An oven heating control system. schematic diagram? block diagram? the feedback operation in the control system? control objective? five basic element of the control system?

Parts Schematic and wiring diagram.

https://www.partselect.ca/Models/CGEB30S9FB3/

Part F161 is the Convection Element. Check it for continuity with a multimeter and also check the connection tags to it as they can melt.

https://www.partselect.ca/PS2361497-Frigidaire-318255504-ELEMENT.htm?SourceCode=20&SearchTerm=CGEB30S9FB3&ModelNum=CGEB30S9FB3&ModelID=899380


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Your wiring diagram and parts schematics are here in the link below. Normally the bottom element does glow read hot after a couple of minutes. Broil elements last a lot longer because they aren't used as much. There is only one Control Board. If I was guessing, I would say the temperature sensor is at fault. Elements either work, or they don't, but you can easily test continuity with a meter. Many parts are discontinued.

https://www.searspartsdirect.com/model/3f7nkrfnvp-001428/frigidaire-pleb30t8ccb-electric-wall-oven-parts

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If your heating elements are not open then the issue lies with the controls and circuitry that operate the heating coils. Get yourself a schematic and trace it out and you will find the culprit.

JC, schematics Google Search

How to Read Schematic

the definition of schematic

http://www.minecraft-schematics.com/

The bake element
is the heating element that is found at the bottom of the oven. Most electric ovens use both the bake element and the broil element in a bake cycle, with the bake element performing 90% of the heating. If the bake element isn't working, the oven may not heat. To help determine if the bake element is defective you should first do a visual check. If the element is blistered or separated then it should be replaced. If the element appears to look normal, then turn the oven on to a bake function for a minute and then turn it off.

Check the element for signs of heating and if it is still cold then it may be defective. Disconnect the power and then remove the back panel. First check the wires as they may have become loose or corroded. If the element appears to be fine visually, test it for continuity with a multi-meter. If the element is burned or no longer has continuity, it will need to be replaced.

Surface burners
are typically either a coil type, solid type or a ribbon coil as used in smooth top ranges. All of these consist of a heating wire that uses electric current to produce heat. Coil type elements can be checked for continuity by removing them from the terminal block and testing them with a multi-meter.

You should also inspect the terminal ends for signs of heat damage or corrosion, and if present, you should replace the terminal block or receptacle at the same time. You will need to remove power from the range to change the terminal block. Solid elements and smooth top elements require raising or removing the main top to gain access. You will need to remove power from the range before lifting the main top. Continuity can then be checked with a multi-meter, once you have removed the wires from the element terminals.

On modern electronic control ranges, the oven temperature sensor
is the part that regulates the oven temperature. If it is not working properly it could be the reason why the range or oven won't start. This part can be found inside the oven on the rear wall near the top. Most modern ovens will display a fault code if the oven sensor is at fault. If you think the sensor may be the issue you can check the resistance with a multi-meter but will need to know the correct resistance of the sensor at room temperature. Remove power from the appliance before performing this test.

The infinite switch
on the control panel controls the power to each surface element. If you have no heat at an element and the element and terminal block check ok, then you may have a defective infinite switch. Disconnect power to the range and remove the console back panel. Locate the switch and check for overheated wires or faulty terminals first. Test the switch's contacts for continuity with a multi-meter. If defective, replace the switch.
If the infinite switch does not appear to be defective, then you should check for proper voltage to the switch. This is a live high voltage test and should only be performed by qualified persons.

Most modern ovens use an electronic control board
to control the oven functions. These models will use the control board to operate the oven safety valve on a gas range or oven, and the bake and broil elements on an electric range or oven. If there is no power to the igniter circuit, or the element circuits, then you should check the control board to verify that there is power at the appropriate output relay. These are live voltage checks and should be performed by qualified persons only. If there is no output voltage then the control should be replaced.

Here is a heated seat TSB for cars built prior to 12/14/07

TSB 09-4-8
03/09/09
INOPERATIVE HEATED SEAT(S) - BUILT
BEFORE 12/14/2007

FORD:
2005-2007 Five Hundred, Freestyle
2008 Taurus X, Taurus

MERCURY:
2005-2007 Montego
2008 Sable

ISSUE
Some 2005-2007 Freestyle, Five Hundred, Montego and 2008 Taurus, Sable and Taurus X vehicles built before 12/14/2007 may exhibit an inoperative heated seat(s). This concern may be caused by an intermittent open element in the heated seat mat.

ACTION
Follow the Service Procedure steps to correct the condition.

SERVICE PROCEDURE
The heated seat system is controlled by the heated seat module located underneath the front passenger seat cushion. The heated seat switches are part of the heating ventilation air conditioning (HVAC) module but the heated seat system operates independently from the climate control system. The heated seat module regulates seat temperature by monitoring resistance of a thermistor type thermostat located in the cushion heater mat. The heated seat module is designed to remain on, heating the seat and maintaining temperature until switched off. For vehicles built before 5/1/2006, the module will time-out and switch off after 10 minutes.

