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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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Electric Shock ?
Hallo members, my Philips brand of DVD player have some kinds of
electric shock if you touch the metal panel. I measure the leakage voltage is 125 volts but the leakage current is too small to kill a person. I 'm curious to know is this normal as the power cord is two pin and this also happen when it is a new set .Thanks Regards |
#2
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Electric Shock ?
wrote in message ups.com... Hallo members, my Philips brand of DVD player have some kinds of electric shock if you touch the metal panel. I measure the leakage voltage is 125 volts but the leakage current is too small to kill a person. I 'm curious to know is this normal as the power cord is two pin and this also happen when it is a new set .Thanks Regards Not enough current to kill? Must be a design defect. Mark Z. |
#3
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Electric Shock ?
Could be a wiring fault in the outlet, neutral and hot reversed. Try
plugging it in another room. wrote in message ups.com... Hallo members, my Philips brand of DVD player have some kinds of electric shock if you touch the metal panel. I measure the leakage voltage is 125 volts but the leakage current is too small to kill a person. I 'm curious to know is this normal as the power cord is two pin and this also happen when it is a new set .Thanks Regards |
#4
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Electric Shock ?
In article . com,
wrote: Hallo members, my Philips brand of DVD player have some kinds of electric shock if you touch the metal panel. I measure the leakage voltage is 125 volts but the leakage current is too small to kill a person. I 'm curious to know is this normal as the power cord is two pin and this also happen when it is a new set. It's common these days - usually RFI suppression. -- *Eat well, stay fit, die anyway Dave Plowman London SW To e-mail, change noise into sound. |
#6
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Electric Shock ?
Is this a single shock that you no longer feel as a tingle once you
have your hand on the unit? If yes, then it is common static build up, probably on your body that is discharging to the path through the metal case. If it is a continuous tingle, then there may be some leakage current in the device. Simply disconnect the dvd player from all other devices (tv, audio, etc), plus it in, and measure the voltage between the metal case and ground with a 1K ohm resistor across the meter leads. If you still measure a significant voltage across the 1K ohm resistor, then there is a problem in the dvd player. Then reconnect it to everything else, if you now measure a significant voltage across the 1K ohm resistor, then you have a problem with another device that is connected to the DVD player. |
#7
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Electric Shock ?
It's normal for most equipment with switching power supplies to have
some relatively studly capacitors across the AC line, center tap to chassis. This is supposed to be to keep any RFI generated inside the box from leaking back out through the power cord, and vice-versa. Older equipment tended to have much smaller capacitors, on the order of 0.005uF, which could still give you a very mild tingle, but nothing like what you get from todays capacitors-- I've seen up to 0.1uf to ground, 0.47uF across the line. |
#8
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Electric Shock ?
How did you determine the leakage current? Is it on the same outlet that
you experienced the shock? Leonard wrote in message ups.com... Hallo members, my Philips brand of DVD player have some kinds of electric shock if you touch the metal panel. I measure the leakage voltage is 125 volts but the leakage current is too small to kill a person. I 'm curious to know is this normal as the power cord is two pin and this also happen when it is a new set .Thanks Regards |
#9
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Electric Shock ?
What you are describing is not right. Check if the AC outlet is wired
correctly. If so, then have the appliance's power supply checked for ground faults. Jerry G. |
#10
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Electric Shock ?
"Jerry G." wrote in message ups.com... What you are describing is not right. Check if the AC outlet is wired correctly. If so, then have the appliance's power supply checked for ground faults. Jerry G. its going to have a earth fault as it does not have one?? I would disconnect all cables apart from the mains and then measure it as it could be the tv or video ETC |
#11
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Electric Shock ?
Thanks members for the early responed, and my further finding for
member's questions is: (1) The DVD player's input voltage is 240 V AC. (2)When reverse the plug in the socket will reduce to 60 volts AC leakage (3) When I measure a cross with 1 K resistor the leakage voltage become zero volt. (4)When measure between the earth and the metal panel is 0.04 in ma range but 137 in ua range. unknow why resultant is different. ? (5) When measure between the earth and the power input ( two pin ) there isn't any ohm. (6) It is not a Single shock Regards |
#12
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Electric Shock ?
