Closed Urgently - zx spectrum psu

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Not that I have any, but which model speccy do you have? It might help in sourcing the right one :)
 

you will need to cut the wire and swap them about as the Spectrum has a negative internal pol, and a positive external one.



That should help you



@Roy

Nice find on the PSU btw!



@Chinners

Good to see you about here my friend, kinda missed you!

The one in the ebay linky IS center negative...??? or am I just being daft?

@Zetro
Nice to see you're still here! :)
 

you will need to cut the wire and swap them about as the Spectrum has a negative internal pol, and a positive external one.



That should help you



@Roy

Nice find on the PSU btw!



@Chinners

Good to see you about here my friend, kinda missed you!

The one in the ebay linky IS center negative...??? or am I just being daft?

@Zetro
Nice to see you're still here! :)




the link i posted,the supply will be fine.i think zetro was just pointing out the polarity.:D(it is wired correctly going by the listing)
 
@Roy / Chinners

Sweet!

I didn't notice the listing stating internal negative pol - sadly I get into a habit of mentioning the polarity every time I read a request for the rubber key power supply plug-pack.


Oh look... in very large letters (Center Tip Negative!)

yeah that about covers it - a good find just became a GREAT FIND!
 
what happens if you plug one in with the wrong polarity?

reason im asking is i tried a 500Ma adaptor at 9v, the speccy buzzed for a bit then went quiet - i havent broke it have i???
 
Sadly its quite likely you have fried a couple of internal components =(

The 9VDC is internally switched up to +12v and -12v - for the memory (as well as +5 for the 7805) - with the polarity around the wrong way I suspect that it would be enough to damage the internal switching circuit.

It is repairable - as long as you have access and a little experience with a soldering iron.

However, you may of gotten lucky, I suggest you get compatible power supply to try first.
 
Does the adapter you tried have a diagram like either of the below?
800px-AC_adaptor_polarity.png
(notice the + pointing to the center in the left, and the - in the right)
If it's like the left image, then you may have damaged something, like the right should be ok. If neither then... um....:unsure:
 
it doesnt, but i just tried my megadrive adapter which is only 300mA - speccy made a low buzz then i unplugged it - heres hoping i havent killed it!
 
a friend brought through a spectrum PSU today....


IT WORKS :) 2 keys dont work but the speccy does :) :) :)
 
it doesnt, but i just tried my megadrive adapter which is only 300mA - speccy made a low buzz then i unplugged it - heres hoping i havent killed it!
9V@300mA is way distant from the power requirement of a Sega Mega Drive, avoid using it! At least 9V@1000mA if you don't want to ruin both your Power Supply and your Console... :)


Cheers,
Oge
 
a friend brought through a spectrum PSU today....


IT WORKS :) 2 keys dont work but the speccy does :) :) :)

You sire, are a very lucky man!!

Congratulations on getting this retro-treasure up and running!! - I suspect that you will need a new keyboard membrane - there relatively easy to fit, if a little awkward - you can get spectrum 48k keyboard membranes from rwap services

Rich is a member-trader here on AmiBay, you can also contact him through his site at rwap software he is a very friendly fellow and I am sure he will help you out with your problematic little spectrum.
 
thanks to the peeps who offered a PSU, but i now have one, roll on the retro-ness :)
 
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