1. Refer to Workshop Manual (WSM), Section 501-10 for pin point test on inoperative heated seat(s).
a. When testing the heater mats resistance and circuits for an intermittent open, technicians should sit in the seat while testing the circuit resistance, move the seat in multiple seating positions and apply pressure to several areas of the heated seat mat to ensure the mat element is not open intermittently.

2. Refer to WSM 501-10 for heated seat element replacement when an open electrical circuit has been identified.

Parts Block
WARRANTY STATUS: Eligible Under Provisions Of New Vehicle Limited Warranty Coverage
IMPORTANT : Warranty coverage limits/policies are not altered by a TSB. Warranty coverage limits are determined by the identified causal part.

OPERATION DESCRIPTION TIME
MT090408 Use SLTS Operations If Actual
Available Or Labor Time
Performed As Actual Time

DEALER CODING
CONDITION
BASIC PART NO. CODE
14D696 28

I hope this helps to solve it.

Hello there:
Here is some Helpful troubleshooting tips i have made up for you
Hope this is very helpful for you.

If the element looks good, then we progress to basic electrical measurements (hint: that’s an illustrative link put there for your edumucation– read it now). Y’see, Hoss, incredibly, the element can look fine from the outside (and usually does) but the inner core, the part that electricity flows through and gets really hot, can be electrically open. So, we’ll start with a simple resistance measurement of the bake heating element. To do this, you have kill power to the oven and then remove the visible and obvious element retaining screws. Then remove at least one wire from the element; you can, of course, remove the entire element from the oven, as shown in the picture (click for larger view). You’ll be making the measurements with your probes on the element’s terminals.
Measure the resistance with your meter; anything less than 50 ohms is good. If you’re seeing a high resistance reading, like something in the thousands of ohms (denoted with the “K” on most meters) then, ding-ding-ding, you just found the problem– come git you a new element.
If the element tests good, then it’s time to graduate to live tests. That means voltage on the circuit, fire in the hole, fry yo’ ace if’n you ain’t careful. If you don’t know how to safely make live voltage measurements, then stop reading right now and call a professional appliantologist. You’ll also need the wiring or schematic diagram of the oven– these are usually hidden inside the control panel compartment, some disassembly required. Make sure you’ve killed power to the oven before going any further, Homer.
Before we get into the actual live test, it would helpful for you to know how the bake element works so you’ll have some insight into how the live test is done. A bake element operates at 240vac, 120vac is supplied to each side of the heating element. One side is tied more or less directly to L1 or L2 (both of which are tied to 120vac)– see your model-specific wiring diagram, I’m just ’splaining the strategery here.
The other side of the heating element is connected to the electronic range control either directly or through some intermediary controls. (Antique, RV, or off-grid ranges may not have an ERC but rather a mechanical thermostat. Ahh, those were the days…)
Now, here’s where the real strategery comes in. The basic idea is that when the bake element is turned on, BOTH sides of that element should get 120vac (remember, the element is supposed to have 240vac to heat up properly). So we’re going to split the problem in half by seeing which side of the bake element power circuit isn’t coughing up its 120vac. Then we shall deal harshly with its insolence.
Ok, are you ready to rock or are you ready to shock? If you’re still rockin’, here’s how we do the live test:

• kill power to the oven (which you already did earlier, right? );
• disconnect one wire from the bake element and then secure it so it doesn’t touch anything else
• clip the common side of your meter to any known ground point, like an unpainted metal surface in the oven;
• re-apply power to the oven;
• measure voltage at both of the element power wire leads;
• the one that isn’t giving you 120vac is the circuit you need to troubleshoot; you can ignore the other side.

See, you just cut the problem in half! Now kill power to the oven again and focus your keen, Vulcan-like squinties on the wiring diagram and locate your problem circuit. Then identify the next component in line between the end of the heating element wire with the missing voltage and wherever it ends up, be it the circuit board or one of the power lugs on the terminal block in the back of the oven. The rest is trivial. Continue applying this essential kata until you find the missing voltage in that circuit.

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Electric Oven: Repairs and Maintenance Electricranges and ovens are generally easy to repair, because there's not muchto go wrong and there's not much you can do. Most repairs are actuallyreplacements, a matter of unplugging the old part and plugging in thenew. Most of the malfunctions that affect electric ranges involvefaulty heating elements.

Caution: Beforedoing any work on an electric range or oven, make sure it's unplugged,or turn off the power to the unit by removing one or more fuses ortripping one or more breakers at the main entrance panel or at aseparate panel. If the range is fused at a separate panel, this panelmay be located adjacent to the main panel or in a basement, crawlspace, or other location. If there is a grounding wire to the range,disconnect it. Make sure the power to the unit is off.

Servicing Fuses

Ifthe range or oven is receiving power but doesn't work, the unit mayhave its own fuse or circuit breaker assembly. This assembly is usuallylocated under the cooktop of the range. In some units, lift the top ofthe range to gain access to the fuse assembly; or lift the elements,remove the drip pans, and look on the sides of the cabinets. Inside theoven, look to the back to spot the fuse assembly.


Ifthe unit has this additional fuse or breaker system, components such asthe oven light, the range heating elements, the timer, and aself-cleaning feature may be separately fused.

