The problem is that instead of using Spice Symbols which have spice models associated with them, you are using Schematic Symbols that do not have spice models associated with them. The reason for this is because you have not read: [https://easyeda.com/forum/topic/How-to-ask-for-help-and-get-an-answer-71b17a40d15442349eaecbfae083e46a](https://easyeda.com/forum/topic/How-to-ask-for-help-and-get-an-answer-71b17a40d15442349eaecbfae083e46a)<br> <br> So you have not read and understood the Simulation Tutorial which explains why it is necessary to use Spice Symbols and where to find them. Please note that there is no spice model available in EasyEDA for the 74LS90. It is an obsolete device. There is however a model for what the 74LS90 might have looked like if it had been ported into the 74HCT logic family. This is the 74HC90 Spice Symbol from the System Spice Symbol library. Please note the header information in the 74HC90E spice model that can be viewed by inspecting the LTspice Netlist: > \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* > \* THIS MODEL IS FOR EDUCATIONAL PURPOSES ONLY\. > \* IT DOES NOT REPRESENT A REAL DEVICE\. > \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* > \* The 74HC90E Decade \(divide by 2 plus divide by 5\) Counter is an > \* obsolete device\. > * > \* It has never been transferred into\, nor is there a direct > \* equivalent in\, any of the CMOS families\. > * > \* This is not an accurate model of the 74LS90\. > \* It is a simplified model of how the device might behave if > \* it was realised in the 74HCT family of devices\. > * > \* As a 74HCT device it would be compatible with 74LS devices\. > * > \* This model does not attempt to represent any performance > \* aspects of the device other than the logical function and a > \* propagation delay similar to that of the original 74LS90 under > \* typical device spreads and operating conditions\. > * > \* The model requires a VCC and ground supply\. > \* It can be operated with any power supply rail but is intended > \* to be used in the 3\.3V to 5V range most commonly used for 74HC > \* devices\. > * > \* Inputs are modelled with infinite input impedance\, zero > \* capacitance and bias current\. They have a switching threshold > \* of 1\.6V so are compatible with 74HC device outputs over the > \* 3\.3V to 5V supply range and may operate with lightly loaded > \* 74HC outputs from a supply down to 2V\. > * > \* The outputs model behaviour similar to 74HC devices over a 3\.3V > \* to 5V supply range\. > * > \* Counter logic based on Fairchild DM74LS90: > *    [https://web.sonoma.edu/users/m/marivani/datasheets/74ls_series/74ls90.pdf](https://web.sonoma.edu/users/m/marivani/datasheets/74ls_series/74ls90.pdf) > \* but with the addition of the R9NAND net to force the R9 to override R0\. > \* All 7490 and 74LS90 datasheets are either incorrect\, incomplete or unclear > \* about how the last stage of the divide by 5 block is implemented which > \* results in R9 not overriding R0 if the logic is implemented as shown in the > \* datasheet\. > \* That error is corrected in this model\. > ** > \* Model developed for EasyEDA by signality\.co\.uk > \* 200603: Updated to correct R9 and R0 behaviour and renamed to 74HCT90\_EE > \* 201130: Reintroduced accidental removal of RR0\_1\, RR0\_2\, RR9\_1 and RR9\_2 > \* input resistors to stop AND gate inputs disappearing when connected to GND\. > ** > \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* There is a typo in the header: where it says: > \* The **74HC90E** Decade (divide by 2 plus divide by 5) Counter is an > \* obsolete device\. it should say: > \* The **74LS90** Decade (divide by 2 plus divide by 5) Counter is an > \* obsolete device\. <br> <br> There is a similar problem with the choice of the NE556 symbol: it is not a valid Spice Symbol. The 556\_BJT\_EE spice symbol is available:   Note also that neither the NE556 or the 74xx90 devices will operate with a 1V supply. The minimum for the 74LS90 was 4.75V (4.5V for the military temperature range 54LS90). The symbol for the 2N3904 also needs to be replaced with:  or either of:   <br> <br>