Benq G2255 doesn't power on - amber power light when plugged in - part 2

[rddube]

Re: Benq G2255 doesn't power on - amber power light when plugged in - part 2

OK, looks like that's actually the firmware for the flash chip, not the eeprom. Glad you found it. The highest tolerated signal on the flash is about 4.6V. As mentioned above, only a few Arduinos are below that. You need to check the specs on the Uno. Not a deal killer, but would require the voltage dividers.

My UNO is the no brand name kind, so I really don't know what the signal voltage is. I guess that's why in the attached photo, the guy uses 1K resistors...he's on the 5V line, but I have a 3.3V line on my Uno that I could use instead of 5V.

I also have a USB ASP board, and a FTD1232 board in case does could be better, but I would not really know how to plug them? I do however use my FTD1232 to update my oscilloscope firmware by using RX, TX and GND it's got VCC 3.33V and 5V that you can select, right now I have it on VCC 3.3V. There is also a DTR and CTS line on this device.

[will62]

Re: Benq G2255 doesn't power on - amber power light when plugged in - part 2

The flash uses SPI, the eeprom uses I2C. The pic below gives the SPI signal levels of different Arduino models. It could still be done, but the programming to read the .bin file and properly copy it to the flash ic, would be non-trivial to say the least. You could start by trying to issue read commands to the ic and see if you get a response.

I'll look over the other items you mentioned above. Maybe there is something open source that you could use with them. If you get to the point of copying the FW to the flash ic, I'd think about buying a new chip. The old one could have bad sectors on it, causing the problem. You can get 5 of them from China for $1.99 (free shipping), but they'll take a few weeks to get here.

https://www.ebay.com/itm/2pcs-25L2O2...-/191816892908



Added:
Watch this video. You can get the programmer for $2.50 on ebay (free shipping). The video has links to download software. That's less than $5 for ic's and programmer.

https://www.youtube.com/watch?v=ycE_ZgVUMfw

[rddube]

Re: Benq G2255 doesn't power on - amber power light when plugged in - part 2

Ok Will, I ordered the chips and the programmer. We're on for an adventure in a few weeks!

I also have this software that I use to update my oscillscope firmware which might work:

http://www.st.com/en/development-too...her-stm32.html

Will let you know as soon as the programmer comes in, because we could always do some tests on the original chip if the other haven't come in yet.

[will62]

Re: Benq G2255 doesn't power on - amber power light when plugged in - part 2

That program is customized for ST micro controllers. Your flash chip has different addresses and commands. One example is the read command for the ST is 11h, and for the flash it is 03h. That won't work for what you need, but there are a lot of other things that you could check while you're waiting on the chips and programmer. I would go ahead and download the software and take a look at it. There should be a chip select database. See if you can find the 25L2026E or something close.

We're not 100% sure the problem is the flash chip. It's just a common problem, and we're attempting to rule it out as cheaply as possible. I would still like to be able to see a good clock signal coming off the TSUMU58 chip, but your scope doesn't have the required bandwidth. At any rate, you have about 3 weeks to rule out as many other things as you can.

[rddube]

Re: Benq G2255 doesn't power on - amber power light when plugged in - part 2

Hi Will,

The guy in the video you sent me the link seems to be using this softwares:

https://tosiek.pl/ch341-eeprom-and-s...sh-programmer/

Do you think that will work?

[will62]

Re: Benq G2255 doesn't power on - amber power light when plugged in - part 2

Watch this one, same guy goes more into the software, problems he ran into and changing languages on the program. Under "show more" there are direct links to the software/drivers.

https://www.youtube.com/watch?v=5NYe21nFSDI

[will62]

Re: Benq G2255 doesn't power on - amber power light when plugged in - part 2

When you get a chance, check some voltages for me:

1. Take voltages on pins 1-7 at J6 (goes to keypad)
2. Take voltage at pin 110 (you can probe at R105). What happens when power button is pressed?
3. Repeat #2 for pin 121 (@R106) & pin 122 (@R107)

[rddube]

Re: Benq G2255 doesn't power on - amber power light when plugged in - part 2

When you get a chance, check some voltages for me:

1. Take voltages on pins 1-7 at J6 (goes to keypad)
2. Take voltage at pin 110 (you can probe at R105). What happens when power button is pressed?
3. Repeat #2 for pin 121 (@R106) & pin 122 (@R107)

Ok, will probably be tonight.

On this:

Added:
Maybe try freezing the eeprom and flash. Watch about 6:20 in to this video:

Tried freezing both the flash and EEprom, but doesn't do anything.

[rddube]

Re: Benq G2255 doesn't power on - amber power light when plugged in - part 2

Here are the voltage readings:

Pin 1 (top) = .007V
Pin 2 :1.56V
Pin 3: 1.51V
Pin 4: 1.566V
Pin 5: 2.05V
Pin 6: 1.96V
Pin 7: 0V

Pin 110 (at R105) = .864V, when pressing power button goes down to 0V
Pin 121 (at R106) = .866V, when pressing power button stays at .866V

[will62]

Re: Benq G2255 doesn't power on - amber power light when plugged in - part 2

Looks like we might have a low voltage problem. In your listing of voltages for pins 1-7, you mention "top" for pin 1. Just to make sure I'm looking at them correctly, pin 1 has a black arrow pointing to it on the pcb, pin 7 has a 7. Is that the way you listed them? The pic that I have is oriented so that I would consider pin 1 on the bottom.

