Making an arcade monitor in reverse.

[Amra]

Wondering if anyone has tried the following, and whether they had any success in doing so.

Purchase an after market replacement arcade monitor chassis. (Wei-Ya Universal Replacement Chassis)

Find a compatible CRT Tube (25"-29", with 1.5ohm+ on the horizontal winding, and 6-12ohm on the vertical winding)

Build a frame that holds the unit.

I've watched and read a few reviews on the Wei Ya chassis and they are mostly positive, there's even a youtube review that goes into a bit of detail and seems to consider it a good viable option ().

This seems like it could be a rather inexpensive way to have a mostly legitimate arcade monitor on the cheap. This particular chassis, as an example, is only 100 USD, and analog CRT TV's are fairly inexpensive for the time being (they will get more and more expensive as time goes on though).  I've picked up several quality CRT TVs in the 25-29 inch range anywhere from free to thirty USD.

Using this method, it seems possible to build a working arcade monitor for less than 200 dollars, which seems quite reasonable for people who can't afford something more expensive. 

I've not tested the waters yet, I figured I should probably ask if anyone has already tried this method first, but even if no one has, its inexpensive enough that it might be worth the effort, even if it results in failure.

Granted there are a few caveats, such as finding the right type of tv with a compatible tube, but it should be possible to make a short list of TVs that have CRTs that are compatible with this particular chassis (or other chassis', if better options are available for replacement arcade monitor chassis'). The way things read though, the chassis is supposedly compatible with a wide array of Tubes.

Anyone have any experience in this type of venture?

[jennifer]

      You got your horiz/vert resistance backwards but Jennifer gets what your saying.... And yes it does work, However its not that cut and dry, It requires quite a workbench to get decent results. And in some cases its not even needed (the 25" Sanyo for example) will accept a wells garner chassis without messing with yokes or convergence.

[Amra]

You got your horiz/vert resistance backwards

Are they? I actually listed those measurements directly from the linked chassis replacement board above, and the video I linked uses the same references, so I'm not sure.

It requires quite a workbench to get decent results

Does it? It seems like all you should need to do is splice in the old yoke and degauss coil into the new wires, make some minor adjustments as necessary. What all do you suspect is necessary to get decent results? Im honestly curious here.

without messing with yokes or convergence.

You should be using the old yoke that was already on the monitor (hence the need to check the windings to make sure they are compatible), the yoke should already be fairly adjusted for the specific monitor you are using, so any adjustments should be fairly trivial (purity and convergence should be really close if you didn't jostle the yoke during the process).

And in some cases its not even needed (the 25" Sanyo for example) will accept a wells garner chassis

That's good to know, and that is very related to this venture. I listed the wei ya chassis simply because its a readily available arcade chassis that is brand new, if you can still find aftermarket wells garner replacement chassis' for a reasonable price, that seems like a good option, the availability of detailed schematics and replacement parts makes it quite viable.

Thanks for the reply Jennifer.

[behrmr]

I am not sure where you live but if there's an active arcade community you might find an actual arcade monitor that size relatively cheap.  In fact I had a friend of mine just throw one away from a showcase cabinet because no-one wanted it.  People are putting MAME in these cabinets and using LCD's and tossing the monitors.  You may want to put some feelers out there in your area.

On the universal chassis just be aware that if the yoke on the donor tube is not 100% compatible you may have convergence issues. I had issues with one where it was supposedly compatible but ended up with a nasty pincushion effect I could not adjust out with any amount of convergence strips.  However that was with a Jen Shinn chassis not a Wei-Ya so YMMV.

[jennifer]

    Pincushion and blooming will be your big problems, (Like behrmr said) So then your into the yokes, and you will find some of these are glued on  (onto the weakest part of the tube May I add) So if your going to mess around with these wear protective gear. 

[Amra]

I am not sure where you live but if there's an active arcade community you might find an actual arcade monitor that size relatively cheap.  In fact I had a friend of mine just throw one away from a showcase cabinet because no-one wanted it.  People are putting MAME in these cabinets and using LCD's and tossing the monitors.  You may want to put some feelers out there in your area.

I have not had much luck here in that regard, I do keep an eye on craigslist and local adds, but I'm not aware of a local arcade community. There is a local arcade, but they do not have any non-working or working monitors they are willing to part with, largely due to their becoming more and more difficult to find in good condition.

On the universal chassis just be aware that if the yoke on the donor tube is not 100% compatible you may have convergence issues. I had issues with one where it was supposedly compatible but ended up with a nasty pincushion effect I could not adjust out with any amount of convergence strips.  However that was with a Jen Shinn chassis not a Wei-Ya so YMMV.

