[seanohue]

I have a problem with a PINT where after a random interval of minutes, the amp cuts off. It will come back on if I turn the amp off and back on again. At first, I thought it was because the 9.6V 170mAh battery I was using was not getting a full charge from a 12V 1A wall wart, so I changed the wall wart to a 15V 500mA and charged it for about 14 hours. The intervals are completely random also; I think the longest it has run is about 45 minutes but it has never been shorter than 5 minutes. Average I'd say is 15 minutes. R1 is a 75 ohm resistor, which puts the trickle rate at .1C. Any ideas?

 

[FallenAngel]

Measure the current draw. Do any of the opamps get hot?

 

[seanohue]

Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif Measure the current draw. Do any of the opamps get hot?

Op-amps feel fine. From where to where do I measure the current?

 

[FallenAngel]

Measure mA between positive battery lead to B+.

What opamps are you using?
2x AD8397 ~ 50mA
AD8397/LM6172 ~ 35mA

 

[seanohue]

Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif Measure mA between positive battery lead to B+. What opamps are you using? 2x AD8397 ~ 50mA AD8397/LM6172 ~ 35mA

2x AD8397. Either there is something wrong with my meter or I am not reading it right. At 2m range I get .004, then a 20m I get .04, 200m .4 and 20 .04. I'm using the unfused measuring tool because the fuse one isn't giving me a reading (stupid thing is probably blown).

Sorry for the noobness; don't know how I got so far in DIY with so little.....

 

[n_maher]

Quote:

Originally Posted by seanohue /img/forum/go_quote.gif 2x AD8397. Either there is something wrong with my meter or I am not reading it right. At 2m range I get .004, then a 20m I get .04, 200m .4 and 20 .04. I'm using the unfused measuring tool because the fuse one isn't giving me a reading (stupid thing is probably blown).

Nothing wrong with you meter, just your method. You have put the meter into the circuit. What I mean is that one probe would be connected to the positive terminal of the battery, the other probe would connect to the battery strap or whatever. Let me know if that doesn't make sense.

 

[FallenAngel]

No idea how you're measuring that.

1) Unclip the positive side of the battery while still having the negative still connected.
2) Turn on the amp - Of course, LED should stay off.
3) Measure mA by connecting the positive lead of the DMM to the battery and the negative lead to the battery clip. LED should turn on.

EDIT: Nate, got it first.
What DMM are you using so I have an idea what those settings mean.

 

[seanohue]

Quote:

Originally Posted by n_maher /img/forum/go_quote.gif Nothing wrong with you meter, just your method. You have put the meter into the circuit. What I mean is that one probe would be connected to the positive terminal of the battery, the other probe would connect to the battery strap or whatever. Let me know if that doesn't make sense.

Yea that's what I was doing. The LED lights up.

Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif No idea how you're measuring that. 1) Unclip the positive side of the battery while still having the negative still connected. 2) Turn on the amp - Of course, LED should stay off. 3) Measure mA by connecting the positive lead of the DMM to the battery and the negative lead to the battery clip. LED should turn on. EDIT: Nate, got it first. What DMM are you using so I have an idea what those settings mean.

The DMM I'm using is nothing special, some cheapo thing I got somewhere. The measures are 2mA, 20mA, 200mA and 2A. Up to 200mA is fused, up to 2A is not fused. I think the fuse is blown because I got no reading. I'm also not plugging anything into the amp (no headphones or source), if that is what I am supposed to do.

 

[FallenAngel]

Ok, I'm not understanding it. What are you gettnig for the 2A unfused?

 

[seanohue]

Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif Ok, I'm not understanding it. What are you gettnig for the 2A unfused?

The values above were from the 2A unfused. I don't get anything from 200mA fused.

 

[FallenAngel]

Correct me if I'm wrong, but doesn't the unfused ONLY work at the 2A setting?

 

[seanohue]

Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif Correct me if I'm wrong, but doesn't the unfused ONLY work at the 2A setting?

I don't believe so, it says up to 20A (sorry, 20A, not 2A) so I'd imagine the other ranges should be usable as well.

 

[FallenAngel]

In that case, your readings make absolutely no sense

The only one that makes any sense is the 20A reading of 0.04A - 40mA and it's fine.

Can you try with a brand new Alkaline, non rechargeable battery? Or just charge your battery somewhere else until you know it's full and try again.

 

[seanohue]

Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif In that case, your readings make absolutely no sense The only one that makes any sense is the 20A reading of 0.04A - 40mA and it's fine. Can you try with a brand new Alkaline, non rechargeable battery? Or just charge your battery somewhere else until you know it's full and try again.

I get the same readings from an alkaline. I am working on a runtime test right now to see if an alkaline cuts out. I'll let you know if it cuts out.

 

[seanohue]

Hmmm my problem seems to have manifested itself. I now get less than 1 minute of play time on both an alkaline and rechargable. It only plays continuously on the 15V wall wart. The op-amps seem to get hotter when run from a wall wart than on battery. I'm going to recharge the battery and see what happens.