Leaked batteries in Tascam DR-07 digital recorder

[steven wan]

I am new here. I have the Tascam and battery fluid leaked onto circuit boards and right near the on/off switch. Now, when you plug in the external 5V. supply, the screen lights up with nothing on it and cannot turn on or off. I have cleaned up as much as I could and tried some contact cleaner on the on/off switch and to clean off the circuit boards with no change in the operation. Does anybody have any suggestions on what might have happened or what to try next? Thank you all!

 

[VenomBallistics]

I guess you could be more vague.
For this, we like pictures so we can better form theories about what caused the result.
But then ... The DP- 32 has some respectable horsepower

 

[steven wan]

Hi...thanks for that. I am not trying to be vague. The unit had (2) AA Duracell batteries, that were not being used because the unit was always powered by the external power supply. One day, when plugged in, without touching the on button, the screen lit up, with nothing on it, and nothing you did to any button did anything. I took the whole thing apart, wiped up all the film I could see on the circuit boards, which otherwise look fine. I also hit the tiny on/off switch with contact cleaner, which made no change, and the circuit boards themselves followed by another wipe clean. When plugged in again, same result as above. I can take pics of the circuit boards if it would make any difference, but even with a 5 power head loop they look fine. Everything is so tiny on those boards that I am not sure photos would show the detail. I just thought that this kind of problem may have been seen before, and someone would have an idea of what to do next other than send it to be fixed which would cost more than getting a new unit. Thanks again.

 

[VenomBallistics]

as I understand it, the LCD's back light is working, but the LCD layer itself is comatose ... likely due to nothing else coming alive
Some of these boards are certainly not for the unseasoned home gamer. I'd just assume it has a fair bank of effects courtesy of a lovely TQFN package chip in the middle of everything.
Might be a job for aggressive use of contact cleaner before sending it in for factory service.

 

[steven wan]

Thanks again. You are correct in that the display backlight is on, but the screen is blank. In addition, as soon as you plug in the power supply, the backlight comes on without touching the on/off button, and pressing the on/off button does not change that. No other button seems to do a thing either. I have to assume that the on/off switch is stuck in the on position, and because of that, it won't go beyond backlighting the screen, because normally you have to hold the on/off button for several seconds for the unit to come alive and boot up. Should I try to remove the on/off switch and replace it or jury wire in something else? As far as contact cleaner, do you think I should spray it all over the 2 circuit boards, and just let them dry, or wipe everything possible? It would cost more than it is worth to send it in for factory service.

 

[VenomBallistics]

"Switch" becomes a little bit fuzzy in these things as the real switching is done by logic and the buttons you interface with are kinda like suggestions. While possible, it's unlikely that any button has failed.
Probability rides on a gob of battery vomit stuck someplace you cannot see it.
Battery vomit corroding an IC leg or trace is a close second.
Chip damage due to being powered while full of battery vomit is also possible.
So ... hose everything down and give a close inspection for fuzzy or fluffy looking joints first
If that dont work, short across the power button for 5 seconds just in case it actually IS that button.
Since the backlight is on when it shouldn't be, i'm not thinking it's the button.

 

[steven wan]

Ok, thanks for that. I will keep trying to locate the problem.