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.

[jr_tech]

Originally Posted by timmy

Using the new dvm if I’m reading it right on 10 amp or the other amp settings it’s showing either 0.055 or 055 so I’m not sure if this means 550ma.

That would indicate 55 mA...where are you reading current?

jr

[timmy]

Originally Posted by jr_tech

That would indicate 55 mA...where are you reading current?

jr

Output of the diode
The last time I used my 500ma meter in the same place and it went to the end of the scale

[jr_tech]

Originally Posted by timmy

Output of the diode
The last time I used my 500ma meter in the same place and it went to the end of the scale

Was the new meter set to “10” and the probes plugged into “com” and “10Amax” positions?

jr

[timmy]

Originally Posted by jr_tech

Was the new meter set to “10” and the probes plugged into “com” and “10Amax” positions?

jr

yes it was

[jr_tech]

Should read “0.55” on the “10” scale if the current is 550 ma, recheck your readings please. Perhaps double check with the other meter, see if it still pegs.

jr

[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.

[Yamamaya42]

Originally Posted by timmy

So back on track hv very good after 15 minute warm up voltages are still not right
275=266 190=187 145=143 not bad but after it running additional 10 minutes the voltage drops off
275=255 190=170 145=130 and no matter where the voltages are still no video. Using the new dvm if I’m reading it right on 10 amp or the other amp settings it’s showing either 0.055 or 055 so I’m not sure if this means 550ma.

The picture shown is a strong indication of a IF problem.

the alignment is most likely off, and is messing the video up.

[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