Making backlights for non-backlight gear

[Feinstrom]

Someone also asked me about this regarding their SR16.

It wasn't a guy called Bert from germany was it?

Hi, it's the guy called Bert from Germany!
I've just found this forum and I'd like to state that I'm still interested in the "SR-16 backlight and bending" job.
Since my last emails haven't been answered (spam folder?) I chose this way to contact Paul - sorry for hijacking this thread!
Could you please get back to me?
Thanks a lot!

Cheers,
Bert

[alienized]

I'm trying to backlight a TR-626 screen with EL film + invertor but I get the issue described (it actually crashes the machine). I haven't tried with a 7805 (5v regulator) (my invertor needs to be fed with 5v). But you mention a TR-707 mod with cathode tubes... Could this work with the 626 ? And where do you get those ?

EDIT : tried with a 7805 but the invertor doesn't like to be fed this way. It sucks all the power and then the 7805 isn't able to give 5V for about 5 to 10 seconds (it drops to less than 1v). Weird...

[Circuitbenders]

http://www.circuitbenders.co.uk/forum/index.php/topic,166.0.html

you can get them from ebay with a 12v invertor for under £10

[alienized]

I see... (although I can only find 30cm long cathodes on ebay...)
But won't I have the same power supply issues with the cathodes that I have with the EL + invertor ? I'll have to get a separate power supply for those... Do batteries work ?

[Circuitbenders]

EDIT : tried with a 7805 but the invertor doesn't like to be fed this way. It sucks all the power and then the 7805 isn't able to give 5V for about 5 to 10 seconds (it drops to less than 1v). Weird...

If you have a 5v inverter and you're supplying 5v from a 7805 regulator i'm guessing you're either wiring it up wrong or the power supply you're using isn't capable of delivering enough milliamps to power the light and the 626.

If you get some short cathode tubes and a standard 12v inverter you could always avoid using two power supplies by running the inverter from a 12v PSU and then using a 7809 regulator for the 9v to run the 626. On the other hand the 626 will probably work fine on 12v with a decent regulated supply

Do a search for 10cm or 4" cathode.

[alienized]

Thanks for the advice Crustypaul.
I was trying to use the TR-626 AA batteries to feed the inverter through the 7805. This might be too much for those 6 1.5v batteries...
I tried to use 4 separate AA batteries without 7805 and this works... But I still get this nasty hiss on the audio outputs when approaching the inverter from the TR-626 circuitry.
So do I have to make a small case with batteries + inverter hooked up to the TR-626 with a long enough wire to avoid the interference ? Isn't there a better solution ?
I still prefer to run my bent stuff on batteries whenever it's possible (I of course use accus to save the planet ;-) ).

[Circuitbenders]

The inverter will produce all kinds of nasty noise that the 626 circuit will pick up every easily. This is why i had to stick the inverter on that 707 mod on the outside of the case. You could just try positioning it in different places but i have a feeling that on a 626 you might have to actually have it away from the main unit entirely.

How long does the  backlight last just running it from 4 x AA batteries? I'd be surprised if it was a long time.

I'm thinking that the 'better solution' you want will be using an external power supply of some sort.

[alienized]

Yes, right, I think I'll try it this way and modify a 5v power supply for it to include the inverter. Thanks for the advice!