Discussion Category:  Balances

Frozen display, no grams reading, buttons beep

Others have had these symptoms, so here's a bit of info.

On these and similar MT balances, the main 12VDC is passed through to the separate "Terminal" display unit. Whenever the main balance is dead, the display will still run, but only shows a software version number. The buttons beep, and the font size changes. But the display cannot talk to the main balance.

On ours, I found a fried SMT inductor in series with 12VDC, failed open (like a fuse.) This removes 12V and shuts down everything. The actual cause was a short on one of the switching regulator chips, an so8 pin LM2674MX-ADJ.

The inductor in my case was an Epcos 3.3uH in a 1210 smt package. There are several on this pcb, measuring 1.2ohms (when not destroyed by overcurrent.) It's a common part, Digikey or Mouser.

 

wbeaty

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wbeaty
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doublechin

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