Crumar Musical Instruments User Group.

Hola,

neurokrash wrote:

>>I don\ufffdt have a Bit One, but check Pin 4 of the TL072 against ground and
>>even Pin7 against ground. Me thinks that the TL gets maybe ground onto
>>Pin4 or Pin7, or some voltages are missing (Pin 4 should have a negative
>>voltage, pin7 a positive, -maximum- at +/-18 Volts!) and that causes the
>>overheat. 
>>    
>>
>
>I'm not detecting any continuity between ground and pins 4 or 7 on any
>of the TL072s.  Is that the right thing to look for?
>  
>
The other poster was right, it is Pin4 and Pin8, i\ufffdm sorry.

>I cannot find 780x or 781x, but there is one 7912 on the PSU board,
>and it measures:
>Left 0
>Middle -17v
>Right -12v
>
>  
>

Middle -17? -Sure- the middle pin? Normally must the left pin provide 
the -17 volts, middle pin ground and right pin the -12 Volt. If the 7912 
gets overheat, it will raise the output voltage. But with overheat i 
mean "burning".....

Yup, better check the PSU first......

Greetings
Stef