She's a runnin, kinda

[freakaftr8]

Sweet! Thanks Jordan

BTW, ajdusting the effiency coil puts the sync lock in a different position on the horiz hold dial, and does not really change the cathode current reading in ma when relocked into sync.. still sits around 214ma, is that normal? I have the coil set so horiz lock is right in the middle of the dial.

Oh yeah, I also ruled out the horiz hold rheostat, I took a measurement, approx 35k ohms to lock horiz hold, so I soldered in a 35k resistor and took the rheostat out of circuit, still flutters and comes off sync and back into sync so it's not that..

[jpdylon]

damn, looks like I have neither.

lotsa 12DW4 and 17DW4 though

[freakaftr8]

Well, thanks for lookin, im going to check a store up here that supplies all the tubes, caps and other parts I need. He's a nice guy and loves his work, he repairs vintage audio and guitar amps.

[Bill R]

So to recap the problem now is that after the set has been on the horizontal sync is not stable, and on startup the vertical is out of sync? Raster is no longer shrinking and loosing focus and brightness?
Sounds like the horizontal oscillator is drifting, or the not locking when it is hot. I would start checking componants in the horiz. oscillator and sync seperator circuits looking for out of value resistors and caps. The fact that you still have more than one problem still could be in the power supply. Remember there are more than one B+ sources. I would check them all to be sure.
The chassis number should have one more number in it. the T or U will not matter. The first three numbers are the chassis series, then the last two numbers are the run number. The letters are production changes with the first letter indicating major electrical changes and the last letter indicating major mechanical changes. So it would be U91? 09 BB. U918 series was 1967 I think, and U911 was late 66 or 67 I think.

Bill R

[Bill R]

I think you have a U919 chassis. 214ma is normal for that set. Sams shows the Horiz hold pot to be a 35K pot. So soldering in a 35K resistor would be like having the control set at one end not in the middle. The control is probably ok. The horiz osc and afc circuit is powered by the 390V source. In fact there is 390V at one end of the hold control. There is a 680 ohm 1 watt resistor connected to the 30mfd filter cap in the 390V source that could be increasing in value as the set heats up causing the voltage to drop just enough to affect the horiz lock.
Your vertical problem could be a weak 6gf7 tube. I also notice the sync seperator tube is a 6gh8 just change it.

Bill R

[freakaftr8]

Ok cool! well I had my suspicions on that 6GH8 as well so I did change it, no difference, the 390v source is stable, I looked at that 680 ohm resistor, It doesn't look happy! Im going to change it out! This might be it!

I got another issue... I just replaced the 2 tube sockets that were cooked, they are the 7 pin sockets for the 6GY6 demods. Now one of the tube heaters will not light up, (possibly due to the old pin was bent over touching pin 2 or a resistor located next to it) Checked soldering with ohm meter and it's good, so I looked under the board and pin 3 solder trace looked bad and broken, so I bypassed it with a wire to the correct source, still wont light up. Im trying to find out where the power for the heater on pin 3 comes from... Any ideas what to look for? I havent done too much research yet...

Originally Posted by Bill R

I think you have a U919 chassis. 214ma is normal for that set. Sams shows the Horiz hold pot to be a 35K pot. So soldering in a 35K resistor would be like having the control set at one end not in the middle. The control is probably ok. The horiz osc and afc circuit is powered by the 390V source. In fact there is 390V at one end of the hold control. There is a 680 ohm 1 watt resistor connected to the 30mfd filter cap in the 390V source that could be increasing in value as the set heats up causing the voltage to drop just enough to affect the horiz lock.
Your vertical problem could be a weak 6gf7 tube. I also notice the sync seperator tube is a 6gh8 just change it.

