How to use Boost Step-Up Converter MC34063
If \$C_t\$ is actually 100uF, as shown on your rendering, it will never work. You need to have something close to the 1nF range. It is not a bypass capacitor like the other two, rather it a timing capacitor that sets the switch "on" time \$t{on}\$.  

Looks like you've also left out the current sense resistor? And the inductor may be on the small side, even for 1500pF \$C_t\$ . You may have damaged the chip in that configuration. I assume you're using the recommended 1N5819, slower diodes such as 1N400x series will not work properly.  

 

Above is most of the information (left column) you need to do the calculations, directly from the datasheet. You can use something like 0.5V for \$V_f\$, maybe 4.5V for \$V_{in(min)}\$, \$V_{sat}\$ is about 0.5V typically. \$I_{pk(switch)}\$ should be kept well under 1.5A. Try running f higher if you want to try to use 100uH.

If that's too much trouble, here's a javascript calculator that does the heavy lifting:

For your 5->12 converter, and 200mA output current, I get 


Ct=1180 pF  
Ipk=1140 mA 
Rsc=0.263 Ohm 
Lmin=104 uH 
Co=1062 uF 
R=180 Ohm 
R1=1.5k R2=13k (12.08V)