38 replies to this topic

[amiman99]

OK, I had some time today and tested the scan doubler for power requirement.
When the unit is powered on w/o any inputs it uses around 250mA, when there is  a RGB input and goes from standby to ON then it uses 400mA.
It does look like the 2A (2000mA) requirement is way over "spec-ed". This is why you can run it using power from the joystick port, I guess the limit for joystick port is 500mA.
Anyone can verify my findings?

[poobah]

amiman99, on Mon Apr 23, 2012 6:43 PM, said:

OK, I had some time today and tested the scan doubler for power requirement.
When the unit is powered on w/o any inputs it uses around 250mA, when there is  a RGB input and goes from standby to ON then it uses 400mA.
It does look like the 2A (2000mA) requirement is way over "spec-ed". This is why you can run it using power from the joystick port, I guess the limit for joystick port is 500mA.
Anyone can verify my findings?

400mA is still quite a lot for the joystick ports.
I'll have to see what the draw is on the ST 5V rail normally.
Where did you find the 500mA spec for joystick ports?

[Goochman]

amiman99, on Thu Apr 19, 2012 9:23 PM, said:

Goochman, on Thu Apr 19, 2012 7:27 PM, said:

What kind of PSU should I get?  I know almost nothing about these.

I'm using 5v 1200mA (1.2A) switching PS with positive center.

Would any of these work?
http://www.amazon.co...ASIN=B001KU44HE

http://www.jameco.co...ode=WSF&CID=GMC

[amiman99]

poobah, on Tue Apr 24, 2012 5:49 AM, said:

amiman99, on Mon Apr 23, 2012 6:43 PM, said:

OK, I had some time today and tested the scan doubler for power requirement.
When the unit is powered on w/o any inputs it uses around 250mA, when there is  a RGB input and goes from standby to ON then it uses 400mA.
It does look like the 2A (2000mA) requirement is way over "spec-ed". This is why you can run it using power from the joystick port, I guess the limit for joystick port is 500mA.
Anyone can verify my findings?

400mA is still quite a lot for the joystick ports.
I'll have to see what the draw is on the ST 5V rail normally.
Where did you find the 500mA spec for joystick ports?

Sorry, I put too many zeros, s/b 50mA http://jack.logicals...amiga_mouse_joy

[amiman99]

Goochman, on Tue Apr 24, 2012 7:06 AM, said:

amiman99, on Thu Apr 19, 2012 9:23 PM, said:

Goochman, on Thu Apr 19, 2012 7:27 PM, said:

What kind of PSU should I get?  I know almost nothing about these.

I'm using 5v 1200mA (1.2A) switching PS with positive center.

Would any of these work?
http://www.amazon.co...ASIN=B001KU44HE

http://www.jameco.co...ode=WSF&CID=GMC

They should fit and work (I verified the dimensions)

[poobah]

So, I've been trying some approaches to cleaning up the sync signals...
On LCD's, results do vary a bit, largely dependent on the scaling hardware in the panel. I've got a couple 4:3 panels that look pretty good.
Dell 24" widescreen, is just OK. Ben-Q widescreen and Vizio 720p tv aren't too shabby
If you are still rocking a CRT, it looks fantastic.

[Lynxpro]

I'm intrigued by this, especially since back in the day I had to drive from Sacramento to Oakland to buy a very rare VGA monitor - for my Falcon - from ATY Computers that actually could support hertz signal of Atari RGB and display it.  I no longer had my SC1224 at that time since I had sold it with my 1040STf to my cousin...

[OBO]

Hi,

I bought one of these (those from sandoubler.info), and I'm not completely satisfied with it as it is right now. (Atari STE, UK version, so with RF)
It's not related to the hardware of the scan doubler, so if the creator comes here, guy, don't worry

The output is somewhat blurry, there a strange effect around moving objects (like a bending of the picture), and I have little white dots blinking on the screen when i'm in 50hz output (OK in 60hz, strangely)... The VGA cable's ok, I tested it with a PC and it works.

Well, it is useful anyway, but I'm kinda spoiled as I'm used to RGB output on Atari computers since my childhood...
In any case, it'll be useful when TV manufacturers will stop providing us in France with SCART input on TVs

My next step will be to try it on an Atari 7800 with SCART output. Do you think the joystick port of the 7800 can provide enough power for it ?

[poobah]

OBO, on Thu Jul 5, 2012 2:45 PM, said:

My next step will be to try it on an Atari 7800 with SCART output. Do you think the joystick port of the 7800 can provide enough power for it ?

It would be far better if you obtained a stand alone power supply for it.

[Stephen]

I agree - the joystick ports are very limited in power output.  Pretty sure it's on the order of just a few mA.

[OBO]

So, most my issues are solved.
I changed the port on which it is plugged : no more white dots blinking on black background.
I bought an overpriced VGA cable instead of my cheap one : no more blurry display.

There's still the "bending" effect of the picture, in low and med res, but not in high. Not much of an issue in fact in most games.

[poobah]

I'd still get the external power supply.
The box is (trying) to draw too much current through the joystick port. The doubler box wont like that and may exhibit odd behavior, and the computer definitely won't like it.
The joystick power tap was a very poor design choice.

[OBO]

I agree.

I only want to be sure of what to use, 'cause I got mixed answers to this.
5V, OK, but the Amp ? on his description he says 2A, whereas 1.2 seems to be enough...

Let's make it clear, I don't wanna fry this box...

[OBO]

Ok, while playing with the cats, I had one of these " Bon Dieu ! Mais c'est… Bien sûr ! "moment when I remembered I had a look at the UK PSU for my SCART to HDMI upscaler.  (whoever find the reference for this french sentence wins... errr... 1 Tunisian Dinar ?)
So, after the little brats stopped playing and I gave them food, I tested and it works.
It's a 5V 2A positive centered PSU

Edited by OBO, Sat Jul 7, 2012 3:08 PM.