levell tg303 signal generator service manual repair

[matt09]

Hi all,

Struggling to find info on this generator for a repair. Can anyone advise?

Thanks

[singapol]

What seems to be the problem?

[matt09]

As I was using it control pot to change frequency simply stopped working. Oscillator etc is all fine just that the frequency for each range is locked.

[singapol]

Quite possible that control pot is broken or wire connection broken which should be easy to fix. BTW this is a
generic type of RC function generator so not to worry.

[matt09]

Obviously I have checked those. There's a fair few devices inside so a schematic would make things MUCH easier. Does anyone know anything about the company Levell? Haven't been able to find much.

[singapol]

Obviously I have checked those. There's a fair few devices inside so a schematic would make things MUCH easier. Does anyone know anything about the company Levell? Haven't been able to find much.

By your reply it seems you are knowlwedgeable about such things. Schmatics are hard to come by online as companies want to protect their IP but they must have inspiration from somewhere first? Please answer a few questions, Is TG303 mircroprocessor controlled as everyone knows one can make a software function generator plus the frequency counter? If it is fully a discrete design does it use opamps , transistors,resistors,capacitors and diodes to first generate a triangle wave then  convert to square wave and then massage to a sine wave to finally to an amplifying stage? Does it have opamps like LM741,LM308, FET transistor, CA3086 transistor array, frequency counter ic, 2N2905 and 2N2904 medium power output ? Or does it use a ICL8038 or MAX038 ic function generator ?

[matt09]

Yeah this place is great for schematics so was hoping someone might have something..
It's pretty old so all old school kit in there, CA3086 and opamps.

Think it could be rip off of this but the board inside is quite different and the frequency control doesn't match the schematic.

https://alexkaltsas.files.wordpress.com/2012/07/voltcraft_fg1617.pdf

[matt09]

Fixed now, it was an opamp gone bad. Nightmare tracing it out without a schematic though.