blindboybenton 1/9/2017 6:00 AM
takamine acoustic electrics issue cp-132sc
Morning

I don't normally touch this sort of thing, But a local guitar shop that i do repairs for asked a favour as they brought it working then it failed
[ATTACH=CONFIG]41993[/ATTACH]
This acoustic has low output. Not pickup or battery. Injected a signal and i can see it til it gets to i ic called 4062
This unit has 3 ic all with different numbers on
signal seems to get going into pin 1 and 2
any assistance ??

have a good day people
 
Jazz P Bass 1/9/2017 9:42 AM
What you see are two different opamps.
UPC4572
ADA4062

The pinouts are standard opamp configuration.

Pin 1 output A
Pin 2&3 Input A
Pin 4 -V
Pin 4&5 Input B
Pin 7 Output B
Pin 8 +V
 
blindboybenton 1/9/2017 9:58 AM
thanks jazz bass. I did look at the ada4062 but pin 1 and 2 are connected together via track ( can see in the picture ) and ive tested with dmm. when i checked the net for pin out on a ada4062 i noticed the 1-2 are input and output so this lead me to believe that it wasn't an ada4062.

will check tomorrow again
 
g1 1/9/2017 11:19 AM
An op-amp with input connected to output is a standard unity gain buffer:
[ATTACH=CONFIG]41995[/ATTACH]
 
Enzo 1/9/2017 12:24 PM
Op amps have two inputs, an inverting one and a non-inverting one. It is very common for one input to tie to the output.


Edit: g1 beat me to it.
 
blindboybenton 1/10/2017 3:20 AM
Many thanks
Ive learnt something new today
 
Jazz P Bass 1/10/2017 10:59 AM
Here are three circuits that I pulled off of the ADA4062 datasheet.
 
drewl 5/18/2017 12:15 PM
here's a couple links with info on the Accuracoustic preamp with schems.

I don't know why they used these crappy electrolytics for signal coupling except for space as they tend to fail, like the one I'm working on.



https://www.musiker-board.de/threads...esucht.399060/


Yustech GT-Guitars and Basses Solution.: Takamine AccurAcoustic Preamp Issues Part II
 
Mick Bailey 5/19/2017 1:17 AM
I've fixed plenty Takemine preamps due to leaking electrolytics. The problem is not tied down to one particular version, either. Often they're so bad the tracks have corroded away. Even more difficult is those that are positioned between sliders and difficult to reach. I've been replacing the low-value electrolytics with Tantalum for the past 5 years and they're holding up fine.