That's some good information, thanks for sharing!  I think the trick, then, would be finding tubes that truly are compatible.  I figured this would be pretty important, hence the caveat in my first post.

Im not sure about the Jen Shinn chassis, but the Wei-Ya does have a pincushion adjustment built onto  the board, though I don't know if that would be sufficient for all situations. Perhaps it could be adjusted further through component replacement, as is occasionally done with vertical/horizontal size on older arcade monitor boards, but that seems a less ideal solution than simply trying a different tube.

I think though, we do have a head start in the right direction for finding compatible tubes.  The video I linked earlier shows a very successful result after being installed into a hantarex polo arcade monitor.  So, if there is a list of TVs that have compatible tubes for that particular monitor/chassis, then, in theory, those tubes should also work nicely on the wei-ya chassis.  Granting of course that theory and practice are only similar in theory.

Pincushion and blooming will be your big problems, (Like behrmr said) So then your into the yokes, and you will find some of these are glued on  (onto the weakest part of the tube May I add) So if your going to mess around with these wear protective gear.

Blooming is where the size of the onscreen image fluctuates with the amount of color/information on the screen, right? I didn't know that could be adjusted via the yoke.  I simply assumed if that were to happen, we would simply categorize that monitor as incompatible and move on to the next one.

 I would also be wary of a glued on yoke anyways, as the risk for damage seems a bit too high.

Of course, I suppose the effort of testing multiple tubes could also be a waste, but if the TVs are cheap enough (often times I find 20-27 inch TVs at Goodwill for a just a few dollars), then the biggest cost is the labor necessary in disassembling the monitors to test them (and disposing of them properly afterwards).

At this point, I don't think I'd categorize it as more trouble than its worth, but there are definitely some considerations necessary before attempting such a venture. Thanks for the thoughts on the matter everyone.

[grantspain]

people tend to over simplify tube/chassis matching-the info is " if the yoke matches it will work"
in many cases you will get lucky as a standard tv will have a yoke that matches standard low impedence arcade chassis and a heater current that matches

the quality of the chassis counts for alot,jen shinn made some brilliant chassis but i am not sure if they are still around,wei ya are not bad but there are an awful lot of chinese copy chassis being sold as wei ya

i think you should consider just grabbing a tv and then read the deflection yoke with a multi meter-then match a chassis

[Paradroid]

At this point, I don't think I'd categorize it as more trouble than its worth, but there are definitely some considerations necessary before attempting such a venture.

Depends if you're going to have fun doing it. Although this hobby can be incredibly frustrating when you've invested heaps of time into something that turns out to be a failure, nothing is better than the feeling you get when it all comes together. No problem experimenting if you keep safe and enjoy spending your time this way.

I haven't had anything experience with matching TV tubes to arcade chassis but I have messed with matching vintage TV chassis to modern tubes. I have had some really good results hooking up older, over-built analog chassis to newer, shinier tubes.

My latest venture is direct injection of RGB into a TV chassis. This is by far the cheapest way to hack together an RGB monitor for gaming use. The results can be extremely good!

[Amra]

people tend to over simplify tube/chassis matching-the info is " if the yoke matches it will work"
in many cases you will get lucky as a standard tv will have a yoke that matches standard low impedence arcade chassis and a heater current that matches

the quality of the chassis counts for alot,jen shinn made some brilliant chassis but i am not sure if they are still around,wei ya are not bad but there are an awful lot of chinese copy chassis being sold as wei ya

i think you should consider just grabbing a tv and then read the deflection yoke with a multi meter-then match a chassis

That seems to me to be the best approach as well.  Ideally one should be able to create a list of fairly common voltages and resistance measurements for tubes based on brand or tube type.  Luckily a lot of them are pretty standard.  For example, I've not seem many CRT heater voltages that deviate very far from 6.3v, though Im not sure how standardized the industry ever became, it would be interesting none the less.

Depends if you're going to have fun doing it. Although this hobby can be incredibly frustrating when you've invested heaps of time into something that turns out to be a failure, nothing is better than the feeling you get when it all comes together. No problem experimenting if you keep safe and enjoy spending your time this way.

I have an AAS in EET, and will be continuing my education in EE to get my BA, so this kind of venture is right up my alley (hence my interest in this project).  Given that I'm only a couple years in, my experience is a bit limited, and I haven't worked on TV's that much. I do understand most components, and their function, but not always their purpose in a given circuit.  That is something that will come with time and experience.  The limiting factor for me is money, if I spend too much I might as well have purchased a new monitor offline.  Finding a way to build an arcade monitor for cheap seemed like a fun challenge, learn some things, as well as a way to save money.

