Any dishwasher experts out there?

My Zanussi dishwasher[1] is playing up. Sometimes it goes right through the cycle with no problem. But increasingly, it gets stuck part way through - and just goes on churning water round without progressing to the emptying and drying phases.
It's a few years old(!) and is the type where the control knob rotates as it goes through the cycle. Behind the control knob is a box of tricks with umpteen wires connected to it and - seemingly - lots of sets of contacts inside to switch various functions on and off at the appropriate time.
I assume that when it gets stuck, something is failing to switch on the little motor to drive the knob round to the next position. This could possibly be some contacts within the box itself which are not making, or maybe it's expecting, but not getting, a signal from a sensor elsewhere in the machine. Sometimes - but not always - if I turn the knob a bit when it's stuck, it will re-engage and carry on with the cycle.
Anyone had one of these programming boxes to bits? Am I likely to end up with bits and springs flying in all directions, with little hope of re-assembly?
Anyone know where I can find a technical description of how the thing is supposed to work with - hopefully - a diagnostic chart to help me to isolate the problem?
[1] The model is DW65TCR, in case that's significant
TIA!
--
Cheers,
Roger
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It might be the motor / gearbox unit, in the past I've fixed washing machines by swapping one over out of the spares box.
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I have the one on washing machines and it is quite handy. These are similar devices with similar set ups of pumps and programmers.
As has been noted the programmer is likely to cost more than the machine, but unlikely to be the direct cause. It is just failing to move because it has not received a signal that the current running process has finished.
In my experience it is usually pumps that are the running process which has not finished, and if you can hear them then this is probably the case. When a vane in a pump is blocked, even by tiny little things, it stops moving, but the motor itself keeps going. When water is still in the machine it will not progress to the next stage. You will probably find either the main filter is blocked, or one of the pumps is blocked. The pumps come to pieces easily, but getting at them may be a puzzle - that hopefully the above manual may help you with.
S
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They sound like a washing machine programme switch - just replace the whole switch... hold the new one side-by-side with the existing, and swap each cable over to its' position on the new switch, rather than pulling all the leads off at once :-}
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in message

Could it be as simple as the knob has been pushed in and is fouling in its recess - or binding on some gunge. Try pulling the knob off and running it. If not then assume friction elsewhere - or motor/gearbox problem as suggested.
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Colin Wilson wrote:

I had a similar problem with an with our first Whirlpool dishwasher (it was probably 12 or more years old by then). You could make it progress through the cycle by giving the knob a little nudge at the right times - but not an ideal solution. So I intended to change the programmer as described - alas when I tracked down a new programmer through CPC's white goods part finder service, they wanted silly money for it (over 100 by the time VAT and delivery was added in). It did not seem worth spending that much on a machine that old.
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Cheers,

John.

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Roger Mills wrote: <SNIP>

I tried that with a similar washing machine program timer once. Full of pingfuckits.
Asuming the knob isn't stuck as others have suggested, spray it liberally with WD40 & see if that helps.
You can pick up new dishwashers for less than 150, may not be worth the cost in parts to repair it.
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Dave - The Medway Handyman
www.medwayhandyman.co.uk
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In an earlier contribution to this discussion,

Thanks. I may try WD40. Of course, now that I've threatened it with a trip to the tip, it worked perfectly this morning! <g>
It's quite a few years old, and doesn't owe us a lot and is definitely not worth spending a lot of money on - which is why I'd like to have a go at repairing rather than replacing the existing components.
[We're hoping for a kitchen move/refurb in a year or two and will probably have a new built-in diswasher at that stage, so I don't really want to have to buy a new stand-alone one in the meantime.]
--
Cheers,
Roger
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If you get stuck, one option is to buy the built in one now and make a ply carcase for it that you can put into the position of the standalone one
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The problems of repairs and replacements are greater with an integrated one. (IMHO)
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Yes I have taken a timer to pieces, and I'll never do it again. They are hellishly complicated. I couldn't see anything wrong, and amazingly I got it back together. There wasn't anything wrong with it. I discovered that the water level switch was not working, and the timer was just waiting for the water to fill up. Check all the switches with a meter to see if they open and close properly. First turn the power off and unplug the leads from the switches!
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In an earlier contribution to this discussion,

Thanks - it's much as I suspected!
Did you manage to find any literature showing the connections and function of each wire? If so, where?
Seems to me it would be very difficult to do any diagnostics without knowing exactly what to look for. For example, you'd need to know which wire came from the water level switch and under what circumstances it should be live.
In my case it's intermittent, rather than a hard failure. So I need to be able to dive in when it makes an unscheduled stop in order to find what signal is missing.
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Cheers,
Roger
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wrote:

But is it due to the motor not getting power to advance the programmer - or is it due to mechanical jamming?
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That dishwasher was fairly old, and the function of each component was fairly obvious. There were a couple of solenoids controlling the water inlet, a water level float switch that was faulty, a drain pump, a temperature measuring switch, and a main motor.

In my case it always stopped at the same point. I can't remember the details but I suspected that it was something to do with filling up. It was easy to check the water level switch with a meter and it didn't open and close properly. I bought a new microswitch for $2 and made it fit, and that worked fine.
Another dishwasher kept stopping sometimes, and I discovered that food had got stuck in the pipe where the water level gauge was.
If it's an intermittent problem that's harder. Check all the connections. It still could be an intermittently faulty switch, so it's worth checking all devices for continuity. Just use a cheap meter to measure the resistance. The timers are surprisingly reliable, possibly because they are out of the way of water, so that's the last thing I would suspect, and it's really too hard to fix anyway.
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I'd check the synchron motor on the timer/programmer isn't stopping, may be loose connections or getting stuck.
New motors are cheap if you can find a suitable one.
A neon on flying leads with piggy back 'lucar' connectors can help tell if things are getting power or not.
cheers, Pete.
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