Bill R

[freakaftr8]

Well I spent all night on tracing down solder joints and paths and I found a burned trace on the board that controls the heater for the x demod down the board where the b+ splits up near a fuse, I don't have schematics for the set so I am bearing on just point and shoot alone, lol. Well that was the color issue. Man this set puts out the colors and the contrast and brightness! Im shocked on the quality of the picture on this set! The demod sockets were shot but on the bottom of the board there is no charing or burning, which is odd due to the replaced CRT, but as far as I can tell, All the tubes besides the rectifiier and HV and the 3CU3 are original, possibly a low hour set? I know the reputation for the 23EGP22 but it's new and hardly used and it looks and tests great! Pincushion is fixed now and so is the convergence, (that was a nightmare). Ill take pics today and post! Still have to change out that 680ohm 1 watt resistor on the 390v supply to fix the horiz fluttering, but looks like this set's a keeper!

Thanks for the help again!

Originally Posted by freakaftr8

Ok cool! well I had my suspicions on that 6GH8 as well so I did change it, no difference, the 390v source is stable, I looked at that 680 ohm resistor, It doesn't look happy! Im going to change it out! This might be it!

I got another issue... I just replaced the 2 tube sockets that were cooked, they are the 7 pin sockets for the 6GY6 demods. Now one of the tube heaters will not light up, (possibly due to the old pin was bent over touching pin 2 or a resistor located next to it) Checked soldering with ohm meter and it's good, so I looked under the board and pin 3 solder trace looked bad and broken, so I bypassed it with a wire to the correct source, still wont light up. Im trying to find out where the power for the heater on pin 3 comes from... Any ideas what to look for? I havent done too much research yet...

[Bill R]

What did you find was the problem with pincussion and convergance?

Bill R

[freakaftr8]

Just some really off the wall adjustments. The CRT was replaced in 1977, and when that was done at the time, I dont believe the sercvice man put any time into readjusting convergence,, yoke attenuation or pincushion phase and trap settings at all! The colors were washy, really bad convergence, and alot of color purity blotching and crooked raster, due to he yoke being out of whack. But almost perfect now!

Bill do know how to adjust the horiz width in this set? I cant find that either and it's stretched a little too much.
Thanks!

[Bill R]

Width is adjusted with the Horiz Linerity control. This is the same adjustment for the HO cathode current. Adjust it for minimum current. Than set the High voltage to 25KV with the brightness all the way down. The current should not exceed 240ma. You said you were at 214ma and that is good so you shouldnt need much adjustment. You could back it down a little. After you adjust the width you will need to adjust the vertical height and linerity for the correct picture geometry.

Bill R

ps: pictures?

[freakaftr8]

I replaced that awful looking 380ohm 1 watt resistor on the filter cap for the 39pv supply. The set still has the same issue.. I am going to go in depth and replace all the resistors in the horiz sweep section that seem out of tolerance. I think one of these are the culprit. Funny thing is as the set is cold, it's doing it still.

[Bill R]

Check the coupling cap in the Horizontal afc circuit. should be 820pf. This couples the oscilator back to the horizontal afc section. Ihave seen the Horizontal phase detector diodes be leaky causing marginal sync. The only high wattage resistor is the 150K resistor off the horiz hold control. Pay close attention to componants off pin 1, 2, and 3 of the 6FQ7 tube. This is the horizontal afc section.

Bill R

[freakaftr8]

Cool thanks for the tip Bill, Ill check that out tonight!

Originally Posted by Bill R

Check the coupling cap in the Horizontal afc circuit. should be 820pf. This couples the oscilator back to the horizontal afc section. Ihave seen the Horizontal phase detector diodes be leaky causing marginal sync. The only high wattage resistor is the 150K resistor off the horiz hold control. Pay close attention to componants off pin 1, 2, and 3 of the 6FQ7 tube. This is the horizontal afc section.

Bill R

[sampson159]

post pics of your combo working. i cant wait to see it in action!

[freakaftr8]

Here are some shots of the Maggie in action, this is before the horiz glitching, as you can see the crt and the raster are nice, crisp, colorful, and full of contrast and bright! Despite the little quirks, this set was well worth restoring!