Products > Test Equipment
Brymen BM86x Backlight Duration Mod
mwb1100:
--- Quote from: shakalnokturn on March 05, 2024, 11:43:36 pm ---I have a dump from a Greenlee BM251 if that's of interest.
--- End quote ---
If I'm not mistaken, that's a Greenlee DM-100A == BM251 with a backlight (approx 30 seconds)?
If someone were willing to monkey around with a DM-100A EEPROM (surely there's calibration data in there, so some risk of really screwing up your meter): I'd look for something like 0x20 in the EEPROM (32 seconds) and see if changing that to a significantly smaller or larger value makes a corresponding change to the backlight duration. Of course even if that works it only hints to the possibility of a BM867 doing something similar, and almost certainly not in the same EEPROM location.
I have a BM257, but don't have access to an EEPROM reader/writer.
coromonadalix:
in the brymen eevblog model, i think DAVE stated at one time, it needed a programmer to access some ..... he would not go that far in explanations
For the higher models ??? duno ??
shapirus:
--- Quote from: IanB on March 05, 2024, 10:48:56 pm ---I don't think anyone knows for sure that there is an EEPROM in the meter. Based on interactions between user joeqsmith and Brymen, it might be that the firmware is stored in non-erasable ROM and the only way to change it is by chip replacement.
--- End quote ---
There should be. The meter has to store its calibration data somewhere, and there is a procedure to recalibrate them, so it's not read-only.
edit: ...but of course the delay time may be hardcoded in the firmware itself, which may be stored in a ROM, which apparently is the case.
joeqsmith:
--- Quote from: mwb1100 on March 05, 2024, 10:01:24 pm ---...I suspect there's a half decent chance that there's a byte in the EEPROM for the number of seconds the backlight stays on.
--- End quote ---
--- Quote from: IanB on March 05, 2024, 10:48:56 pm ---... Based on interactions between user joeqsmith and Brymen, it might be that the firmware is stored in non-erasable ROM and the only way to change it is by chip replacement.
--- End quote ---
The following was from my discussions with Brymen about increasing the BM869s's backlight timeout.
Me:
--- Quote ---Is it possible to upgrade the two meters I have with the new firmware? I would have no problems changing the IC if that is what it takes, assuming it would not cause a problem with the meter's alignment. Enough people have asked about it that I would take the time to demo this feature as I doubt very many people are aware of it.
--- End quote ---
Brymen:
--- Quote ---... BM869s uses OTP chip. Its firmware can not be updated directly. The only way is to replace its U6. To change U6 may have the chance to affect its performance. Generally re-calibration and retest are recommended after replacing chip. ....
...new U6 were sent to you as a special arrangement. To prepare and to send new U6 would be a heavy service burden. We will not offer new U6 to other users to replace their BM869s. Please kindly understand.
--- End quote ---
Me:
--- Quote ---I appreciate you sending out the new ICs for me to try it out. I will make it very clear when I demonstrate the new feature that the ICs are not available to the general public.
--- End quote ---
shakalnokturn:
--- Quote from: mwb1100 on March 06, 2024, 07:48:29 am ---
--- Quote from: shakalnokturn on March 05, 2024, 11:43:36 pm ---I have a dump from a Greenlee BM251 if that's of interest.
--- End quote ---
If I'm not mistaken, that's a Greenlee DM-100A == BM251 with a backlight (approx 30 seconds)?
--- End quote ---
It's a DM-200A, backlight is about 30s.
I have a second one around that I'll dump when I clean the switch. It will at least show the memory locations that have identical values on 2 different meters.
--- Quote from: joeqsmith on March 06, 2024, 01:42:16 pm ---
Brymen:
--- Quote ---... BM869s uses OTP chip. Its firmware can not be updated directly. The only way is to replace its U6. To change U6 may have the chance to affect its performance. Generally re-calibration and retest are recommended after replacing chip. ....
--- End quote ---
--- End quote ---
That only makes half sense to me:
Calibration constants can't be in OTP MCU (at the best they could store coarse default values) and various photos show EEPROMs, replacing the MCU is not replacing the ADC so their comment is true only if the new firmware uses different EEPROM addresses for calibration.
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