I think I have fixed the FTP server problem that was preventing WxServer downloads. I turned off Advanced Settings/Services/FTP
Server in the Windows Firewall, and instead added FileZilla.exe as an exception.
I am guessing that Advanced Settings/Services/FTP Server is for active FTP, whereas a program exceptions allows Windows
Firewall to track the open service ports for passive FTP. That's how it was acting, anyway. I don't know for sure because
I have not been able to find any authoritative source that explains the Windows Firewall policy in enough detail. And don't
start with me on running Ubuntu. I have my reasons.
For some reason, Windows Firewall started blocking my FTP server in random and unpredictable ways. If you are having
trouble downloading WxServer, you might want to retry the connection a few times. If that doesn't work, use the form at the
bottom of the page to send me email. I will email a copy to you.
Windows Firewall is supposed to be a stateful firewall, and FTP support includes opening ports for PASV FTP. It seems
to work sometimes, but after a while, it stops working. I'll figure it out eventually. In the meantime, please bear with me.
I just spent the last couple of hours searching the internet for information about which trimpot inside a SONY CPD100VS
15-inch multimedia display controls the CRT screen grid voltage. This is a 15 year old monitor that I am using on a server
computer. If I wanted to spend any money on that display, I would have replaced it years ago, but it is adequate for what
it does. So I was very much annoyed to find that I would have to shell out $15.00 US to purchase a service manual just to
find this one bit of information. I am posting my results here in hopes that I can help someone else avoid having to purchase
a manual for more money than the current value of the display itself -- assuming Google ever indexes this site.
Why do I care about setting the screen grid voltage on a 15 year old CRT monitor? Well, the display was getting very
dim. I had the brightness and contrast set to the max, and it was still too dark. The video amplifer was starting to clip.
Since I know a little bit about CRT technology, I know that often just a bit more screen voltage will brighten up an aging, dark
CRT. In fact, that minor adustment can add another ten years of useful life to the device.
So where is the screen control, and how did I find out which one it was? Well, there are three trimpots on the unit.
One is located on the HV power supply (on the main board), one is mounted right by the neck of the CRT, and one is along the
top edge of the CRT circuit board. I figured with three pots, a bit of trial-and-error would do the trick.
I started at the HV power supply. Noting where the pot was set originally (they painted some enamel on the shaft when
they set it at the factory, so it was easy to return to the original setting), I rocked the control back and forth and watched
the screen. The screen brightness didn't change, but the height did, slightly. Wrong control. It was probably a voltage regulator
setting. I put it back where it was.
The next control was by the neck of the CRT. I rocked it back and forth slightly. There was no visible change, so I put
it back where it was. It could be focus, but I don't know. I wasn't watching for that.
Finally, I tried the tiny trimpot at the top of the CRT PCB. Voila! The screen brightened up beautifully. To adjust it,
I turned the brightness and contrast all the way down, and then advanced the screen voltage until I could just see retrace
lines on the screen, and then backed it off until they were no longer visible. The best setting was just slightly below the
center of rotation, so I wasn't pushing the envelope at all.
I also took the opportunity to blow the dust out of the unit, replaced the back cover, and buttoned it all up. It's good
for another ten years.
NOTE: This might not actually be a screen control (I don't have the manual, after all). Some monitors have a "black level"
or "master brightness" adjustment (which might be another name for "screen voltage"). No matter. It did the trick.
WARNING: CRT displays employ very high voltage (the anode voltage is easily around 25 kilovolts, give or take a few thousand).
This will easily electrocute a person, so keep one hand behind your back at all times, and use an insulated screwdriver or
plastic adjusting tool to operate the internal controls. And if you're not sure what you're doing, for Pete's sake, don't
open the case!
