Motorola ts907 low hv

[timmy]

It starts at 5k and slowly rises to 6.30k

[Yamamaya42]

Originally Posted by timmy

I’m getting a really bad reading on pin 8 of v1 should be 3200ohms 3.2k I’m getting 6.30k I figured I would check resistance on v1 and v2

You are aware of the note “measured from the output of X2” that would be the cathode of the diode, before L54, and not ground, if this is what you are doing, then it's a good sign the power resistors are bad, but if you are measuring from ground, your readings are wrong.

[timmy]

The reading starts at 5k and rises slowly to 6.30k while it should be 3200ohms 3.2k

[timmy]

No I’m not measuring from ground I’m on the second diode which would be x2 output

[Yamamaya42]

Originally Posted by timmy

No I’m not measuring from ground I’m on the second diode which would be x2 output

Then, that seems to point right at the power resistor networks I pointed this morning, replace all the 2-3 watts in the area, and the power diodes, cost from mouser, 10-15$

[timmy]

I’ll post the other resistance readings from v2 v3 because they are way off

[Yamamaya42]

As it has been mentioned before, by myself and others, your best hope to get this working is not to touch any capacitors in the area what so ever, and VERY CAREFULLY replace all resistors with 2% or better carbon film types, paying close attention to placement and lead dress, IE, try to make it look as close to the original as you can, and since technology has changed so much over the years and they have gotten smaller, it never hurts to go up one size in power rating, cause even if you do, what you are putting in will be physically smaller than what you take out, they are that much more efficient than the old ones.

[timmy]

Ok v2 and v3 are within good range only v1 is a problem
The only pin that’s not right is pin 8 should be be 3.2 but it’s measuring 6.30

[Yamamaya42]

R39,R40,R41 obviously, get all 3 in 3w, but I would not stop there, you should have R48,R49,R50 on hand as well in case. It would not hurt to change R22 as well.

[jr_tech]

Originally Posted by timmy

I’m getting a really bad reading on pin 8 of v1 should be 3200ohms 3.2k I’m getting 6.30k I figured I would check resistance on v1 and v2

Did you measure from output x2, like it says in the note?


Edit
Never mind, I responded to an older post,I missed a page!

jr

[Yamamaya42]

Originally Posted by jr_tech

Did you measure from output x2, like it says in the note?

jr

I already asked him about that.

[timmy]

R22 is a trap

[Yamamaya42]

Originally Posted by timmy

R22 is a trap

my error, that's R38, I jotted down the "22" next to the right number! :P

[timmy]

I will tell you I have the chassis out on the bench but this circuit should do what it has to on the bench and I put an antenna input and the voltage goes up very little so it’s resistor time I doubt it would have made any difference it it were in the set at this point

[timmy]

Ordered the resistors but I’m wondering where the 7 volts is coming from on v1 pin 2 it’s almost like the tube is locked on there for pulling the voltage down on pin 8 where on this tube is there something that would make it conduct or turn on full or partial.