Continuing to test. I have no raster with the CRT/Yoke/Focus Coil in the set. The set uses a 12LP4 per the schematic. This CRT was replaced at one point, but is unlabeled other than a label on the base that says "AST Inc", but does test very strong with 12LP4 settings on my CRT tester.

- B+ is right on
- I have a good -4v from the PS.
- My HV is around 8kv (low?)
- I used my Sencore Sweep Circuit tester and it shows the Yoke and Flyback to be okay by substituing the yoke and checking deflection on the Flyback (70 degrees indicated).
- HOT cathode current is about 150ma
- HOT bias is -10v and is suppsed to be -5v
- I have about 250v on pin 10 of the CRT.
- I have an adjustable static noise/squeal from speaker. No sound other than that.
- All tubes test okay, and I have also swapped the Damper, HO tube, HZ Osc and 1B3.
- I do not see corona arc, but will check again in the dark
- Checked all resistors in HO area - all paper caps have been replaced (nearly all were very leaky).
- When connected to my test CRT/Yoke, I have a raster - but the focus coil is out of the circuit (not that it matters for a quick check) and there is what appears to be a lot of HF noise in the picture.

- Lastly - The Ion Trap. The one on the tube (not installed in picture below) is a single magnet and was oriented to the bottom of the neck when found. The part number on the ion trap is correct per SAMS. I've tried moving the ION trap all over to see if I could get a raster. The magnet does attract a screw driver. My reading indicates this style gun in the CRT would require a double magnet trap. Can anyone tell from the pic below?

Any and all help is welcome!

check R128 for drift may account for the off spec bias voltage.

8kv sounds low to me, I have a RCA that has 10-11k, but that should still produce a raster.

If the horz freq is far off you HV will suffer, but you should hear that, it would be an awful squeal. This is where I like to use a freq counter to confirm the drive freq to the HOT.

check the screen voltage of the hot.

look for 5% resistors around the horz osc tube. they can make it so the horz freq adj slug will be out of range.

are you sure the tube is not aluminized? can you see silver where the dag is not covering the glass?

Well I have it basically working. There was an error in my Sams on C95 (Hrz sync couplng cap) and fixing that got me to 9kv. I dug out my Wallace Telaide and it cleared up a lot of my problems (should have done that earlier). The Telaide indicates 9kv is correct. My set is at Run 7, so there also were numerous differences with the Sam's. I also got the ion trap adjusted and seems to be way off from where I found it. I only found one location, nearest to the base that worked at all. Just about the entire HV cage has been redone - new 1B3 filament resistor, HV filter resistor, HV lead/cup and cleaned up the corroded socket. I still have to work on the overall horiz sweep adjustments, linearity, etc - but overall it's generally working and voltages/temperatures are good. And the set is drawing an even 2 amps at 117v per spec.

The only DVD I had handy...


My wife laughs at me... I have my main shop in the basement, but seem to gravitate to the garage to do these projects. Lots of up and down the stairs, but I'm calling it exercise - plus I can light up a cigar out here...

I've had sam's induced errors a couple of times now.....since then I take all info contained with a grain of salt.
If you have a spare ion trap that is good I'd try that one considering that weak traps are not unheard of (you could also try removing and flipping your trap around so it is on backwards and see if that helps).

That is "Spirited Away" your playing if I'm not mistaken.

I used to have a shop in the garage, but lack of climate control, and other things tended to drive me back into my room or the living room.

Looks good so far!...only a bit more left to do.

Tom C.

I'd be interested in checking the horz freq via a frequency counter (assuming 15.734 kHz). Specifically, where would you pick this off? I see Sams has a procedure for checking/adjusting the Horz sweep (see below) and plan to follow this - but would like to be able to do a quick check beforehand to see how far off it is.

I use a 10x setting on a scope lead at the control grid of the HOT, but if you are getting a pic at all then you must be pretty close. those directions are a bit better that what I have (they give you better starting points on where the lock in and drive settings should be). The setting of the wave from is easy with the scope.

Sounds good - I will do the procedure with a scope, but may also try your quick test to see where I am. So you used your counter with a 10x scope probe?

yep that works fine on the freq counter, just dont try it at the same test point as used for setting the wave form you will way high numbers there, you want to clip at the grid of the HOT for looking at the freq. Its kinda neat as you can see the free running freq then give it a signal and you will see the freq snap to 15735 or what ever it is.

I like to scope around and see how things look. that'w what I like about the factory service manuals, like the one on the T-120.

Great - I will try that.

Yes - with the Sams there are no example traces on their schematic. But the Telaide has them (must be from Riders) so I can now check each of the critical areas with my scope. And that's next - re-validate voltages and waveforms per the manual, do the Horiz Sweep procedure, then linearity. Hopefully the alignment is close enough. I do want to try a full alignment sometime, but not sure this is the set (or if I'm ready).

If the picture is locked in, and your photo shows that it is, then the the horizontal is running at exactly the right frequency.

what Tom says..

I did the freq counter thing when I had NO hv as quick check to see I was way off and in which direction (fast or slow).

Good tip though. I am going to try it just to get some practice. Referencing alignment, I meant trying an IF alignment someday soon! On this set, I haven't touched anything in the IF section with the exception of two paper caps last in the stage. Once I am sure the sweep sections are 100%, I'll look at the front end and take it from there.

Quick update - I seem to have the Horizontal and HV sections all sorted and working per spec, but suddenly have a new minor issue. On channels 2-6 (56-88 mhz), I hear a steady audio tone, volume control adjustable - almost like a signal generator tone. Weak on channel 2, loudest on channel 4 and weak again on channel 6. And non-existent on channels 7-13 (174-216 mhz). As it's strongest at channel 4, I'd expect to look for something oscillating in the 66-72 mhz range.

Any initial thoughts? My Horizontal section a good place to start? Environmentals have been checked and there is nothing new added/started in the house recently.

Do you have another TV available? If so, connect it to your signal source to verify that it is clean. Do you see anything funny in the video.

It's doing this with no video source connected...