Is it possible to (DIY) replace the digital clock/timer on a microwave oven. Some parts of the LCD display have gone so it is difficult to tell what some of the numbers are. It is a Sharp R-254 and a new one can be purchased for
We replaced a 20 year old Sharp with your model 18 months ago and skipped it for the same problem you have. The replacement was an Aldi cheapie and we are over the moon with it.
probably not practical. Bear in mind microwaves contain lethal electrics (thousands of volts stored in there after unplugging)
NT
Sling. It should be easy enough to change but it won't be worth the 50GBP you paid for the spare part, even after the repair.
However, if you open it up and disconnect and reconnect the display - you may find it was only bad contacts..
How can you be sure that it is the LCD display that is faulty and not some other part that feeds the display?
I'm not sure. The real point of my question was, is it cost effective and safe to do it, as I have heard it can be very dangerous to open a microwave oven (no not the door!) if you don't know what you are doing.
Cheers
John
microwaves and tvs are the 2 domestic electrical nasties, with nukes being the clear winner. Fine if you know what youre doing, if not then better left alone.
NT
Strongly agree. A microwave oven is essentially a very short wave and quite powerful radio transmitter, in a metal box. Not only are the voltages inside very high indeed (2000 to 5000 volts) and can be lethal; but the unit radiates microwaves that can cook you, just as surely as a piece of meat and/or cause more subtle long term damage to the human animal. It is important for example to make sure the outside case of the microwave is refitted correctly after being opened. Suggest: Keep away from it and DO NOT work on it yourself unless you are a good/knowledgeable electronics technician. Having said that it's probably not worth fixing (unfortunately in this throw-away age!). Brand new microwaves that comply with our fairly strict Canadian safety standards, are frequently available here for less than $100 plus 15% sales tax, or roughly less than 50 quid. Saw older used ones in a thrift store yesterday for as little as $10 to $20! But again being knowledgeable of the hazards involved I'd be very careful about using a used one.
I repaired my early 90's microwave for all of £4.50 from CPC a while back. Basically went bang and blew internal 6A fuse. Replaced fuse just in case old age and bang blown again. It was the HV rectifier diode gone short circuit (and probably taken out the capacitor protector), thus shorting the
2.5KV secondary, which is why the fuse blew. Also you need to verify the HV cap still works (capaciance meter) has say 10M internal resistance so it self discharges. £4.50 from CPC later, microwave worked fine. Yes you can operate it with the lid off, the microwaves are contained inside, BUT there are exposed 2.5KV and 5KV metalwork so be careful, use a switched extension lead so you can turn on and off power remotely and leave say 1/2hour ofer power-off before fiddling.
if the cooking cavity is rusted, massive leakage can occur with the cover off. The tester's head will typically be close to this source.
You show unreasonable faith in leakage resistors. This is dangerous advice.
This is why I dont suggest working on them unless you actually _do_ know what youre doing. 'Jo said' isnt good enough on equipment like this, there are too many dangers for the unwary and half wary. I'm not the nanny type, but some things arent worth the risk. The reward/risk ratio makes fixing your own nuke a bad idea.
NT
|Ian_m wrote: | |> I repaired my early 90's microwave for all of ?4.50 from CPC a while back. |> Basically went bang and blew internal 6A fuse. Replaced fuse just in case |> old age and bang blown again. It was the HV rectifier diode gone short |> circuit (and probably taken out the capacitor protector), thus shorting the |> 2.5KV secondary, which is why the fuse blew. Also you need to verify the HV |> cap still works (capaciance meter) has say 10M internal resistance so it |> self discharges. ?4.50 from CPC later, microwave worked fine. Yes you can |> operate it with the lid off, the microwaves are contained inside, | |if the cooking cavity is rusted, massive leakage can occur with the |cover off. The tester's head will typically be close to this source.
In the RAF c1960 I worked with Magnetrons, Klystrons and the like. No obvious problems to any of my mates.
Presumably you and/or they were trained, or the equipment was designed to be safe with whatever you were doing with it.
