Flyback replacement on a historical arcade machine.

spam@flipp...om works - just use the email responder. Or go to my web site - listed in my signature and find my email there.

Still trying to get legible copies. I have 10 different B&W Taito monitor schematics!

John :-#)#

he CRT?

rom the

sformer

nnected.

Don't waste your time trying. CRTs don't short that way. If the CRT is ful l of air, the tube will arc loudly. You could ground the second anode cup to the metal frame and it still won't smoke the flyback. Any secondary sho rt will destroy the horiz output or open the B+ fuse (or both) way before t he flyback can smoke. If the flyback smokes, it's bad.

Why do you insist that the flyback is bad? Have you tested it with Bob Parker's LOPT/Flyback ring tester? Or is it physically broken?

Bob's meter can be bought from us (read the assembly manual as that goes over the theory):

and others of course.

John :-#)#

ok I stand corrected :-) I've never happened to find a bad flyback anyway. Why the B+ fuse don't open (or the output transistor blows) when the transformer primary is shorted? The load should be quite far away from normal. Maybe it has other secondaries with shorted loads?

Frank IZ8DWF

Actually I have had a few that did, mostly Sonys.

But you are right on the rest of it, at the very least the output transistor will fail before it can burn up the flyback.

as original as possible. I realise that may not be possible >eventually, b ut I so want to try. I have bought a converter ready, >and tested it but c ould not for the life of me get an image to show."

I think most of those convertors are designed for NTSC input, and this migh t not be NTSC. It could be anything.

If you have to retrofit a different fly in there that can be hairy, even sc ary. The first thing to know is how many pins are used. It may have eight o r ten pins, but the less of them used the better. Also look se if there is a focus output, if monochrome it might be automatic focus which gets you of f the hook there.

Ideally, there would only be three pins on the bottom connected. If so you got to balance three parameters. One is the pulse width and amplitude for t he yoke. Then you have to get the right HV level at the same time. It may r equire compromises.

If there are scan derived sources off of it the plot thickens. Best to just figure on replacing those sources somehow.

Now, if you get a flyback for it with an open core you can put some winding s on it. Either bucking or boosting, or maybe for a supply. I had to put a bucking winding on one a long time ago to match a yoke on a replacement CRT because the yoke native to the chassis would not converge properly. But th at was then.

Scan derived sources are not as common in stuff like this as they were in T Vs. You might get lucky.

Retrofitting the wrong fly in there can be tricky. You will need a variac. Also probably a selection of capacitors. And then you might have to install a regulator to get the HV where it needs to be.

In this case, since it is probably reactive scanning, the vertical sweep wi ll tell you when you got it right. You are playing with the horizontal so y ou can't count on that.

This can be done, it is just a matter of how much time and trouble it will take.

I used to get dead monitors from a Burroughs service tech, and some of the CRTS were shorted internally. That caused spectacular failures, when they shorted. Just because you have never seen one doesn't mean that it can't happen. These were 12" TTL input monitors for computer terminals and they had some internal welds that had failed.

Hi Chris,

I have now scanned my files and they are legible. Is there any marking on your monitor? Letter and number codes? Failing that, what is the number on the picture tube?

I scanned these as TIFs and they are huge (100mb) because they are blueprints. If anyone can convert scanned blueprints to straight B&W I would be happy to share these via dropbox.

My return email is valid! Or replace spam with jrr if you prefer.

John :-#)#

Pretty sure I can do that in PSP, and save them in JPG format so they aren't so huge.

Thanks for all the chat. The flyback had smoke emanating from the point where the cable comes out. I switched it off and am trying to find information on what I should and shouldn't be doing to repaid the chassis pcb.

t as original as possible. I realise that may not be possible >eventually, but I so want to try. I have bought a converter ready, >and tested it but could not for the life of me get an image to show."

ght not be NTSC. It could be anything.

scary. The first thing to know is how many pins are used. It may have eight or ten pins, but the less of them used the better. Also look se if there i s a focus output, if monochrome it might be automatic focus which gets you off the hook there.

u got to balance three parameters. One is the pulse width and amplitude for the yoke. Then you have to get the right HV level at the same time. It may require compromises.

st figure on replacing those sources somehow.

ngs on it. Either bucking or boosting, or maybe for a supply. I had to put a bucking winding on one a long time ago to match a yoke on a replacement C RT because the yoke native to the chassis would not converge properly. But that was then.

TVs. You might get lucky.

. Also probably a selection of capacitors. And then you might have to insta ll a regulator to get the HV where it needs to be.

will tell you when you got it right. You are playing with the horizontal so you can't count on that.

l take.

That's super advice and well advanced. I am clearly in over my head. I wi ll start reading and learning more on the subject, before I attempt to fix it. I really do want to keep it original for the sake of preservation. I'm not trying to make a buck or just to play the game. I'm exited to bring i t back to life. ...One day.

I switched it off and am trying to find information on what I should and shouldn't be doing to repaid the chassis pcb.

Look Here?

Colin

For a converter you want to get the Composite Video style, not the RGB. Your game (SI) puts out B&W composite video...

Something like this:

John :-#)#