HAMI 8" Mod: S-video input

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I'v got a 8" Hami lcd that got a/v and vga inputs. (Some versions got RF also). The menu where input source is selected however show three alternatives: vga, a/v and s-video. This made me wonder if s-video were supported but just missing the connector.

After spending a few hours looking in datasheets, guessing and measuring with my multimeter I got to the conclusion that it should be possible to add a s-video input. And so I did.

Here is some pictures of how.
Here is one of the connection on the controller pcb. The 3 pin connector and a capacitor were missing. I soldered cables to where the connector should go and moved a capacitor that were connected to an unused a/v input of the circuit. (It has support for several a/v and/or s-video channels).


  • solder.jpg
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Unfortenately I did not measure the capacitance while I had it removed, so I don't know. I found it easier to move one instead of waiting a few days to be able to buy one.

As for the schematics, what do you want the schematics of?
The connection is just three cables.
The inputs comes in and goes through a 18 (or something like that) ohm resistor and then the capacitor in series. Then straight in to the chip.

Have you tried to compare the picture, with A/V and S-video inputs? I can connect my satellite TV box to my video-to-VGA converter (that sends XVGA to my projector LCD), using either type of interface. With the S-video connection, the screen image looks MUCH better.

Can you give us the model number and specifications for your 8" Hami?
the pdf for tw9903(pines compatible with tw9905 that my uses hami8001) this in emule(600k great) it is called:datasheet9903.pdf


the results in this type of controller,de moment are not good. image in b/n
in the forum frances est masters explained.:whazzat:
Megaman said:
Looks like I'm not the first to do this. Too bad I don't understand french, could have saved me a few hours of work.

Seems like they use a 22nF capacitor.
Looking through the application information in the datasheet of the ic tells me it should be 47nF though.
if, your you are right 47 he is ok(pero seems that with 22 also it works) in your type of controller.
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