ZX Spectrum Max 128 PAL/RBG/Composite video out advice

[T-Man]

Hello all. A bit of a shot in the dark but after buiding and then after some delay programming the ROM and FPGA I was excited to get the following screen. At first I thought this was a PAL/NTSC issue, but on the schematics the RBG output comes before the video processor (AD724JR0 IC). The AD724 converts the RBG to composite and S-video and yes the chip is set to PAL. But I am getting the image on RGB and composite. Also, it's not the same sync appearance I've seen with other PAL NTSC incompatibilities. I have tried multiple SCART to VGA, Scart to component, SCART to composite, direct composite, S-video on multiple monitors (Sony CRT with component and composite; Samsung sync master VGA, Apple 2 green composite, Panasonic plasma with component composite s-video; overhead projector via and composite). The picture here is Apple IIgs with VGA converter set to PAL is the most stable although all either simply do not detect or have a similar over sized image without sync.

Anyway, in a big picture short version, is there anyone who has seen a similar output from RBG (overscanned and poor sync) who can give me a starting point for trouble shooting this?

 

[joevt]

Use an oscilloscope to check the timing? Composite sync signal is correct?
https://www.brutaldeluxe.fr/documentation/cortland/v6/Apple - IIgs RGB monitor - Timing chart.pdf
https://dn790000.ca.archive.org/0/items/Apple_Color_RGB_Monitor/Apple_Color_RGB_Monitor.pdf
https://68kmla.org/bb/threads/apple-iigs-pal-video-timing.46186/
https://gswv.apple2.org.za/a2zine/faqs/Csa2MONITOR.html
https://ia600402.us.archive.org/8/i...iagram/Apple A2M6014 RGB Monitor - Manual.pdf
https://wiki.console5.com/tw/images/c/c0/AppleColor_RGB_Monitor_Technical_Procedures.pdf
https://savagetaylor.com/TIL/TIL02036.pdf
https://www.applefritter.com/files/2022/07/21/[Apple] IIgs RGB monitor - Schematic diagram.pdf

 

[T-Man]

Thank you.

Strange but fixed. Lots of focus on the video circuit and resolution. Checked the main oscillator and it was slow. I thought there would be no way I was getting any kind of picture if this wave form was accurate. One of the caps connected to the oscillator had a trace, like manufactured, shorting the capacitor. At first I thought the I just didn't understand the circuitry, but after looking at the schematics just cut the trace to see......it worked.

Output is PAL (50mhz) RGB and composite and to get both color and no roll, only the II gs monitor with an adapter works. The Commodore monitor shows a picture on composite but no color. Strange, but I have a 1990's Sony TV that I thought would take PAL but it willnot.