CurtPalme.com Home Theater Forum

koldby

Hi

I am about to put in some P19LCP tubes in a 9500LC ultra equipped with new style neckboards and P19LUG tubes.
I know the pinout for the 2 tube types are different and I can see the new necboard apparently is preparede for both types?

So what I think I should do is to remove the strap from A to B on the backside of the new NB and make a wire that connects A to Pin 2 on the LCP tube.

What about the NC pins 1 and 6?
Should they be connected to ground the same way NC pin 1 and 2 on the LUG tubes are?

And what about Pin 7 (KH(1) on the LUG types). It is apparently only a 1 meg resistor to ground , so I suppose I can leave that be?

barclay66 · Posted: Thu Jul 23, 2015 12:06 pm Post subject:

Hi,

It's much easier:

- Remove the jumper at Position A
- Solder in the jumper at Position B

That's all I needed to make them work with LCP tubes...
Make sure that the G2 voltage is taken from the designated connection point near R57 (10K Resistor, black-brown-orange).

Regards,
barclay66

koldby · Posted: Thu Jul 23, 2015 12:25 pm Post subject:

barclay66 · Posted: Thu Jul 23, 2015 12:27 pm Post subject:

Hi,

I just edited my post and added a new picture...

barclay66 · Posted: Thu Jul 23, 2015 12:38 pm Post subject:

Another thing:

Nothing gets shorted when putting the jumper in the 'B' location. There it connects the tube's pin 6 together with pin 7 and ties them to ground via a 330k resistor.
The G2 line is left open and with the G2 wire (has to be added if it's not there) You connect G2 to pin 2 following the LCP pinout...

Regards,
barclay66

koldby · Posted: Thu Jul 23, 2015 12:40 pm Post subject:

koldby · Posted: Thu Jul 23, 2015 12:41 pm Post subject:

Opps you posted that just before I posted

koldby · Posted: Thu Jul 23, 2015 12:42 pm Post subject:

No need to connect the NC pins to ground as they do with th LUG tubes?

barclay66 · Posted: Thu Jul 23, 2015 12:48 pm Post subject:

koldby · Posted: Thu Jul 23, 2015 12:52 pm Post subject:

koldby · Posted: Thu Jul 23, 2015 12:55 pm Post subject:

Misread your picture with the jumper.
In "B" position , pin 6 & 7 are connected together and via 330k to gnd.
G" just routed via wire to pin 2..

barclay66 · Posted: Thu Jul 23, 2015 12:56 pm Post subject:

koldby · Posted: Thu Jul 23, 2015 1:06 pm Post subject:

barclay66 · Posted: Thu Jul 23, 2015 1:23 pm Post subject:

It's a bit more:

- Four resistors
- One transistor
- One potentiometer

koldby · Posted: Thu Jul 23, 2015 1:29 pm Post subject:

Pot R64
Resistors R20 R49 R47
Transistor M1

Cant find the fourth resistor

barclay66 · Posted: Thu Jul 23, 2015 1:46 pm Post subject:

Resistor R48 is the missing one.
Now to the tricky part: What is the correct procedure for adjusting R64?

koldby · Posted: Thu Jul 23, 2015 1:52 pm Post subject:

Sure ...

I have a bunch of tubes (LUG) that is worth nothing else as giny pigs for experimenting with spot kill circuits!!

barclay66 · Posted: Thu Jul 23, 2015 2:29 pm Post subject:

Unfortunately, the setting that is adjusted via R64 is not the spotkill part but the beam current limit. Maybe there's a document describing how to adjust that on the older style neck boards. The service manual mentions that this section is critical for safety but there's nothing to be found on its adjustment procedure. These potentiometers are ususally glued to a factory setting...

BTW, there's a thread with some info on it: https://www.curtpalme.com/forum_archived/viewtopic.php@t=10252.html

koldby · Posted: Thu Jul 23, 2015 3:42 pm Post subject:

Would it be possible to measure the voltage @ +vf2 (and -vf2) and adjust with the new components to the same value (difference)?
Do you think it is the over-i sense that limits the performance. I would guess the spotkill cannot affect the performance..?

barclay66 · Posted: Thu Jul 23, 2015 5:31 pm Post subject:

Using reference measurements could be a suitable way indeed. What could be used too is testing with different video input levels in order to see how the I-sense output on the neck boards behaves and when the over-I signal kicks in.
I'm quite convinced that the different beam current control circuit is responsible for the lower contrast and brightness level...

Regards,
barclay66