Fernseher aus Berlin - Nr. 5

Well, I've been in Berlin for over three weeks now and I've already got too much too report... already falling behind with sharing my discoveries here.

I've collected five SCART TVs so far but I'm not going to start my Berlin with TV #1. Instead, I'll start where I'm currently working...

I picked up this (apparently) defective Loewe for it's tube only. This is a 100 Hz television and you're about to see why 100 Hz processing sucks dogs balls when it comes to retrogaming. However, the tubes used in the later model Loewes are stellar when combined with an older, analog chassis.

Before I gut this unit and chunk all but the tube, I figured I'd take the opportunity to show exactly why 100 Hz is so damn awful.

Before we get to the nasty stuff, here are some details on the unit in questions:

Loewe. Profil 3570 Z
100 Hz/Blackline
Chassis type: Q4400

Tube sticker

Tube type: A66EAK552X54

Also, I should mention that the collection of this SCART television was rather memorable. I turned up at Micheal's house (the eBay seller) with my hand cart, ready to cart this thing back on the subway. Instead, Michael loaded the TV, my trolley and myself into his car and drove me across Berlin back to my apartment. What an awesome guy!

Okay, now let my try to explain the worst that 100 Hz processing has to offer...

Red on Black

This is probably the most obvious place to start when going on a 100 Hz hate fest.

In the following example, I photographed the Taito logo from Rainbow Islands with 9 different color settings (i.e. the color balance setting in the TV's picture menu). I started with color at minimum (value of 0) and worked up to the maximum (value of 63) in steps of 8. As you'll see, the greater the color intensity, the greater the visual distortion of the Taito logo.

Note: I placed a small sticker on the glass of the tube and focused my camera at this point for each image. You can see the sticker stays in focus, assuring you that my camera wasn't simply out of focus in the later images.

Color = 00

Color = 07

Color = 15

Color = 23

Color = 31

Color = 39

Color = 47

Color = 55

Color = 63

Ouch! What a mess!

Now, did you notice how the white "CORPORATION" text stayed crisp while the red became over saturated and distorted? It took me a long time to realise that the artifacts created by by 100 Hz processing where exacerbated by the color balance setting. Later I discovered that the color balance on most SCART TVs doesn't have any effect on the incoming RGB signal. In my mind, this is a good thing. The signal passes untouched.

So, with the color set to a low value, the image is sharp and not too distorted. The problem is, of course, that then the image looks washed out and loses that classic CRT vibrancy.

When I first started out with an 80+ cm Loewe unit with a Q4400 it was very frustrating to see these artifacts. I thought maybe my my particular unit was defective or there was something wrong with my homemade VGA to SCART cable. As it was pointed out to me on a forum, the problem lies with the 100 Hz processing.

Further examples

Next, let's check out a random assortment of gruesome 100 Hz pixel murders, starting with a bunch of Rainbow Island examples:

Note the "Focus!" sticker... it's sharp! Also, white stays true.

Red on Black = Disaster

Everything is going wrong here...

Oh my... look at the ghosting!

Compare the clarity of the white text compared with the manic colors

Notice the random lines coming from the A and D characters?!

More icky red text

Check out the color distortion in the text!

Observe the distorted rainbow

Willow's title text suffering from 100 Hz processing

Check out the edges of the "Game Over" rectangle...

Street Fighter II loses its crispness

We could go on all night finding more disastrous examples of this kind of built-in image processing. It's a real shame because the focus, stability and overall clarity of this TV is amazing.

Conclusion

100 Hz. Don't do it! Unless the 100 Hz television your neighbor is giving away also has a VGA port (which would most likely bypass this digital processing debacle) or has a tube your want to plunder, say "thanks but no thanks". It's just not worth the disappointment.

And, it gets worse. The images I've shown are bad enough but seeing what this processing does to animation is just awful... I'll see if I can capture some video for a future installment.

Blaupunkt Revival!