I haven't had anything experience with matching TV tubes to arcade chassis but I have messed with matching vintage TV chassis to modern tubes. I have had some really good results hooking up older, over-built analog chassis to newer, shinier tubes.

Doesn't seem far off from each other, I will be reading your website shortly. I wish us yanks had adopted something similar to SCART, would make things a lot easier. (have considered making a RGBHV to YPrBr converter instead, which seems like it would be cheaper and easier, though it would require a newer TV set (2000+?) with the right inputs).

My latest venture is direct injection of RGB into a TV chassis. This is by far the cheapest way to hack together an RGB monitor for gaming use. The results can be extremely good!

Ive considered something similar, I've read that some of the more modern Jungle IC's have inputs where you could inject an RGB signal , then one could maybe use composite input for the sync, though I'm sure there are some other thing's to it that I haven't considered.

Thanks for the reply, great stuff, and I will be keeping an eye on your projects, they look quite promising, and relevant to my interests.

[princess prin prin]

a heater current that matches

I've not seem many CRT heater voltages that deviate very far from 6.3v

Current, not voltage (common misunderstanding).

Depending on the manufacturer the current ratings of the heating filaments vary, sometimes a lot.

Look at these tubes:

http://lefcom.narod.ru/datasheets/A59EHJ13X01.pdf

http://www.propago-cz.cz/Pdf/A59EMZ43X.pdf

One is 6.3V 0.7A and the other 6.3V 0.3A. The voltage is the same but the current is very different, so much in fact that if you drive the 0.3A tube with the chassis of the 0.7A tube
you will exhaust the tube quickly (the reverse combination would give a dim picture). So it's essential to first measure the heater current of the donor tube running with its
own chassis and then adjust the new (arcade) chassis so that it outputs the correct amount of current (this is done by changing the value of the resistor in series with the heater).

Here I am measuring the heater current of a Videocolor tube in a Seleco TV (the same tube type is also used in some Hantarex monitors):

[Amra]

Current, not voltage (common misunderstanding).

Depending on the manufacturer the current ratings of the heating filaments vary, sometimes a lot.

Look at these tubes:

http://lefcom.narod.ru/datasheets/A59EHJ13X01.pdf

http://www.propago-cz.cz/Pdf/A59EMZ43X.pdf

One is 6.3V 0.7A and the other 6.3V 0.3A. The voltage is the same but the current is very different, so much in fact that if you drive the 0.3A tube with the chassis of the 0.7A tube
you will exhaust the tube quickly (the reverse combination would give a dim picture). So it's essential to first measure the heater current of the donor tube running with its
own chassis and then adjust the new (arcade) chassis so that it outputs the correct amount of current (this is done by changing the value of the resistor in series with the heater).

Here I am measuring the heater current of a Videocolor tube in a Seleco TV (the same tube type is also used in some Hantarex monitors):

Right, but if the circuit is providing a constant voltage (i.e. straight from the Flyback, 6.3v) than the current the tube heater draws is entirely dependent upon the resistance of the heater itself, not the amount of current the chassis is capable of supplying.

In other words, using the example tubes you referenced, the resistance for one of the heaters would be 21ohm (0.3a), and the resistance of other heater would be 9ohm (0.7a).  So, if you change the chassis, the tubes would still get the correct current, because ohms law (v/i=r, v/r=i).

If, however, its a voltage divider network, then the voltage drop across the neck will change because you've changed a resistor in the voltage divider network (i.e. 21ohm to 9ohm or vice versa), and thus the current will change as a result, but only because the voltage has changed. In this case, you should be able to change the resistor in series with the heater to correct the voltage being supplied to the heater back to 6.3v and the current will necessarily return to exactly what it should be, 0.3a for one tube, and 0.7a for the other tube, as the only reason the current would be different in either of the tubes is if the voltage is incorrect, for example 6.5v through the 9ohm heater would result in a current of 0.722a, which is too high, thus over-driving the CRT and reducing its life. Right?

You cant change the chassis and then get 0.7a through the heater that only requires 0.3a, because the only way to get 700ma through the 21ohm heater is to have a supply voltage of 14.7v, and the chassis is only supplying 6.3v, so the current draw must only be 0.3a.

Hopefully that makes sense. If that's wrong, which is always a possibility, please explain what I am misunderstanding.