Saeco Magic> pump works all the time

[mrozek]

Hello everyone,

First of all I would like to say that I really admire this forum members both for professional and helpfull approach to all the problems appeared here. Thank you guys for great job and google for online translator

Let me describe my problem with saeco magic comfort and ask for your support:
- right after I power on my coffee machine it starts the pump
- I am sure this is sth wrong with the electronic (motherboard). This problem occured 6 months ago and I changed a motherboard to another one (second hand). Unfortunately the replaced one has just produced a small amount of smoke and does not work at all. So I do not want to change it to another shitty thing again and decided to try to fix original one.

I know that you guys are very keen on electronic so please advice me what and how to check/change if I want my motherboard working fine again.

Many thanks in advance for your help,
greets from Poland,
mrozek

 

[hmilbradt]

Hi,

Your pump fault is the result of a shortened triac or the result of a triac that is being selected permanently by the microprocessor. Look at the diagram of a Royal pump ..... Pumpe

regards
Harry

 

[mrozek]

Thanks Harry for your help.

ok, so there are few more infos:
Because I found a very similar problem right here in the forum: http://www.saeco-support-forum.de/magic-serie/9622-pumpe-laeuft-standig-beim-einschalten.html I replaced both the triac T7 and varistor RV8 and I've just done it twice:
=> new varistor: 07d391k (guy at electronic shop said should work fine for me)
=> first replace was for the very new triac bt136/800 (believed as a replacement part). Results: no changes.
=> so, I decided to change the triac with the t410/700T (from my second hand baked motherboard). Results: no changes.

And as far I am stucked because as you said there are one more possibility: the microprocessor (the thing I am not able to replace anyway).

BTW I can not find out how Chawan from the topic I specified above handled with the problem. Looks like it was very similar to mine but translatation of last post just fails

Thank you again,
greets, mrozek

 

[hmilbradt]

Hi,

in the Royal diagram is an IC = ULN 2003 (signal amplifier) in the triac gate circuit. It's possibile that your board follows this diagram and the ULN 2003 is broken resulting in a permanent triac gate ON-signal.

regards
Harry