I finally got brave enough to tackle the burnt-out flyback in my favorite ever Blaupunkt.

I'd had the new flyback that I'd purchased from Dönberg sitting around for weeks and I finally cleared enough space in my tiny little computer/music/storage/geek/cave to get a clear run at the repair.

I'll spoil the ending right now and reveal that this story has a very happy outcome!

I guess this post is about demonstrating how easy this kind of repair is if you have the right tools and nothing else blew up when the flyback bit the dust. I've heard all sort of tales of HOTs and other components burning out when a flyback blows but, fortunately for me, the damage seem to be isolated the fly. Perhaps it had to do with the fact that I was watching TV when the flyback shat itself and I quickly cut the power.

So, here goes!

The solder side of the old flyback

Top view of the old flyback

Old flyback desoldered. Only a 5 minute job with a Hako 808!

New & old. Notice the burn marks...

New unit soldered in

All hooked up and ready to glow!

The moment of truth arrives...

Once soldering in the replacement part in I said a little prayer and hit the power switch. I was pretty nervous because I paid a pretty penny for the new fly and I had waited ages for it to arrive. I was ready for disappointment but knew I'd feel pretty down if it didn't work out...

After flicking the switch I was pretty thrilled to hear the familiar sound of static filling the tube. Then, I turned out the screen pot on the neckboard and was greeted with a glorious sight:

Magical snow!

It was an amazing feeling to see this beauty spring back into life! This is seriously one of the sweetest units I have ever seen and it was a real shame when it died. Getting it back is a really nice thing.

R-Type Leo

Willow

Close up... it's REAL good!

As you can see, it's a pretty amazing TV. As good as I remember it! The photos don't really do it justice... it's even better in person.

This television hits the sweet spot for me. Stable, great focus, vivid colors but not clinical like a Sony PVM or overly digital like some modern Loewes and Grundigs. Add the analog pots into the mix and it's pretty much perfect.

Pretty happy!

Another UMSA update

Hey! Long time no SCART...

I just added a few pics of the UMSA running on a couple other TVs (Grundig and Loewe models) to my review!

I know I've been really quiet (holidays, moving house, blah) but there'll be some more updates really soon!

Willow running with UMSA on a Loewe CT1170 (E300 chassis)

Old yoke, fresh tube

I've been wanting to try this for weeks now: transfer an old Philips yoke onto a new "black matrix" Philips tube. I love the look of the black matrix tubes but whenever I try to hook up older Grundig boards the image is too wide and the geometry is distorted. I figured that a full yoke swap might fix those issues...

I finally gave it a try today and it worked perfectly!

I used the Philips 28GR5775/30B (chassis G110) that I found recently as a guinea pig. The tube (A66EAK51X03) on that is an older type that looks quite grey. Contrast is nothing compared to the tubes used in brands like Loewe. So, I used a knife to slice through the silicon that holds the yoke steady and I unscrewed the clamp on the neck. The yoke slid straight off and I put it onto a newer tube (A66EAK71X01) that I kept from a non-working Blaupunkt. Fired it up... wow! So much more contrast and the colours were vivid. While the yoke was loose, I rotated it to line the picture up perfectly with the top of the shadow mask. Very cool.

Next, I tried the same trick on a black matrix Philips tube (A66EAK071X01) from a Loewe CT1170 television. After playing with the Screen and Focus pots I got the image looking superb. With this 1989 chassis and Philips tube circa 2000 I've got another great looking MAME TV! The Philips actually has a trimpot for vertical size and horizontal hold. I can resize for Street Fighter 2 (224 lines) and Mortal Kombat (256 lines) without any problems. Nice! Haven't nutted out the service menu yet. Either need better batteries for the original remote or the terminals need cleaning. There's some slight pincushion that prevents the image from being classed as perfect.

Can't wait to upgrade my customised Blaupunkt to a black matrix tube!

Philips G110 chassis in test position (i.e. the floor)

GroovyMAME running Willow

Patching geometry controls (and tube swapping!)

