Savel brain dump in English!

It was hot. And very damp air. The windows was open, 00:15AM, but the computer inside room raised temperature to 26°C and humidity is 90%. I needed brain cooler. Some time ago, I wrote that in eBay I bought some Peltier heat pump. So I connected it to some CPU cooler and here is some device:

As mine brains are well closed, I used copper cylinder for my testing. I is removed from some big P4 cooler. The fan in connected to simple wall adapter. But for Peltier I used car battery charger- I need lots of power.

This car charger have dual output 6 and 12V. When I connected Peltier to 6V output, build in ampermeter was showing about 6A. Total power used for heat pump is about 36W. When I connected it to 12V output, the ampermeter was overloaded. If the heat pump is linear device, total power could be 144W. The current is high, the wires connected to the elements become hot and very flexy. It’s a pity, but the CPU cooler can handle such powers and hot side of the element is overheated. And all system fails. The only result is a bit cold copper cylinder with few drops of condensed watter. Some sort of mini dew machine.

I need some transformer for one experiment (I’ll post it in near future). So I dig my trash pile and found Soviet transformer with double windings. The idea was to run the transformer with double overload. The transformer I selected was TC-180-2 from old tube tv set (in real, if you find cool Russian device, try to run web search using original Cyrillic. Even if the English version look same. So, check the ТС-180-2. This is different to TC-180-2 🙂 . Here is the photo:

Then writing TC means “power transformer”, in Russian-трансформатор сетевой. Next numbers is the nominal power in Wats. Nominal power, not some RMS or other Chinese or western invention. Nominal power means that I can get such power for unlimited time without any damage to the device. So I can get 180W of pure power from it. In bigger TV set I’ve seen even 270W transformers. Such 270W transformers are bigger than in my Maranz audio amplifier. And Maranz is rated 6x80W (480W!)…

These transformers gets to many hobbyist hands with removed connection wires. It is great luck, that mine transformer was with the sticker. But this sticker have some caveats.

It is written: 1-2-3, 1`-2`-3` = 127V/220V, 1.51/0.87A. But this text is quite uninformative. The real description of primary winding must be something like this:
1-2-3 means 0-110V-127V on one coil. On the second coild something similar: 1`-2`-3` means 0-110V-127V.

It is symmetrical coils. Now the simple arithmetic’s come to the first place: between 2 and 3 pin there is 17V.

If we have mains output 220V (old Soviet standard), we need to connect 2x110V. The connection is made in such way: mains cord is connected to 1 and 1`. The jumper wire is placed between 2 and `2. Now we have EU and more wide standard: the average voltage is 230V. (Also, this transformer is a bit overloaded, so we need to use more windings to improve the efficiency of the device). So we can place jumper between 2 and `3 or even 3 and `3. So we get 237 and 254V primary.

Secondary winding are made in similar way. The only difference, that the sticker now is correct:

5-6 is 59.5V/0.5A
7-8 is 43.5V/0.38A
9-10 is 6.4V/4.7A
11-12 is 6.4V/1.5A.

The out voltage is calculated holding in mind the circumstance, that input voltage is standard. As transformer is linear device- if we put a bit more volts in the input, in the out we get more too.

For my experiment I needed higher voltage. So I connected transformer in auto-transformer schematics.
Input 1 and 1`. Jumpers placed 2 and 2`, 6 and 6`, 5 connected to 1`. So I get: 220+59.5+59.5=339V. The output is connected to 1 and 5`.
In real world the output is a bit more, as mine mains voltage is 235V. This all stuff will be connected to variable auto-transformer and I’ll receive output from 0 to 400V.

Few warnings: out voltages are lethal. Auto-transformer connection is dangerous as even is device output few volts, the output pins can be at the high potential regarding ground. Before connecting untested transformer, measure isolation between primary and secondary windings and transformer core. As measure of the windings resistance didn’t show internal short circuit connections between same core windings, measure idle current of the transformer. It must be low. This particular transformer is overloaded from manufacturer, so idle current is about 150mA. It is high current for such power transformer. If we connect primary in “light mode”, the idle current is about 50mA. I recommend to use isolating transformer in your experiments and ground trip current relays. Don’t forget to ground the chassis of your devices.

