Homeplug Homeplugs playing me up no PLC light

I run 4 x tp Link homeplugs and have done for the past 4-5 years TL-PA201, 1 downstairs connected to the router and 3 upstairs.
Suddenly one of them upstairs decides not to connect power and ethernet but no PLC light. When I swap over the main living room homeplug for this dodgy bedroom homeplug and use it as the main living room homeplug it works. I
It's as though the one upstairs and living room are clashing either in the fw or router and when I add the pair together one doesnt light up the PLC light. As soon as I use either without the other it will work
any way round this as I think its a SW issue rather than a HW. Also, is there anything in the router that might be upsetting it ?.

There seems to be a bit more to it,m it's like the router does not pick up or allow any one of 4 homeplugs to connect to the nirmin router using an ethernet cable nevermind pair them.
I reset all 4 via the small button you use a paperclip on then one at a time using the same wall socket and otyhers with different cables and all 4 will not connect to the router virmin 3.0
the power-ethernet-PLC lights come on then after 15 seconds the PLC goes off and non show up in "Connected devices" in the router config page, it's as if the router has decided to block all 4 home plugs even when their indaviually connected to the router via cable.
Pishing me off no end , can anybody help please

have they all been paired m8 on my develo plugs I ran some software to pair them.

yeah , I've been on with tp link live chat and they pair fine in 3's but as soon as I add a 4th ,,,wooosh it all goes t*ts up.
I've ran these plugs flawless for about 4 years. Bar the odd re-pair I've never had a problem. I have connected them and added them using SW and the PC but it doesn't allow a 4th,really weird

Well strange

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I have gone over it again this morning and one plug looks to be knackered. I've paired the other 3 via the PC and all are working bar this one.
I got on tp link live chat again this morning and they said they cant locate the FW for them as their old. I was gonna reflash it just to see if I can bring it back to life before I bin it.
These are the ones I've got, if anyone drops on the FW for them please let me know as I'm struggling to find any;-
http://www.tplink.com/resources/software/201042010364915.pdf

when I open the utility program to reset them is says the firmware is
INT6400-MAC-4-1-4102-00-3679-20090724-FINAL-C
But I'm struggling to get any kind of a link to it

Turned out to be a faulty homeplug