kodak80 H4 build (x2)

[kodak80]

Here is my work at the moment. I am using 2x680R as I do not have any 330R resistors.

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[exxos]

Hard to make it out.. Looks like you have 2x100R in parallel for 50R ? not 330R ?

Though the SMT 75R are just lifted out, and the cap & 330R in series , then soldered to the 2 pads where the 75R ones were.

With 75R termination on the monitor end, this would give 0.7V max output voltage. So I don't know how you ended with more like 2.5V there.

Maybe measure the red output voltage on the the DAC and verify its around the 3V level as the pdf states ?

[kodak80]

DAC video fix applied to my board using 10k POT and happy to report video output looks great now. POT sits nicely aligned to the modulator rear hole and will allow tweaking once in a case.

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[Icky]

Nice neat job @kodak80

[kodak80]

@icky Thanks. I did test the 2 resistors (10k and 4.7k) and the output looked fine, but kept the POT to allow for differences in monitors I use with the H4 board.

[exxos]

Does it make any odds to the various monitors if series caps are used in the 75R ? On future boards its likely to be the fixed resistors, so want to make sure the caps have zero effect else I will add them on future boards.

[kodak80]

Parallel port solder into place and I have successfully used PARCP-USB to transfer files from my laptop to my SatanDisk so I would say parallel port is wired correctly.

I have my SatanDisk on the internal 20 pin header and this is also working as normal after a warm reset the disk boots up from C: drive. I currently have the LS245 buffer IC jumpered across.

[exxos]

Great stuff!

[kodak80]

I noticed on my board that capacitor C900 has been chipped and bent by the PSU metal leg. I would suggest relocating this capacitor more to the left on the next board version.

[exxos]

Can you post a image of this ? I did moved a lot of caps away from the PSU legs already, I was limited on space after all the track moving in most places.