I don’t like software with skins. Period. But sometimes I am forced to use such software as lame programmers love skins. Typically, the programmers builds some useful software, then he update it and make lots of bug-fixes. Then he didn’t know what to add, but he wants to make “new software”, so he invents skins…
These skins introduces lots of new bug and so, programmer have a job for next few years. 🙂

So if you program software, please leave option to start it without skins. Just plain windows user interface. Also, test your skins to other possible font combinations and screen font dpi. Also, don’t forget to test your software in “handicap” mode- if it possible to navigate in your software without mouse, is it working in strange screen settings, check all keyboard shortcuts. Be sure, that your software is in unicode mode (this is special message to Russian programmers- Hey! We do not use old computer with fucking strange KOI code page. Hello! There is 21-st century here! Use unicode. For chinese friends I have some messages too- sometimes you love to use your big-big unicode font for english text.
Also, check if your HEX table is using fixed width font. Look at this China made masterpiece:

I know, that Windows interface is ancient. Thanks to Bill, programmer have to navigate in pixel coordinates when designing GUI. I could be nice, if Microsoft corporation could buy Magic User Interface idea (MUI, not Windows multiuserinterface) from Stefan Stunz. This is unique dynamic interface with complete end user adaptation- end user even can “skin” any button. This interface was build before Win95 was invented. Few M$ could help modest shareware programmer to live. 🙂

And here is example of the ugliest skin. Made by China programmers- due to their unique imagination we have this masterpiece. It make my hands shaking when I see it:

Bigger image.

My co-worker bought notebook. It was some from Fujitsu Siemens Amilo series. So from cheaper ones. At the same time I’ve bought similar computer, but more expensive few bucks. So my co-worker was very happy that this time he was smarter and managed to beat my price.

After some time, we decided that 512Mb of RAM sucks. So I bought some memory for my notebook. My counterpart decided to do the same. I only offered him to open the notebook to check the type and options for memory expansion. So we did this procedure:

WTF? Where is the SO-DIM/DDR slot? There is place and even silkscreen on the PCB, the the slot itself is missing. I examined documentation and I didn’t found any notice about memory expansion options. It is just the non expandable version of computer. Or maybe some manufacturer error?

Yeap, it is full mishap! 🙂

Sometimes I try to fix LCD monitors and I have some leftover LCD modules from various LCD monitors. I place then in various spaces to prevent screen from scratches. I noticed one LCD module on my windows and I remembered one gad how to convert LCD monitor to video/computer overhead projector. So I disassembled the LCD module, removed all plastic and metal part. Now I have only the glass module with some chips glued to it. It is (I think) Chungwa 17″ module from Samsung monitor (Yes, not all Samsung monitors are made by Samsung). The LVDS control chip is made by Novatec. The matrix have some flaw typical to this Samsung model- white horizontal line and all image disappear after some time. The problem is in the row decoder (counter) chip. One chip is very hot and when it overheats, whole screen is switched off. The switched off LCD screen in transparent.

You can see bad chips on the side of the screen. In this photo it is in the top the image, as LCD module is rotated.

You can see, that LCD module is transparent. The photo is not very good, that you can imagine, that light can go threw the screen.

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I have Thrustmaster LCD in my LCD collection for more that one year. The exact model is: XL Screenmate. I was trying to sell it in my online shop, but nobody was interested. Our local electronic hobbyist are not very open minded and still stuck to smaller projects.

After some digging in the internet I found some pinouts and example schematics how to connect this LCD to analog RGB source with standard TV timing (PAL or NTSC).

I connected to Philips DVD player as it is easiest way to find analog RGB source with 50Hz/15kHz timings. It is possible to connect it using scart connector, but I don’t have male scart connector in my stock. So I connected directly to may PCB of the player.

The image is a bit dark. Maybe it is old technology LCD matrix, or maybe the RGB level is too low. Also, the power supply of the DVD player is to weak to drive this screen. Original connector is labeled 7.5V with internal regulator in LCD screen. On RGB connector is +5V pin, but I never tested it. The DVD PSU has 5V and 12V output. When connected to 12V the PSU become very hot- it was overloaded. So if I want to integrate this screen to DVD player box I need to install more powerful power supply. In fact, current power supply is to weak to drive even the DVD player. When player starts to spin the disk, the image gets darker- it seams, that PSU is lowering all voltages- some sort of brown out.

Here is closer look to the device. That ugly green plastic is already removed. I just was too lazy to make new photo for this web log.

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Somehow I received “several” bad Philips DVP 3010-02 DVD (DivX/Xvid) players. They were sold in local market about year ago for about 100$.
All the devices have same flaw- not reading disk due to the damage of flexible conductor. This is design error. I think Philips must pay me some money for discovering such errors 🙂

First off all, the only thing from Philis is brand name sticker on the device and few bitmaps in firmware. It is generic DVD player with Mediatek processor. It is same CPU as in VIDO player (and many other). Disk reading device is made by ASATECH.

To repair this player just open the box, remove disk holder and look to flexible conductor. If one end, near laser is bended to sharp angle the problem is located. All you need is to change this conductor… or just spend some time and repair it.

