Electronics > Repair

What more i can do?

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PGPG:

--- Quote from: 222Lab_Test222 on October 30, 2024, 12:03:19 am ---Can you explain a bit more?

--- End quote ---

Your following sentence looks to deny what I was thinking about:


--- Quote from: 222Lab_Test222 on October 30, 2024, 12:34:50 am ---when that long beep occurs either its the CMOS battery is dead ...
If i change that things, maximum times those beep is gone and boards is working normal.

--- End quote ---

I just supposed that there are some crc in configuration in RAM in RTC IC or the time that is after its reset (1970 ?) not accepted, but as replacing dead battery helps probably it is not this.

From what you write now it looks that it starts from testing everything and any error = beep.
I would expect error number somewhere. Once upon a time we send just after power on the device information through its normal LED and used foto-detector connected to COM port to read it.

222Lab_Test222:

--- Quote from: PGPG on October 30, 2024, 01:07:19 am ---
--- Quote from: 222Lab_Test222 on October 30, 2024, 12:03:19 am ---Can you explain a bit more?

--- End quote ---

Your following sentence looks to deny what I was thinking about:


--- Quote from: 222Lab_Test222 on October 30, 2024, 12:34:50 am ---when that long beep occurs either its the CMOS battery is dead ...
If i change that things, maximum times those beep is gone and boards is working normal.

--- End quote ---

I just supposed that there are some crc in configuration in RAM in RTC IC or the time that is after its reset (1970 ?) not accepted, but as replacing dead battery helps probably it is not this.

From what you write now it looks that it starts from testing everything and any error = beep.
I would expect error number somewhere. Once upon a time we send just after power on the device information through its normal LED and used foto-detector connected to COM port to read it.

--- End quote ---

After couple of weeks test here and there, i somehow find that those MSDOS are not getting input address bus voltages.
A16 and A17

Harry_22:

--- Quote from: 222Lab_Test222 on October 30, 2024, 12:34:50 am ---All the boards have same issues, Normally on other board when that long beep occurs either its the CMOS battery is dead, or RAM or bios is dead.
If i change that things, maximum times those beep is gone and boards is working normal.

--- End quote ---
Seems the answer is here.
What do you mean under "bios is dead"?


--- Quote from: 222Lab_Test222 on October 30, 2024, 01:29:06 am ---
After couple of weeks test here and there, i somehow find that those MSDOS are not getting input address bus voltages.
A16 and A17

--- End quote ---

The chip type (UV EEPROM size) is set in the Bios?
Take out them on working board and check it for beep (Check the working board without chips).

radiolistener:
since it is very old, it is possible that ROM chips are loss their information, so the beep may be a signal that ROM checksum is failed

222Lab_Test222:

--- Quote from: Harry_22 on October 30, 2024, 06:07:54 am ---
--- Quote from: 222Lab_Test222 on October 30, 2024, 12:34:50 am ---All the boards have same issues, Normally on other board when that long beep occurs either its the CMOS battery is dead, or RAM or bios is dead.
If i change that things, maximum times those beep is gone and boards is working normal.

--- End quote ---
Seems the answer is here.
What do you mean under "bios is dead"?


--- Quote from: 222Lab_Test222 on October 30, 2024, 01:29:06 am ---
After couple of weeks test here and there, i somehow find that those MSDOS are not getting input address bus voltages.
A16 and A17

--- End quote ---

The chip type (UV EEPROM size) is set in the Bios?
Take out them on working board and check it for beep (Check the working board without chips).

--- End quote ---

yes there is beep if those EPROM is removed from working board.
I think thats the BIOS.

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