On 13 Feb 2006 00:51:10 -0800, wrote:
Thanks members for the early responed, and my further finding for member's questions is: (1) The DVD player's input voltage is 240 V AC. (2)When reverse the plug in the socket will reduce to 60 volts AC leakage That would bother me the RFI caps on switching supplies should divide the voltage equally since they tend to be identical to the "ground" chassis connection. (3) When I measure a cross with 1 K resistor the leakage voltage become zero volt. That's good. (4)When measure between the earth and the metal panel is 0.04 in ma range but 137 in ua range. unknow why resultant is different. ? That's not what I'd expect, but this isn't a hard connection. You seem to be measuring the voltage through a capacitor and/or resistor in the RFI filter. (5) When measure between the earth and the power input ( two pin ) there isn't any ohm. Shouldn't be, but the type of tester you should be using is called a hi pot or high potential tester and that would tell you if it is safe or insulation breaks down with high applied voltage - the typical ohm meter may not be the best tool to check ohms or safety. (6) It is not a Single shock Regards I'm guessing you have an IEC power cord? Thingee that is designed for three wires? And you've gone and cut the ground off? You are probably "safe," at the moment at least. It may be safe indefinitely. Safety devices are to protect you when things go wrong. If it were me I'd ground it and wouldn't be using it without a ground. If I couldn't ground it (in an apartment with no access to a ground, for instance) I'd take care that the parts I touched were insulated. -- ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
#13
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Electric Shock ?
On 13 Feb 2006 12:31:54 -0800, wrote:
I comfirm that is a two pin power core. Describe the plug end and machine end. Are the pins in the plug round or flat? Is there any other thing (like small piece of metal on the plug with a hole in it) on the plug end? Does the machine end have an IEC connector? Machine end would be a recessed, keyed (only goes in one way) male on the machine female on the cord. What has me baffled is that the whole purpose of a filter with caps or resistors in it (the part causing the shocks) is to filter noise to ground. Most filter line-to-line and each line-to-ground. Now without providing a ground . . . how's the noise supposed to drain to ground? Presumably they could count on the TV or Stereo to do it but that's not in any safety specification I've seen. -- ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
#14
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Electric Shock ?
Hi morning., thanks for your reply. It just a two hollow pins inlet at
the back of the dvd player, as most of our members belive may cause by filter circuit, I will open the dvd layer look for the filter. I would like to said big thank you for members who responed in this topic & happy valentime day. Regards |
#15
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Electric Shock ?
default wrote in message news On 13 Feb 2006 12:31:54 -0800, wrote: I comfirm that is a two pin power core. Describe the plug end and machine end. Are the pins in the plug in the UK we have two pin figure of 8 connectors like this http://www.itx-warehouse.co.uk/Produ...?ProductID=475 its a two core cable no earth and not keyed so you can plug it in both ways and quite happily plug live to neutral and visa versa |
#16
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Electric Shock ?
On Tue, 14 Feb 2006 08:40:15 GMT, "Mr Fixit"
wrote: default wrote in message news On 13 Feb 2006 12:31:54 -0800, wrote: I comfirm that is a two pin power core. Describe the plug end and machine end. Are the pins in the plug in the UK we have two pin figure of 8 connectors like this http://www.itx-warehouse.co.uk/Produ...?ProductID=475 its a two core cable no earth and not keyed so you can plug it in both ways and quite happily plug live to neutral and visa versa From your link: "Description Generic Main lead - UK to Figure 8 Mains lead with UK style 3 pin plug, terminated with Figure 8 style moulded connector." Says three pin plug. We (US) had some plugs shipped over here that were supposed to be for the UK at a place I worked. They were large round molded bodies with two smooth polished round pins and the pins had insulating sleeves near the plug body. They had three wires blue, brown, green/yellow and an IEC connector at one end. There was a third flat metal piece on the plug that had a round hole that went through the plug body. It was connected to ground and its purpose seemed to be to add a pin or perhaps a screw to keep the plug in place? Just speculating . . . I was on line looking for UK electrical requirements. They seem to be the same as here in the states. Three wires with a hot neutral and ground . . . only difference I saw was in the wiring of electrical light switches they don't show the ground going to the switch - perhaps that was an oversimplification. We have some two wire appliances with GFI protection built into the plugs and "wall wart" switching supplies with only two wires. Computers are three wire. The area I live at has adapted an electrical code that requires four wires on 240 volt electric stoves. There's still a lot of two wire appliances - many of those have all-plastic bodies. Houses and new construction here require GFI protection on outlets outside the house, in most garages, all bathrooms and kitchens, on hot tubs etc.. Workplace safety hasn't caught up - I tried to promote GFI's in a laboratory where I worked - we had large volumes of water (and electrolytes) and lots of electrical equipment. It wasn't required, so they wouldn't do it, but they put one on my workbench because I worked on the equipment - and I didn't ask for it, had no water nearby, etc.. I inadvertently got connected to a leaky coffee maker - the GFI tripped and I could feel the current. Just now put a 12K resistor across the hot to ground and tripped the GFI - instantly. UL rules he GFI required to trip at 6 milliamps within 5.6 seconds 50 ma in 270 milliseconds 100 ma in 100 milliseconds 250 ma in 27 milliseconds In practice, 6 milliamps will cause a trip in 50 milliseconds or less. -- ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
#17
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Electric Shock ?
