View Full Version : TLL monitor on CGA graphics card?

July 31st, 2004, 09:02 AM
Hello everyone. Whilst rummaging through my vast collection of computer crap I came across a 286 motherboard and suddenly had the urge to make a machine for no real reason...

... so I put it all together and I realized I still had an amber monochrome Zenith monitor lying around - which I assumed was plain ol' CGA - and decided to use it with this haggard system I was creating: 3 1/2 and 5 1/4 drives, Seagate ST-157A 44MB IDE hard drive, yadda yadda.

So I turn on the computer and look at the screen, the graphics card configured optimally for a mono CGA monitor. I see text! But for some reason the horizontal is out of sync. While not moving or flickering about, the last 3 or 4 lines that would appear at the bottom of my screen are pushed out of view and they appear at the top of the screen. Adjusting the V. hold on the monitor does nothing to solve this. After some brief researching, I learned the monitor I'm using is TLL.

Now for my questions: what is TLL, exactly? Is it possible to correct this problem? Am I forced to only use a TLL video card if I want to use this monitor, and if so, where can I get one?

It's a perfectly fine monitor and I would like to keep and use it if at all possible.

Thank you.

Terry Yager
July 31st, 2004, 09:54 AM
First of all, it's not TLL, it's TTL, which stands for transistor - transister logic, mainly to distinguish it from the older RRL, or resistor etc. Usually you wont get anything at all displayed on TTL mono monitor with a normal CGA card. Some CGA cards support both CGA mono & TTL mono. As far as the problem with the display, it sounds like you have a bad CGA card and/or monitor.


August 1st, 2004, 01:07 PM
Wow! I have such great luck when it comes to older computers...!

I decided to investigate my few other legacy video cards and I came across my ATi VGAWonder XL24, which I actually intended to use with a VGA monitor.

When I plugged it into my VGA display, I was shocked to find out that this very old video card has one megabyte of video memory, which I found shocking because all of my others had no more than 128 and 256K. So, I decided to investigate this card further...


... and found out that it supports a wide range of monitors including TTL monochome.

My Zenith monitor actually appears crisper on this ATi card than it did on the original 64K Zenith system the monitor came with when I had it. No weird screen syncs or anything.


Terry Yager
August 1st, 2004, 01:18 PM
ATI has always had some fantastic products. Glad ya got yr '286 goin'.


August 1st, 2004, 07:26 PM
Yes, now my only problem is to find a suitable CMOS replacement battery. The original barrel battery died long ago. I've tried two AA cells (3V) but it doesn't seem to do the trick on this system.