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Good Morning,
I have a Miele H4270BP electric oven. I believe I have a fault with the bridge rectifier in the control unit of my oven. When I set the temp and close the door, instead of the element and light activating, I got a loud buzzing sound that I have isolated to the relay coil in the control unit. If I push the relay closed manually, the light and element activate, but as soon as you release the door switch and close again, the relay will not re-engage without assistance.
I have removed the control unit and found that the relay coil will activate and operate normally when voltage is supplied directly from a 9V battery, so I am assuming the fault is not with the relay coil and likely with the bridge rectifier not providing the correct voltage. (I have not checked this with a multimeter yet as tricky to access when connected to the mains).
I am looking for some advice on whether the rectifier is on board with the relay and if I pay Miele the £300 for a new unit, if this will solve the problem, as Miele do not accept returns.
It might be worth noting that there are two relays side by side on the board, the other controls the fan and seems to be working fine.
Many Thanks in advance
Dan
bridge recs can fail but its not common unless they are over currented. more likely is the smoothing capacitors
as for the other relay you might find it is eneergised a split second earlier so it takes most of the power
if it is the bridge rec they can be checked in situe with a multimeter
Dave
Hi Dave,
Thanks for the response. I have tried to attach some photos but I am getting an error (Upload failed due to your usergroup’s upload quota. This file will require 884.6 KB but you only have 19.5 KB of 19.5 KB remaining.) I don’t think I can access the rectifier and not sure which caps are likely to be the smoothing element. Is there another way I can upload some images?
Thanks again
Dan
if you want to add photos host them on another site and post a public link
its done to save server space and cost
Dave
Thanks for the advice. Sorry new to posting on forums.
Here are the links to the photos.
Thanks
Dan
https://drive.google.com/open?id=1OvbwCZbLu_duMr9kpJHRGwH5-rz8ah_K
https://drive.google.com/open?id=1I58ogf60lYStfLhmgdpJc04CfU16YKRA
https://drive.google.com/open?id=1N6cxaImy7u2Fn-Nh2r0bJmgV9tQlL4Oz
https://drive.google.com/open?id=1XlqlO8Bp5HPtFsJdnn1y3LwUqZ1GdQ_i
https://drive.google.com/open?id=1SUbzfs6T2iD-c4XX1bq2yvFN7idY72yw
oh thats interesting
if it was me i would change the capacitorposs right part but i dont know the lead spacing on the old one
https://uk.rs-online.com/web/p/polyp…itors/8829512/reason its highly likley this component supplies the power to the board and its a known fault they lose value with age and the board voltages drop
DaveThank you Dave.
I will check the dimensions and order.
Once I have it replaced, I will give you an update. Might take me a bit as the connections are a tad tricky to access.
Dan
Just had a look and I can’t check the lead spacing as they are pretty well hidden under the LCD panel, but the top of the capacitor is 32mm x 8.9mm.
Would you be able to help me locate the correct item?
Dan
https://www.ebay.co.uk/itm/Iskra-KNB…cAAOSwB-1Yr06j
would this do the trick?
the one i linked to has a lead spacing of 22.5mm any other demensions should not realy be a problem as you have room around it
hopefully you can just spring the display a little to get at the solder joint
Dave
managed to slide a neighbours vernier under the lcd and got a reading between leads of 27.76, I am assuming I can just bend the new wires to meet that requirement. Sorry for all the questions, just want to make sure I am doing things right.
Thanks for your patience with me.
Dan
thewylo wrote:https://www.ebay.co.uk/itm/Iskra-KNB…cAAOSwB-1Yr06j
would this do the trick?
yes
that will be ok its still an X2 cap
Dave
Hi there,
Just wanted to say a massive thank you for your help and support. The new Cap turned up this morning, I installed it, put the oven back together and hey presto, it all came to life!!
I really appreciate the time you gave me to help solve this problem. You managed to take a potential £300 fix down to a £5 fix and I am in your debt.
Electrofix Dave, you are a gentleman and a scholar!
Thank you so much
Dan
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