Nothing but trouble I had with the microprocessor controlled thermostat of my refrigerator.
Contact burning of the much too ‘light’ relay on the pcb and after putting a few new relays onto it, at last the power-supply gave it up.
I used two 12V=DC 500mA power-adapters to power the kits separately.
Some time ago I bought a batch of #92 of those adaptors. So I’ll better start using them.
I opted for outside use so these adapters wouldn’t heat up everything inside.
After breaking one open, I yanked out the pcb with rectifiers and electrolytic capacitor. This way I got a simple AC power-supply. This is needed to synchronise the clock.
Because the K6001 Temperature Sensor (transmitter) does not consume much power, the voltage went up to 15 Volts. With a 7812 I got rid of that problem.
The output of the transmitter/sensor kit (K6001) is connected to the (K6002) controller kit with 30cm shielded 1-wire cable.
The KTY10 sensor is connected to the transmitter (K6001 sensor kit) with a shielded 1-wire cable of almost a meter.
I adjusted the OFFSET (RV1) on the transmitter kit and when I measured the voltage of the output, the voltage went up & down a bit which indicates a data signal.
But always after powering up, the display of the controller keeps displaying ‘[color=#FF0000]FAIL[/color]’.
This also happens when the transmitter isn’t connected, but it is.
Has there been a bug fix for this kit?
Is the transmitter already broken because of the 15V it was supplied at first?
Supplying power to the controller from an original Velleman PS905AC adapter also doesn’t help.
Maybe the transmitter (K6001) must be placed a certain distance away from the controller kit (K6002) or the KTY10 sensor may not be connected with a longer than 50cm cable from the transmitter kit. The manual says to connect with a +/-50cm screened wire.
At the moment the voltage of the output signal of the transmitter flickers between 284 and 295 millivolts, which could be the result of the difference in frequency of the pulse width modulation of the output and the sample frequency of my digital voltage meter. Maybe I need to take my Velleman PCS500 out of it’s box.
How do I know the KTY10 sensor is OK?
How can I test the working of the kits?
The manual should be more technical. A lot more.
Where do I go from here?
This is the output signal of the K6001 temperature sensor. (picture by PSC500 Transient Recorder)
The signal doesn’t seem to change when I turn any trimmer.
This is it:
What should it look like?
The signal between the two pins of the KTY11:
This is the output signal of IC1 (pin6) which is input signal (pin9) of IC2 of the K6001.
All I still get is [color=#FF0000]‘FAIL’[/color] !
I replaced IC1 & IC2 with the ones I have in the box of an other, still unassembled, K6001 kit.
These were a CA3160E and a CA3524E, which gave an identical result.
If I adjust RV2, the pulses (output of K6001) are closer together or further apart.
Signal 1 is the output of the K6001 and signal 2 is the output signal of the TIL111.
(I had to put Signal 2 AC mode, or it would not appear on the screen)
Than taking the sensor out of the ice-water and warming it to about 35°C gave this:
What should the signals look like?
What do I need to check?
Still I get [color=#FF0000]‘FAIL’[/color] !
So now I’ve assembled a second K6001 kit I had laying around and I still get the same results.
Is there any way I can check the workings of the K6002 controller?
Certain voltages I need to measure at certain test points?
Can I insert some voltage onto the K6002 boards which simulates the working?
From all the kits I have, this is the first one which doesn’t work immediately (or after trimming).
P.S.
This older kit, probably from may 2005, came with one wrong resistor. (Can happen)
I must say of all the kits I bought, this is the first time this happened.
R7 should have been a 1K8 resistor, but an 18K resistor was packed in the kit.
For a moment I thought this could be the same problem on the other K6001 board, but I always double-check when putting together a kit. I not only read the value printed on the resistors, but also measure them with a digital multimeter. The resistor could be a faulty.
I ones had a new light-bulb for the headlamp of my car, which blew the fuse every time. Nothing at all to see, but internally there was a short circuit.
Sorry about the colours in the pictures. I took them using a 200x web-cam/hand-held micro-scoop which has build-in LED-lighting. These LED’s don’t give the full spectrum.
If you can call it a micro-scoop?
200x isn’t such a big magnification, but it’s very suitable to detect faults on a pcb.
The above pictures of the IC’s are also taken with this cam.
I’m glad I bought this small camera. It wasn’t even expensive.
IC’s are correct type.
K6001 signal looks OK.
If this signal reaches K6002 PIC, it should work fine.
You are sure K6002 is fed with an AC voltage.
At this time, we do not know why it does not work.
We can suggest to examine both kits if you return them to:
I will check the input signal of the K6002’s PIC.
What should it look like? What amplitude?
Yes. I tried two different powersupplies. One of them the Velleman PS905AC adapter.
Could the voltage be too high or too low? Does it need to be ‘exact’ 9V-AC?
[quote=“VEL417”]IC’s are correct type.
K6001 signal looks OK.
If this signal reaches K6002 PIC, it should work fine.
You are sure K6002 is fed with an AC voltage.
At this time, we do not know why it does not work.
We can suggest to examine both kits if you return them to:
We can check the correct operation of both kits, if you return them.
If the problem is caused by a manufacturing error, it will be fixed for free.
If the problem is caused by an assembly or application error, a small fee will be charged.
Please note that warranty does not include shipping.
Sorry, we cannot tell how much shipping will be, this depends on different factors such as carrier, country, etc…
