K5synth

Hi Nick,

    I measured the transformer this evening for you whilst replacing 
my backlight :-)

    If you look at the transformer connector that plugs into the PSU 
circuit board, you'll notice the colours of the wires from top to 
bottom is Red, Black, Red, Orange, Orange.

The AC voltage between the first (top) red and the black is 9.96V, 
between the black and bottom most red wire is 10.54V, and across the 
two reds is 19.57V.

Across the two orange wires is 9.6V

On the power supply, the regulators are 7805 which gives +5 at 1A 
maximum, 7806 +6V at 1A maximum, 7906 -6V at 1A maximum and a very 
small regulator like a transistor a 79L15 (-15 at 100ma).

Each regulator needs about 3V headroom to work correctly. So you may 
have a choice with the transformers. Please check the windings on the 
secondary thoroughly, but I think it is (red-black-red 10-0-10) and 
(orange-orange 0-10). I hope - check it please! If you run from too 
high an AC voltage the regulators may get hot and the heatsink isn't 
really up to much abuse...

The only problem is the original 'low profile' transformer - you 
might get something similar, or perhaps a toroidal one????? ;-)


Back to the backlight. Mine came from backlights.co.uk, and they did 
an excellent job, it arrived very fast, and the contacts were not far 
off the original. I don't intend to advertise, but the lights are 
nice :-) The bit about undoing the aluminium clip isn't really 
necessary, They slide in nicely. Quick repair, nice result, enough 
said!

Cheers, Nick

Adam


--- In k5synth@yahoogroups.com, "tuff_gnarl_69" <tuff_gnarl_69@y...> 
wrote:
> Hi, its nicccck  , sorry to bother you again, ive already found the 
> problem. Its the transformer. The primary is open, so i had 220v on 
> the input, but no current was going thru it. I checked continuity, 
> and resistance but i couldnt measure any. So i came to the 
> conclusion that the primary is open. 
> Ive already checked the schematics, but in order to get a new 
> transformer i need to know the ac outputs. They arent specified on 
> the schematics .
> so if anyone is willing to help me ill keep checking my mail.
> 
> thanx a lot ,
> sorry to bother yyou again really .
> bye
> nic