PLEASE HELP

I have a project to simulate and build a low cost function generator. This can be either using Op amps, IC timers or Function Generator IC's.

I must first simulate this or many examples/types of function generators using the Multisim sotware. It must include a switch for the type of wave (sine,triangular,square) and also a switch to vary frequency.

I have successfully simulated 2 circuits so far using Multisim. The question I am about to post is based on 1 of them. It is a function generator based on a LM158 Op amp and 3 other 741 opamps.

The problem i have at the moment is trying to get all the waves to the same amplitude. I want them to be at +5/-5V peak to peak. I have achieved that with the square and triangle waves but i cant get the sine wave to get to that amplitude...right now it is at around +2.5/-2.5V pk to pk. I am changing the external resistors and capacitors of the sine wave shaper and i cant get it to budge without totally altering the shape of the sine wave....PLEASE HELP.

View attachment FG741.pdf