A different microwave question

[Charlie Bress]

This is a Panasonic microwave that is about 10 years old. It works just fine. The problem is that it has become fussy to open In the picture at the link you can see the inside portion of the gray opening button. It has a small projection that lifts the part of the latch mechanism that is white. The latch works ok. The part of the gray plastic does not seem to lift the white latch part high enough to release the latch.

If I just reach in and raise the latch mechanism by hand from the right place, the door unlatches ok I have tried putting a small piece of Lucite on top of the gray actuator, to increase the throw, but that is not particularly successful. It almost seems as if there is a bind .in the whole thing. At its age I am pretty sure that part replacement is a lost cause.

All this is done with the unit unplugged and I am staying well away from voltage carrying areas.

Except for the latch release the unit works as it should. All the safety switches are in place and operating.

I am looking for informed opinion on how to proceed. Please do not tell me it is dangerous. I know and have worked around high voltage environments before. Don't tell me to buy a new one. I can figure that out by myself.

Answers to the Newsgroup only. We can all learn from each other.

Many thanks

Charlie

[Matt]

Have you gone to

to see if the parts are available?

[Matt]

Also, even though you specifically asked this opinion not be given -

I recc. either buying new or taking it in for repair. For me, there are different categories of DIY, and one category I consider before I make an attempt is: Can this thing kill me when I'm working on it (plugged in or not), or can it kill me later after I *think* I've fixed it? Obviously, almost any repair can be thrown in this category, but some appliances carry a clear risk when attempting a DIY.

Microwaves and furnaces fall into the "Death risk" category (IMO).

I'm guessing you can probably fix your latch and all will be OK. On the other hand, what if during the repair the door alignment gets wacked? Service centers always perform a test after they repair a microwave, to ensure that nothing is leaking.

Just my .02

[Joseph Meehan]

Assuming you know enough to drain any large capacitors in there and know what you are doing, I rank this one as one of those projects that you can only do by making guesses and decisions as you go based on what you see at each step in the process. My only real warning is to make sure you don't deactivate any safety device when working on it.

In the few I have opened up, it was not hard to figure out what parts did what. I also quickly figured out that in I needed a replacement part, I doubt if I would be able to find one. Of the three I worked on, I fixed the first one and the other two were never reassembled since it was clear I did not find the problem.

[Lola]

I think in the end, it might just be worth it to get another. They are so cheap these days... and if you take it to a repairman, it just might cost more than it is worth. Just MO. The problem with modern electronics... even ones that are 10 years old.

[JerryMouse]

I have no idea.... BUT

If you can't figure out how to repair the thing, or if parts are not available, you perhaps could disable the locking mechanism.

The you could install some sort of device, externally, to hold the door mostly shut: screen-door clasp, velcro strap, whatever.

[Charlie Bress]

Nope, that won't work. The safety interlock switches are mounted to the latch mechanism. That's why you can't operate the oven when the door is not securely latched.

Charlie

[Charlie Bress]

That,s why I am here. This is a DIY project. I am looking for expert advice.

Charlie

[do_not_spam_me]

Try a Google Groups search of sci.electronics repair for Panasonic microwave interlock ?

Panasonic's National Parts Center sometimes has very old parts at reasonable prices, but MCM Electronics or Fox International may have them as well.

The electrical portion of the door interlock mechanism can be fully tested with the oven unplugged, by using an ohm meter or low voltage test lamp on its microswitches (to prevent damage to any electronics, unplug the switch wires first, noting where they went originally).

Does the mechanism bind less if you retract the microswitch (maybe 2 switches since manufacturers don't want door interlocks to fail in a dangerous way) manually and then operate the interlock? If so, then clean the plastic where it rubs against the switch, and it's possible the plastic should be greased there. Switches and nylon (white plastic) can withstand common automotive lithium grease, but silicone grease is more inert. If that doesn't help, I might try disassembling the mechanism and clean everything (alcohol or brake parts cleaner). If the parts were originally lubricated, apply lithium grease to them. Cracks in nylon can't be fixed well with glue but only by heat welding them with a soldering iron (clean tip). If filler plastic is needed, shave slivers off the nylon parts because other types of nylon, such as that in nylon wire ties, probably won't stick well. The grey pushbutton is probably made of ABS, which is best repaired by solvent welding it (hobby shops sell liquid glue, but lacquer thinner or carburetor spray work equally well). Solvent glue should be allowed to evaporate for at least 12-24 hours before subjecting the plastic part to stress again. If solvent doesn't affect the grey plastic, then most likely it's polypropylene, which is also best repaired by heat welding it.

[Charlie Bress]

I had considered silicone spray, but I am always hesitant to just rush in without the voice of reason backing me up. Nothing seems to be broken. A little judicious silicone may very well prove to be the answer. I have made a quick search for part replacements , but that has been stymied by the inability to locate a model number anywhere. I have looked on the door frame, the back of the box and the bottom. All I have found are the safety and regulatory labels.

Thanks for a helpful post as compared to some of the drivel that gets posted.

Charlie

[Joseph Meehan]

I doubt if there is any expert advice available. Expert advice usually comes from someone who has a fair amount of experience in the subject. The fact is there are few if anyone with that experience since it is just not a practical thing to do with the falling prices and better equipment being made. Add to that the fact that the manufacturers and not designing the units to be repaired and needed parts are just not available.

[willshak]

On 1/14/2005 8:34 AM US(ET), Charlie Bress took fingers to keys, and typed the following:

I have never seen the inside of a microwave, but I am usenet compelled to respond. :-) It appears that the dark grey thing at the bottom left is the door button. What happens if you operate the button and/or door while observing what happens inside? Does anything appear to be hanging up? Does that tab at the top right of what may be the button, and which appears to have a clearish pad on top, release the whitish nylon projection just under the screw? Is that clearish pad cracked (it looks like it may be in the photo)? Is that door button thing hinged underneath, and is the hinge just a thin bendable piece of plastic? Is the 'hinge' cracked? Well, that's it for me. Good luck!

[Computer Discount]

Throw it away Charlie its 10 years old