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Drakon
Admin
Posts: 1117
Join date: 2012-01-25
Age: 32
Location: Toronto Canada
 | | Subject: The CXA2075 AV Famicom Wed Feb 08, 2012 9:10 pm | |
| Today I soldered together the video circuit of one of the kits I ordered. I wanted to test if it's possible to replace the cxa1645 that comes with the kit with a cxa2075 so I didn't solder in the encoder chip. Since I just wanted to test if the chips would be compatible I wired up the cxa2075 in such a way that it would easily be removable. So I present you with...... The cxa2075 av famicom prototype:  And does it work?  Better than I expected! Now I'm going to clean up my gaming area and test to see if the video quality looks improved over the cxa1645. There's also a chance that the picture quality will be even more improved with the encoder soldered right onto the kit but I ran out of loose cxa2075 chips and I'm waiting on the next batch to show up. |
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Drakon
Admin
Posts: 1117
Join date: 2012-01-25
Age: 32
Location: Toronto Canada
| | Subject: Re: The CXA2075 AV Famicom Wed Feb 08, 2012 9:12 pm | |
| Did some testing and indeed the picture is sharper than before! Also I think the colour encoding looks a little better than before! I ordered some more loose cxa2075 encoder chips a while ago so I'll wait for those to show up before I solder one directly onto the kit pcb.
Last edited by Drakon on Wed Feb 08, 2012 9:28 pm; edited 1 time in total |
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teknix1
Posts: 9
Join date: 2012-02-09
| | Subject: Re: The CXA2075 AV Famicom Thu Feb 09, 2012 4:07 pm | |
| Nice work Drakon! I'll be ordering the chip to replace the 1645 in my kit. Was it a simple drop in replacement or did you have to change the circuit surrounding it a little?
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Drakon
Admin
Posts: 1117
Join date: 2012-01-25
Age: 32
Location: Toronto Canada
| | Subject: Re: The CXA2075 AV Famicom Thu Feb 09, 2012 4:37 pm | |
| | teknix1 wrote: | Nice work Drakon! I'll be ordering the chip to replace the 1645 in my kit. Was it a simple drop in replacement or did you have to change the circuit surrounding it a little?
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It's almost a drop in replacement. The composite video circuit is different and I havn't messed around with wiring that yet. |
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Drakon
Admin
Posts: 1117
Join date: 2012-01-25
Age: 32
Location: Toronto Canada
| | Subject: Re: The CXA2075 AV Famicom Thu Feb 09, 2012 11:05 pm | |
| CXA1645:  CXA2075:  |
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teknix1
Posts: 9
Join date: 2012-02-09
| | Subject: Re: The CXA2075 AV Famicom Thu Feb 09, 2012 11:09 pm | |
| Nice work! Seems like there's a slight change in brightness or contrast. Regardless, I'm very anxious to see where you can get from here by playing with the circuit.
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Drakon
Admin
Posts: 1117
Join date: 2012-01-25
Age: 32
Location: Toronto Canada
| | Subject: Re: The CXA2075 AV Famicom Thu Feb 09, 2012 11:36 pm | |
| | teknix1 wrote: | Nice work! Seems like there's a slight change in brightness or contrast. Regardless, I'm very anxious to see where you can get from here by playing with the circuit.
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Yeah the 2075 kit I weakened the resistor because the s-video from these kits looks a bit dark. Really there's nothing to "play with" at this point it's as good as it will ever get right now. |
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teknix1
Posts: 9
Join date: 2012-02-09
| | Subject: Re: The CXA2075 AV Famicom Wed Feb 15, 2012 4:41 pm | |
| This is awesome, any chance you might share the specifics of this mod? What value of resistor, etc... I got my board yesterday. Still waiting on the CXA2075, should be a matter of days now.
Thanks in advance!
Nic |
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Drakon
Admin
Posts: 1117
Join date: 2012-01-25
Age: 32
Location: Toronto Canada
| | Subject: Re: The CXA2075 AV Famicom Wed Feb 15, 2012 4:44 pm | |
| | teknix1 wrote: | This is awesome, any chance you might share the specifics of this mod? What value of resistor, etc... I got my board yesterday. Still waiting on the CXA2075, should be a matter of days now.
Thanks in advance!
Nic |
Uhh I already have extra cxa2075 chips you didn't need to order any. Anyway the av famicom kits I use are designed for the cxa1645. The cxa2075 is meant to be a pin compatible drop in replacement for the cxa1645 which it is. I only changed one part from a cap to a resistor but even that part's only necessary for composite video. Anyway just check the datasheets for the cxa2075 and the 1645 and you'll see for yourself. |
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teknix1
Posts: 9
Join date: 2012-02-09
| | Subject: Re: The CXA2075 AV Famicom Wed Feb 15, 2012 5:14 pm | |
| Sounds good, I'll take a peek at the datasheets then.
Thanks
Nic |
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Drakon
Admin
Posts: 1117
Join date: 2012-01-25
Age: 32
Location: Toronto Canada
| | Subject: Re: The CXA2075 AV Famicom Sun Feb 19, 2012 10:24 am | |
| After extensive testing this mod is a complete success and 100% finished. The only thing my cxa2075 video circuit lacks is composite video but I don't care at all about composite video so I consider this mod as completed. |
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