Checking hv

[Yamamaya42]

the forward voltage of the 25z6 is 22v and the forward voltage of the 1n4007 is lest than one, you gain almost 21v by changing to so;id state.

[timmy]

Originally Posted by Yamamaya42

The only thing that makes sense to me to raise positive bias is to remove the 25z6 and replace with one1n4007 , leave the heater connected, and wire in the diode from the 10 ohm resistor on the plates to the 40 UF / spkr field coil, making sure to keep the cathodes p 4/8 unhooked.

This will raise the B+ by a lot, but may also have an effect on the negative bias.

Well I would have watch the voltage that it don’t exceed the caps rating in there already and there is a resistor already in there to take the place of the field coil. Why not just pull the tube out and put a resistor in place for the heater

[timmy]

Originally Posted by Yamamaya42

the forward voltage of the 25z6 is 22v and the forward voltage of the 1n4007 is lest than one, you gain almost 21v by changing to so;id state.

Well that would bring it close to 150v as riders says

[Yamamaya42]

If it were me, I would leave the tube in for ascetic values, and for the balance of the heater load, and just put in the new diode under it, making sure that the old tube is out of circuit for the new diode.

[timmy]

Originally Posted by Yamamaya42

If it were me, I would leave the tube in for ascetic values, and for the balance of the heater load, and just put in the new diode under it, making sure that the old tube is out of circuit for the new diode.

I already have a diode in there so all I have to do is the disconnecting and then check voltage riders says 150v with the negative tube 35w4 so if it’s higher it should be good for negative

[jr_tech]

Why not increase the B- supply as well, it is also used by the vertical deflection circuit.

jr

[timmy]

Originally Posted by jr_tech

Why not increase the B- supply as well, it is also used by the vertical deflection circuit.

jr

With a diode ?

[timmy]

That may bring voltage to high don’t know yet

[jr_tech]

Originally Posted by timmy

With a diode ?

Yes, but remember that you are working with a negative supply, so pay attention to getting the diode polarity correct.

jr

[timmy]

Originally Posted by jr_tech

Yes, but remember that you are working with a negative supply, so pay attention to getting the diode polarity correct.

jr

Lol yeah I don’t want fire works

[timmy]

Well that idea is out since warmed up it’s 147v if I do the diodes and cut out the positive tube the voltage will be to high likely for the caps in there even though it drops but initially it would be high.

[jr_tech]

Did the vertical scan improve when you increased the B- supply?

jr

[timmy]

Originally Posted by jr_tech

Did the vertical scan improve when you increased the B- supply?

jr

I didn’t increase the voltage because it was at 147v and if I got the voltage up it may have been to much for the power supply caps.

[jr_tech]

lAccording to the data sheet for the D5-100, the deflection sensitivity is about 100volts per centimeter when operating at 2000 volts. I believe that the hv in the Pilot is closer to 2500 volts, which would reduce the deflection sensitivity to around 125volts per centimeter.

http://www.r-type.org/pdfs/d5-100gh.pdf

The vertical height of the D5 is about 3 centimeters, so it would require about 375 volts to scan from top to bottom of the screen.

The voltage that you have available from your B+ and B- supplies, which power the vertical circuit is less than 300 volts total, so you can’t achieve a full vertical scan.

jr

[jr_tech]

Originally Posted by jr_tech

The voltage that you have available from your B+ and B- supplies, which power the vertical circuit is less than 300 volts total, so you can’t achieve a full vertical scan.

jr

I missed the connection between the vertical output and the hv supply (from the bottom of the focus pot). Perhaps io would be possible to increase vertical deflection voltage by changing or eliminating the resistor above or below the focus pot.


jr