Author Topic: Upgrading Mainboard in Lecroy DDA-3000 (aka WavePro 7300a?)  (Read 98833 times)

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Offline Converter

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Re: Upgrading Mainboard in Lecroy DDA-3000 (aka WavePro 7300a?)
« Reply #725 on: January 19, 2021, 06:31:34 pm »
Advantech's office asked for $500 for optimizing the firmware for the LCD matrix NL10276BC20-04. To do this, they ask to send them to Taiwan my matrix, motherboard and all connecting cables.

However, I was able to successfully modify the firmware myself.
For this I used the Chrontel CH7511B Utility, and some instructions on how to use them, which were not easy to obtain.

The task is quite simple, it was enough for me to correct only 2 DTD parameters: HB (Hor. Blanking) and VB (Ver. Blanking), which are calculated using the factory specifications of the LCD matrix presented in

Datasheet according to the formula : HB = Hsync Period - Hsync Active; VB = Vsync Period - Vsync Active. And also the clock frequency (DCLK) has been slightly adjusted and the size of the visible area.

Thus, the LCD matrix now works perfectly. As you can see in the attached photos, now the image scaling occurs correctly, both in DOS mode and after loading Windows.

Perhaps it will be useful to someone else in the future, so I am attaching to the letter my firmware optimized for the NL10276BC20-04 matrix (Lec1.bin): https://drive.google.com/file/d/1pVnBnOJF5OahTJMiuA6iCdQS9HPOywiH/view?usp=sharing
« Last Edit: January 19, 2021, 07:09:18 pm by Converter »
 
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Re: Upgrading Mainboard in Lecroy DDA-3000 (aka WavePro 7300a?)
« Reply #726 on: January 19, 2021, 09:16:05 pm »
Sorry, I just saw your post.

Good job! I did the same thing last year for my DDA-3000, mated AIMB-584 with NL10276BC20-04 display. A lot of trial and error experiments with Chrontel utilities.

Pro tip (don't ask how I know  ;D ) - backup the I2C EEPROM for the Chrontel chip first before playing with the Chrontel tools :)
 
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Re: Upgrading Mainboard in Lecroy DDA-3000 (aka WavePro 7300a?)
« Reply #727 on: January 19, 2021, 10:51:42 pm »
Hi, Did you get the same settings as mine?
Did you connect the power control of the LCD lighting inverter in the same way?
There it is advisable to turn off the LCD glow at some moments of time during the loading of the operating system.
Since the standard LeCroy controller no longer does this for obvious reasons, I started a separate wire from the ENBKL from the connector on the motherboard.
In principle, it is worth taking from this connector all other voltages for the LCD inverter. In particular, I am interested in the LCD brightness control signal (VR signal), but I cannot see how this is controlled by the motherboard.
In the Chrontel utility chip programming menu there is an option "Enable OSD display" - I activated this item, but did not see this OSD display panel anywhere in a running system. How is LCD brightness and contrast provided here? How do I call this menu? Do you have information about this?

Quote
Pro tip (don't ask how I know  ;D ) - backup the I2C EEPROM for the Chrontel chip first before playing with the Chrontel tools :)
Yes, I know what you mean. At some point, I was forced to unsolder the EEPROM chip and fix the firmware using the programmer (fortunately, I had 2 AIMB-582 boards), because the only DOS utility that I had at that moment was powerless to resurrect this brick, even with trying to return the original firmware  ;D. But later, when I got access to Chrontel CH7511B Utility and studied the theory, the modification was successful on the first attempt.

Update. Now I redid the power supply to the LCD inverter entirely from the motherboard (not just using a single contact ENBKL)

 I found brightness control in the Intel video driver control menu. As I determined, this does not affect the modes of operation of the inverter. I am sure that this is enough for adjustments during use of the oscilloscope, but fluorescent lamps will always be at maximum power, which is not good for their service life.

Update. I tried to change the power of the inverter by flashing the duty cycle parameter in the range from 6.25 to 100%, but this does not change the VR control signal - there is always about 3.5V DC voltage (not PWM). Does it work differently for you?

Update. I have determined that this motherboard does not support inverter duty cycle control: the CH7511B chip pins PWM_OUT0 and PWM_OUT1 are not connected anywhere on the board. The board already has printed wire for using these pins, and even a jumper to select analog/digital brightness control, but some radio components are not installed. Thus, the VR output works in a simplified way, it is always in the same 3.45V state. I think I can fix this by modifying the motherboard.

Update. I have restored the power control function of the LCD inverter. To do this, I simply connected pin #48 of the chip CH7511 to the "VR" pin of the inverter control connector (pin #4) through a 1k resistor. I tried adding a smoothing capacitor to get analog control, but as it turned out, this is not necessary, since the original NEC 104PWBR1 inverter is digitally controlled, so that 0V corresponds to 60% power and 3.3V to 100%. Thus, I set 50% duty cycle by firmware (with a frequency of about 200 Hz), which corresponds to 80% power for this inverter, and this is optimal in my case. I use pin #1 of the CN3 connector of the inverter (see the red wire that comes from pin #3 "ENBKL" of the motherboard) to control the screen dimming at certain points in the system boot, otherwise it flashes white.
Perhaps it will be useful to someone, the datasheet for the inverter is here: https://drive.google.com/file/d/1IJD30KvEBOUBRz3n3wEN9s3FfgjuztT2/view?usp=sharing
« Last Edit: January 26, 2021, 11:11:02 pm by Converter »
 

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Re: Upgrading Mainboard in Lecroy DDA-3000 (aka WavePro 7300a?)
« Reply #728 on: January 20, 2021, 08:44:23 am »
Hi, Did you get the same settings as mine?
Did you connect the power control of the LCD lighting inverter in the same way?
There it is advisable to turn off the LCD glow at some moments of time during the loading of the operating system.
Since the standard LeCroy controller no longer does this for obvious reasons, I started a separate wire from the ENBKL from the connector on the motherboard.
In principle, it is worth taking from this connector all other voltages for the LCD inverter. In particular, I am interested in the LCD brightness control signal (VR signal), but I cannot see how this is controlled by the motherboard.
In the Chrontel utility chip programming menu there is an option "Enable OSD display" - I activated this item, but did not see this OSD display panel anywhere in a running system. How is LCD brightness and contrast provided here? How do I call this menu? Do you have information about this?

Update. Now I redid the power supply to the LCD inverter entirely from the motherboard

 I found brightness control in the Intel video driver control menu. As I determined, this does not affect the modes of operation of the inverter, but I am sure that this is enough for adjustments during use of the oscilloscope.

Update. I tried to change the power of the inverter by flashing the duty cycle parameter in the range from 6.25 to 100%, but this does not change the VR control signal - there is always about 3.5V DC voltage (not PWM). Does it work differently for you?

I don't remember now. It was a year ago and now my entire lab is in boxes and will stay there for a while (moving & other reasons) so I cannot check. I think I didn't bother and just powered on the inverter from the motherboard, without any brightness control or blanking, no big deal :)
 


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