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UK diy (uk.d-i-y) For the discussion of all topics related to diy (do-it-yourself) in the UK. All levels of experience and proficency are welcome to join in to ask questions or offer solutions. |
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#1
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18v supply into 16v entry phone.
Hullo.
I have an existing, failing, video phone entry system. Not completely broken, but it needs replaced. The handset uses a 18v power supply, which the long ago installer embedded someplace unknown, and I don't want to hack the plaster off to find out where. Could I replace the handset with a 16v system? i.e. I found a potential replacement, but it only needs 16v - could I plug the 18v supply into it and expect it to work properly? I measured the supply and it actually reads 18.5v Any advice appreciated. |
#2
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18v supply into 16v entry phone.
Devany laid this down on his screen :
Hullo. I have an existing, failing, video phone entry system. Not completely broken, but it needs replaced. The handset uses a 18v power supply, which the long ago installer embedded someplace unknown, and I don't want to hack the plaster off to find out where. Could I replace the handset with a 16v system? i.e. I found a potential replacement, but it only needs 16v - could I plug the 18v supply into it and expect it to work properly? I measured the supply and it actually reads 18.5v Is that AC or DC? Assuming DC, you might be able to get away with putting diodes in series to drop the voltage. Each forward biased diode drops 0.6 to 0.7 of a volt. Three in series would drop around 1.95v, so the 18v would become 16v. -- Regards, Harry (M1BYT) (L) http://www.ukradioamateur.co.uk |
#3
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18v supply into 16v entry phone.
On Nov 8, 1:41*pm, Devany wrote:
Hullo. I have an existing, failing, video phone entry system. Not completely broken, but it needs replaced. The handset uses a 18v power supply, which the long ago installer embedded someplace unknown, and I don't want to hack the plaster off to find out where. Could I replace the handset with a 16v system? i.e. I found a potential replacement, but it only needs 16v - could I plug the 18v supply into it and expect it to work properly? I measured the supply and it actually reads 18.5v Any advice appreciated. Most small appliances work fine on similar voltages. But there are a minority that seriously object. If they're both dc supplies you could use a couple of diodes, each will drop around 1v under load (not 0.6). If theyre not both dc its more complex. NT |
#4
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18v supply into 16v entry phone.
Harry Bloomfield wrote:
Devany laid this down on his screen : Hullo. I have an existing, failing, video phone entry system. Not completely broken, but it needs replaced. The handset uses a 18v power supply, which the long ago installer embedded someplace unknown, and I don't want to hack the plaster off to find out where. Could I replace the handset with a 16v system? i.e. I found a potential replacement, but it only needs 16v - could I plug the 18v supply into it and expect it to work properly? I measured the supply and it actually reads 18.5v Is that AC or DC? Assuming DC, you might be able to get away with putting diodes in series to drop the voltage. Each forward biased diode drops 0.6 to 0.7 of a volt. Three in series would drop around 1.95v, so the 18v would become 16v. Yes DC. Thanks for the tip. I foresee a visit to Maplins. |
#5
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18v supply into 16v entry phone.
"NT" wrote in message ... On Nov 8, 1:41 pm, Devany wrote: Hullo. I have an existing, failing, video phone entry system. Not completely broken, but it needs replaced. The handset uses a 18v power supply, which the long ago installer embedded someplace unknown, and I don't want to hack the plaster off to find out where. Could I replace the handset with a 16v system? i.e. I found a potential replacement, but it only needs 16v - could I plug the 18v supply into it and expect it to work properly? I measured the supply and it actually reads 18.5v Any advice appreciated. Most small appliances work fine on similar voltages. But there are a minority that seriously object. If they're both dc supplies you could use a couple of diodes, each will drop around 1v under load (not 0.6). If theyre not both dc its more complex. NT Check of course, if it's a typical coaxial DC plug, that the polarity is correct. Some years ago, the Japs had a thing about the centre pin being negative. Then, everybody else seemed to standardise on the centre being positive. If you put the diodes in series, then if you had got wrong polarity, and you'd put them in assuming that tip was +ve, then no harm would come to the equipment - it just wouldn't work. Arfa |
#6
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18v supply into 16v entry phone.
