Does anyone know how to extend time of backlight of Brymen multimer (eg.BM829S)?

[chemik22]

Hi,


I have small issue with my Multimer Brymen BM867S/BM829S. The time of backlight is only 32s and it is the thing which annoys me in this very good tool.


Does anyone know how to make hardware/software "hack" it to extend the time ?


Best,
Tomasz

[lordvader88]

On el-cheapo meters there's some external cap used for the timing, no idea on this 1, I own a BM869. I'm tempted to get a 2nd 1 for the price/quality/etc, as a 2nd good DMM.

I'm not going to mod this 1, but I'm powering it off a UPS 12V rechargable battery w/ a LM317 on my desk 

[coromonadalix]

the main chip datasheet  hasn't been found ...   

[chemik22]

So I guess it is not so easy task.. I know that the timer issue (backlight of only 32s) occur in the couple different multimetrs eg. BM867/869, BM828, BM525 etc...


Anyway if anyone know how to hack it for any kind of the Brymen multimetr pleas let me know ! probably it woud be easly transformable to the whole family of Brymen multimetr...

[coromonadalix]

why not ask brymen, sure it  will void any warranty, maybe they will answer how to do a mod, if its possible

[chemik22]

I asked Brymen before posted here and answer was like: "There is not enough ROM memory to insert such function, we know that this issue is problematic, in the next generation of multimetrs we solve this problem"... Well not nice answer...

[lordvader88]

Well have u tried tracing back from the light ?

I added 3mm LEDs to a Vici VC99, but my improvised defuser didn't work, so I tried SMD LEDs and at least with the low 5-10mA current I used, they where useless even without a diffuser.

So for now it has won

I shall go play Star Craft 2 WofL instead

[coromonadalix]

there was a capacitive touch backlight project with an Uni-T meter on this forum ... maybe you could do something like it ??