Famicom AV mod problems

[knux123]

Hi
I've a Famicom which was modded to output AV, but the image on the screen has weird colors, trembles and most of the time occupies the upper half of the screen, like if it was bigger than usual.
I've looked inside the console, and it's different than other mods i've seen.
Is it the whole mod that is bad or maybe i can fix it resoldering?
http://www002.upp.so-net.ne.jp/jsrc/densi/fcav.html
if I do this mod, do I only have to solder what is shown in the picture, or do I have to do something else?
Thanks
Post Merge: June 12, 2011, 08:46:12 am
http://imageshack.us/photo/my-images/16/12062011204.jpg/
http://imageshack.us/photo/my-images/233/12062011205.jpg/
http://imageshack.us/photo/my-images/691/12062011206.jpg/
added some images of the board

[Xious]

Fact One: That system has a PAL conversion board (probably from Makko), and it's possibly interfering with the signal timing. Without knowing exactly how the mod is connected, and exactly how that RF/Power board is modifying the system signals and clock, it's going to be impossible to give any serious help.

Fact Two: I see some components in photo 12062011206.jpg, and I can guess that one of them is either a capacitor , or a badly deformed cousin of Bender from 'Futurama'. The photo is so out of focus that it is impossible to distinguish any part from another, or even to tell what is on the board, so I have no way to counsel you. There simply isn't enough to see to hazard any guess at what's causing your issues.

Fact Three: You didn't mention to what type of display you were interfacing it. Is it a  CRT Television, Commodore/Magnavox  monitor, LCD, Plasma display? What is your local video standard, and the one used on your display (e.g. PAL-B/G, NTSC, SECAM, other). This is very important information in solving this issue... The RF/Power board, if it is what I think it to be, is designed to change a standard-issue Famicom from Japan to PAL-B video for use in Hong Kong. If you are in a PAL area, you should try connecting it via RF as well. In addition, there may be a 60/50 Cycles switch on the rear, and flipping that may improve matters.

If you want further help, please take clear, close-up photos of the modification, the Power/RF board and the back of the system (where you see the power/rf/etc ports and switches) so that we can easily see how it is modified and make some suggestions as to what you can do to correct it.

If there are any markings on the board, it would also be advisable to note them here.

Although off-topic, I should also mention that I hate ImageShack and their horrendous, notorious Pop-Back adverts. Viewing the photos and trying to enlarge one (which did nothing, so I presume it's at maximum size by default) caused four windows to open in hiding that slowed my system to a halt and almost crashed FireFox... There's something seriously evil about websites that do that sort of thing. I suppose should count my blessings: They were closable without killing the entire Firefox process.  

[knux123]

Yeah, I guess that's what you get when you take a photo with a shitty cellphone camera.
The television by the way I used is a PAL LCD television, tried on a CRT too.
Oh, unfortunately the modder removed the rf plug and no 60/50hz switch.
I'm sorry about the photos, I will take some more of them tomorrow. (with a better camera)
I live in italy, so the pal standard is PAL-B

[Xious]

No worries.

As far as I know, PAL FC systems can still be tapped for composite signals normally, but not all PAL displays will like the signal.

The Makko board is, as I recall, a clone of the PAL-B board used
in early-type HK Famicom models, but I don't havea Makko kit to evaluate the differences.

I'll need to see what connectors are on your unit. I don't see why anyone would remove the RF port, as there's no need and (in Europe especially with a Makko board living in there), it's a good back-up plan to retain it.

What do tou see on your LCD display as compared to the CRT?

The native, amplified signal is NTSC, so keep that in mind. Your display will need to have an NTSC full-compatible mode (I don't think PAL-60 will cut it) for it to work.

Honestly, I think you'd be best-off using the PAL signal over RF with a 1970s-to-1990s CRT television.

If you want to redo the A/V, I make kits that may interest you: The RetroVideo AV.

[knux123]

Yes; on the crt it's black and white, but the lcd is ntsc compatible (I use every ntsc console i have there).
The image on the crt seems more "stable": when playing smb2j, on the lcd the image sort of "trembles" and the colors change all the time.
For the RF; I only see the av connectors on the back. Maybe I can use the video connector for RF too?
Post Merge: June 15, 2011, 04:16:42 am
I tried doing what i said before, and while the tv seems to show something, the image is completely unrecognizable. tried pressing start to see if something would change, but the tv shows always the same thing.
EDIT: I checked your kits: if I order the bare-bone pcb for 9$, what will be missing in comparison to a pre assembled one?

[Xious]

That depends on what you have at hand and what you need to buy. I won't pretend to know what any of the parts will cost you locally, though you could potentially salvage the transistor from your system and some of the caps. That depends on how they were trimmed before soldering...

The most expensive parts for me are the RCA wires, which add $4.50 in parts alone to the build cost for the short (1M) dual-lead set-up. I can sell you either an un-assembled kit or a soldered kit with no RCA wires. That might save you some money, though the postage is the same either way. The board can be used with the 1815 series transistors (although I use another type when I build them), and the resistors and caps are very inexpensive parts in bulk. I can work out a price sheet for you for all of the parts, as a kit to solder, and you can make it by hand that way, as well as selecting what you want.

There is a small error on the silkscreen for assembly, so you'll need to pay attention to the written instructions. I modified the design in post-production and forgot to change the silk layer to reflect it. The next run, whenever that may be, will correct this, but the parts that I supply would be identical to those I use on the finished kits.

I'd also consider trading a working FC PCB a d RF board (NTSC) for your PCB setup (with the Makko kit) so that I have one to examine for future. It may be a bit before I could do this though, as I'm still sick and need to catch up with posting parcels to Europe and South America...

Don't forget the updated photos...