NT
|Dave Fawthrop wrote: |> On 19 May 2006 05:58:29 -0700, snipped-for-privacy@care2.com wrote: |>
|> |Ian_m wrote: |> | |> |> I repaired my early 90's microwave for all of ?4.50 from CPC a while back. |> |> Basically went bang and blew internal 6A fuse. Replaced fuse just in case |> |> old age and bang blown again. It was the HV rectifier diode gone short |> |> circuit (and probably taken out the capacitor protector), thus shorting the |> |> 2.5KV secondary, which is why the fuse blew. Also you need to verify the HV |> |> cap still works (capaciance meter) has say 10M internal resistance so it |> |> self discharges. ?4.50 from CPC later, microwave worked fine. Yes you can |> |> operate it with the lid off, the microwaves are contained inside, |> | |> |if the cooking cavity is rusted, massive leakage can occur with the |> |cover off. The tester's head will typically be close to this source. |>
|> In the RAF c1960 I worked with Magnetrons, Klystrons and the like. |> No obvious problems to any of my mates. | |Presumably you and/or they were trained, or the equipment was designed |to be safe with whatever you were doing with it.
You presume wrongly, never heard *one* word about any risks. The Urban Legend was that it was a good idea to spend a day in front of the transmitter before having leave with your girlfriend ;-)
Yes, extremely dangerous, even to the initiated. The repairfaq spells it out, and tells how to do it safely
I'm still presuming it was 'designed to be safe with whatever you were doing with it' probably because it was not 2.45GHz. The main danger in working on domestic ovens is not from the magnetron.
NT
It looks very thorough, but is riddled with errors, myths, unsafe recomendations and so on.
NT
|Dave Fawthrop wrote: |> On 19 May 2006 07:48:16 -0700, snipped-for-privacy@care2.com wrote: |>
|> |Dave Fawthrop wrote: |> |> On 19 May 2006 05:58:29 -0700, snipped-for-privacy@care2.com wrote: |> |>
|> |> |Ian_m wrote: |> |> | |> |> |> I repaired my early 90's microwave for all of ?4.50 from CPC a while back. |> |> |> Basically went bang and blew internal 6A fuse. Replaced fuse just in case |> |> |> old age and bang blown again. It was the HV rectifier diode gone short |> |> |> circuit (and probably taken out the capacitor protector), thus shorting the |> |> |> 2.5KV secondary, which is why the fuse blew. Also you need to verify the HV |> |> |> cap still works (capaciance meter) has say 10M internal resistance so it |> |> |> self discharges. ?4.50 from CPC later, microwave worked fine. Yes you can |> |> |> operate it with the lid off, the microwaves are contained inside, |> |> | |> |> |if the cooking cavity is rusted, massive leakage can occur with the |> |> |cover off. The tester's head will typically be close to this source. |> |>
|> |> In the RAF c1960 I worked with Magnetrons, Klystrons and the like. |> |> No obvious problems to any of my mates. |> | |> |Presumably you and/or they were trained, or the equipment was designed |> |to be safe with whatever you were doing with it. |>
|> You presume wrongly, never heard *one* word about any risks. |> The Urban Legend was that it was a good idea to spend a day in front of the |> transmitter before having leave with your girlfriend ;-) | |I'm still presuming it was 'designed to be safe with whatever you were |doing with it' probably because it was not 2.45GHz. The main danger in |working on domestic ovens is not from the magnetron.
You missed "In the RAF c1960" If you did your 2 years National Sevice without obvious problems, that was safe enough. In the late 1970s, one only had to make industrial processes as safe as "reasonably practicable" I was a Safety Rep at the time, and knew exactly happened.
The world has gone mad now, with safe being defined as without risk :-( Irrespective of the fact that you take risks by getting up in the morning and greater risks if you stay in bed.
I'm not mentioning my age, but I am familiar with the pre-pc pre-safety-obsessed world. Didnt miss the unsafe option, just didnt see any point mentioning it. I think this is getting pointless. :) its fairly obvious what the options are.
NT
Really? Last time I read it I thought it was invaluable advice. ASFAIK it is quite well read and respected, so if you can be more specific on the errors etc, preferably with corrections, I'm sure Sam Goldwasser the author would be grateful, as would the rest of us that sometimes dabble with microwave cookers.
Phil The uk.d-i-y FAQ is at
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