"Arfa Daily" wrote in message ... "NT" wrote in message ... On Nov 8, 1:41 pm, Devany wrote: Hullo. I have an existing, failing, video phone entry system. Not completely broken, but it needs replaced. The handset uses a 18v power supply, which the long ago installer embedded someplace unknown, and I don't want to hack the plaster off to find out where. Could I replace the handset with a 16v system? i.e. I found a potential replacement, but it only needs 16v - could I plug the 18v supply into it and expect it to work properly? I measured the supply and it actually reads 18.5v Any advice appreciated. Most small appliances work fine on similar voltages. But there are a minority that seriously object. If they're both dc supplies you could use a couple of diodes, each will drop around 1v under load (not 0.6). If theyre not both dc its more complex. NT Check of course, if it's a typical coaxial DC plug, that the polarity is correct. Some years ago, the Japs had a thing about the centre pin being negative. Then, everybody else seemed to standardise on the centre being positive. If you put the diodes in series, then if you had got wrong polarity, and you'd put them in assuming that tip was +ve, then no harm would come to the equipment - it just wouldn't work. I picked up a handy (cheap) little gadget in Maplin's that identifies the polarity on those coax plugs. Already been useful on several occasions. http://www.maplin.co.uk/module.aspx?moduleno=32161 -- Tinkerer |
#7
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18v supply into 16v entry phone.
On Nov 9, 9:58*am, "Tinkerer"
wrote: "Arfa Daily" wrote in message ... "NT" wrote in message .... On Nov 8, 1:41 pm, Devany wrote: Hullo. I have an existing, failing, video phone entry system. Not completely broken, but it needs replaced. The handset uses a 18v power supply, which the long ago installer embedded someplace unknown, and I don't want to hack the plaster off to find out where. Could I replace the handset with a 16v system? i.e. I found a potential replacement, but it only needs 16v - could I plug the 18v supply into it and expect it to work properly? I measured the supply and it actually reads 18.5v Any advice appreciated. Most small appliances work fine on similar voltages. But there are a minority that seriously object. If they're both dc supplies you could use a couple of diodes, each will drop around 1v under load (not 0.6). If theyre not both dc its more complex. NT Check of course, if it's a typical coaxial DC plug, that the polarity is correct. Some years ago, the Japs had a thing about the centre pin being negative. Then, everybody else seemed to standardise on the centre being positive. If you put the diodes in series, then if you had got wrong polarity, and you'd put them in assuming that tip was +ve, then no harm would come to the equipment - it just wouldn't work. I picked up a handy (cheap) little gadget in Maplin's that identifies the polarity on those coax plugs. * Already been useful on several occasions.http://www.maplin.co.uk/module.aspx?moduleno=32161 In all honesty I'd put that £1.79 towards getting a multimeter. NT |
#8
Posted to uk.d-i-y
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18v supply into 16v entry phone.
In message , Tinkerer
writes "Arfa Daily" wrote in message ... "NT" wrote in message ... On Nov 8, 1:41 pm, Devany wrote: Hullo. I have an existing, failing, video phone entry system. Not completely broken, but it needs replaced. The handset uses a 18v power supply, which the long ago installer embedded someplace unknown, and I don't want to hack the plaster off to find out where. Could I replace the handset with a 16v system? i.e. I found a potential replacement, but it only needs 16v - could I plug the 18v supply into it and expect it to work properly? I measured the supply and it actually reads 18.5v Any advice appreciated. Most small appliances work fine on similar voltages. But there are a minority that seriously object. If they're both dc supplies you could use a couple of diodes, each will drop around 1v under load (not 0.6). If theyre not both dc its more complex. NT Check of course, if it's a typical coaxial DC plug, that the polarity is correct. Some years ago, the Japs had a thing about the centre pin being negative. Then, everybody else seemed to standardise on the centre being positive. If you put the diodes in series, then if you had got wrong polarity, and you'd put them in assuming that tip was +ve, then no harm would come to the equipment - it just wouldn't work. I picked up a handy (cheap) little gadget in Maplin's that identifies the polarity on those coax plugs. Already been useful on several occasions. http://www.maplin.co.uk/module.aspx?moduleno=32161 And for a couple of quid more, you could have bought a multimeter, which would have been SO much more useful -- geoff |
#9
Posted to uk.d-i-y
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18v supply into 16v entry phone.
