Power supplies

Discuss the CreatiVision hardware: models, revisions, fixing, hacking and modding.
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jpx072
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Re: Power supplies

Post by jpx072 » Sun May 11, 2014 12:04 pm

Thanks for the answer, I will try something and post my results later. I will not remove anything, just solder two wires from PC PSU directly to output pins of 7805 and 7812.
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Scouter3d
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Re: Power supplies

Post by Scouter3d » Sun May 11, 2014 5:15 pm

Hi, i think it would not be so easy... as to use +5V and +12V, the CV also Needs -5V (as the 4116 RAM Chips Needs all three voltages to be present and i do not know how the -5 are created. AND: the Tape port provides unregulated 9V to the Tapedrive, i think this is simply the 9V AC after the rectifiers and smoothing caps... so i think the safest way (if you do not Need the +9V unregulated on the Tapeport) would be to use +5,+12 and -5 from an AT PSU and connect it to the right places...

PS: Hi jpx072! and welcome to the Forum ;0) it is such a small world ;0)
PS: Do you Need the schematics for the CV?

Greetings TOM:0)
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Scouter3d
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Re: Power supplies

Post by Scouter3d » Sun May 11, 2014 5:19 pm

Hi it's me again...

Just looked at the schematic and it seems the -5V are created from the +12V so it might be enough using +5 und +12 (if you leave the tapeport without 9V)

TOM:0)
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carlsson
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Re: Power supplies

Post by carlsson » Mon May 12, 2014 11:36 am

My motivation to find a 9V+16V solution is for those who lack a power supply but don't want to perform internal modifications to feed other voltages, even if it technically might work great. As I never got a response from Doss themselves, I have now sent a question to Radio Parts, and would in third hand ask either of the two eBay sellers.
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jpx072
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Re: Power supplies

Post by jpx072 » Mon May 12, 2014 1:00 pm

Hello Thomas! Yes a schematic would be great, as I need to figure out where to put the input, because my original plan with powering the regulators' output pins doesn't work.
Good thing is that a PC PSU has all three needed voltages (+5,-5,+12) and I don't have a tape extension.
I soldered wires from the bottom of mainboard, so they can be removed very easy and without any trace of "modding".
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MADrigal
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Re: Power supplies

Post by MADrigal » Mon May 12, 2014 1:08 pm

I have just sent you the schematics - I suppose Thomas is too busy to send them to you now! :D
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Scouter3d
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Re: Power supplies

Post by Scouter3d » Mon May 12, 2014 1:16 pm

Hi,

Did the PC PSU start? Do you use an AT or an ATX PSU? AT are simply Switched on, but Need a "burden" on the 5V line to start, ATX Needs 2 Pins connected to start at all...
Did you get a Picture? or nothing at all?

TOM:0)
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jpx072
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Re: Power supplies

Post by jpx072 » Mon May 12, 2014 7:21 pm

Thanks for the schematics!
I am familiar with PSU functioning ;) I have measured voltage inside CV on the regulators and it was ok, so I will study the schematics first.
I do have an image, the TV recognizes AV input, and I have dark blue screen. With cartridge I get a small short white line in the top right corner.
Console works with standard adapter (well home made to be exact) normally.
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Scouter3d
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Re: Power supplies

Post by Scouter3d » Tue May 13, 2014 5:40 am

Hi,

You could check for -5V on Pin1 of one of the 4116 Rams...

Maybe the MKII has a different schematic?

TOM:0)
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MADrigal
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Re: Power supplies

Post by MADrigal » Tue May 13, 2014 7:52 am

The MK2 has the latest revision of the PCB, that's 700319 model. The power circuit should be the same in the most recent MK1 and in the MK2.

Check the diagrams here: http://www.madrigaldesign.it/creativemu ... itemod.php
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