Hi Applefritters,
I recently acquired an Apple ][europlus. The major problem with it was the lack of video. After some playing with this box I concluded, that apart from the lack of picture it works fine (I was able to run short BASIC programs producing some beeps, etc). So, I started to probe it with my rather simple osciloscope - to my surprise the composite signal looked fine, and the three major components (signal, sync, and color) also seemed more or less fine. I don't have a professional digital muiltichannel osciloscope, so I was only able to verify that signals resemble more or less the proper one. Normally I use a NVOX LCD TV/montior with all the old hardware that I test and it has never failed me. I even checked today, and yes - it still works fine with my Apple IIe. But, just in case, I connected the europlus to an old Nec 9" monitor - and viola! The picture was there!
Of course I am aware, that digital monitors are more restrictive than CRTs when it comes to signal format, etc. But as I stated - this monitor works fine with my other Apple IIs. And of course I have ruled out bad cables, etc. So I guess, there must be something wrong with the signal. The voltage level looks OK. What's funny - sometimes, the monitor reports "PAL" and the screen turns black, but in most cases it just says "no signal". Any clues where should I start?
Greg
A few questions:
1. On the CRT is the image color or monochrome, if you run some game?
2. What is the frequency written on the crystal: 14.250 MHz or 14.318 MHz?
3. What does this part of the motherboard look like:
60Hz.jpg
I am asking, because I am suspecting mod to NTSC-50, if the monitor was sometimes showing PAL. Or it's just a stock "monochrome" Europlus and your monitor doesn't like that.
Hi CVT,
The CRT is monochrome, so it's hard to tell :) But - the machine is genuine "Apple IIeruoplus" - at least the case is genuine europlus, The jumpers on mb are revesed with respect to your picture - i.e. the upper jumper is open the two below is are soldered. The crystal is labeled as "NYMFH 197-0002". I would rather suspect the monitor to dislike NTSC more then PAL (it was made for the european market and bought in Europe), but of course one never knows...
Greg
Yep, this is a stock Apple II Europlus with a 14.250 MHz crystal and the motherboard is set to 50 Hz. If increasing the video level from the potentiometer on the upper right corner doesn’t fix the issue, you will need to use another monitor.