has worked fine for me.
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Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. |
19th Nov 2022, 8:26 pm | #3 |
Dekatron
Join Date: Jan 2004
Location: Newcastle upon Tyne, Tyne & Wear, UK.
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Re: Marconi TF1041 Meter glass refixing, and large deflection when stood up
H Chris, I think a form of black Bostik was used in the day.
It sounds as if the meter is out of balance. If you look carefully at the movement you will seethe pointer attaches to a cruciform piece that is part of the movement. On the arms of this piece are tint springs, slotted on and often held in place with shellac. Application of soldering iron heat allows the shellac to soften and the springs to be moved along the arm. The movement can then be balanced in H&V panes in this manner. HTH Ed |
19th Nov 2022, 10:42 pm | #4 |
Octode
Join Date: Jul 2004
Location: Dundee, UK.
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Re: Marconi TF1041 Meter glass refixing, and large deflection when stood up
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20th Nov 2022, 10:10 am | #5 |
Pentode
Join Date: Sep 2007
Location: Fareham, Hampshire, UK.
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Re: Marconi TF1041 Meter glass refixing, and large deflection when stood up
I used araldite for the meter glass of one of the meters in a TF801 signal generator. After a couple of years the glass cracked, and I am certain the meter had not been knocked. I think it was due to stress in the meter movement when the signal generator was moved around. I have used Evo Stick ever since as it allows some "give." Silicone sealant would do the same.
Andrew |
20th Nov 2022, 2:30 pm | #6 | |
Octode
Join Date: Sep 2004
Location: St. Albans, Hertfordshire, UK.
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Re: Marconi TF1041 Meter glass refixing, and large deflection when stood up
Quote:
It certainly sounds like it. If the needle has a different deflection depending on its orientation it must be so. But that does beg the question of how it got unbalanced. It was presumably OK when it left the factory, so what's happened to it? Has it suffered some severe mechanical trauma, have bits fallen off, or what?
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Regards, Richard, BVWS member |
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21st Nov 2022, 1:47 am | #7 |
Nonode
Join Date: Aug 2007
Location: Walsall Wood, Aldridge, Walsall, UK.
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Re: Marconi TF1041 Meter glass refixing, and large deflection when stood up
Unfortunately I can't tell, as it was a "sold as seen" purchase, however there's certainly no signs on the case to suggest it has been dropped, no dents, paint/enamel chipped off, etc!
I bought it because it came complete with probes and leads, all complete as in Marconi's book! If it is possible to rebalance the meter as Ed Dinning suggests, I might pm him and ask him how much he'll charge me for sticking the glass back and having a go for me – the "common zero control" swung the pointer over so the meter certainly isn't o/c! Chris Williams
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It's an enigma, that's what it is! This thing's not fixed because it doesn't want to be fixed! |
21st Nov 2022, 3:33 pm | #8 |
Nonode
Join Date: Jun 2007
Location: Coulsdon, London, UK.
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Re: Marconi TF1041 Meter glass refixing, and large deflection when stood up
I recently glued a glass to a vintage bakelite meter housing.
The original adhesive seemed to be a brittle black material like shellac. I wanted some flexibility in the bond and the option of removing it if the glass broke. I used a clear 'hybrid' adhesive/sealant which is similar to silicon sealant but is over-paintable and does not contain acetic acid. I originally bought a cartridge of this adhesive for caulking & property maintenance. Removing the unwanted adhesive that had been squeezed out onto the front of the glass had to be done after it had set. This was difficult. The temptation is to use a sharp metal tool but this could scratch the glass. I used some hard plastic. |
21st Nov 2022, 5:54 pm | #9 |
Nonode
Join Date: Dec 2012
Location: Kirk Michael, Isle of Man
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Re: Marconi TF1041 Meter glass refixing, and large deflection when stood up
Chris, I used to have a 1041C, excellent unit. However, never had a 1041B, but I don't recall the 1041C as being intended to sit any way other than upright. I have a GEC/SEI bench top meter, similar spec to AVO 8, and like the AVO is clearly intended to sit down or stand up, so it must be fully balanced in both planes.
Is the 1041B INTENDED to lie down? If not, you may be chasing a non-fault. Perhaps somebody else with one would comment. Les. |
21st Nov 2022, 9:38 pm | #10 |
Nonode
Join Date: Aug 2007
Location: Walsall Wood, Aldridge, Walsall, UK.
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Re: Marconi TF1041 Meter glass refixing, and large deflection when stood up
Evening Les!
I'll have another read of the bookwork and make sure – sometimes the makers state if the instrument has to be used in a particular position or not! Chris Williams
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It's an enigma, that's what it is! This thing's not fixed because it doesn't want to be fixed! |
25th Nov 2022, 2:58 pm | #11 |
Triode
Join Date: Oct 2020
Location: Calgary, Alberta, Canada.
Posts: 22
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Re: Marconi TF1041 Meter glass refixing, and large deflection when stood up
There are a couple of very small spiral coil weights on the meter pivot movement, and if one or both are missing, the meter movement is not balanced and will self adjust to the new balance point...
I found this out the hard way, but luckily for me, the spiral coil was still inside the sealed meter and I managed to find it and re-attach it to the tiny metal "arm" where it is normally attached. I used a very very small drop of super glue to fix the coil/weight and it's fine now... Good luck with your 1041B...I love mine...!!! 73...Jordan VE6ZT |