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Re: Schreiber problem
ok I’ve completed the schematic and my original suggestion would appear to be correct.
The relay coil has two zener diodes in series, wired parallel to the coil which regulate the supply voltage from the bridge rectifier.
These are two 6v zeners giving 12v as the coil supply. Note since these are zeners and in parallel the supply voltage is clamped at 12v and can never go any higher.
Underneath these two zeners is another which is tied to ground and is in parallel with the PIC, this regulates the PIC voltage to 6v.
The PIC uses two transistors to short the 12v supply to the 6v supply when the relay is to be switched off.So the relay is not powered to the specification in the data sheet. 😳
We have two possible causes:
1. The designers did a bad job and just thought they could get away with supplying half the voltage to the relay. 😡
2. The PCB manufacturers placed the wrong part and the 24v relay was fitted instead of the 12v. :rolls:
Either way this design was wrong as it left the manufacturers – this board will fail over time – some sooner, some later but they will fail.
I’ve contacted MFI who sold the freezer and will see how it goes.
If no joy there then it’s off to watchdog …celebrity beckons 😆Re: Schreiber problem
Nice work trukkie. 🙂
Now we just need to hear that the newer boards do indeed have a 12V relay fitted at the same position, and you’ve proved your point 100{e5d1b7155a01ef1f3b9c9968eaba33524ee81600d00d4be2b4d93ac2e58cec2d}.
The circuit sounds quite ‘economical’ shall we say. Please tell me there are some smoothing capacitors somewhere on the d.c. side of the bridge rectifier ? Can you post a piccie of the board?
Re: Schreiber problem
I’ve been told it is the board that has gone on my freezer (Schreiber APP6403) – I’ll try and find out more about the board when it is fitted. My husband has a friend in the trade who will fit it so it will be easy to ask him. He told my husband this was a common fault on these models and he fitted 3 last month! I’m glad it wasn’t me who picked it in the first place ( was inherited from the previous occupant) and I certainly wouldn’t chose this model in the future!!!
Re: Schreiber problem
Yep there are two electrolytic smoothing caps one is in parallel with the 2 zeners and the relay coil, the other is in parallel with the PIC and its supply. Additionaly there is a decoupling cap across the PIC.
I didn’t mention them in my other post so that the intent of the circuit would be clearer in text.
I’ll get a photo posted showing the offending items and will draw up the schematic in a printable doc which explains all.
If the new boards are anything like the one posted on this site it looks like a complete redesign, the original is very different, make what you will of that.
cheers
Re: Schreiber problem
trukkie, did you manage to do the above?
I’ve removed my circuit board and the relay is 24v, so by what I’ve been reading it should be 12v?
So when I get a new board the relay should be 12v, I mean they wouldn’t send me a new board with a 24v relay on it? 😕
the new pcb are completly made by a different company and redesigned there is only one relay which is rated at 250v to 305v.
Re: Schreiber problem
I’ve got a new PCB but there’s no relay on it 😕
Have they sent me the wrong board?
Re: Schreiber problem
Ok, fitted this board and the motor sprang to life.
So back to my orginal post, did they send me the wrong board as it has no relay? 😕
On a separate issue… why is the date and time wrong on this post??
It’s Wed 25th July 2007, 7pm…… 😕 as I type
Re: Schreiber problem
Sounds like I have exactly the same problem can anybody tell me the part number of the control board required and the best place to source this?
Schreiber APP6403 built in freezer.
Re: Schreiber problem
karlmac wrote:Sounds like I have exactly the same problem can anybody tell me the part number of the control board required
546039400 (now 546039402)
karlmac wrote:and the best place to source this?
Right here:
http://shop.ukwhitegoods.co.uk/product_ … cts_id=687
😀
Dave.
Re: Schreiber problem
“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”
This is exactly what has happenede to mine after an engineer had come out to tell me my compressor had gone!
After a day it is working better than ever!Is this just a false dawn and what if anything is my next move.
Symptoms have been exactly as specified in the first couple of posts on this thread.Re: Schreiber problem
Hi
Ialso have a problem with my Schrieber integrated freezer (APP6403). it stopped freezing.
the little warning lights are flashing and the buzzer sound comes on.I changed the 24volt relay on the PCB, to a 12v relay, but it has made no difference, and there is no sound from the compressor.
any help please.Re: Schreiber problem
HI
I BOUGHT A SCHREIBER FRIDGE FREEZER S/N 20054116012-038103003-03 ABOUT 3YRS AGO I DONT KNOW THE MODEL NUMBER (IF ANY ONE CAN TELL ME I WOULD BE VERY GRATEFUL) IT BROKE DOWN ON ME I HAD NO IDEA WHAT THE PROBLEM WAS, I HAD A CONTRACTOR COME ROUND AND HE TOLD ME THE THERMOSTAT NEEDED REPLACING. CAN ANYONE GIVE ME A QUOTE FOR SUPPLYING AND FITTING A NEW THERMOSTAT MODULE. THEY WERE ADVISING ME TO REPLACE THE WHOLE FRIDGE FREEZER BUT I WOULD LIKE ANOTHER OPINION. 🙁
THANKS
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