25" TV Monitors for Starwars Cockpits Project

omegaman said:
That looks pretty good, I doubt you would even notice in game play.
Click to expand...

Unfortunately, I notice. :( The "white" stars look like stacks of two dots, especially if I skew the mismatch to favor the top (so the text looks reasonable) the stars in the middle and bottom look even worse.
 
The problem Mcgovern has is EXACTLY what I have with a WG6100 set-up and low-res tube.

The problem is that it seems you would need to shift the yoke further up the neck while that is physically no longer possible.

You mention the rings Dezbaz and I have a feeling that this is the key to that problem. I haven't tried another set yet (would have to find one that fits first).
My uncle mentioned that those permanent magnets can loose their strength over time.

The inward bowing is typical for all SW monitors I've seen so far. Clay was going to make his V3 version of the mod-kit for this available, but I've asked him many times but they never got done I suppose.

@Omegaman: it sure doesn't look great. I wouldn't say it's unplayable, but like Mcgovern, it irritated me to hell. Esp. the texts look wacky on the top and the bottom.

Please not that my own (original) Amplifone 25" in my own cockpit is simply beautiful convergence wise (and otherwise, the only issue is the bowing). It's on other people's machines that I see problems...
 
Level42 said:
The problem Mcgovern has is EXACTLY what I have with a WG6100 set-up and low-res tube.

You mention the rings Dezbaz and I have a feeling that this is the key to that problem. I haven't tried another set yet (would have to find one that fits first).
My uncle mentioned that those permanent magnets can loose their strength over time.
Click to expand...

I have tried several sets of rings with no real improvement. I am beginning to think I need to find another pin compatible tube, other than the A63ADG type.
 
Over the years some of the locals here have collected old TVs from local verge collections.

A mate of mine was saying he had so many 25" TVs once, that he dropped them off to Jomac. (I am guessing every knows Jomac)
Joey actually said the NEC ones were medium res, and he was quite excited to take them off the guys hands naturally.

Maybe the other brands are Low res.

Mine is an NEC and seems to be giving a good pic so far. Maybe it's a med res screen.

I will give Joey a call on Monday and confirm if you like

EDIT, I have purchased a chassis off joey before, and by memory the chassis he sells for the NEC TVs were duel freq, as they were capable of 15 and 24 KHz

Sounds like Med Res to me
 
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That sounds totally weird to me.

Why would a _TV_ be dual freq ??

Since the line frequency (number of lines per second) is 15625 Hz (625 lines x 50 Hz / 2), the colour carrier frequency calculates as follows: 4.43361875 MHz = 283.75 * 15625 Hz + 25 Hz. (This is for PAL, but the equation is almost the same for NTSC since although it has more fps, it has less lines per frame).

The 15kHz freq. is very much locked to the number of frames and lines per frame of transmitted TV signals (both PAL and NTSC).

There was no source that could produce 24kHz signals for a TV to reproduce, unless you'd hook up a computer that was capable of that (non were in the 80's not sure how old the TV's you mean are)

The same is true for a med-res tube. Even if it was a med-res tube, the picture wouldn't benefit from it because the signal it reproduced was still low res.
Again, a totally other source (computer) would be needed to output anything med-res.


Anyway, it's easy to see if a CRT is low or med-res, I can see it with the eye.
If you look closely at a med-res CRT like the original Amplifone /Rauland CRT, you will notice that the "dots" are much smaller compared to a regular (low) res tube.


I think you (or Joey) maybe mixing up with some monitors that NEC produced, I think in the late 80's/early 90's that were called Multisync (those were TRUELLY Mutlisync, meaning that they could do signals from 15 kHz up to 35 kHz modes.
Those monitors would work great with f.i. Atari ST's which had different frequencies for color (low) and b/w (med I guess) outputs.

The later Multisyncs lost the 15 kHz capability, but the name was SO settled that it sticks even today with LCD monitors (interesting, how to multi"sync" an LCD ??)
However, I'm absolutely positive that no 25" original true multisyncs were ever made. They were 14" which was a normal computer monitor size those days. Only "pro's" had some very special 19" b/w monitors for DTP (wow, that's a term you don't hear anymore those days....;) )
 
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Level42 said:
That sounds totally weird to me.

Why would a _TV_ be dual freq ??

