Roundie left edge purple

[DaveWM]

Got it. My problem was not a problem at all. after changing out the horz osc tube and a few other componets it was looking good. but my scope indicated low HOT drive. Turns out I had setup the scope wrong, all was good.

I am calling this one done, I will be adding the squirrel cage blowr on the HV tower top and butting it up.

[DaveWM]

after a longer viewing time I went to adj the focus, the plastic adj piece was very loose in the bore of the coil. I had noted before that when cold the focus is frozen, after a few min the adj loosens up and feel normal now when hot it practically falls out.

the Horz defection coil blue lead it tied to this coil.... hmmmm

I checked the resistance, 1.6 ohm should be 30. now this is with it in circuit, but I see nothing across it that would reduce the resistance but for a 100k resistor so unless that is shorted I would not expect to see this.

I have a new coil on order. Perhaps this will finally address the underscan, yes I got it to fill out the screen by careful adj of the centering control and careful selecting of horz tubes, but I think it should not be this critical, so perhaps a shorted coil would result in an impedance mismatch in the horz circuit that could put a drag on the fly. I check the waveform and PP on some other stuff like the horz blanking signal which comes off this coil, it was way down from spec too like 40% low.

[DaveWM]

dumb me did not see that the focus coil was across a fly winding, after taking it out of circuit it checked fine. Darn... i will try a new one anyway since this one is all gummed up with a waxy stuff that make the adj gooey.

I also set up the chassis to do a B+ current check. I may end up putting a fuse on the B+ as well. esp since I still have the orig filter caps (they check like new for leakage and capacity so I just can bring myself to restuff them)

I did not check EVERY section of the two caps so if the B+ show excessive draw I will do. I know that if the B+ is low that would explain my width issues so that is the main reason I am checking. Overall the B+ is not that far off so I dont think I will find anything major here.

I did run a fan on the fly and after 1 hour it was barely warm so I will def be looking into how to set that up on a perm basis. It was pretty noisey so I will be looking for a smaller quieter fan. I want to make the fan install a no mod to the HV cage. I am thinking of making a plenum that will adapt to a partially open cage top. it will take a bit but I really like keeping that fly cool.

[ctc17]

I wonder if the flyback has COPD, ED, BPH or leaky prostate syndrome causing the current to be a tad high.
Do you think there may be a chance the fan will suck stray electrons out and cause someone radiation poisoning?

[DaveWM]

well the B+ went just of the 500ma scale with no signal (full raster), with a signal it dropped down to about 480-500ma depending on the scene.

the sams call out 460ma with no signal so its a little high.

I will prob end up stuffing all the caps just to be sure.

I should have let it run for a while to see if it went higher or lower. The cans to get pretty warm but they sit right next to the power tranny and one of them has a big sand resistor on the bottom soldered to the terminals.

[DaveWM]

got a new yoke on the way, figure it cant hurt to try it.

[DaveWM]

went ahead and installed the new focus coil, improvement, will play with it some more. Have another focus coil to try later. The problem is these are alternate PN coils so I want to try them both and see which works the best.

[DaveWM]

got the new focus coil in it. maybe better but still I think its a bit under scanning. The focus coil seemed to help a bit with the cathode current on the HOT and "maybe" the scan.

I have a new yoke (the triad) but am just a bit burned out on this one. the pic looks real nice, color wise. The focus seems a touch soft (I have the focus coil slug all the way in, it effects the focus but does not seem to peak).

I did replace the focus rectifier just in case, no change. Overall the pic is very very good, and I am tired of fooling with it.

I double checked the filter caps, they test like new so I will leave them be.

I did add the B+ fuse a 750ma (normal current is about 450-500ma) so if the filters ever do short out the tranny will not have to wait for the main circuit breaker. the fuse is in one of those in line jobes, properly strain reliefed of course. The HOT cathode fuse is a micro fuse that has a neat holed soldered directly to the jumper term strip, mounted on top of the chassis, VERY easy to pop the fuse and check the current. I soldered in a .1uf cap across the fuse holder so you dont even have to bypass when checking. I thas a 310ma fuse, cathode current is right around 220-240 depending on beam current.

I still plan to buile a plenum to fit in the cage and direct air from two micro fans (the kind on cpu's). I need two as they dont move much air. The plenum will be made from cardboard and will direct the air to the main body of the fly. the intake will come from the back side of the fly, the cage door left open. the exit will be from the existing convection louvers. The fans run off
12vdc, I will prob just power them from a wallywart transformer. I am not going to do anything that cant be undone and returned to the stock configuration.

watching Kojak on it now

[ctc17]

Run your 12vdc PC fans on 5 volts. They will slow down and be quiet while still keeping the fly cool. Most PCs vary the voltage depending on heat load so they dont sound like a jet all the time.

You could also use the rectify and filter the 6 volt filament supply for the fans.

[DaveWM]

still not satisfied.

I chaged the pic format, so there would be a margin all around the pic (cant recall which format but it was on the convert box).

in this smaller format I could see the pic was clearly not centered, so I centered with the horz centering pot.

switched back and now I have the dark bar on the extreme left edge.

Now the Raster is fine (full screen) its just the pic that causes the dark vert bar on the left.

I did some more reading and I am back to looking at blanking. There is a triode section of a 6GH8 that takes a pulse a the grid, and is coupled from the plate to the cathode of the chorma driver tubes.

IF for some reason the tubes were cut off too long I assume this is what it would look like.

But there is just not a lot of parts involved, so I will be checking them AGAIN and doing some tube rolling.

I guess I could compare the CRT grid voltages to the composits video signal on my dual trace scope and see if they line up.

I threw my net over on ARF and fun with tubes to see if any one else has some input on this dog.

Just for fun I am going to try the one OTA transmission on UHF and see how it looks. the problem is its such a weak station that the pic is awful.

I am just try to eliminate the converter box as an issue (it works fine on other tv's).