Nice video! Sorry about commenting in English; my Japanese writing is very bad. As a friend pointed out to me, this kind of cable can be dangerous to use on some systems because it may draw too much current from the output circuitry. It's safe on the FM-7 because the FM-7 has extremely robust DRGB video output circuitry: the video chip output pins drive 7407 buffers with open collector outputs that have a strong (330Ω) pull-up from the +5V power supply line.
@yomiya-ch2 жыл бұрын
Thank you for the comment. I have just check "Sub CRT interface" schematics on FM-7/8 KATSUYOU-KENKYUU. Yes, that's right, driver is 7407, open collector and pulled-up with 330ohm resister. Current is not so much, and the current is forced from Vcc. Drive capacity is enough at FM-7 Other some system, that have totem-pole driver, output current will be reached to 33mA at 150ohm(+75ohm). it may be critical. Addition, I also found series resister of 22ohm on display signal line. Then, re-calculate output voltages, they are 0.65V at 150ohm, 0.5V at 330ohm. they matched my examination at this movie.