Motorola ts907 low hv

[timmy]

I did notice I get activity from all vertical controls except the vertical centering it does absolutely nothing no movement of the screen so I’m not having video maybe I Should look into vertical maybe the horizontal and vertical cannot sync because of a vertical problem. What could cause the vertical centering to quit while everything else works.

[timmy]

Yes I think when it was on 10a it was 0.55 I mentioned in a previous post I didn’t put the decimal

[timmy]

I have to again ask myself if I messed up with the power supply caps since there is 3 different voltages and I checked and double checked if I had maybe one of the 190 and 275 backwards that would explain everything like the 145v to the tuner that comes from a higher voltage with a resistor to drop it to 145v it don’t make sense to have 2 feeds for 190 and 2 for 275 I would think the 275 would have had 3 feeds and 190 have 1 because there is 24 arrow connections while the 190 only has 9 arrow connections but I’m going to go back and check these arrow connections again.

[timmy]

Can someone that has the Motorola ts907 schematic tell me what the letter z means it has a 275 arrow where would this be marked where it goes.

[jr_tech]

Originally Posted by timmy

Can someone that has the Motorola ts907 schematic tell me what the letter z means it has a 275 arrow where would this be marked where it goes.

Z and W are connected to the CRT heater...the connection of the heater winding of the transformer to the 275 volt supply is to elevate the CRT heaters to a voltage near that of the CRT cathodes, to reduce the likelihood of s heater/cathode short.

jr

[timmy]

So if this is only drawing 550ma then the diodes should not be getting hot not warm but hot. Another mystery.

[timmy]

Sams shows c1 and c2a in series which makes sense but this pic of the Motorola original schematic note the c1 and c2a is it me or is this showing 2 negatives together +— — + I have these caps in series like the sams shows.

[Yamamaya42]

clearly an error on the Motorola schematic.

[timmy]

Yes I do see that now sams is usually known for that

[timmy]

What I find odd is the voltages on v1 v2 210 on pin7 and pin 8 100 but I’m getting 198 pin 7 and 60 on pin 8 but if I pull v1 the voltages on pin 7 come up to 130

[timmy]

I could use any idea what would cause vertical centering to not work at all but all other vertical works hold, linearity, height, but no centering screen don’t move at all. The centering pot measures 1.5meg but sams shows it to be a 2meg.

[Yamamaya42]

Originally Posted by timmy

I could use any idea what would cause vertical centering to not work at all but all other vertical works hold, linearity, height, but no centering screen don’t move at all. The centering pot measures 1.5meg but sams shows it to be a 2meg.

You have nothing to center on the screen, no video.
if there was something to see, then you would see the effect of the adjustment.

if you were to feed video in like before, then you would see it working most likely.

[jr_tech]

Originally Posted by timmy

I could use any idea what would cause vertical centering to not work at all but all other vertical works hold, linearity, height, but no centering screen don’t move at all. The centering pot measures 1.5meg but sams shows it to be a 2meg.

The vertical centering pot (R-16) is 10 ohm! It is shown on an output winding of the vertical output transformer (T-2).

jr

[timmy]

Originally Posted by jr_tech

The vertical centering pot (R-16) is 10 ohm! It is shown on an output winding of the vertical output transformer (T-2).

jr

Yes your right I knew that lol my mistake

[timmy]

I thought the whole screen goes up and down not the image alone.