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polarity of power cord - gateway fpd1520
We recently got a gateway fpd1520 (15" lcd flatscreen) monitor from
ebay. It didn't have a power cord. It says it's a 12v dc 2.5a but it doesn't give the polarity. A person from gateway said he thought it wouldn't hurt the monitor if it got plugged in backwards but I'd rather not try it. Would appreciate any help. |
#2
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polarity of power cord - gateway fpd1520
"zirath" wrote in message news:0f2Hj.7616$Yy2.1091@trndny04... We recently got a gateway fpd1520 (15" lcd flatscreen) monitor from ebay. It didn't have a power cord. It says it's a 12v dc 2.5a but it doesn't give the polarity. A person from gateway said he thought it wouldn't hurt the monitor if it got plugged in backwards but I'd rather not try it. Would appreciate any help. If it has got any external metal parts such as RCA (phono) connector outers, BNC connector outers, 'D' connector surround etc, or possibly screws for a stand, as these often go right through the plastic case, and into the internal chassis, then try measuring from any such metal to each of the DC power input connector's terminals in turn, using an ohm meter. Chances are you'll find a direct connection, and that will be your DC ground ( "-" ) connection. The other will then be the "+". Assuming that it's a 'standard' co-axial DC connector, on most modern equipment, 'pin' is "+" and side contact is "-" although that's not cast in stone. Be aware when you are obtaining a replacement PSU, that the plug is often a slightly abnormal size, being a little larger than those you typically find on 'general' power supplies. Also, make sure that you get one well rated for the job, as these monitors do draw quite a lot of current, and may well surge up close to the quoted 2.5 amps at startup, as the LCD backlights first fire up before settling to their run current. As to whether it would be safe to reverse connect it, I wouldn't like to say. Some equipment is perfectly well protected against such 'consumer antics', but it is by no means guaranteed, and if it is not adequately protected, the result is often an item that's fried beyond repair, for no other reason than unobtainable power supply devices, as many previous posts on this subject over the years, will attest ... Arfa |
#3
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polarity of power cord - gateway fpd1520
"Arfa Daily" wrote in message
... If it has got any external metal parts such as RCA (phono) connector outers, BNC connector outers, 'D' connector surround etc, or possibly screws for a stand, as these often go right through the plastic case, and into the internal chassis, then try measuring from any such metal to each of the DC power input connector's terminals in turn, using an ohm meter. Chances are you'll find a direct connection, and that will be your DC ground ( "-" ) connection. The other will then be the "+". Arfa, you're usually dead-on, but this is quite incorrect. The side of the connector that's "grounded" is not necessarily negative! A transistor radio using PNP transistors would (presumably) have a positive ground, not negative. Assuming that it's a 'standard' co-axial DC connector, on most modern equipment, 'pin' is "+" and side contact is "-" although that's not cast in stone. No, it's not. I have Sony equipment where the pin is negative, not positive. Rather than seeing which side of the power connector is grounded, I would look to see which side of the electrolytic capacitors is grounded. |
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polarity of power cord - gateway fpd1520
"William Sommerwerck" wrote in message . .. "Arfa Daily" wrote in message ... If it has got any external metal parts such as RCA (phono) connector outers, BNC connector outers, 'D' connector surround etc, or possibly screws for a stand, as these often go right through the plastic case, and into the internal chassis, then try measuring from any such metal to each of the DC power input connector's terminals in turn, using an ohm meter. Chances are you'll find a direct connection, and that will be your DC ground ( "-" ) connection. The other will then be the "+". Arfa, you're usually dead-on, but this is quite incorrect. The side of the connector that's "grounded" is not necessarily negative! A transistor radio using PNP transistors would (presumably) have a positive ground, not negative. I think you'll find that on 'most' modern - and I did say "modern" in my original reply - equipment, this has been pretty much standardised such that DC "-" *is* common ground. Sony kit that I have seen in recent years has all obeyed this 'convention', so I'm willing to bet that any Sony items that follow the opposite 'convention', are not "modern". Pin = "-" used to be the 'convention', but for all mainstream manufacturers whose equipment I work on, this has not been the case for many years. It was only usually the Japanese manufacturers that followed this anyway, as I recall. As for a transistor radio that uses PNP transistors, I haven't seen one that uses transistors at all for many years, let alone PNP ones, so I think you might be struggling to fit that into my "modern" category, also. Assuming that it's a 'standard' co-axial DC connector, on most modern equipment, 'pin' is "+" and side contact is "-" although that's not cast in stone. No, it's not. I have Sony equipment where the pin is negative, not positive. Rather than seeing which side of the power connector is grounded, I would look to see which side of the electrolytic capacitors is grounded. This is, of course, the very best way, if the owner wants the trouble of taking it all to bits, and identifying a suitable electrolytic to use as his reference. However, I would put my name on the line that the method I quoted before, would 99.5% yield the same result, with any 'modern' item using a coaxial DC socket. Perhaps someone out there with a Gateway monitor could confirm which way round it is, then neither of us will be applying guesswork to experience and coming up with sage advice ... d;~} Arfa |
#5
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polarity of power cord - gateway fpd1520
