Model JVM1790SK 01 Where/how do you change the

a screw at the back side when removed get access to the bulb.Usually 40Watts bulb with1/2 " threaded

GE has the manuals for most of their appliances on their site: http://www.geappliances.com/service_and_support/literature/ . Just enter the model number and click Submit.
The direct link to the manual for the JVM1790 Over-the-Range Convection/Microwave oven is here: http://products.geappliances.com/MarketingObjectRetrieval/Dispatcher?RequestType=PDF&Name=49-40480-1.pdf . GE only lists the JVM1790CK, JVM1790BK, JVM1790WK and JVM1790SK.

I hope this helps.

Cindy Wells

HELLO.

Since the outlet is live,the power problem is from the microwave.

check on the back of the microvave to locate the fuse that control the supply of power to the microvave.

Change the fuse because it is unable to control power supply.

Then plug the microwave to the outlet.

Thanks .

That's probably a shorted relay on the control circuit board.

We regularly repair such control units for customers nationwide by mail for $39.95 postpaid with a one-year guarantee.

At our Web site, we have a video available showing how to remove a typical over the range control panel assembly in under 5 minutes.

We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.

Remove the screws from around the rear of the oven and slide the cabnet off to the rear. You should be able to access the bulb from here.
WARNING: any time you work on a microwave you have to be careful of the capacitor. Unpluge the microwave and discharge the capacitor with a large screwdriver with a plastic handle.
Be careful.

The megatron tube is not working. The microwave should turn off when the door is opened for safety. If it is still under warranty, return it. If not, you may consider replacing the unit. I know its expensive, but its just taking up cabinet space tonight.

Unplug unit before entering.

The light bulb is behind the air vent at the center top of the microwave. Remove two screws at the very top front of the microwave and pull the vent cover forward at the top. Sliding left is sometimes necessary to release the bottom tabs of the vent cover. The light fixture will be behind this cover.

Good Luck. Reverse the above process to reassemble.

If there's no obvious removable cover over the bulb (and the owner's manual doesn't address it) some disassembly may be required.

Always unplug a microwave before removing or installing any bulbs.

On an over the range type, remove the vent grille across the top and see if bulbs can be accessed there. There may be a panel on the bottom covering the light(s), instead.

If not, chances are you'll have to remove it from the wall, then remove the outer cover. If so, the installation instructions are very handy, and it's best to have two people since the microwave can be heavy and awkward.

You can download GE owner's manuals and installation instructions here.

Once it's out of the wall, the outer cover (wrapper) will need to be removed, just as you'll need to do on a counter top model.

Be sure to put all the screws back in the right holes, since some may be special grounding screws.

Bulbs can be had in most grocery stores, hardware stores, home improvement centers, and big box or department stores.

Many models use halogen lamps. You must not touch the new one with your bare skin, as the oils will shorten the bulb life.

We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.

The interior oven light can be accessed in the following way:
1.Open door and remove the top grill via the 2 screws along the top edge.
2. In the interior light will be under metal plate with fasten by single screw. The halogen bulb is rated at 120V 20watt. Looks like a G-8 bulb with 8mm pin spacing with o.a.l. 1-5/8" long

Get these bulbs cheap at http://www.1000bulbs.com/120-130-Volt-G8-Base-Halogen-Light-Bulbs/

If you or a friend decide to work on it, we have *critical* safety and disassembly info at our site, which is linked at our listing here on FixYa: http://tinyurl.com/yzjozk You can find helpful exploded view diagrams and order parts by entering your base model number (without the suffix) here: http://tinyurl.com/gv383 You may have a bad door switch. We also have a file on door switches at our site.