default wrote in message ... On Tue, 14 Feb 2006 08:40:15 GMT, "Mr Fixit" wrote: default wrote in message news On 13 Feb 2006 12:31:54 -0800, wrote: I comfirm that is a two pin power core. Describe the plug end and machine end. Are the pins in the plug in the UK we have two pin figure of 8 connectors like this http://www.itx-warehouse.co.uk/Produ...?ProductID=475 its a two core cable no earth and not keyed so you can plug it in both ways and quite happily plug live to neutral and visa versa From your link: "Description Generic Main lead - UK to Figure 8 Mains lead with UK style 3 pin plug, terminated with Figure 8 style moulded connector." Says three pin plug. correct all our outlet plugs have three pins but not all are used as all our cables are not three core?? we have two and 3 core cable there are two pin plugs that look like an 8 hence the term "figure of 8 style" that plug into the equipment that have no earth requirement or are double insulated |
#18
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Electric Shock ?
In article ,
default wrote: "Description Generic Main lead - UK to Figure 8 Mains lead with UK style 3 pin plug, terminated with Figure 8 style moulded connector." Says three pin plug. Yehbut figure of 8 is two. For domestic use all UK plugs are three pin, but if the device conforms to the appropriate regs the cord may well be just two. -- *Welcome to **** Creek - sorry, we're out of paddles* Dave Plowman London SW To e-mail, change noise into sound. |
#19
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Electric Shock ?
In article ,
default wrote: I was on line looking for UK electrical requirements. They seem to be the same as here in the states. Three wires with a hot neutral and ground . . . only difference I saw was in the wiring of electrical light switches they don't show the ground going to the switch - perhaps that was an oversimplification. Line neutral and earth in the UK. And neutral and earth are connected together at some point - but not at the actual appliance. Either the nearest substation or where the supply comes into the house - in some cases. So only the line is 'hot' although in practice there may be a small potential between neutral and earth in some installations. With lighting, the neutral doesn't usually go to the switch enclosure, but the earth does. -- *I just got lost in thought. It was unfamiliar territory. Dave Plowman London SW To e-mail, change noise into sound. |
#20
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Electric Shock ?
default ha escrito: On Tue, 14 Feb 2006 08:40:15 GMT, "Mr Fixit" wrote: default wrote in message news On 13 Feb 2006 12:31:54 -0800, wrote: I comfirm that is a two pin power core. Describe the plug end and machine end. Are the pins in the plug in the UK we have two pin figure of 8 connectors like this http://www.itx-warehouse.co.uk/Produ...?ProductID=475 its a two core cable no earth and not keyed so you can plug it in both ways and quite happily plug live to neutral and visa versa From your link: "Description Generic Main lead - UK to Figure 8 Mains lead with UK style 3 pin plug, terminated with Figure 8 style moulded connector." Says three pin plug. We (US) had some plugs shipped over here that were supposed to be for the UK at a place I worked. They were large round molded bodies with two smooth polished round pins and the pins had insulating sleeves near the plug body. They had three wires blue, brown, green/yellow and an IEC connector at one end. There was a third flat metal piece on the plug that had a round hole that went through the plug body. what you are describing is a schucko plug TYPE F used in Europe NOT the Uk . uk plug has 3 flat pins in triangle formation, TYPE G. top one (earth) slighly longer to enable spring-loaded shielding in the socket to move downwards revealing the live /neutral only when a plug inserted.. see: http://users.pandora.be/worldstandar...city.htm#plugs -B. |
#21
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Electric Shock ?