"geoff" wrote in message ... In message , Tinkerer writes "Arfa Daily" wrote in message ... "NT" wrote in message ... On Nov 8, 1:41 pm, Devany wrote: Hullo. I have an existing, failing, video phone entry system. Not completely broken, but it needs replaced. The handset uses a 18v power supply, which the long ago installer embedded someplace unknown, and I don't want to hack the plaster off to find out where. Could I replace the handset with a 16v system? i.e. I found a potential replacement, but it only needs 16v - could I plug the 18v supply into it and expect it to work properly? I measured the supply and it actually reads 18.5v Any advice appreciated. Most small appliances work fine on similar voltages. But there are a minority that seriously object. If they're both dc supplies you could use a couple of diodes, each will drop around 1v under load (not 0.6). If theyre not both dc its more complex. NT Check of course, if it's a typical coaxial DC plug, that the polarity is correct. Some years ago, the Japs had a thing about the centre pin being negative. Then, everybody else seemed to standardise on the centre being positive. If you put the diodes in series, then if you had got wrong polarity, and you'd put them in assuming that tip was +ve, then no harm would come to the equipment - it just wouldn't work. I picked up a handy (cheap) little gadget in Maplin's that identifies the polarity on those coax plugs. Already been useful on several occasions. http://www.maplin.co.uk/module.aspx?moduleno=32161 And for a couple of quid more, you could have bought a multimeter, which would have been SO much more useful I've got a multi meter and find it confusing to use; maybe because the person who wrote the instructions assumed that everybody reading it was already fully acquainted with the instrument and held a diploma in electronics - some pages look more like a mad scientists formulas. This little gadget on the other hand is dead simple (put in the plug and a light comes on) and it fits in my pocket. -- Tinkerer |
#10
Posted to uk.d-i-y
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18v supply into 16v entry phone.
In message , Tinkerer
writes "geoff" wrote in message ... In message , Tinkerer writes "Arfa Daily" wrote in message ... "NT" wrote in message ... On Nov 8, 1:41 pm, Devany wrote: Hullo. I have an existing, failing, video phone entry system. Not completely broken, but it needs replaced. The handset uses a 18v power supply, which the long ago installer embedded someplace unknown, and I don't want to hack the plaster off to find out where. Could I replace the handset with a 16v system? i.e. I found a potential replacement, but it only needs 16v - could I plug the 18v supply into it and expect it to work properly? I measured the supply and it actually reads 18.5v Any advice appreciated. Most small appliances work fine on similar voltages. But there are a minority that seriously object. If they're both dc supplies you could use a couple of diodes, each will drop around 1v under load (not 0.6). If theyre not both dc its more complex. NT Check of course, if it's a typical coaxial DC plug, that the polarity is correct. Some years ago, the Japs had a thing about the centre pin being negative. Then, everybody else seemed to standardise on the centre being positive. If you put the diodes in series, then if you had got wrong polarity, and you'd put them in assuming that tip was +ve, then no harm would come to the equipment - it just wouldn't work. I picked up a handy (cheap) little gadget in Maplin's that identifies the polarity on those coax plugs. Already been useful on several occasions. http://www.maplin.co.uk/module.aspx?moduleno=32161 And for a couple of quid more, you could have bought a multimeter, which would have been SO much more useful I've got a multi meter and find it confusing to use; maybe because the person who wrote the instructions assumed that everybody reading it was already fully acquainted with the instrument and held a diploma in electronics - some pages look more like a mad scientists formulas. So who ties your shoelaces for you in the morning ? This little gadget on the other hand is dead simple (put in the plug and a light comes on) and it fits in my pocket. Set the dial to volts DC, stick one probe on the centre pin, one on the outer sheath and look at the display simples -- geoff |
#11
Posted to uk.d-i-y
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18v supply into 16v entry phone.
