question about a 8-t-241

[stusnyder]

Originally Posted by Penthode

Hmm. That rules out the divider at least. If the voltages are then wrong, it appears that something is conducting heavily when the set is running if the voltages are incorrect.

Can you provide the as measured voltages against the voltages the schematic advises? This may provide the clue.

I can try to test some of the voltage points....if I can figure out where by the schematic...

[Penthode]

Originally Posted by stusnyder

I can try to test some of the voltage points....if I can figure out where by the schematic...

If you look at the schematic near where the power transformer is drawn, you will see the sections of the divider resistor. Measure the junction nodes indicated with respect to chassis and provide us the readings against what it should be. For example, downstream from the 5U4 at the first node (section A of C148 elctrolytic positive it should read +215v to ground. You could measure from the focus control as that is a convenient access point.

The next point should read +135 volts to chassis.It may be accessed at C148B positive connection.

The voltage at the C147C positive should read -60 volts to chassis and the can of C147 should read -120volts to chassis.

[stusnyder]

Originally Posted by Penthode

If you look at the schematic near where the power transformer is drawn, you will see the sections of the divider resistor. Measure the junction nodes indicated with respect to chassis and provide us the readings against what it should be. For example, downstream from the 5U4 at the first node (section A of C148 elctrolytic positive it should read +215v to ground. You could measure from the focus control as that is a convenient access point.

The next point should read +135 volts to chassis.It may be accessed at C148B positive connection.

The voltage at the C147C positive should read -60 volts to chassis and the can of C147 should read -120volts to chassis.

Ok I measured directly on the divider resistor, here are the readings from right to left:
1st term (under trans) 202v
2nd term 340v
3rd term 0
4th term 15
5th term 31

measured in dc scale, black to chassis

[Penthode]

Originally Posted by stusnyder

Ok I measured directly on the divider resistor, here are the readings from right to left:
1st term (under trans) 202v
2nd term 340v
3rd term 0
4th term 15
5th term 31

measured in dc scale, black to chassis

I assume that the DC voltages on the 4th and 5th terminals are negative with respect to chassis?

The second terminal which is supposed to be +135 volt measures 340 volts: is that correct? I assume you have changed the electrolytics. If the 135 volt line is so high, it may be that the wiring may be incorrect. Please check the wiring closely around these points.

In addition, the -15 volts and -31 volts show the correct division ratio of about 2 to 1. (It should be -60v and -120v). This would imply that the other end of the divider is open or high resistance. Otherwise something is pulling down the -120v.

Please check the wiring.