[andy2]

Re: Do you prefer electronic timers?

I think you are right about the cost Kenneth, even more so with the advent of surface mounted technology where the PCB is virtually untouched by human hand. Once the tooling cost is covered,these boards must cost peanuts relative to the cost to the customer, and certainly many times cheaper than its electro-mechanical counterpart.

To be fair electronic modules are pretty reliable (let me finish before you all jump on me).

Many faults are caused by external componants failing and taking out tracks / componants on the module. And this can happen on electro-mechanical timers too where contacts get welded or burned out due to a s/circ componant

Other common faults are often on componants that strictly speaking are not electronic – relays – due to the fact that they do all the donkey work in handling large currents.

The same applies to triacs which although electronic get all the hard work to do.

Apart from these stressed componants I believe that relative to their complexity they are reliable. Lets not forget that contacts burn out in e/m timers for the same reasons. How many HPT timers have you had where the ON/OFF switches or the heater contacts go faulty?

Because many of these modules use a switched mode power supply based around an IC I find that faults in this area are rare, unlike many of the earlier modules where wire wound resistors were a major culprit – great little earners though!

The main problem with Mr Merloni’s modules is their situation in the machine where they are prone to damp, the effect of which can be seen clearly on the modules surface and especially on the edge connector pads.
You just don’t see this sort of problem on Hoover, Zanussi, Hotpoint etc modules which are under the lid. Apart from this and one or two poorly routed tracks Merloni modules are probably no different to the others. After all the componants all come from similar suppliers, even the microcontroller IC’s probably begin life as a generic componant that is programmed for a specific manufacturer. Mr Merloni could probably make his modules much more reliable (if he wanted to) by giving the assembled PCB a quick spray with a waterproof coating on the track side, but this would still leave the connectors exposed.

I think the only machines that you might find using e/m timers in the near future are those from the far east. Because labour costs are so low they might be able to produce them (at least for a while) cheaper than the electronic version. I say this because the assy cost must be the most expensive aspect of e/m timers (but i might be wrong) and the initial cost of setting up a PCB assy line must be quite high.

I noticed that the Haier machines have a very simple e/m timer.

Personally I like electronic modules as long as the fault codes are available, as you know, without them it’s the needle in the haystack scenario and a nightmare. They are much easier and quicker to repair than electro-mechanical timers which vastly increases the number of jobs that are economically viable. This greatly enhances your image in the eyes of your customer when you save them XXX£’s and it only costs you £1 for a new relay or a few pence for a triac plus you can charge for repairing the module as well!

Surface mounted componants raise a new challenge to DIY board repair but with the right gear and a good magnifier they are no harder to repair than through hole componant boards. You can spend a grand+ on an sm rework station but a small gas powered iron with a hot air tip does a good job. Add rework flux and some solder paste or fine solder and you are in business. CPC do a small rework kit for £22 +VAT which has some needle point tweezers, just the job for handling those tiny componants.

Andy 🙂

[andy2]

Re: oven cleaners

Chris, if you had lived in the Victorian era you would probably have been one of those people who stuffed kids up chimneys to clean them out !

Without a doubt the best oven cleaner is the little wifey – if you want to spoil her buy her some rubber gloves first – maybe as a birthday present.

That will make her feel ‘special’ and she will want to be nice to you 😉

This way you get your oven nice and clean and a few treats as well!

Good eh? 🙂

[andy2]

Re: Indesit W12SUK

Well Chris you have me sussed, OK I admit it, I do have a ‘thing’ about Merloni (sorry Indesit Co) machines and especially modules.

There i’ve said it!

Maybe this is my first step to recovery from the morbid fascination which
has ruled my life for what now seems a lifetime………endless nighmares………..a dreamworld filled with flashing lights and endless clicking noises that fill my ears and my mind until it seems that I can endure no longer……………

😯 😯 😯 😯

[andy2]

Re: SPARES ACCOUNTS

Yep! Seme Nedis doubling the carriage threshold certainly makes a difference. 😥

Also noticed that Seme prices are creeping up. Lots of parts used to be cheaper than Connect but many now similar or even dearer. 😥 😥

Sometimes life can be a real female dog, and thats for sure! 😥 😥 😥

[andy2]

Re: Elusive fault

The thing that i don’t understand is that these modules in common with others use a small switched mode power supply based around a TOP209P IC, and i would’nt have thought that interference on the mains supply would get through onto the DC supply, but it seems that somehow it can.

maybe someone can explain how.

