17

The PAL video encoder was not a bottleneck of any kind. It is left out because the unit is not a PAL model, but a SECAM model, which needs a different kind of encoder. So the chip is not needed and it would be useless and just cause extra cost and power consumption in the SECAM model. The necessary SECAM encoder is integrated to the separate board with the ...


15

That portion of the video signal is generated directly by the ULA; early ZX81s just don't generate a back porch, which was seemingly good enough for the majority of televisions but problematic enough to be fixed in a later revision despite the machine's commercial lifetime being only a year. As you've observed, the absence of a back porch causes some ...


11

Whatever would have taken place occurred inside the RF modulator: I haven't been able to find a C128 schematic that includes the modulator, however if it's anything like the C64 modulator, there's a current limiting resistor in the path between +9V UNREG, a couple of transistors (only the last of which is shown here) and ground. For this particular C64 ...


9

The C128D modulator uses 5V for power supply, and the composite output (pin 4) is driven with luma signal via an emitter follower and a 120 ohm resistor, and with chroma signal via an emitter follower and a 150pF capacitor. Normally the composite output is disconnected when using the RF modulator, but when using the composite output to a TV, it will be ...


8

Based on the information provided, I'd recommend the following first steps: Clean the monitor jack on the 800XL using contact cleaner. Inspect the monitor jack while inserting and removing the cable several times. It should slide in and out smoothly and the pins remain clean. Also the monitor jack itself should not flex or move appreciably. If there is any ...


8

The spec you posted says the TV has composite in (i.e., your yellow connector from the Nintendo). The manual at that web site shows composite video going to the leftmost phono socket, labelled Video/Y. That is, one socket does double-duty for component and composite. The relevant part of the diagram is here. As to whether it'll work with your Nintendo, ...


7

There are four groups of connectors (Line A, Line B, RGB/Component, and Ext Sync), and each group should be treated as a whole. As it's a monitor, I assume you have an "out" for each "in", and the "out" is just connected to the corresponding "in" (because "out" otherwise doesn't make sense for a monitor). You'...


7

The 130XE has two display outputs, as you've probably already seen. The easiest one to use is a VHF/UHF TV output, which should go to a TV that supports analogue TV standards. It should be relatively easy to find a TV antenna cable; you can combine it with the output of a set-top box, if needed, with a UHF Y adapter. You'll need to tune the TV to ...


6

The manual for the TV only lists 480i/p and higher resolutions as explicitly supported over component (which likely translates to support over composite as well). Most Nintendo 64 games ran at 240p, and as such might not be compatible with your TV. You will likely need to use a separate upscaler to bring the signal to one of the supported resolutions. Those ...


6

No. The Mac SE vertical and horizontal scan frequencies (designed into both the CRT yoke and the analog sweep generator circuits) are different from NTSC (and PAL) composite timing. And the Mac SE analog board requires separate vertical and horizontal sync inputs, not just a video signal. The analog board sync inputs need to be at TTL voltage levels, ...


6

No, for many reasons. The yellow connector that you are talking about is called composite video. It's called "composite" because it combines several signals: vertical synchronization, horizontal synchronization, blanking, luminance (the black-white part), and chrominance (the color part). No model of Macintosh bothered to combine these signals, ...


4

I'd suggest using a chain of discrete counters clocked with 4x chroma and generating a composite signal directly from that, using resistors as a crude DAC for the output stage. If e.g. you have use a two-bit DAC that can generate sync, black, and two levels above that, you could fairly easily generate 81 colors by outputting a repeating sequence of four non-...


4

An unmodified Amiga 500 provides two outputs: analogue and digital RGB through its DB23M connector monochrome composite through its RCA connector Colour encoding is identical in both PAL and NTSC variants on the RGB output, and not present on the RCA connector, so the vast majority of screens with the corresponding inputs will work fine with either (they ...


4

So when I have a Composite Cable with Video/L/R means, I put the cable into Video IN (Line A) and Audio In (Line A+B)? It looks to be mono audio only so you can either get an adapter that connects left and right audio together or run your stereo audio through a separate amplifier. Either Audio A or B (but not both) will be selected along with the ...


3

from: https://www.facebook.com/groups/840633719349481/permalink/4031384456941042 The R38 potentiometer it's has to be replaced. Edit: the potentiometer was replaced (and also a "hack" on the motherboard to enable the S-Video signal), here is the sample:


2

Retrograde has done a good analysis of the available schematics. However, there is a more general analysis that should apply to nearly any retro computer. Composite video outputs are designed to have 75 ohm output impedance for proper match to the coaxial cables used. You can think of this as a 75 ohm series resistor, even though it can be composed of ...


2

My previous TV had 1 combo component/composite input (basically, if you wanted composite (RCA, the yellow/white/red), you'd plug in white and red to white and red and yellow (video) went into the green/yellow plug; for composite, you'd do red/white audio and red/green/blue video. My newest TV is like the one you show, e.g. component only. So, AFAIK, yes, ...


2

Partial answer: Having looked at the manual, the only connection is a two-wire cable to video aux. They also say that any composite monitor connected to the internal Apple video must be NTSC composite compatible. As the Apple 6502 keeps running, I would assume they have the Apple display a black screen, and then sync up and overlay their own pixel outputs on ...


2

The Atari XL/XE machines (“all but 400, NTSC 600XL, SECAM 800XL/130XE/XEgs”, according to the FAQ) have a video port broadly compatible with the Commodore 64. The connector (180° 5-pin DIN) and important pins are the same: 2 — Ground; 3 — Audio Output; 4 — Composite Video. So unless you have a SECAM 130XE, a cable described on ebay something like “...


1

A standard VDC chip of the early eighties is the Motorola 6845. While originally intended not for pixel-addressable, but rather character-addressable frame buffers, it can easily be tricked into generating a pixel-adressable bitmap display (like used in many Amstrad computers)- The chip does not generate the video itself, but rather does the ghard work only ...


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