CPCWiki forum

General Category => Amstrad CPC hardware => Topic started by: kris2222 on 12:51, 17 December 19

Title: GX4000 5V question
Post by: kris2222 on 12:51, 17 December 19
Hi!


A simple question - is it ok to power the GX4000  5V power input with 4.5V or 6V? Or does it have to be exactly 5V?
Asking because my current PSU has only these settings.


Thanks!
Title: Re: GX4000 5V question
Post by: Token on 14:53, 17 December 19
arg
Title: Re: GX4000 5V question
Post by: Token on 14:56, 17 December 19
Hi
Center should be positive, better arround 1.5A or more and must be 5V. Also I think it only work in RGB mode.
Title: Re: GX4000 5V question
Post by: gerald on 21:21, 17 December 19
Quote from: kris2222 on 12:51, 17 December 19
Hi!


A simple question - is it ok to power the GX4000  5V power input with 4.5V or 6V? Or does it have to be exactly 5V?
Asking because my current PSU has only these settings.


Thanks!
Simple answer : NO.
When using the 5V input, the GX4000 has absolutely no protection. 
Standard IC are rated for 5V +/-5% which mean 4.75V to 5.25V.
It may work with 4.5V, but will kill your C4CPC with anything higher than 5.5V.

If you cannot provide a clean regulated 5V supply, use the 9V input.

Also, when using the 5V input, you have to use the DIN output. Scart will output darker than expected colour with 5V.

Last note : if your supply only have 4.5 or 6V that mean it's at best a so called stabilised supply (read crap supply). If it is able to go up to 7.5V, you may try to use it on the 9V input. 750mA should be enough for a GX4000 and make sure you've got the right polarity : positive on center.
Title: Re: GX4000 5V question
Post by: 1024MAK on 21:25, 17 December 19
@kris2222 (http://www.cpcwiki.eu/forum/index.php?action=profile;u=3498)

Could you post some photos of your PSU please.

Thanks

Mark
Title: Re: GX4000 5V question
Post by: kris2222 on 11:29, 18 December 19
Quote from: 1024MAK on 21:25, 17 December 19
@kris2222 (http://www.cpcwiki.eu/forum/index.php?action=profile;u=3498)

Could you post some photos of your PSU please.

Thanks

Mark


Ok, I will post it later on today.
Title: Re: GX4000 5V question
Post by: kris2222 on 11:31, 18 December 19
Quote from: gerald on 21:21, 17 December 19
Simple answer : NO.
When using the 5V input, the GX4000 has absolutely no protection. 
Standard IC are rated for 5V +/-5% which mean 4.75V to 5.25V.
It may work with 4.5V, but will kill your C4CPC with anything higher than 5.5V.

If you cannot provide a clean regulated 5V supply, use the 9V input.

Also, when using the 5V input, you have to use the DIN output. Scart will output darker than expected colour with 5V.

Last note : if your supply only have 4.5 or 6V that mean it's at best a so called stabilised supply (read crap supply). If it is able to go up to 7.5V, you may try to use it on the 9V input. 750mA should be enough for a GX4000 and make sure you've got the right polarity : positive on center.


Thank you!


Yes, I'm using it for the DIN RGB.


Does this mean that 4.5V is safe to try?
Title: Re: GX4000 5V question
Post by: kris2222 on 11:32, 18 December 19
Quote from: Token on 14:56, 17 December 19
Hi
Center should be positive, better arround 1.5A or more and must be 5V. Also I think it only work in RGB mode.


Thanks!
Title: Re: GX4000 5V question
Post by: gerald on 19:54, 18 December 19
Quote from: kris2222 on 11:31, 18 December 19

Thank you!


Yes, I'm using it for the DIN RGB.


Does this mean that 4.5V is safe to try?
A proper 4.5V could work.
I've done some test and manage to have something working at 4V, but there seems to be some sound issue I did not had at 4.5.
Now, i did the test with a lab supply. I have no idea on how your universal supply will perform.
As long as the voltage never exceed 5.25V, there is no risk of damaging the GX4000.
Title: Re: GX4000 5V question
Post by: kris2222 on 21:47, 19 December 19
So, this is the PSU I got today:


https://i.imgur.com/BScVZrA_d.jpg?maxwidth=640&shape=thumb&fidelity=medium


The real output on the 4.5V setting is 4.8V (checked with multimeter). It came out that my GX4000 works great with it (DIN RGB output).






Title: Re: GX4000 5V question
Post by: 1024MAK on 01:12, 21 December 19
That appears to be a universal mains input switch mode type. These use a type of feedback and may be semi-regulated, or fully regulated.

So, as the voltage is 4.8V, as you have found, it should be just about okay. Have fun  ;D

Mark
Title: Re: GX4000 5V question
Post by: kris2222 on 11:10, 21 December 19
Quote from: 1024MAK on 01:12, 21 December 19
That appears to be a universal mains input switch mode type. These use a type of feedback and may be semi-regulated, or fully regulated.

So, as the voltage is 4.8V, as you have found, it should be just about okay. Have fun  ;D

Mark


Thank you! There's a lot of fun to be had indeed, as I have just got the C4CPC form Gerald :)
Powered by SMFPacks Menu Editor Mod