Thread Number: 48916
Arthur-Martin 792.08 washing machine modification.
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Post# 708436   10/10/2013 at 16:20 (3,343 days old) by statomatic (France)        

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Hi, these Arthur-Martin machines are very nice (click on the link to see the pics on my photo album) but they are strangely designed, the half load function can be used only on delicate programs.
After making a slight wiring mod (by changing the order of the half load button and two timer switches) the half load function can be used on normal programs (but there is no cooling down at the end of wash).

Here is the original schematic diagram:


Post# 708440 , Reply# 1   10/10/2013 at 17:02 (3,343 days old) by statomatic (France)        
The modified diagram and a small circuit description:

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On the left there is the 220V line and the main switch.
Then the step by step timer motor controlled by the 64-58 switch for cam positioning, A-B for going to the next step, 31-25 for temperature control and 33-39 for reduce the final spin time.
The 62-60 switch is opened when the timer is in cam positioning mode for prevent timer switches destruction.
The 4-6 switch is used for stop the machine at the last rinse (anti crease function) mode when 1-1A of the selector is open.
The pressure switch (pressostat) supply the electrovalves by 12 for the low filling level (washing and half load) or by 22 for the high filling level (prewash and rinses).

On the original diagram the 28-30 switch is used on the normal programs for the high filling level, it is directly connected to the pressure switch therefore the half load button (1/2 charge) cannot work.
When connecting the "28" wire to the "26" wire instead of the 22 pressure switch the half load function can be used on normal programs :)

Post# 708441 , Reply# 2   10/10/2013 at 17:07 (3,343 days old) by statomatic (France)        

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Taking apart the control panel block:

Post# 708443 , Reply# 3   10/10/2013 at 17:18 (3,343 days old) by statomatic (France)        
Detailed view of the timer

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This is a "Sibel" timer (made in France) with two motors:
The big one on the left for step by step and cam positioning (very convinient feature because the timer button is easy to turn).
The shorter one on the right for the fast cam (washing motor reversing) and the timing.

Post# 708444 , Reply# 4   10/10/2013 at 17:23 (3,343 days old) by statomatic (France)        

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Another view of the timer, without the protection cap of the fast cam.

Post# 708449 , Reply# 5   10/10/2013 at 17:41 (3,343 days old) by statomatic (France)        

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Taking apart the internal components support plate.

Post# 708452 , Reply# 6   10/10/2013 at 17:49 (3,343 days old) by statomatic (France)        
End of the modification

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A jumper wire is added between timer 26 and 28.
The wire that goes to the 22 of the pressure switch and the wire that goes to the 1D of the half load button are connected together by another jumper (the 6.35mm connectors are insulated with a shrink tube).

The dismounted parts were reinstalled in reverse order, now I can use the half load function on the normal programs !

Post# 709223 , Reply# 7   10/14/2013 at 07:05 (3,339 days old) by chestermikeuk (Rainhill *Home of the RailwayTrials* Merseyside,UK)        

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Great work, those timers look so complicated I wouldnt know where to start!!
Are these washers made by Philips for Arthur Martin or do they make their own models?

Thanks for taking us through the process!!

Post# 1160370 , Reply# 8   9/25/2022 at 10:33 by chetlaham (United States)        
Thank you for the diagram and pictures!

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Nowhere near the most complicated electrical, far from it, however the timer can be significantly simplified. I could get timer down to one motor, 8 single pole double throw contacts and 8-9 wires. Lots of unnecessary complexity IMO. But love seeing this none the less! Many thanks.

Post# 1160646 , Reply# 9   9/29/2022 at 13:29 by statomatic (France)        

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Thanks, yes these machines are quite complicated but that's not the worst I've seen.
This Sibel timer has a nice feature that makes the knob easy to turn.
There's a clutch between the knob and the cams, you turns the knob to the chosen program, this closes a switch turning on the program cams motor, it stops when the cams are in sync with the knob and the program starts.
Some Thomson machines also used this feature.

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