Schreiber problem

[mcintosh]

Hello,

I have a problem with my Schrieber integrated freezer (APP6403, s/n 20031922281-036103009-03). A while ago it started defrosting itself randomly but we could get it going again by pressing the little booster button. Now it has completely given up and the little warning lights are flashing and we can’t start it. Is this something we can fix with spare parts or do we need to get a new freezer?

Very thankful for all help

Warm regards

Karin

[kwatt]

Hi Karin,

It sounds like a compressor failure but you’d have to have it checked to be sure.

K.

[expertcat]

its the pcb at that age mfi are requesting when an engineer fits one the old one has to nbe returned as they have changed the design.

pm if you require a partas i hold these instock.

[mcintosh]

Re: Schrieber problem

Thanks for the advice. Epertcat, sorry for my ignorance but I didn’t really understand what you meant, could you please explain?

Thanks

[expertcat]

The printed circuit board has been modified.

When an engineer is called via mfi the pcb has been requested to be returned due to problems which happens at the age of yours.

Very rarly will you have a compressor failure on your age but the new ones are different with everyone being a compressor.

[mcintosh]

Re: Schreiber problem

what do you think it would cost to fix it? should we even bother or just get a new one?

[PL]

Re: Schreiber problem

Hi there

For what its worth I had a problem with my schreiber freezer, the same model as yours. I fitted a new control board and it sprang into life.

I ordered the board from the white goods site I think it was about £50

The procedure in changing the board is very simpleand can be performed by anyone.

Procedure
1: Turn off the power
2: Remove any screws fastening that are securing the freezer in its place under the worksurface
3: Pull the unit out about 6 inches
4: On the top of the freezer you will see a plastic cover which is grey in colour. This pops out very easily
5: Remove the plastic rod that goes through the circuit board and alters the temprature. This can be pulled out
6: Pull the circuit board up and remove the two connectors
7: before you replace the board make sure that you turn the temperature control as far as it will go in an anti clockwise direction. ( this will ensure the teperature control rod slides back into the freezer in the zero position)
8: Put the two connectors onto the board and place the board back into its position
9: Put the plastic rod back through the location hole in the front of the freezer and make sure it is in the zero position
10: Last but not least replace the grey cover and push the freezer back into position. Turn the power oin and that should be that

I hope this helps It certainly worked for me

Best regards Pat

[trukkie]

Re: Schreiber problem

mmm and I think I know what the problem with the design is.
I did some measurements of the PCB and found the voltage across the relay is 12V. But the relay is rated 24V for the coil voltage.
So basically when your relay is fairly new it trips in as it should but as it gets older and becomes a bit more sticky it starts to fail to switch.

If your freezer has stopped working and the alarm is going off try shutting the door very firmly and see if the compressor kicks in.
It will then take the freezer down to the set temperature and trip out.
That proves that your thermostat is ok. The trouble is as the temperature comes up the relay can’t trip and your back to alarm again.
I found this worked every time with mine – not much use though other than as a debug tool 🙁

I tried contacting ISPRA controls – the pcb manufacturers but they wouldn’t respond.

Thinking about it, if what I found is correct then this would explain why MFI want the old boards back – no evidence!
This is a flawed assembly and the customer is footing the bill – I think I shall have a word with trading standards.

cheers

[Optimist?]

Re: Schreiber problem

trukkie wrote:… But the relay is rated 24V for the contact voltage….

I’m guessing that we’re talking about an old traditional electromechanical relay?

Presumably you mean the coil rating of the relay is 24V?

It’s not unheard of to supply such a relay with 24V very briefly, to energise the coil fully and make a positive changeover of the contacts, but then to back the voltage off to a holding level (which could easily be as little as half the rated voltage) in order to save power and reduce self-heating.

As I don’t know the circuit schematic, I can’t say for sure that your interpretation isn’t the correct one, but mine is certainly an alternative explanation that might be true…

Pete

[trukkie]

Re: Schreiber problem

Yes it’s a mechanical relay – OMRON G5LE the data sheet is easily found with a quick search.

Sorry I meant coil not contact – contact is rated 250VAC.

I don’t have a schematic either but I am reverse engineering it and looking at it I don’t think the circuit is that clever – you have a bridge rectifier connected directly on the supply side and a PIC on the other. But yes that is possible – I’ll get the oscilloscope out and see if I can trigger on anything > 75{e5d1b7155a01ef1f3b9c9968eaba33524ee81600d00d4be2b4d93ac2e58cec2d}Vmax(coil).

So the other possiblity then is that the PIC doesn’t maintain the surge voltage for long enough and again as the relay ages it starts to fail.

So still a manufacturing design defect hence the quiet recall.

Thanks for the input !

[dpm]

Is this freezer an Ignis clone? If so, I had one die recently, failing insulation on the top of the unit caused condensate to make it’s way along the extension shaft for the thermostat, water corroding the PCB at the front and the thermostat at the rear (under the L-shaped cover.

If there’s any sign of the same kind of water build up, the unit is scrap IMHO.

[trukkie]

Re: Schreiber problem

No there is no condensation build up and no corrosion.
The problem is that the relay can no longer trip, the cause is a PCB design flaw .
It’s a schreiber integrated into an MFI kitchen – I’ve no idea who makes ignis.

cheers

[expertcat]

its made by servis

[Dales-Electronic]

Re: Schreiber problem

My dear chap – Antonio Merloni NOT Servis :kermit:

[Optimist?]

Re: Schreiber problem

trukkie wrote:…The problem is that the relay can no longer trip, the cause is a PCB design flaw .

Don’t suppose anyone’s got a ‘latest revision’ circuitboard they could look at, and see whether this relay has changed to a 12V coil type? If that’s the only visible difference, then it would lend a lot of support to your hypothesis trukkie!

Pete

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