1040STf Video Confusion

[InstantArcade]

I have a 1040STf and I've been trying to hook it up to a Sony PSOne LCD screen via RGB. I can get a picture, but it does not lock vertically and rolls pretty fast. Has anyone had any luck with this setup? It works fine for my arcade boards which are negative sync.

 

Secondly, I tried to hook up composite video instead using pin 2 of the video connector. After some research it seems that the STf doesn't output composite since there's no modulator, but I hooked it up to my scope and I can "see" a weak video signal there, it looks like composite, but I really can't tell. Can anyone tell me what I'm seeing on pin 2 if it's not composite?

 

I've burned so much time on this already. I wish I still had my Philips CM8833 MkII

[Rybags]

I have a similar problem with my HDD recorder.

 

The ST is even worse than the A8... the A8 does 312 (262 NTSC) lines progressive, but the ST does 313 lines which seems to confuse the machine even more.

 

Also, both machines have a VSync signal that doesn't have the pre or post-equalisation pulses, and doesn't have the mid-scanline sync pulses either.

 

The result of that is that they won't work with lots of modern "digital guts" TVs and STB devices due to one or both of those reasons.

[+Mitch]

I have a 1040STf and I've been trying to hook it up to a Sony PSOne LCD screen via RGB. I can get a picture, but it does not lock vertically and rolls pretty fast. Has anyone had any luck with this setup? It works fine for my arcade boards which are negative sync.

 

Secondly, I tried to hook up composite video instead using pin 2 of the video connector. After some research it seems that the STf doesn't output composite since there's no modulator, but I hooked it up to my scope and I can "see" a weak video signal there, it looks like composite, but I really can't tell. Can anyone tell me what I'm seeing on pin 2 if it's not composite?

 

I've burned so much time on this already. I wish I still had my Philips CM8833 MkII

 

You need to combine the v-sync and h-sync together to get the needed c-sync from an ST that is missing the modulator. I haven't tried it on an ST but you can probably run the sync signals together with a couple of ~500 ohm resistors.

 

Mitch

[InstantArcade]

You need to combine the v-sync and h-sync together to get the needed c-sync from an ST that is missing the modulator. I haven't tried it on an ST but you can probably run the sync signals together with a couple of ~500 ohm resistors.

 

Mitch

 

Cool, I will try that. Thanks!

[amiman99]

to combine v and h sync signals use a non polarity capacitor, I dont know the value, capacitor blocks DC V and passes AC/frequency. There got to be a formula for that. I have noticed that if you combine both syncs you loose signal, with capacitor you can see something.

[Rybags]

I'm fairly sure you need to do a logic XOR of VSync and HSync.

 

On the Atari, the HSync is a momentary pulse, lasting reasonably close to the 4.7 uSec standard. VSync goes for 3 scanlines, and HSync pulses during VSync should momentarily return the signal to Blanking level.