One Chip Video Test Generator

[kf4rca]

Have you seen the one chip video test generator? (Search simplest pattern generator.) It uses the CD4060 chip and a crystal as a counter oscillator to produce a six level stairstep signal. Easy to construct. You can use a 1,2,4,8, or 16 MHz. crystal depending on which "Q" outputs you use.
It works well with analog TVs and monitors but digital sets don't like it at all. Operates off a single 9V battery.
Useful in setting up greyscale balance on color sets and as a general video signal source.

[ppppenguin]

This ultra simple approach to test pattern generation reminds me of the crosshatch (grille) generator I built c1975 from a design published in a UK journal. It used about 4 simple TTL chips and relied on extracting sync pules from the TV you were working on. Simple as it was, it allowed me to converge my first ever colour TV.

Hardly surprising that the simple grey scale generator is rejected by modern TVs. It's taking severe liberties with the waveform, including absence of field sync pulses.

[kf4rca]

One is the ELM304 which is even simpler. Uses a 3.58 crystal. Produces a 4 step pattern and also has vertical sync and appears to be RS170 compliant.
Its pricey though. About $8 from its Canadian mfgr and they charge an $8 shipping fee also. So its $16.
Another is the ZNA234e which produces several patterns. Its more complicated to construct and uses an oddball crystal (2.52 MHz.) Believe it also produces vertical and is RS170 compliant.

[dieseljeep]

I remember reading about that Chinesey little tester, that's available as a kit or factory built. It tests all kinds of components, caps for esr, transistors etc.
It's actually a rather tricky little instrument to have around. I use it quite a bit.
Slight derailment of the original post.

[Electronic M]

Originally Posted by dieseljeep

I remember reading about that Chinesey little tester, that's available as a kit or factory built. It tests all kinds of components, caps for esr, transistors etc.
It's actually a rather tricky little instrument to have around. I use it quite a bit.
Slight derailment of the original post.

That thing is based on the same microprocessor chip that the Arduino UNO boards use....I briefly considered building one using my UNO and some junk parts, but I still use my arduino occasionally, and it is cheaper and easier to just buy one of those testers pre-assembled, and make your own case.

Mine has already paid for it's self a few times over....The Dell computer I use to watch internet videos and odd file formats on my tube TV sets had bad caps in it's mother board and PS, and was dying. I was able to selectively recap it with parts from scrap boards using that tester. The audio still gets lousy after ~12 hours of continuous on time, but I can live with that.

Moving back towards topic: I wonder if those TV signal generator pens that were discussed on this forum some years back are singe chip.....I can't imagine fitting more than 2-3 in there unless it was all TINY surface mount stuff.

[ppppenguin]

I remember the Ferranti ZNA134 and ZNA234 chips. For 625 the xtal frequency was a realtively standard 2.5MHz. There were also the Philips SPG chips; the SAA1043 which really needed a bit more than 5V to work properly and the later SAA1101. I've played with all of these over the years, including designing the SAA1043 into a broadcast grade SPG.

I've not played with PIC, Arduino or Raspberry Pi etc but I reckon you could make a pretty good job of a simple pattern generator with a PIC and a few resistors. The resistors would be arranged as a R-2R DAC. The Domino 625 to 405 converter used a couple of PICs as its main timing logic.