After messing around with my analogue chassis Blaupunkt IS 70-33 VTN last week, I started to realise how fast and easy it is to adjust the sizing and geometry of these TVs compared with their digital counterparts. With digital, you have to enter the service menu, navigate to the required section or menu, select the value you want to edit, save the value, exit the service menu, reset, etc. Of course, every brand is different but, basically, these types of TVs give you great options for setting up a perfect picture for a single resolution. However, when using MAME, we want to change the resolution quite often (unless you only every play the same game, of course!) That means frequent trips to the service menu which gets very time consuming.

With analogue TVs (the ones I've tried at least) there are a series of trim pots that adjust the picture size and shape. On my Blaupunkt you have to take the plastic casing off to access them. They're also on the mainboard at the very rear. To adjust them, watch the picture and also avoid getting electrocuted is pretty hard to do! So, I got thinking: "what if I ran a patch cable from the mainboard to the front of the TV so that I could adjust the picture and see the resultant changes?" Well, today I did just that! Instead of attacking the Blaupunkt straight away, I decided to mess with my analogue Grundig first. Since GroovyMAME can be setup to provide near perfect resolutions for each game with only height adjustments needed on the monitor, I decided to start with this control.

The great thing about this Grundig is that there are a series of daughter boards that can easily be removed for servicing. All the controls for size and geometry are on the one card.

First, I desoldered the vertical size trimpot using some solder braid:

Nice clean holes

Here's the potentiometer in question:

100 ohm variable resistor

Then, I soldered the 100cm patch leads to the legs of the pot:

Nothing beats colour coded heatshrink!

After that, I soldered the other ends to the daughter board:

Where's my V-size pot gone?!

Stuck the board back in the TV alongside the others:

Various daughter boards including RGB, audio, tuner, etc.

Moment of truth time... I turned on the TV and hoped for the best. Initially, the picture was all messed up because the other pots had moved position when I cleaned the daughter board. However, the externalised vertical size pot worked just fine! And, it was such a joy to be around the front of the screen while adjusting the height!

The vertical amplitude pot is on the floor in front of the screen

After that success, I made patch cables for the other 5 controls (vertical linearity, vertical position, horizontal size, pincushion and trapezium). I made this shorter (250 mm) to avoid a big tangle. I just wanted to get them out of the electrocution zone since they were really tricky to get at while the TV was running.

The other trim pots removed

Leads attached

After patching the leads, I was able to work out exaclty what each control did (the list I gave before was unconfirmed before this process). Unfortunately the vertical position pot was extremely brittle and the turning part literally crumbled after a few turns. Oh well. Gonna need a new one. I guess that's what 20 years of cooking inside a TV does to you. Also, I couldn't find a horizontal position pot. Not sure if this will be a problem or not...

The long term plan is to get hold of some proper panel mounted pots and drill holes into the front panel of the TV, underneath the front of the screen. That way once GroovyMAME has done it's best to get everything sized and centred I can do the last few tweaks with hardware. I reckon it's going to be a killer system!

Now... this is where the day got wacky. After the success of my trim pot experiment I couldn't help fiddling with some other stuff. Long story short, I ended up performing a full tube swap! I took the awesome Phillips tube out of a faulty Loewe CT1170 and attached it to this Grundig chassis. Amazingly, it worked first try! Considering that I'd never even discharged a monitor before today I was pretty pleased with myself. The best part is that this old school Grundig chassis hooked up to the high-end Loewe tube looks AWESOME.

This whole process is worthy of a blog entry in itself but time is getting away from me... crazy day of television hacking. Gotta get some sleep then clean up the huge mess I made in the morning.

Grundig analogue chassis with the tube from a Loewe digital! Oh yeah!

Minecraft at 240p anyone?

Home made discharge tool

Super vivid R-Type Leo

Wow, what an adventure. I can sense a new obsession coming on... tube swapping! Enough already!