Also, with a possible voltage problem, I'm going to need the voltages with and without the keypad connected. Let me know "connected" or "not connected" on the voltages above, and take new voltages for the opposite.

[rddube]

Re: Benq G2255 doesn't power on - amber power light when plugged in - part 2

Hi Will,

Thanks for catching my errors, you're right I read those upside down (when I wrote top pin, I meant top pin in the photo and that really is pin 7). So here are the results with and without the keypad connected, this time in the right order:

With / Without
Pin 1 0V / 0V
Pin 2 1.96V / 4.958V
Pin 3 2.05V / 4.986V
Pin 4 1.566V / 1.572V
Pin 5 1.58V / 1.584V
Pin 6 1.56V / 1.573V
Pin 7 .007V / 0V

Looks like there is a problem on pin 2 & 3?

[rddube]

Re: Benq G2255 doesn't power on - amber power light when plugged in - part 2

Ok so I checked the button panel the switches, the resistors etc. And everything looks fine. Checked the connectors and the flat cable and they look normal,

[will62]

Re: Benq G2255 doesn't power on - amber power light when plugged in - part 2

No, no problems with the 7 pins for the keypad. It does however confirm that the 5 outputs from the main chip to the keypad are down. Now we're hoping that the chip is down because the main chip is unable to load the firmware from the flash chip. We'll find out when you receive the new flash chips and programmer.

Pins 2 & 3 that you were wondering about, are the power for the bi-color led (yellow/green). If the main chip was working correctly, you'd only have that much voltage to one color. The circuit uses 2 pnp transistors as high side switches. 2 outputs from the main chip, normally keep one pnp off (or limited), and the other pnp on. Both outputs are down (bases = low), so both pnps are on. You are seeing an amber (yellow) light because it is the dominant on the bi-color. You see the voltages drop when you connect the keypad because of the load of the led. The other 3 pins (4,5 & 6), are on outputs that have 4.7k pull-up resistors to 3.3V. That's why they have similar voltages. Pins 1 & 7 are ground.

I'll post again if I think of anything else to check. Otherwise, I guess we'll see what happens when you receive the parts.

[rddube]

Re: Benq G2255 doesn't power on - amber power light when plugged in - part 2

Ok Will, I'll let you know as soon as the parts come in.

[rddube]

Re: Benq G2255 doesn't power on - amber power light when plugged in - part 2

While waiting for the chips and programmer, I did some searching on reading and writing to I2C eeprom chips.

I think this guy has pretty much documented it:

https://www.youtube.com/watch?v=L0ChYNwunUE

Let me know what you think!

[rddube]

Re: Benq G2255 doesn't power on - amber power light when plugged in - part 2

Still waiting for the programmer and chips. However I've figured out (thanks to Will62's video link) how to program the MX25L2026C flash with the updated software from this site:

https://tosiek.pl/ch341-eeprom-and-s...sh-programmer/

as in the link from Will62, the software being used is an old version (2004), but the updated version is in the link above. Will62's video shows however how to connect the chip on the programmer and that will be very useful.

I'll keep you posted as soon as it arrives. To be continued.......

[will62]

Re: Benq G2255 doesn't power on - amber power light when plugged in - part 2

Is the software capable of checking for bad blocks on the chip? Also curious if it can compare source code on 2 different chips. When you remove the old chip, you need to make a copy of what is on it (bin file). Would be nice to be able to compare the old file with the new. Whatever you do, don't erase what is on the old chip.

[rddube]

Re: Benq G2255 doesn't power on - amber power light when plugged in - part 2

Hi Will,

I can read the chip (from looking at the software) and save it into a .bin file. Then I could compare both. There is a Verify Chip command that I can use, but only once I have the device installed.

I'm anxious to get going!

And don't worry Will62, I'll do this step by step with your guidance!

Tks!

[rddube]

Re: Benq G2255 doesn't power on - amber power light when plugged in - part 2

Hey Will, I got the chips yesterday and the programmer today. So I am ready to test. What should I do first, try and program one of the new chips, remove the other from the board and try and read it? Waiting for you advice.

[will62]

Re: Benq G2255 doesn't power on - amber power light when plugged in - part 2

Why don't you program 2 of the new chips, then see if the software will compare contents of each and show a match. Once you figure out how to do that, remove the old chip and compare contents with one of the new chips. Can the software look for bad blocks on the chip? If the old chip doesn't have bad block(s), or corrupted data, your problem may be somewhere else.

Once you get to that point, you may as well make a backup copy of what is on the old chip, and solder in one of the new chips with the new firmware. I've never used that programmer or software, so I won't be of much help guiding you past any problems. Look forward to hearing about the results.