Turning a 25" tv into an arcade monitor

[PacManFan]

I'm feeding the rgb signal into the driver circuitry, not just tieing
onto the crt pins. It helps to know that they are current driven. What
are the voltage and current levels used to drive the rgb signals on
the neck board? Can you link to a schematic or description to help me
build an amp? Unfortunately, I don't have a schematic. It's a Sear
brand TV from about '88 or so.

Thanks,
-Steve


"James Sweet" <jamessweet@hotmail.com> wrote in message news:yEcqb.113883$Tr4.318642@attbi_s03...

"PacManFan" <steveh@crosslink.net> wrote in message
news:c9ad4bde.0311050628.7c70d0fd@posting.google.com...
Hello everyone,
I'm trying to turn a 25" TV into an arcade monitor. The TV has only an
RF input on the back, So what I'm tring to do is feed the RGB signal
directly to the RGB guns on the neckboard. I'm feeding the composite
sync through the RF input (Modulated to channel 3 through an RF
modulator). I set the TV to channel 3, and I've got a VERY bright and
washed out picture of my video game playing on the tv. The RGB signal
I'm feeding in is in the range of 0..1v p-p.
I think if I build an RGB video amp with an adjustable gain and bias
offset I'll be good to go.
What range of voltages are used to drive the neck board RGB tubes?

Thanks in advance.
Steve H.

Are you feeding the signal to the driver stage on the neck board, or are you
trying to go directly to the pins on the CRT? The transistors that control
the guns are current driven, you should trace the circuit further back and
tie in on the main chassis, make sure you run the TV off an isolation
transformer though, as most arcade monitors do. This is one situation where
a schematic will be very helpful.