If thesecomponents or features fail to work, don't overlook the possibilitythat the fuses have blown. To replace a blown fuse, unscrew the oldfuse and install a new one of the same type and electrical rating. Ifthe unit has circuit breakers, push the breaker or reset button, whichis usually located on the control panel.

Replacing Range Heating Elements

Whena range heating element burns out, it's easy to replace. But before youdisassemble the range to check or replace an element, make sure therange is receiving power. Here's what you can do:

Step 1:Check the power cord, the plug, and the outlet. Then look for blownfuses or tripped circuit breakers at the main entrance panel or at aseparate panel.

Step 2:Check the fusing system inside the range. If the circuit is broken,restore it. If the range is receiving power, go on to check the element.

Step 3:When the element is cool, remove it. In most ranges, each top heatingelement is connected to a terminal block in the side of the elementwell. To remove the terminal block, lift the element and remove themetal drip pan that rests below it. The element is held by tworetaining screws or is push-fit into the terminal block. To remove ascrew-type element, remove the screws holding the wires. To remove apush-type element, pull the element straight out of its connection.


©2006 Publications International, Ltd.
To remove a range heating element, remove the screws holding the terminal
wires, or pull the element straight out of its connection.Step 4:Test the element with a volt-ohm-milliammeter (VOM) set to the RX1scale. Disconnect one of the electrical leads to the element and clipone probe of the VOM to each element terminal. If the element isfunctioning properly, the meter will read between 40 and 125 ohms; ifthe meter reads extremely high, the element is faulty and should bereplaced.

To test a range element without using a VOM, remove aworking element from its terminal block and connect it to themalfunctioning element terminal. Don't let the test element overlap theedges of the element well; keep the element inside the well, even if itdoesn't fit perfectly. Turn on the power to the range. If the workingelement heats, the suspected element is bad and should be replaced. Ifthe working element doesn't heat, the terminal block wiring or theswitch that controls the element may be faulty. Call a professionalservice person.

Step 5:Replace a burned-out range element with a new one made specifically forthe range. Take the old element to the appliance-parts store; ifpossible, take the make and model information, too. This data willprobably be on a metal tag attached to the back service panel of therange. To install the new element, connect it the same way the old onewas connected.

Replacing Oven and Broiler Heating Elements

Electric oven and broiler elements are often even easier to test and replace than range elements. Here's how:

Step 1:If the oven element doesn't work, first check to see if the range isreceiving power. Don't overlook the fusing system inside the range.

Step 2: If the range is receiving power, set the timer on the range to the MANUAL position.

Step 3: If the element still doesn't heat, turn off the power to the range and test it with a VOM set to the RX1 scale.

Step 4:Remove the screws or plugs that connect the element to the power.Remove the retaining shield, which is usually held by two screws, andremove the element from the brackets that hold it in the oven. Theelement is usually held in these brackets by screws.


©2006 Publications International, Ltd.
To remove an oven or broiler heating element, remove the screws or pull
the plugs that connect it. Remove a retaining shield and lift out the element.
Step 5:Clip the probes of the VOM to each element terminal. If the element isin working order, the meter will read from 15 to 30 ohms. If the meterreads higher than 30 ohms, the element is faulty and should bereplaced. If the element tests all right but doesn't work, the problemmay be at the terminals. Make sure the terminals are clean and tight atthe element connections.

Oven and broiler elements cannot betested without a VOM. If you don't have a VOM, take the element to aprofessional service person for testing. The problem is usually amalfunctioning element; however, you aren't risking much by replacingthe element without a professional test.

Step 6:Take the burned out element with you to the appliance-parts store tomake sure you get the right replacement part; if possible, take themake and model information, too.

To install the new element,place it in the same position as the old one. Connect it the same waythe old one was connected, using the same screws to hold it in place.Just about all the other components of an electric range or oven(including its door gasket, oven controls, and timer) are virtually thesame as the components used on gas ranges.

Most problems withgas and electric ovens or ranges are easier to fix than you think. Thekey is knowing how the various parts work and when to replace them.

Have a look at these websites to find parts and details :

http://www.appliancepartspros.com/appliance_range_oven.aspx
http://www.gallawa.com/microtech/dataselect.html

You may still have a bad Electronic Range Control (ERC). This is your timer that you mentioned. The oven is controlled by the ERC. There is a separate circuit for the BROIL and BAKE functions. Does the BROIL element still work? Or, are both elements not working? You may want to double check all your connections from the element to the control board as well. Sometimes the wire lugs can oxidize and not make good contact. Check the ERC to see if there any obvious signs of failure. Burned components are common. These boards are considered "non-serviceable" and usually requires replacing. You can attempt component-level troubleshooting if you are savvy with electronics. There's usually a basic block diagram that comes with your appliance mounted somewhere inside the operator console or on the back panel of the range.

The ERC for your range would cost in the neighborhood of about $100 - $140 to replace. Prices will vary between model versions and will also depend on where you get it. It is a very simple repair job if you wish to pursue this yourself. I can give you step-by-step instructions if you need further assistance. I hope this helps you.

PS The reason all your surface elements still work is because they are controlled by infinite switches behind the control knobs. There is a separate switch for EACH burner.