NABU #3 Fixing the Washed Out Picture on my NABU.

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Жыл бұрын

How I made my NABU video image look better on my capture device by attenuating the video signal.
This hack might help you too if you have a washed out picture and/or are having trouble with your horizontal or vertical sync. (Or what your grandpa might refer to as the horizontal or vertical 'hold'.)
Related:
Greg Stark shows his NABU is blue and ponders why some are not in this video here: • Does your NABU have th...
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Music used in this video (Vibe Tracks, Alternate) was downloaded from the KZfaq Audio Library: kzfaq.info_...
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Пікірлер: 34

@GORF_EMPIRE Жыл бұрын

Thanks again John, I'll have to try the series resistor as the S-Video adapter didn't work out either. I'm thinking about using a micro pot for testing purposes. I'll let you know how it turns out.

@DJSures Жыл бұрын

Such a great video thank you, John. The colors have bugged me for a while! Purply purple purps

@JohnsBasement Жыл бұрын

🤔 I am starting to think that many TMS9x18 designs I've seen out there could use a simple, low cost, EZ-build DC restoration board project.

@DavidLatham-productiondave Жыл бұрын

On tinder?!? A dating website for nabu video adapters. 🤣🤣

@0toleranz Жыл бұрын

I nearly died at that 😂 was sipping my morning coffee! Luckily not at my computer!

@RudysRetroIntel Жыл бұрын

Excellent video and work! Will have to try the same fix in mine. My Nabu shows a blue screen on a monitor but video capture device shows a purple/pink background. Thanks for sharing

@JohnsBasement Жыл бұрын

Someone suggested that perhaps a signal diode like a 1N914 with the anode on the NABU end might work instead. I'll try it on mine next time I can get it on the bench.

@PebblesChan Жыл бұрын

How does the video signal look with an inline 75 ohm BNC feedthrough terminator at the DSO input terminal & input coupling set to AC? Did you ever try inline 0.1uF through 2200uF AC coupling capacitor?

@JohnsBasement Жыл бұрын

I played with a coupling cap at one point. But it did not pass a viable signal. I think I need to try it down-stream from the 75 ohm terminator (In the capture device) OR between the VDP (after the 480 terminator) and the input of the emitter follower.

@microhobbyist Жыл бұрын

I got my Nabu 3 weeks ago. But I haven't played around with it much... yet... too busy with my own ZedEighty Project. LOL

@JohnsBasement Жыл бұрын

I can relate to that! If I get organized, I should be able to make my Z80 Retro! video projects portable to the NABU.

@Silvertone58 Жыл бұрын

@johnsbasement How can I arrange a conference call? I need to debug a couple s100 boards

@JohnsBasement Жыл бұрын

Send me a message on discord. I'm not a proficient user of it... But we should be able to make that suit our needs. Eh?

@JohnsBasement Жыл бұрын

On Discord, I am John Winans#5685 I also have a Z80 Retro! Invite code you can use: jf73DRZvh5 Which, I believe, you can make into a URL and just warp in like this: discord.gg/jf73DRZvh5

@hermanhoekstra7498 Жыл бұрын

Hello John can you put the resistor inside the NABU or must it go on the cable

@JohnsBasement Жыл бұрын

Your NABU, your choice. I think it's less of a risk to put it in the cable... Since it may vary across different monitors.

@hermanhoekstra7498 Жыл бұрын

John i think you are right

@bitplanes Жыл бұрын

I have a NABU that outputs colorful composite to a cheap old VCR/TV combo, but when plugged into my N. American NTSC Daewoo MSX monitor the video is torn at the top and the color is missing altogether! (My TI99/4A looks beautiful on that same MSX monitor) Could this potentially be the same issue?

@JohnsBasement Жыл бұрын

Yep. It could be.

@bitplanes Жыл бұрын

@@JohnsBasement I gave it a try (with a 32ohm resistor as that's all I had around) but seem to have no difference. I notice a trim pot and a crystal next to the video chip. If I rotate the trim pot any amount, I see no change to the video. Would you know if the trim pot/crystal is related to video timing?

@JohnsBasement Жыл бұрын

@@bitplanes Your 99/4A has a much better video output circuit than the nabu. That trimmer is not a pot. It is a trim cap. I didn't note any change when playing with it on mine either. I suspect it has to do with the oscillator duty cycle. You ARE putting the resistor on the signal wire (not the ground wire). Yes? You can also try a signal diode instead of the resistor. Put the end with the stripe on the TV-side of the cable. (Most any rectifier diode may do.)

@bitplanes Жыл бұрын

@@JohnsBasement LOL yes it's on the signal (center). I tried a diode and got the same result (also confirming that turning the cable around results in no picture).

@JohnsBasement Жыл бұрын

@@bitplanes I suspect that each nabu is a little different. Try putting two diodes in series. That'll drop the voltage even more. If things like that, or maybe a diode and a resistor, don't fix it for you then you're going to have to get more creative with the output amplifier circuit. Have a look at the schematic of the TI 99 and see if something like its video output amp is in your wheelhouse.

@pikadroo Жыл бұрын

Welp, cheers… i understand, youtube made you do it.

@JohnsBasement Жыл бұрын

😕

@andymouse Жыл бұрын

Can't find any more Nabu on ebay, I missed that boat !...cheers.

@RudysRetroIntel Жыл бұрын

More coming in s few weeks. The guy is super busy getting the 750 units out. He has 2000 units. So stay tuned

@pikadroo Жыл бұрын

Don’t bother they will cost 3x as much now.

@andymouse Жыл бұрын

@@pikadroo Good point..

@Bob-1802 Жыл бұрын

May be a single diode 1N4148 in series (anode toward Nabu) would level shift the signal enough while preserving its full intensity. I don't have Nabu but someone could try it out.

@JohnsBasement Жыл бұрын

🤔 Definitely worth a try!

@JohnsBasement Жыл бұрын

I just tested it on my Retro VDP board... It helps (in the obvious since you mentioned it way!) Thanks! I'll have to record something about it.

@Bob-1802 Жыл бұрын

@@JohnsBasement Glad to know it helps!