Hello, a while ago I posted the circuit from the forum64 thread about what is needed in place of the RF modulator. The original circuit was meant for a 6569 VIC and used a 470 Ohm pullup resistor in the luma driver. This is too small for a TED, the datasheet suggests 1 KOhm. If you use 470 Ohm, the picture is rather dark. I'd expect the same to be the case with the HMOS-II VIC (8565 if it's PAL). So here's the adjusted circuit for TED, tested today, brightness is now OK on the C16 I tried it with: Video amp for TED or VIC-II. To be used in place of the RF modulator, generating better signal quality. Note: This circuit removes the CVBS output! It's Y/C only! ___ R1 chroma in -----|___|---+ +5V | | | | R2 | | ___ | |/ +----|___|---*----| T1 | |\ | R4 R3 V | ___ ___ | *--|___|--*--|___|--+ | | | | || C1 --- +--------||---------- chroma out GND || D1 R5 +5V ___ | luma in ---|<|--*--|___|--*-------------------+ | | | | | | | |/ === C2 +-------| T2 | |\ | V | | R6 R7 | | ___ ___ | +--|___|--*--|___|--* | | | --- | GND | +--------- luma out T1 = T2 = BC547B D1 = 1N4148 R1 = R2 = 510 Ohm R3 = 68 Ohm R4 = 270 Ohm R5 = 1 KOhm R6 = R7 = 150 Ohm C1 = 1nF C2 = 100nF Do _not_ use metal film resistors, keep connections short. luma in = pin 23 on TED, pin 15 on VIC-II chroma in = pin 13 on TED, pin 14 on VIC-II luma out = pin 1 on video output chroma out = pin 6 on video output Message was sent through the cbm-hackers mailing listReceived on 2013-02-24 16:00:03
Archive generated by hypermail 2.2.0.