EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: gab_au on January 27, 2020, 12:55:54 am
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Hi,
I have an E4407B here that has a fault that I am unable to find any info on.
When turned on the screen is white. Most times it will not boot correctly with some instances taking a couple minutes before the boot LEDs light and it attempts to load firmware from floppy. When it gets there DS7 and DS13 are alight, a combo not discussed in the manual.
When it boots, it will then either read the loader disk and prompt for disk 1 or sometimes will stop 3/4 way through the loader. If it does get all the way through it fails a few tracks into disk 1. The floppy doesn't step and the screen remains white with the disk access light on.
Has anyone seen this sort of behaviour before, and any hints - short of a replace the cpu board? Would faulty flash do that?
If it does come to cpu board replacement, can I use an E4401-60059 rather than the E4401-60206 if I swap the personality eeprom?
Thanks
Greg
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I would make sure that all of the power supply voltages are in spec and with low ripple. Also look for flaky tantalum capacitors.
I would also bet that the electrolytics in the power supply are probably suspect.
Sam
W3OHM
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Did you get anywhere with your repair?
I have the same symptom, DS1/DS7/DS13 is firmware checksum error
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I've been wrestling with another issue (keypad not responsive), but have had a similar issue... screen is white, and DS7/DS13 lit. I did not have exactly the same floppy drive symptom, but I did have an issue where the firmware did not work correctly on the floppy. I reformatted the floppy, reinstalled disk 1, and was able to see the firmware continue screen, and DS7/DS13, cleared. There is also a green light on the board near the back. That light should should blink on and off every second or so. In my case, it was solid until disk 1 successfully booted to firmware continue screen.