Motorola ts907 low hv

[Yamamaya42]

there is only 2 places for the power to be going then, R94 (internally bad ) or V10 has a short grid to cathode. this will be evident by the wrong voltage on pin 7.

[timmy]

Ok I’ll look into that r94 that’s a 56k that measured 61k v10 I tried a new one befor ever removing that resistor and it made no difference. Would the vertical hold pot being disconnected have any impact on this.

[timmy]

So actually the 190 is feeding the 560k resistor to v10 where it’s being pulled from that point when it’s attached to v10.

[Yamamaya42]

Originally Posted by timmy

So actually the 190 is feeding the 560k resistor to v10 where it’s being pulled from that point when it’s attached to v10.

yes, R93 R94 is supply power to the grid of V10 A pin 7

[jr_tech]

Originally Posted by timmy

So actually the 190 is feeding the 560k resistor to v10 where it’s being pulled from that point when it’s attached to v10.

How far is the voltage dropping?

jr

[timmy]

Originally Posted by jr_tech

How far is the voltage dropping?

jr

From 190v to 40v

[jr_tech]

Originally Posted by timmy

From 190v to 40v

Since it is unlikely that the small current through the 560k resistor, even if it was shorted to ground (only 0.34 ma for 190 volts), would load down the 190 volt supply, the real load appears to be that V10 gets turned on hard when the 560k resistor is connected, and it’s increased plate current is loading down the weak 190 volt supply.

jr

[timmy]

Originally Posted by Yamamaya42

there is only 2 places for the power to be going then, R94 (internally bad ) or V10 has a short grid to cathode. this will be evident by the wrong voltage on pin 7.

I’ll clip that resistor and check it again but it can’t be a short grid to cathode since the short is still there with the tube out.

[timmy]

Originally Posted by jr_tech

Since it is unlikely that the small current through the 560k resistor, even if it was shorted to ground (only 0.34 ma for 190 volts), would load down the 190 volt supply, the real load appears to be that V10 gets turned on hard when the 560k resistor is connected, and it’s increased plate current is loading down the weak 190 volt supply.

jr

When v10 is out short still there.

[Yamamaya42]

None of this makes any sense here, given on the info provided.

You are saying this.
If R93 is disconnected, 190v is no longer loaded, and you get HV, but it's not C66 or V10 cause you tried it w/o them in the line.

Odd.

Things to try.
Disconnect R93 from the 190v line and hook a 620k 1w resistor from the 190v line to gnd ( aprox R93 +R94).
If it's able to keep 190v up and get hv, then the resistors in the set may be bad, even if the meter says good.

Or C65 is leaking, the 190v line does not have the power for the plate on pin 8 of the 6hs8 if C65 is leaking and trying to power it.

Also this could be a combo of things.
What is the voltage in/out and across R215.


Here are all points 190v feeds.

1- V6 cathode p1 C61
2- V6 g3 p9 R90,R89
3- V10 g1 p7 R93,R94
4- V12 g2 p3 R124
5- V21 plate p1 / cathode p7 R168
6- pullup R160
7- V21 g1 p2 r169 r170
8- pullup r149

[timmy]

Ok here is an admission I hate to say but in looking for a problem with the horizontal oscillator I came across the 560k and I went and used a 560k wire wound 3 watt temporarily not knowing this won’t work then temporarily I put together 2 resistors to make up 560k well this obviously didn’t work so I did find the right resistor and no more short got hv but could this resistor having been at .800 k have caused the horizontal oscillator to quit. I hope this resistor restores the IF and sound I don’t know if this resistor is critical in if it drifts up some it will affect the IF and oscillator.

[Yamamaya42]

Originally Posted by timmy

Ok here is an admission I hate to say but in looking for a problem with the horizontal oscillator I came across the 560k and I went and used a 560k wire wound 3 watt temporarily not knowing this won’t work then temporarily I put together 2 resistors to make up 560k well this obviously didn’t work so I did find the right resistor and no more short got hv but could this resistor having been at .800 k have caused the horizontal oscillator to quit. I hope this resistor restores the IF and sound I don’t know if this resistor is critical in if it drifts up some it will affect the IF and oscillator.

This is getting very confusing...
you are talking about R93? “.800 k” is 800ohms, way wrong for the part.
What is marked on the part exactly?

[timmy]

R93 560k when I first checked it was.800k.

[Yamamaya42]

which should have been marked green blue yellow silver (20%) gold for 10%

but...
.800k = 800 ohms.

does it still test like that out of the circuit ?

[timmy]

Well your right I screwed up again 560k green blue yellow but I just realized that the 560 I have here is green blue brown but it tests 560k some meters once over 500 it will show k or meg so now I have find one that shows k ohms without the decimal befor the 500. Omg this set is making me nuts the old 560k I took out measured .800k