Monday, 29 July 2013

For Sale: Another Sony KV-C27!

Another Sony KV-C27 comes out of the woodwork...

As the auction description says, I just can't get used to Trinitrons! This is the last Sony I'll pickup... they're awesome but they just don't give me the same tingle as a traditional curved '90s tube. I've tried several times but I've convinced myself that I'm never going to truly love Sonys even though so many others do.

eBay auction here.

Tuesday, 23 July 2013

Adjusting vertical linearity

While fiddling with the E3000 chassis recently, I came to reaslise how important vertical linearity is to the attainment of good overall geometry.

I decided to experiment with creating my own test patterns to check the linearity of my Calida 5072. I created a black and white bitmap in MS Paint with 5 equally distributed lines. I used an odd number of lines so that I can get the 5 lines equally spaced. Since I play so many 224 lines games, I created a 225 line mode to use for testing:

225 line linearity test screen
I used Arcade_OSD to access my test modeline and then displayed my test image fullscreen. Next, I used a small ruler to measure the space between each line. Much to my surprise, my even looking lines had up to 15mm difference in the spacing between them!

I got thinking... there had to be a way of getting this accurate. Here's the solution I came up with:

Paper mask with equidistant marker lines
Close-up of the mask
I prepared an A3 paper mask to help me line up the 5 test lines. I had to juggle between V-Amp, V-Pos, V-Lin and V-Sym in the Service Menu. Changing one value will most likely require an adjustment of the other. However, despite the interaction, it only took me around 10 minutes to get this as close to perfect as possible.

After that, I loaded up regular cross hatch and adjusted the horizontal size and centring. Next, I fiddled with the EW and Trap controls. The resulting grid wasn't perfect but it was extremely close for a CRT!

The benefit of all this fiddling is how good the games now look, especially when you have a vertical scroll effect. So even and smooth now!

Sunday, 21 July 2013

Exploring the Loewe E3000 chassis

Recently the flyback on my prized Blaupunkt fried itself. It was pretty crazy because my girlfriend and I were watching r a g e at the time. The screen starting shaky, the colors got freaky and then a big cloud of evil black smoke started coming out the back. Luckily I was quick on my feet and cut the power before things got too crazy. Pretty sad day though... I'm surprised I didn't actually cry after that event! I've ordered a replacement flyback through Dönberg so hopefully that unit can be brought back to life

In the meantime, I picked up a super-rare Loewe Calida 5072. I've only seen one other specimen like this in 2 years of daily searching. This TV features a semi-flat 68cm Philips tube and the fabled E3000 chassis. I paid premium for this beauty and the picture quality is a amazing!

Street Fighter III
Calida 5072 (E3000 chassis)
The images produces are super-crisp and stable. The only problem is that while the E3000 produces a superb picture, it's extremely fussing about the signals it gets sent. There are certain refresh rates that won't sync and it crops lines from many games.

After some intense testing I have learned that the TV has two basic modes: PAL and NTSC. The Service Mode allows you to set separate geometry values for each mode.

The PAL mode will show a maximum of 285 lines and will sync up to 52 Hz.
The NTSC mode will show a maximum of 233 lines (pretty poor) and will sync down to 57 Hz.

This means that the TV is far from ideal when it comes to running native resolutions and refresh rates for the wide range found in MAME. However, the awesome picture quality makes the TV worth persevering with... especially for the quality it can bring to 224 line arcade games.

I'm currently in the process of confirming these observations and constructing a thorough set of monitor specs for use with GroovyMAME. I'll be reporting back here shortly...