These ovens are simple, so it must be the repair people. The ignitor is really a 'glow plug'- it runs off house electricity. It takes a minute or two to get hot-before it allows the gas to flow. And if you remove your racks and lift out your oven floor, you can see if the plug gets red. Once red, the gas should flow to the burners and light up. If the glow plug is red (give it two minutes)but the gas doesn't come on, it's the thermopile- basically a wire and sensor that 'allows' the gas to go to the burner by opening a solenoid valve or relay switch. If the glow plug gets red but the burner doesn't light, this is the problem. Sometimes it's as simple as moving the sensor closer to the glow plug.
As the oven heats up, there is another sensor/thermostat, that is controlled by the knob to cycle the flow of gas on and off to keep an approximate temp in the oven . This regulates the temperature. And I 'think' it works by cutting the electricity to the glow plug.
Now I have never worked on my Bluestar oven, but I have replaced thermocouples on old Wedgewoods, and worked on many old gas furnaces that work similarly.(except they have pilots). But I put new controls and thermostats in them.
From what you said, I think it's the thermopile. (Also called a thermocouple)or the solenoid valve it controls. Otherwise you would have heat. When the oven worked once and shut off - it would have been interesting to see if the glow plug got red again-if it didn't, then the thermostat was bad, but if the glow plug went red but the burner didn't go back on, it's the thermopile.
If the glow plug doesn't get red hot, then it's the glow plug, but like I said, you can see that if you lift out the oven floor.
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Colored hanging lights
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