Help! Stingray doesn't play

[Burdin]

Hi,

I have problem with my Stingray, manufactured in 1991, 2 band EQ. Sudenlly it stoped play. At home I'm playing over external sound card, when I roll gain and master to maximum, I can hear the bass, but it seems that bass control doesn't work too. I changed battery but nothing changed.
So I made an audio probe and went over the circuit, signal form pick up is strong and clean, signal is OK until it reaches OP Amp, on input to OP amp signal is OK, but on output from OP Amp signal is weak, weaker then on input. So, I decided to change OP amp but nothing changed (I used TL072 instead of LM4250, but according to datasheet pin inputs should be same) . Does anybody knows what to do or what is a problem?

Thank you for answers

 

[Rod Trussbroken]

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Email Customer Service for advice:

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[PaulBass]

wrong opamp

You can't use the TL072 in place of the LM4250. TL072 is a dual amp and LM4250 is a single amp. They aren't interchangeable. You have to use the TL071

 

[Bert]

Agree. An TL071 will work fine.

 

[nhbassguitar]

Unfortunately, identical pinouts do not identical ICs make. My first thoughts when I saw this were differences in a) recommended minimum supply voltages, and b) quiescent supply currents. (Re. the latter: What, if anything, is MM doing with pin 8 on the 4250?) I'm not saying replacing a 4250 with an 071 absolutely will not work in a MM preamp; all I'm saying is that these devices are not directly interchangeable, considering all parameters.