"geoff" wrote in message ... In message , Tinkerer writes "geoff" wrote in message ... In message , Tinkerer writes "Arfa Daily" wrote in message ... "NT" wrote in message ... On Nov 8, 1:41 pm, Devany wrote: Hullo. I have an existing, failing, video phone entry system. Not completely broken, but it needs replaced. The handset uses a 18v power supply, which the long ago installer embedded someplace unknown, and I don't want to hack the plaster off to find out where. Could I replace the handset with a 16v system? i.e. I found a potential replacement, but it only needs 16v - could I plug the 18v supply into it and expect it to work properly? I measured the supply and it actually reads 18.5v Any advice appreciated. Most small appliances work fine on similar voltages. But there are a minority that seriously object. If they're both dc supplies you could use a couple of diodes, each will drop around 1v under load (not 0.6). If theyre not both dc its more complex. NT Check of course, if it's a typical coaxial DC plug, that the polarity is correct. Some years ago, the Japs had a thing about the centre pin being negative. Then, everybody else seemed to standardise on the centre being positive. If you put the diodes in series, then if you had got wrong polarity, and you'd put them in assuming that tip was +ve, then no harm would come to the equipment - it just wouldn't work. I picked up a handy (cheap) little gadget in Maplin's that identifies the polarity on those coax plugs. Already been useful on several occasions. http://www.maplin.co.uk/module.aspx?moduleno=32161 And for a couple of quid more, you could have bought a multimeter, which would have been SO much more useful I've got a multi meter and find it confusing to use; maybe because the person who wrote the instructions assumed that everybody reading it was already fully acquainted with the instrument and held a diploma in electronics - some pages look more like a mad scientists formulas. So who ties your shoelaces for you in the morning ? This little gadget on the other hand is dead simple (put in the plug and a light comes on) and it fits in my pocket. Set the dial to volts DC, stick one probe on the centre pin, one on the outer sheath and look at the display simples -- geoff Well yes, it is simple to those of us who use multimeters every day in our working lives, but if the little Maplin gadget suits Mr Tinkerer, then I see no problem with that ?? Arfa |
#12
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18v supply into 16v entry phone.
"geoff" wrote in message ... In message , Tinkerer writes "geoff" wrote in message ... In message , Tinkerer writes "Arfa Daily" wrote in message ... "NT" wrote in message ... On Nov 8, 1:41 pm, Devany wrote: Hullo. I have an existing, failing, video phone entry system. Not completely broken, but it needs replaced. The handset uses a 18v power supply, which the long ago installer embedded someplace unknown, and I don't want to hack the plaster off to find out where. Could I replace the handset with a 16v system? i.e. I found a potential replacement, but it only needs 16v - could I plug the 18v supply into it and expect it to work properly? I measured the supply and it actually reads 18.5v Any advice appreciated. Most small appliances work fine on similar voltages. But there are a minority that seriously object. If they're both dc supplies you could use a couple of diodes, each will drop around 1v under load (not 0.6). If theyre not both dc its more complex. NT Check of course, if it's a typical coaxial DC plug, that the polarity is correct. Some years ago, the Japs had a thing about the centre pin being negative. Then, everybody else seemed to standardise on the centre being positive. If you put the diodes in series, then if you had got wrong polarity, and you'd put them in assuming that tip was +ve, then no harm would come to the equipment - it just wouldn't work. I picked up a handy (cheap) little gadget in Maplin's that identifies the polarity on those coax plugs. Already been useful on several occasions. http://www.maplin.co.uk/module.aspx?moduleno=32161 And for a couple of quid more, you could have bought a multimeter, which would have been SO much more useful I've got a multi meter and find it confusing to use; maybe because the person who wrote the instructions assumed that everybody reading it was already fully acquainted with the instrument and held a diploma in electronics - some pages look more like a mad scientists formulas. So who ties your shoelaces for you in the morning ? Actually, there comes a time when those new fangled shoes with velcro fasteners are very attractive ;o) This little gadget on the other hand is dead simple (put in the plug and a light comes on) and it fits in my pocket. Set the dial to volts DC, stick one probe on the centre pin, one on the outer sheath and look at the display simples I shall give that a try. But in fairness, I was given the multi meter some years ago and have only used it a couple of times for simple continuity tests, and that only because I couldn't find my old home made battery and bulb test lead that I originally put together for setting the timing on cars. You will gather that I can handle mechanicals happily but electronics are a closed book. -- Tinkerer |
#13
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18v supply into 16v entry phone.
