Replacing microwave display?

Maybe just a bad solder connection.

--- sam | Sci.Electronics.Repair FAQ:

Repair | Main Table of Contents:

+Lasers | Sam's Laser FAQ: | Mirror Sites:

Important: Anything sent to the email address in the message header above is ignored unless my full name is included in the subject line. Or, you can contact me via the Feedback Form in the FAQs.

Or, it could be a bad connection from the display to the pwb via the ribbon cable that so many manufaturers use.

Bob Hofmann

Or, it could be a bad connection from the display to the pwb via the ribbon cable that so many manufaturers use.

Bob Hofmann

The display is probably fine, likely just needs the connections cleaned if it uses one of the rubber contact strips, or the solder touched up. Read the FAQ on microwave safety, then once you've done that this is most likely something you can fix yourself.

Tossed my 2-yr old Sharp R425E because of a bad display. The replacement display costs more than what I paid for the whole oven!!

Unfortunately, Sharp (et al) have seen fit to make these displays a permanent part of the CPU board -- that is, the flex trace ribbon is bonded in such a way as to make repairs practically impossible. Even if you _could_ replace only the LCD module, you can't BUY only the LCD module, you have to buy the entire display/controller assembly. The replacement cost of your display/CPU board is $118.12 from Tritronics.

Alternatively, if you're a gambler, you can ship your board off for repairs:

Even if you're lucky enough that only a very simple repair is needed, at $32.50 labor plus parts plus shipping... well, which option you choose depends on how fond you are of your oven I guess.

I purchased that R425E because my old oven was a Montgomery Ward which was built by Sharp. It lasted 15 years! I was hoping I'd have similar luck with a new Sharp, but alas they've also decided to produce junk now.

So I thumbed my nose at Sharp and replaced it with an Amana (Maytag), which is covered with a full 5-year warranty (factory standard, not "extended") on the display/electronics. That's 4 more years than most manufacturers offer! I hope this means it's designed to last at least twice as long as the Sharp did.

Good luck, Ray

Sadly, these are not that simple anymore. The display ribbon is glued/taped to the controller board. There is no solder -- good contact depends on pressure from the ribbon (it's bent in a "U" loop) and the tape pulling from the opposing side of the board. If you peel off the display cable to clean the contacts, GOOD LUCK getting it realigned with the tightly-spaced traces and maintaining good contact. Solder can't be substituted for the method used, as the heat will absolutely destroy the business end of the display cable. In my case, the display started missing a couple of segments, then a bunch of them went soon afterward. All the discrete components on the controller board tested ok. The controller IC still worked as far as the oven functions were concered. The IC itself isn't replaceable (it's the "black blob" type), so there are only two options: buy a new board set which costs more than the oven or buy a new oven. This is a blatant example of a product designed to ward off repairs and to have a relatively short lifespan.

I've got a Sharp with the same problem, bad LCD display unit. Like you said they want way too much for a replacement. In my case nearly 50 bucks just for the crystal module. all else works fine on the oven, you just have to push the buttons carefully to get whatever time and cooking level desired.( I'll find a donor some day with a dead magnetron that'll hopefully have a good display. Untill then it's push the buttons slowly and carefully.)

Is there room to drill a hole in the board on each side of where the ribbon connects? If so you could cut a little block of aluminum, file it so it has a ridge down the middle, then thread holes in the ends and screw it to the board so the ridge presses on the ribbon and holds it to the contacts.

Should be room on the later model Sharps. As these are layered boards, be careful with the locations of the clamp holes. If necessary, use a plastic strip for the clamp, held down with nylon thru screws (or rivets) or plastic spacers as feed-thru bushings for the metal screws if the nylons aren't available.

From what I've since read on Sharp ovens, problem contacts don't appear to be the common failure mode. Still, for those lucky individuals where the only prob may be dirty or loose contacts, this is a perfectly acceptable fix -- actually, it would be a much superior method over the crummy original design!

Thanks for the various suggestions to my original post. Two question: (1) How do I access the display on this model? (2) Assuming I don't want the expense of a new board and that I lack the expertise to perform some of the procedures listed above, what's one "simple" fix I might be lucky enough to encounter when I get a look at the display? Dust on the ribbon, haha. Thanks.

You might have some luck wedging something between the display and the board to put pressure on the ribbon, hunk of styrofoam or something. Never seen inside that model so I can't offer specific help though.