[andy2]

Re: indesit 6 flashes

Forgot to mention:- to read the code off the switch the processor must set one of the bits high and read the output from the remaining five. I have checked the outputs corresponding to each switch position and have found that in all cases except three bit six is common, therefore this is probably the bit that is usually set high.

So in order to check these selector switches for possible faults just check the continuity between pad six (nearest to the motor connections) and any of the other five, you should get continuity to various combinations of the other pads.

Also check motor continuity as if the controller attempts to move the switch the binary output should change. If it does’nt then the controller will possibly detect an error condition.

Andy 🙂

[andy2]

Re: indesit 6 flashes

Usually this is down to a bad connection.

Try taking the plugs on and off the connectors a few times on the module termination and the motorized selector. Also you can try respringing the little connectors in the plugs using a fine sewing needle so that they make a tighter fit, and carefully clean up the pads on the PCB and switch.

These selector switches unlike the hoover (which has an analogue output) send a binary code to the controller on the first six pads of the connector, each code corresponding to a unique position on the selector. This gives 64 possible positions of which 33 are used. The other two are motor connections through which the timer can be advanced by the processor.

Its probably worth checking all the smaller IDC connectors as the ones which go to the spin & temperature controls may possibly also cause an error.

Andy 🙂

[andy2]

Re: Elusive fault

It was’nt through any genius on my part. My last visit to this machine was to replace the mains filter which had spilled its guts.

Fixing this has also eliminated the other problem which is why i arrived at my conclusion

Andy 🙂

[andy2]

Re: Diplomat 8112 D/W error code required

Thanks you guys for all your help – did the reset with the door s/w open circuit and it worked OK.

Actually i feel a bit of a thicky for not thinking of that 😳

Just the door s/w etc to sort now

Cheers Andy 🙂

[andy2]

Re: Diplomat 8112 D/W error code required

Tell – sounds good to me – never thought of that!

Obviously the s/w would be open with the door open.

Will try that – Thanks

Andy

[andy2]

Re: Diplomat 8112 D/W error code required

Aaagh!!

I tried the reset proceedure it went into its test program OK.

When I tried to cancel the test according to the instructions it would not happen.

Eventually left it to complete the test sequence and it went through OK to the end – no errors – everything seemed to function OK and all the lights flashed signifying the end of the test sequence.

Switched off the machine and on again to see if it would allow me to select a program, but no joy! It reverted back to its original fault except that now the first light flashes instead of the fourth.

I think that this is because it has reverted to its default startup – prog 1, the lady normally uses 4 and it normally starts up showing this light.

Its looking like a module fault to me as everything seemed to work on the test, it just won’t accept a program, but would appreciate any suggestions before I order one.

Andy 🙂

[andy2]

Re: Multiple capacitor failure on creda C dryers

Forgot to make the point that my post was addressing the original topic of capacitor failure and that it is due to the breakdown of the dielectric.

Apart from low quality construction this is generally attributabe to too small a margin between the working voltage and the supply voltage (again its down to cost). 🙁

[andy2]

Re: Multiple capacitor failure on creda C dryers

Bob

What you say is theoretically true, but in practice it does not make a noticable difference. I have sometimes substituted a 20mF cap for a 14mF for instance and the machine functioned perfectly well, the motor showing negligable temperature increase.

My statement was probably too loose as I did not mean to imply that the capacitance value is irrelevant, but rather that it is not as critical as the earlier posts would suggest ie. should I use a 7 or an 8mF ?

Good point about the condenser dryers though.

Andy 😀

[andy2]

Re: Multiple capacitor failure on creda C dryers

The actual capacitance value is not important as long as it is large enough to handle the current demand of the motor, any excess capacitance above this is simply not used. The main reason that smaller capacitors are used is they are cheaper!

What is critical is the working voltage of the capacitor. The higher this is rated above the supply voltage, the less stress upon the capacitor dielectric and consequently longer life.

Andy 😀

[andy2]

Re: Hotpoint Minstral FF72P PCB part PTC1?

Hi Tony

The device PTC1 is probably a thermistor (Positive Thermal co-efficient) these work opposite to the usual NTC (negative thermal co-efficient) thermistors like the ones that you replaced on the evaporator.

As the temperature of the PTC increases so does its resistance, thus limiting the current that flows to the fan. As they often exhibit a steep rise in resistance the current to the fan will be negligable above a certain temperature. If the current increases above normal (as in a stalled fan due to ice buildup) the PTC heats up and shuts down the fan.

Your PTC was probably faulty shutting down the fan too early.

This type of thermistor is used in place of compressor starter relays to shut down the current to the start coil after the initial surge has started the motor thus preventing the start coil from burning out.

Andy 😀

[Author]

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