Optoelectronics Scout 40 with reverse power damage

U is a common designation for integrated circuit. i would go direct to the company first.

they might send you a schematic as a courtesy.

On Fri, 07 Apr 2006 06:15:23 -0400, NightRunner put finger to keyboard and composed:

It's a LP2980IM5-5.0 Micropower 50 mA Ultra Low-Dropout Regulator by National Semiconductor.

- Franc Zabkar

Hey man that was great of you, thanks!!! I'm checking out the specifications PDF file now... If I can route 5V power around this thing, then I can at least test the rest of the device and ascertain whether there are any further damages. I'll keep y'all posted on how it goes with this!

Thanks again!

Rick

On Sat, 08 Apr 2006 06:50:12 +1000, Franc Zabkar was reportedly seen on the White House lawn holding a large picket sign and screeching the following:

"The usual approach of science of constructing a mathematical model cannot answer the questions of why there should be a universe for the model to describe. Why does the universe go to all the bother of existing?"

- Stephen Hawking

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Interesting news with this little bugger... I have it almost repaired! Thanks to Franc's post, I got out two irons and very gently removed the regulator chip, and found as I should have forseen that this had zero to do with the unit being dead. The regulator's only job is to lower the 12v adapter voltage to 5v so it can run the unit without smoking it yet again. The real damage remained at that point unseen, and might have plagued me MUCH longer except that a tiny glint of copper caught my eye between the power and filter switches, and on closer inspection I discovered that it was another heat stressed part of the board. I very gently removed a large diode that this heat stressed trace ran beneath, and discovered much to my joy that it was completely burned in half. I then took a small piece of wire and completed the circuit with external batteries powering the unit, and presto, it powered right up, and ummm... stayed powered even after I removed the jumper wire. It must be a flipflop type of power on/power off toggle. Anyways, I carefully took the whole delicate in hand and got out one of my FRS walkie talkies, and it tests out perfectly. I still have some major repairwork to do, but I can't say how pleased I am... I've wanted one of these buggers like forever and just could never justify the expense. Now I have a fully functional $360 frequency recorder for a mere $60! Well, ok, a bit more than that after that IC, but still!

THANKS both of you for helping me!! Now all I need is a new regulator IC and some VERY delicate work to repair that melted trace, and I'll be all set! :-D

Rick

"The usual approach of science of constructing a mathematical model cannot answer the questions of why there should be a universe for the model to describe. Why does the universe go to all the bother of existing?"

- Stephen Hawking

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On Fri, 07 Apr 2006 20:05:35 -0400, NightRunner put finger to keyboard and composed:

Maybe you had it switched on for long enough to partially recharge the battery???

- Franc Zabkar

a trick i learned long ago was to use bare 'wire wrap' wire to repair the thin traces. i don't know how commonly available it is anymore. one spool lasts approximately one lifetime if used only for repair work.