The power in our MV1608WW by gold star (LG) just cut out. how do we replace the internal power supply?

http://www.searspartsdirect.com/partsdirect/part-model/Goldstar-Parts/Microwave-Parts/user-manuals/manual-downloads/Model-MV1608WW/1366/0123370?modelNumber=MV1608WW&diagramPageId=&documentId=

Made by LG may be a recall

If there is no heating it is possible that the MAGNETRON has failed provided there is supply feed to the unit when the microwave is powered. Normally the magnetron along with the fan and light comes on when the microwave power is triggered. So since the rotation is absent it is possible that there is no power feed from the processor board which can be related to a driver failure. You need to check the output from the PROCESSOR to confirm and pinpoint the defective component. Check the relay to the magnetron trigger as this can be a suspect.

You didn't mention your brand or model, but F9 code on an LG sometimes means either a bad door switch or a loose door switch mount.

See this file on door switches.

If a switch is all you need, we offer a universal type for only $5 postpaid which you can order here.

Here is more info on F9 as it relates to some brands and models:

Sears Kenmore Whierlpool LG 721.63683300

"F-9 on this microwave IS inverter related. There is a service tech troubleshooting document stuffed in behind the control board cover which has some testing proceedures. My problem was the magnatron and checked out bad with the help of this document. It would run for a few seconds making clicks and then say F-9. It has been working great since I replaced the magnatron PN 6324w1a002c."

"f9 model 721.63764300
Kenmore Elite 36 " over tne counter microwave is supplied by LG made by Gold Star, made in China. It's main problem is the high voltage inverter board supplyed by Sears Parts. If you get a F-9 code on your microwave display screen and the micro quits it's probably this board. Reset the machine by pulling the power plug and waiting an hour. If it is the high voltage board is at fault it will probably fail after 45 seconds of start up. This part is really hard to get at but is less than $100. A qualified technician should be able to remove and repair this item in less than hour. Some techs will quote you $300 labor, don't buy it, it should cost a $100 or less. No need to buy another microwave."

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

This applies to several models:

"f9 model 721.63764300
Kenmore Elite 36 " over tne counter microwave is supplied by LG made by Gold Star, made in China. It's main problem is the high voltage inverter board supplyed by Sears Parts. If you get a F-9 code on your microwave display screen and the micro quits it's probably this board. Reset the machine by pulling the power plug and waiting an hour. If it is the high voltage board is at fault it will probably fail after 45 seconds of start up. This part is really hard to get at but is less than $100. A qualified technician should be able to remove and repair this item in less than hour. Some techs will quote you $300 labor, don't buy it, it should cost a $100 or less. No need to buy another microwave."

You can usually find exploded views and order parts by entering your model number at the Sears parts site.

BUT once you have the part number from the Sears site, you can often get the parts cheaper here.

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

Quoting another board:

Sears Kenmore Whirlpool LG 721.63683300. F-9 on this microwave IS inverter related.

There is a service tech troubleshooting document stuffed in behind the control board cover which has some testing procedures. My problem was the magnatron and checked out bad with the help of this document. It would run for a few seconds making clicks and then say F-9. It has been working great since I replaced the magnatron PN 6324w1a002c.

f9 model 721.63764300
Kenmore Elite 36 " over tne counter microwave is supplied by LG made by Gold Star, made in China. It's main problem is the high voltage inverter board supplyed by Sears Parts. If you get a F-9 code on your microwave display screen and the micro quits it's probably this board. Reset the machine by pulling the power plug and waiting an hour. If it is the high voltage board is at fault it will probably fail after 45 seconds of start up. This part is really hard to get at but is less than $100. A qualified technician should be able to remove and repair this item in less than hour. Some techs will quote you $300 labor, don't buy it, it should cost a $100 or less. No need to buy another microwave.

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

Goldstar owner's manuals can be downloaded here.

If yours in not there, for more Goldstar / LG / L.G. help, call 1-800-243-0000 (M-F, 7am-8pm CT, Sat 8-5 CT) and choose the appropriate prompt from the menu or visit here.

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

For Goldstar / LG / L.G. help, call 1-800-243-0000 (M-F, 7am-8pm CT, Sat 8-5 CT) and choose the appropriate prompt from the menu or visit them here.

Goldstar owner's manuals can be downloaded here.

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

replace thermal fuse in line with the power cord. Open cover, follow power cord to a small cylinder about 3 milimeters across. It is pointed on one end. Cut it out and take to an appliance repair store. solder the replacement thermal fuse back in.

Plug fuse may have blown. Replace that first or test.
Internal temperature trip may have cut out (if present)
Microwave generator (magnatron) may have failed.
Internal power supply may have failed due to moisture.

Very likely this machine is dead.
Save energy - and cash, by feeding birds stale bread and raw seed and corn.
Hopefully the next microwave oven will last longer.

The cost of repair may be more than the cost of replacement. Ask your nearest repair shop how much to replace the microwave unit, and check the power supply.

Sorry I can't offer a quick fix for you.