In ,
Arfa Daily typed on Fri, 28 Mar 2008 12:52:58 GMT: [...] As for a transistor radio that uses PNP transistors, I haven't seen one that uses transistors at all for many years, let alone PNP ones, so I think you might be struggling to fit that into my "modern" category, also. Well Arfa... they still use transistors (both NPN and PNP types) in modern equipment. The reason you don't see them anymore is do to the magic of minturization. But they are still there, just neatly packaged into what is known today as the intergrated circuit (IC chip). -- Bill |
#6
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polarity of power cord - gateway fpd1520
"BillW50" wrote in message . com... In , Arfa Daily typed on Fri, 28 Mar 2008 12:52:58 GMT: [...] As for a transistor radio that uses PNP transistors, I haven't seen one that uses transistors at all for many years, let alone PNP ones, so I think you might be struggling to fit that into my "modern" category, also. Well Arfa... they still use transistors (both NPN and PNP types) in modern equipment. The reason you don't see them anymore is do to the magic of minturization. But they are still there, just neatly packaged into what is known today as the intergrated circuit (IC chip). -- Bill And I though I was pedantic !! Yes, of course ICs contain transistors, and yes, I would accept that some of them may be PNP types, depending on block function within the IC, but I don't think, with the best will in the world, that this is the level of transistor existence that William was referring to with his "transistor radio using PNP transistors" scenario. In any event, in the case of an IC taking a single polarity rail, it is irrelevant whether the transistors inside are NPN or PNP or FETs or whatever. PNP transistors are just used 'upside down', as are discrete PNP transistors when used in any piece of single polarity rail equipment. The ground is still (typically for //modern// equipment) the "-" side of the power supply / battery. Anyway, this is getting out of hand. The OP aked a simple question, and I gave a simple answer. This afternoon, I was in a friend's computer repair shop. Bear in mind that he deals with monitors of all types and makes on a daily basis. I asked him how he would go about determining the polarity of such a monitor, and he said that he would stick one side of his ohm meter on one of the D connector locking screws, and the other on each pin of the DC connector. When he found the pin that read short to the connector locking screw, it was his contention that he would have identified the "-" side of the power supply. So that's pretty much exactly what I said. He also frowned and shook his head, and said that he couldn't remember how many years it had been since he had seen a DC connector that had the pin as the "-". Which is also pretty much what I said ... Arfa |
#7
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polarity of power cord - gateway fpd1520
zirath wrote: We recently got a gateway fpd1520 (15" lcd flatscreen) monitor from ebay. It didn't have a power cord. It says it's a 12v dc 2.5a but it doesn't give the polarity. A person from gateway said he thought it wouldn't hurt the monitor if it got plugged in backwards but I'd rather not try it. Would appreciate any help. http://www.lcdpayless.com/productpage.php?productId=237 shows it as 12 VDC 3.5 A center positive. -- aioe.org is home to cowards and terrorists Add this line to your news proxy nfilter.dat file * drop Path:*aioe.org!not-for-mail to drop all aioe.org traffic. http://improve-usenet.org/index.html |
#8
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polarity of power cord - gateway fpd1520
On 3ÔÂ28ÈÕ, ÏÂÎç4ʱ45·Ö, zirath wrote:
We recently got a gateway fpd1520 (15" lcd flatscreen) monitor from ebay. It didn't have a power cord. It says it's a 12v dc 2.5a but it doesn't give the polarity. A person from gateway said he thought it wouldn't hurt the monitor if it got plugged in backwards but I'd rather not try it. Would appreciate any help. Do you want access to China's massive pool of electronic manufacturers... but lack the time to contact suppliers, negotiate contracts, arrange shipping or monitor product quality? Don't worry - Let seriouswholesale deal with all that for you. *Check out the huge range of Gadgets, MP3 / MP4 Players, Car DVD / Audio, and Computer Accessories now by visiting the online wholesale catalog at seriouswholesale. com You'll have peace of mind thanks to the seriouswholesale Quality Control, 12-month Warranty on all products, and easy secure payment by credit card through Paypal. Selling on eBay or your own online store? Send products direct from our warehouse to your customers using our unique drop-shipping service. You can profit by selling hundreds of different products, without holding any of your own inventory! Any questions you have will be answered by the seriouswholesale English-speaking customer support team... Their aim is to make your China electronics importing business easier to run than ever before. Welcome to http://www.seriouswholesale.com. seriouswholesale - Buy from the source, profit without the hassle. - 12 Months Warranty - No minimum order restrictions - Drop-shipping with no additional fee - Pay by safely by PayPal seriouswholesale Wholesale Co., Ltd.: Chinas original and best online electronics wholesaler & drop-shipper: seriouswholesale. com |
#9
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polarity of power cord - gateway fpd1520
On the monitor it should be marked or say something
in the manual. "The Lady from Philadelphia" forgot the obvious. Power sockets almost always have their polarity marked. |
#10
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polarity of power cord - gateway fpd1520
"James Sweet" wrote in message news:kjhHj.461$oE1.370@trndny09... "William Sommerwerck" wrote in message . .. On the monitor it should be marked or say something in the manual. "The Lady from Philadelphia" forgot the obvious. Power sockets almost always have their polarity marked. I've certainly seen plenty of them that didn't though. Likewise Arfa |
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