Since the line frequency (number of lines per second) is 15625 Hz (625 lines x 50 Hz / 2), the colour carrier frequency calculates as follows: 4.43361875 MHz = 283.75 * 15625 Hz + 25 Hz. (This is for PAL, but the equation is almost the same for NTSC since although it has more fps, it has less lines per frame).

There was no source that could produce 24kHz signals for a TV to reproduce, unless you'd hook up a computer that was capable of that (non were in the 80's not sure how old the TV's you mean are)

The same is true for a med-res tube. Even if it was a med-res tube, the picture wouldn't benefit from it because the signal it reproduced was still low res.
Again, a totally other source (computer) would be needed to output anything med-res.


Anyway, it's easy to see if a CRT is low or med-res, I can see it with the eye.
If you look closely at a med-res CRT like the original Amplifone /Rauland CRT, you will notice that the "dots" are much smaller compared to a regular (low) rest tube.
Click to expand...

Jomac has built several chassis, as most know to suit arcade machines. The NEC TVs are capable of handling 24Khz, as some arcade games run 24KHz
 
I just spoke to Jomac.

He confirmed the 25" TV tubes are low res. but they can handle the med resolution raster games - ie 24k hz

So they can be used but will not be as good as using the med res original tubes

He also said all the convergence rings are basically the same

He also said focus can not be improved by increasing the HV, and the only way he to get more focus is to make sure the heater is getting the correct voltage (MAX 6.3v)

I will check mine tonight, the voltage on an amplifone's heater comes from a little 3 turn coil on the flyback transformer

He said that 6.3v can come from anywhere, so i could bring it in from my own source if need be

He said the .33 ohm resistor in series with that wire coil is for protection, so no chance of changing that

Great to have a guy like Joey local, great bloke Thanks Joe
 
If for some reason your HV transformer wasn't giving out the correct voltage(low) on the wire that goes to your screen/focus block then increasing the voltage would help the focus issue. The resistor is current limiting for the heater fillament. The circuit is so basic, if your HV board is running then there is no reason the 6.3vac wouldn't be there.
 
Level42 said:
Running 24kHz on a TV that's designed for 15kHz is surely overstressing it. May work, but I doubt it's a healthy thing to do for the HVT.
Click to expand...

We could cover that in a different thread maybe :)
Doesn't really apply to the Amplifone project.
Jomac knows what he's doing, he's the monitor guru, like Ken Layton I guess.

In the nicest possible way, can I ask why that is bothering you Andre? :)
 
I don't care at all, I'm just technically interested.

Normally everybody who knows a bit about monitors/TV's know that running a TV/Monitor's HVT at almost twice the frequency that it is designed for will very likely blow up the HVT.

Also, I'd hate it if anyone's SW got burnt down because of trying this...


Also, why would a TV be running at 24 kHz, while the dot-pitch of the CRT is low-res ? It won't improve picture quality for sure...in fact the screen would become totally de-synced.
 
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Level42 said:
I don't care at all, I'm just technically interested.

Normally everybody who knows a bit about monitors/TV's know that running a TV/Monitor's HVT at almost twice the frequency that it is designed for will very likely blow up the HVT.

Also, I'd hate it if anyone's SW got burnt down because of trying this...


Also, why would a TV be running at 24 kHz, while the dot-pitch of the CRT is low-res ? It won't improve picture quality for sure...in fact the screen would become totally de-synced.
Click to expand...

Ok, 24Khz is a raster frequency

Some Raster games use that frequency. This was the only way these games (tekken, MK etc) were kept going, by making a duel res universal chassis. - allowing a TV screen to be used. I know of guys using these duel res chassis & 25" TV screens for years - no ill effects

That has nothing to do with vectors

Star wars machines are not going to burn down, all will be fine

If it doesn't last as long - no big deal, I will get another TV screen in the machine

Hopefully that puts this to rest :)
 
Check your 6.3V heater voltage boys

I have fitted a bob roberts flyback, and straight out of the box it supplies 12.2 VAC (Suicidal !!!!)

Should be 6.3VAC
On good advice, that's why I can't focus the screen
 
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I rigged up a 6V AC supply, and fed it in directly to the brown twisted pair wires (Heater wires), and I have improved focus on the screen

There you go

I may just leave that temporary transformer there for now, until I try an arcadecup flyback in my 2nd Amp HV board

We will see what voltage that puts out
 
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