Official parts list

Topics regarding the Uzebox hardware/AVCore/BaseBoard (i.e: PCB, resistors, connectors, part list, schematics, hardware issues, etc.) should go here.
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uze6666
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Re: Official parts list

Post by uze6666 » Mon Nov 15, 2010 4:20 pm

XGS AVR video signal is generated in software but there's color helper hardware to generate the colorburst part of the video signal.
I've always wondered how it worked for the XGS. And how does it manage to deal with the luminance and chrominance modulation at the same time? Does it output something like 3 bits for luminance, 3 bits for chrominance and 2 bits for saturation for each pixel on a single port ? How does it handle the chrominance modulation phase?

-Uze

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mapes
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Re: Official parts list

Post by mapes » Wed Feb 16, 2011 5:32 am

Hi everyone, I'm new to the Uzebox community and have my parts on order through Digikey. However, while reviewing the schematic and Bill of materials, I have some questions and also found a minor typo on the BOM.

This question may already have been answered, but I'm trying to find the reasoning for this:

On the Uzebox schematic, http://belogic.com/uzebox/schematics/Uzebox-rev-E1.pdf there are 6 capacitors connected in parallel between VCC and Ground C6, C7, C8, C9, C12 and C13) which would sum to 30.3uF of capacitance. In addition, there is a double star (**) recommending to replace the 3 electrolytic capacitors with tantalum caps For optimal video results.

Now VCC should always be 5 volts with 'minimal' ripple due to U8 and the capacitors, but if we used a 33uF capacitor wouldn't it be the same since it would shunt high frequency noise on the circuit to ground?

I thought that maybe we were trying to do a band pass filter, but that doesn't make much sense since the load is everything connected to VCC and the capacitors are shown deliberately by the video encoder.

The only other explanation I could think of would include transmission theory, but due to the short traces, lower frequencies we are running, and that this is a 5 volt DC source, it doesn't add up either.

Capacitors C11 and C16 are paralleled similarly, holding the input voltage before it is regulated to 5 volts at VCC and 3.3 volts at VSS. I would think 1 capacitor would work.

- Regarding the Bill of materials, there is no three star (***) item on the bottom. The last two are both four star (****)

-Mapes

jaak
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Re: Official parts list

Post by jaak » Wed Feb 16, 2011 7:04 am

Short answer, some of the capacitors are used for decoupling. This helps prevents one sub-section of the circuit from interfering with another section. (not only are ICs susceptible to noise they also put out noise as they operate)

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uze6666
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Re: Official parts list

Post by uze6666 » Wed Feb 16, 2011 5:45 pm

Hi mapes, welcome on board!
On the Uzebox schematic, http://belogic.com/uzebox/schematics/Uzebox-rev-E1.pdf there are 6 capacitors connected in parallel between VCC and Ground C6, C7, C8, C9, C12 and C13) which would sum to 30.3uF of capacitance. In addition, there is a double star (**) recommending to replace the 3 electrolytic capacitors with tantalum caps For optimal video results.

Now VCC should always be 5 volts with 'minimal' ripple due to U8 and the capacitors, but if we used a 33uF capacitor wouldn't it be the same since it would shunt high frequency noise on the circuit to ground?
The AD725 is a mixed design analog/digital chip, hence the two sets of caps on the APOS and DPOS pins. All these caps are used for decoupling, but the electrolytics usually push heavier, more constant current while the ceramics are used to handle high frequency spikes (the AD725 generates a lot). The tantalum capacitors remarks, along the caps values comes from the recommend design in Analog Devices tech sheet.
Regarding the Bill of materials, there is no three star (***) item on the bottom. The last two are both four star (****)
You're right, that's a typo. It's been corrected.

-Uze

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Harty123
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Re: Official parts list

Post by Harty123 » Mon Mar 28, 2011 8:47 pm

Hi,

I'm looking for SNES controller sockets. Where do I can buy such sockets?

-Harty

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uze6666
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Re: Official parts list

Post by uze6666 » Mon Mar 28, 2011 9:20 pm

I've got a truckload of them which I sell a cost to the community for 2$/each. Send me a PM with your address and I'll give you the final price including shipping (usually between 2$-5$).

-Uze

davbrwn
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Re: Official parts list

Post by davbrwn » Wed Jun 01, 2011 2:55 pm

can i order some more SNES controller sockets?


http://reseau-eau.educagri.fr/wakka.php ... ileBooster
How To Increase The Cell Signal For Wireless Telephones foyersruraux34.org/new/wakka.php?wiki=GSMBooster
Last edited by davbrwn on Mon May 25, 2015 2:25 pm, edited 3 times in total.

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uze6666
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Re: Official parts list

Post by uze6666 » Wed Jun 01, 2011 5:30 pm

can i order some more SNES controller sockets?
Sure, just send me a PM with the qty and your shipping address and I'll give you the final price.

-Uze

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Firedawg
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Re: Official parts list

Post by Firedawg » Fri Jun 03, 2011 2:54 am

@UZE

Parts arrived yesterday, so the Rev. F1 PCB build is under way. The question I have is on the revision F1 the (L1) component has a CHOKE RF MOLDED 68UH 10% FERRITE (Digi-Key Part Number M8654-ND), but the PCB has the marking for a barrel type component, but looking at your completed PCB it looks like a INDUCTOR FIXED 68UH 10% RADIAL (Digi-Key Part Number M9991-ND). Can you advise as to the component on your completed PCB board?

Big Thanks,
The Dawg

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uze6666
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Re: Official parts list

Post by uze6666 » Fri Jun 03, 2011 4:49 pm

Parts arrived yesterday, so the Rev. F1 PCB build is under way. The question I have is on the revision F1 the (L1) component has a CHOKE RF MOLDED 68UH 10% FERRITE (Digi-Key Part Number M8654-ND), but the PCB has the marking for a barrel type component, but looking at your completed PCB it looks like a INDUCTOR FIXED 68UH 10% RADIAL (Digi-Key Part Number M9991-ND). Can you advise as to the component on your completed PCB board?
I'm no analog guru and this is the part I could never be quite sure about. There's all kind of inductors with all kinds of parameters. I had a discussion with Harty (maker of the EUzebox) and seems the M9991-ND was not the appropriate type. Based on his recommendations, I found M8654-ND. Naturally this happened after I had the boards made, hence the radial footprint. I haven't ordered and tested the new part yet. You may want to keep it last and check if it makes any difference on the composite output image quality. M9991-ND gave marginal results at best. I'd be curious to know if new one fares better.

-Uze

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