In message , Tinkerer
writes "geoff" wrote in message ... In message , Tinkerer writes "geoff" wrote in message ... In message , Tinkerer writes "Arfa Daily" wrote in message ... "NT" wrote in message ... On Nov 8, 1:41 pm, Devany wrote: Hullo. I have an existing, failing, video phone entry system. Not completely broken, but it needs replaced. The handset uses a 18v power supply, which the long ago installer embedded someplace unknown, and I don't want to hack the plaster off to find out where. Could I replace the handset with a 16v system? i.e. I found a potential replacement, but it only needs 16v - could I plug the 18v supply into it and expect it to work properly? I measured the supply and it actually reads 18.5v Any advice appreciated. Most small appliances work fine on similar voltages. But there are a minority that seriously object. If they're both dc supplies you could use a couple of diodes, each will drop around 1v under load (not 0.6). If theyre not both dc its more complex. NT Check of course, if it's a typical coaxial DC plug, that the polarity is correct. Some years ago, the Japs had a thing about the centre pin being negative. Then, everybody else seemed to standardise on the centre being positive. If you put the diodes in series, then if you had got wrong polarity, and you'd put them in assuming that tip was +ve, then no harm would come to the equipment - it just wouldn't work. I picked up a handy (cheap) little gadget in Maplin's that identifies the polarity on those coax plugs. Already been useful on several occasions. http://www.maplin.co.uk/module.aspx?moduleno=32161 And for a couple of quid more, you could have bought a multimeter, which would have been SO much more useful I've got a multi meter and find it confusing to use; maybe because the person who wrote the instructions assumed that everybody reading it was already fully acquainted with the instrument and held a diploma in electronics - some pages look more like a mad scientists formulas. So who ties your shoelaces for you in the morning ? Actually, there comes a time when those new fangled shoes with velcro fasteners are very attractive ;o) This little gadget on the other hand is dead simple (put in the plug and a light comes on) and it fits in my pocket. Set the dial to volts DC, stick one probe on the centre pin, one on the outer sheath and look at the display simples I shall give that a try. But in fairness, I was given the multi meter some years ago and have only used it a couple of times for simple continuity tests, and that only because I couldn't find my old home made battery and bulb test lead that I originally put together for setting the timing on cars. You will gather that I can handle mechanicals happily but electronics are a closed book. There's really no magic to it From earlier, it seems that your brain just switches off, you stuck it on an inunderstandable" pedestal - forget the formulae and whatever, all you need to do is measure a value presented between two probes, that's it Its not a hard barrier to overcome if you try -- geoff |
#14
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18v supply into 16v entry phone.
In message
, Owain writes On 10 Nov, 09:49, "Tinkerer" wrote: I shall give that a try. * But in fairness, I was given the multi meter some years ago and have only used it a couple of times for simple continuity tests, and that only because I couldn't find my old home made battery and bulb test lead that I originally put together for setting the timing on cars. * You will gather that I can handle mechanicals happily but electronics are a closed book. I hardly ever use the multimeter now - got an electric test which shows a range of voltages on an LED ladder and beeps with continuity. No worries about sticking the multimeter on the wrong range onto a live circuit and frying it. A cheaper version of this sort of thing http://www.screwfix.com/prods/61568/...ectricians-Too ls/Circuit-Testers/Kewtech-KEW1700-Voltage-Tester But its only a crude multimeter, at the end of the day Most multimeters are self ranging, and even those which aren't won't blow anything up if connected to the wrong range (although measuring the mains when set to resistance might well do) -- geoff |
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