In this image you can see the broken part of flexible pcb. Also, when removing the conductor, remove some scotch tape holding it. This tape is placed in wrong place- there is very small room to flex pcb. If the tape was glued near the main PCB, the player would be working without any problem.

In this image you can see where the flexible conductor was glued (1) and the place were it is broken (2).

Here is the image of repaired device. The conductor is glued in other place, so it can curve in lots of space. Some players were with special pcb holder, but the flaw is the same.

To fix player you need:

1. Screwdriver “star”
2. Screwdriver “philips”
3. Scissors.
4. Some Scotch.
5. Good thermoregulated iron (if you want to fix pcb instead of buying new one)
6. Some other tools and steady arms.

Here is software, source code and excel worksheet to check citizens personal identification code used in Lithuania. Checking the code is mandatory when filling various legal documents.

Here is the checker as independent MS Visual Basic program. As I have only old version of the basic, the software is not Unicode compatible. Download ID checker software.

The program may require MS Visual Basic runtime. You can download it at MS web site.

The algorithm is very same. It can be ported to any other programming language:

Backslash “\” means the you don’t need to break line.

Private Function chksum(ak)
Dim c, c1
c = Val(Mid$(ak, 1, 1)) + Val(Mid$(ak, 2, 1)) * 2 + 
\ Val(Mid$(ak, 3, 1)) * 3 + Val(Mid$(ak, 4, 1)) * 4 + 
\ Val(Mid$(ak, 5, 1)) * 5 + Val(Mid$(ak, 6, 1)) * 6 +
\ Val(Mid$(ak, 7, 1)) * 7 + Val(Mid$(ak, 8, 1)) * 8 + 
\ Val(Mid$(ak, 9, 1)) * 9 + Val(Mid$(ak, 10, 1))
c = c Mod 11
c1 = Val(Mid$(ak, 1, 1)) * 3 + Val(Mid$(ak, 2, 1)) * 4 +
\ Val(Mid$(ak, 3, 1)) * 5 + Val(Mid$(ak, 4, 1)) * 6 +
\ Val(Mid$(ak, 5, 1)) * 7 + Val(Mid$(ak, 6, 1)) * 8 +
\ Val(Mid$(ak, 7, 1)) * 9 + Val(Mid$(ak, 8, 1)) * 1 + 
Val(Mid$(ak, 9, 1)) * 2 + Val(Mid$(ak, 10, 1)) * 3
c1 = c1 Mod 11
If c <> 10 Then
    chksum = c
ElseIf c1 <> 10 Then
    chksum = c1
Else
    chksum = 0
End If
End Function

Private Function ak(s)
Dim i
i = chksum(s)
If Mid$(s, 11, 1) = i Then
    ak = True
Else
    ak = False
End If
End Function

The source above as text file.
And here is the same software in MS Excel sheet. Don’t forget to adjust security setting to allow running macros and visual basic commands.

There is special term- memory leak. What it is? Looks similar to brain leak, or that old joke from old zombie movie: brains brains…!

In real world, the bug in memory management is described as memory leak. Every program use some memory (RAM, Video RAM, virtual RAM) to store some data. In modern operating system, program must request from OS for some memory. After using it, the program must release the memory. But there are bugs in software, and sometimes requested memory is a bit more than released. There is not a big problem, if the program is working for a short time- after the termination of process, all allocated memory is released (unless the OS have memory leak itself). But some software is running all the time computer is on. Especially in servers, where uptime is calculated in days, months and even years.

So, one buggy piece of software is Bittorrent client. Here is the result after running it for some days…

This image is more informative… 1.3Gbytes (!) of RAM is quite many for background file transfer.

I was forced to build some VPN (virtual private network)… I examined all my available documentation, did all RTFM and consulted with some gurus from local unix newsgroup.

I selected first available VPN type: PPTP. I am using Linux Debian stable on local servers. As server is running for a long time, the system was “old” stable version. So simple command “apt-get install pptd” didn’t work. There were lots of problems and missing components. So I selected other method- in some trash I picked up old Fujitsu Siemens computer. It very small, pizza box size computer with Pentium III cpu with integrated video, lan, sound and etc. I added two additional realtek ethernet boards to make “router” look cooler. If everything will be working fine, I’ll transfer stuff to real server.

Here are just illustration: screenshots of WindowsXP VPN configuration screens.

I downloaded and installed latest stable Debian. It was “etch”. All devices were installed without any problem. I installed only “base system” as I like to install all needed stuff by myself.

apt-get install mc iptraf lynx ssh

I like these programs, so I installed them. Especially “mc” as I love old style, norton-alike file manager.
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