On 14 Feb 2006 19:02:33 -0800, "b" wrote:
what you are describing is a schucko plug TYPE F used in Europe NOT the Uk . uk plug has 3 flat pins in triangle formation, TYPE G. top one (earth) slighly longer to enable spring-loaded shielding in the socket to move downwards revealing the live /neutral only when a plug inserted.. see: http://users.pandora.be/worldstandar...city.htm#plugs -B. Thanks -- ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
#22
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Electric Shock ?
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#23
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Electric Shock ?
In article .com,
Just Another Theremin Fan wrote: It's normal for most equipment with switching power supplies to have some relatively studly capacitors across the AC line, center tap to chassis. Not in the UK it's not! All equipment fitted with 2 pin plugs must be double insulated for exactly this reason. One leaky cap' could make any metal lethal. I can assure you it is common. But the amount of current leaked to the chassis and accessed via a phono socket screen etc is too small to be a risk. But you can still feel it under certain conditions. -- *A snooze button is a poor substitute for no alarm clock at all * Dave Plowman London SW To e-mail, change noise into sound. |
#24
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Electric Shock ?
It is a FACT that capacitors DO sometimes go short circuit and although
it is some time since I worked on domestic equipment I simply cannot see a such potentially dangerous practise as caps' directly connected to external metalwork from the mains getting past the design stage. I will check latest spec' and get back.... |
#25
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Electric Shock ?
Just Another Theremin Fan wrote:
It is a FACT that capacitors DO sometimes go short circuit and although it is some time since I worked on domestic equipment I simply cannot see a such potentially dangerous practise as caps' directly connected to external metalwork from the mains getting past the design stage. I will check latest spec' and get back.... Any mains input filter I have ever seen, contains those capacitors,and all computers and periferal equipment have them . If they would not have them, they could never pass the high frequency leak rules, and your mains wiring would turn into nice transmitting arials so that all radios and tv's in the neighbourhood would become useless. Those filters look like a nice solid block,but inside are some blocking ferrite coils and decoupling capaciters to ground. And you should not use any hardware without a ground connection, it stops radiating interference, and without the ground connection you can blow your hardware when connecting a cable between them,even if they are switched off(when signalwire makes contact before the groundwire). It also stops you from feeling tingling (or worse). As for the capacitor going shortcicuit, as long as you are using ground, it will safely blow the fuse or the leak protection. |
#26
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Electric Shock ?
On 2006-02-15, Sjouke Burry wrote:
Any mains input filter I have ever seen, contains those capacitors,and all computers and periferal equipment have them . If they would not have them, they could Those are X2-rated (or similar) capacitors. Manufacturer guarantees that they will not short circuit when broken. However, eventually some of them will (nothings perfect). So, current flows to protective earth and fuse blows. As long as equipment is properly grounded, there's no problem. If it ain't, there might be lot's of 'em. Like burning the whole machine and getting electric shock. -- - Mika Lindblad |
#27
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Electric Shock ?
Mika Lindblad wrote: As long as equipment is properly grounded, there's no problem. Yes that is what the thread is about. 2 pin mains supply which probably won't be grounded so why should a person get a shock from touching a customer accessible part of the cabinet? |
#28
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Electric Shock ?
In article . com,
Just Another Theremin Fan wrote: It is a FACT that capacitors DO sometimes go short circuit and although it is some time since I worked on domestic equipment I simply cannot see a such potentially dangerous practise as caps' directly connected to external metalwork from the mains getting past the design stage. IIRC, they're not normally connected direct to the signal earth or case but via a high value resistor. And those don't fail short circuit. RFI suppression using this sort of technique has been common for probably 30 years or more. The usual answer is to plug in the signal leads before applying the power - which is good practice anyway. -- *A picture may be worth a thousand words, but it uses up a thousand times more memory. Dave Plowman London SW To e-mail, change noise into sound. |
#29
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Electric Shock ?
Dave Plowman (News) wrote:
In article . com, Just Another Theremin Fan wrote: It is a FACT that capacitors DO sometimes go short circuit and although it is some time since I worked on domestic equipment I simply cannot see a such potentially dangerous practise as caps' directly connected to external metalwork from the mains getting past the design stage. IIRC, they're not normally connected direct to the signal earth or case but via a high value resistor. And those don't fail short circuit. RFI suppression using this sort of technique has been common for probably 30 years or more. The usual answer is to plug in the signal leads before applying the power - which is good practice anyway. Any resistor would make them totally useless. The cap resitance must be near zero for high frequency's.And plugging with power off does not protect your inputs,the filter comes before your main switch, and the cap current can damage a mosfet input,even if it is only microamps,the voltage is half the mains voltage,when there is no ground path. |
#30
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Electric Shock ?
"Sjouke Burry" wrote in message . .. Just Another Theremin Fan wrote: It is a FACT that capacitors DO sometimes go short circuit and although it is some time since I worked on domestic equipment I simply cannot see a such potentially dangerous practise as caps' directly connected to external metalwork from the mains getting past the design stage. I will check latest spec' and get back.... Any mains input filter I have ever seen, contains those capacitors,and all computers and periferal equipment have them . If they would not have them, they could never pass the high frequency leak rules, and your mains wiring would turn into nice transmitting arials so that all radios and tv's in the neighbourhood would become useless. Those filters look like a nice solid block,but inside are some blocking ferrite coils and decoupling capaciters to ground. And you should not use any hardware without a ground connection, it stops radiating interference, and without the ground connection you can blow your hardware when connecting a cable between them,even if they are switched off(when signalwire makes contact before the groundwire). I think you need to do some investigations into this as none of my HiFi TV DVD CD's or VCR's has an earth connection as its all connected via 2 core mains cables?????? and this is how it was designed to work from the manufacturers It also stops you from feeling tingling (or worse). As for the capacitor going shortcicuit, as long as you are using ground, it will safely blow the fuse or the leak protection. |
#31
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Electric Shock ?
IIRC, they're not normally connected direct to the signal earth or case
but via a high value resistor. And those don't fail short circuit. No but resistors do change value. High resistance ones usually downwards. RFI suppression using this sort of technique has been common for probably 30 years or more. The usual answer is to plug in the signal leads before applying the power - which is good practice anyway. "Good practise"? Err this is customer devices we are talking about.... BTW, I have just opened up my recent DVD player to have a look (UK) and there are NO capacitors going from mains to chassis. |
#32
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Electric Shock ?
Hi Good morning members, I'm curious to know if a circuit without earth
connect to the ac main, how to reduce noise from the circuit, like the dvd or hifi player ? thanks Mr Fixit wrote: "Sjouke Burry" wrote in message . .. Just Another Theremin Fan wrote: It is a FACT that capacitors DO sometimes go short circuit and although it is some time since I worked on domestic equipment I simply cannot see a such potentially dangerous practise as caps' directly connected to external metalwork from the mains getting past the design stage. I will check latest spec' and get back.... Any mains input filter I have ever seen, contains those capacitors,and all computers and periferal equipment have them . If they would not have them, they could never pass the high frequency leak rules, and your mains wiring would turn into nice transmitting arials so that all radios and tv's in the neighbourhood would become useless. Those filters look like a nice solid block,but inside are some blocking ferrite coils and decoupling capaciters to ground. And you should not use any hardware without a ground connection, it stops radiating interference, and without the ground connection you can blow your hardware when connecting a cable between them,even if they are switched off(when signalwire makes contact before the groundwire). I think you need to do some investigations into this as none of my HiFi TV DVD CD's or VCR's has an earth connection as its all connected via 2 core mains cables?????? and this is how it was designed to work from the manufacturers It also stops you from feeling tingling (or worse). As for the capacitor going shortcicuit, as long as you are using ground, it will safely blow the fuse or the leak protection. |
#33
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Electric Shock ?
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