Help with pcb issue

[narkeleptk]

Since cloning the mcu is not an option for PIC (assuming its secured, do we even know if it is?),
Maybe you guys can help get him sorted to determine if the PIC is defective or not. Since I have nothing of value add on that subject I will bow out. Good day, and good luck to you TS.

 

[hyedenny]

...since I am a native speaker born and raised I take it more as you are insulting my education...

WOW!
Sorry, my mistake!
I wasn't insulting your education, I was giving you the benefit of the doubt as an explanation for your poor grammar, diction, spelling, and syntax. Next time I'll know better -- my apologies.

 

[hyedenny]

I’ve pulled the transistors and attached a image of the results, hope this helps

Now, check the voltages with each switch pressed at the pin corresponding to whatever switch you're pressing.
If you have a scope, or other way of measuring frequency, check to see if the oscillator -- the blue 3-pin component at pins 8 and 9 -- is working.

 

[narkeleptk]

WOW!
Sorry, my mistake!
I wasn't insulting your education, I was giving you the benefit of the doubt as an explanation for your poor grammar, diction, spelling, and syntax. Next time I'll know better -- my apologies.

All good Sir,
Thankfully there is a ignore button you can push by highlighting my avatar. Then you will not have to be bothered by my outlandish claims of impossible feats of wizardry and nonsensical drivel!

 

[Ashly90]

Now, check the voltages with each switch pressed at the pin corresponding to whatever switch you're pressing.
If you have a scope, or other way of measuring frequency, check to see if the oscillator -- the blue 3-pin component at pins 8 and 9 -- is working.

Unfortunately I don’t have a scope. I’ve tried to trace the buttons back to the pins but can’t see where they go as there’s components in the way. I managed to get voltage changes on 4 of the buttons on certain pins. Some of the buttons may not change voltages as they have to do a sequence ( top 3 buttons select pipe size first, then the next 2 do freeze or defrost, then the bottom button starts it ) I don’t know if I will see voltage change across all of the buttons because of this?

 

[narkeleptk]

you only need a dmm to trace the buttons. Do you have one? If so un-power the device and set your meter to resistance mode (u should see less then 1ohm using this mode) or better use continuity mode if your meter has it. hold one probe on the button and use the other probe to follow the circuit. If its direct to the pins of PIC Then you can just probe the PIC pins to find the direct path. If it goes through resistors then you will need to find them first. Then move your buttons probe to the other side of said resistor and continue like this until you get to the pins of the PIC.

 

[Ashly90]

you only need a dmm to trace the buttons. Do you have one? If so un power the device and set your meter to restance mode (u should see less then 1ohm using this mode) or better use continuity mode if your meter has it. hold one probe on the button and use the other probe to follow the circuit. If its direct to the pins of PIC Then you can just probe the PIC pins to find the direct path. If it goes through resistors first then you will need to find them first then move your buttons probe to the other side of said resistor and continue like this until you get to the pins of the PIC.

‍ So sorry I didn’t even think about that. I’ll do it tomorrow and post my results

 

[Ashly90]

you only need a dmm to trace the buttons. Do you have one? If so un-power the device and set your meter to resistance mode (u should see less then 1ohm using this mode) or better use continuity mode if your meter has it. hold one probe on the button and use the other probe to follow the circuit. If its direct to the pins of PIC Then you can just probe the PIC pins to find the direct path. If it goes through resistors then you will need to find them first. Then move your buttons probe to the other side of said resistor and continue like this until you get to the pins of the PIC.

Also forgot to mention, when the transistors were in the machine was stuck beeping all the time ( should only beep on button push and then every 10 seconds once a pipe has been frozen ) it is no longer stuck beeping. Not sure if that helps. I’ll do the checks tonight on the buttons

 

[Ashly90]

So

you only need a dmm to trace the buttons. Do you have one? If so un-power the device and set your meter to resistance mode (u should see less then 1ohm using this mode) or better use continuity mode if your meter has it. hold one probe on the button and use the other probe to follow the circuit. If its direct to the pins of PIC Then you can just probe the PIC pins to find the direct path. If it goes through resistors then you will need to find them first. Then move your buttons probe to the other side of said resistor and continue like this until you get to the pins of the PIC.

so I did a resistance test and each button is going to all the pins between 1 and 2 ohms?

 

[narkeleptk]

I'm no expert but that does not sound right did you have power connected?
You need to make sure it is not connected when checking continuity or resistance

 

[Ashly90]

I'm no expert but that does not sound right did you have power connected?
You need to make sure it is not connected when checking continuity or resistance

Definitely no power connected, each button had ohms on every pin it just varied between 1-2 ohms on each pin. Not sure what’s happening there

 

[narkeleptk]

what happens if you check pin to pin on PIC? 0'ish ohms? hopefully the other guy who knows the chip will come backand help you But it seems you have a pretty nasty short

 

[Ashly90]

what happens if you check pin to pin on PIC? 0'ish ohms? hopefully the other guy who knows the chip will come backand help you But it seems you have a pretty nasty short

If you mean black and red lead on different pins on pic then I get anything from 0.3-1.8 ohms

 

[narkeleptk]

have you tried opening the buttons and cleaning the contacts?

 

[DrG]

In a sense, I admire your fortitude...especially if it is successful. Would you mind of I asked some questions?

First, can you offer up the name of the unit as in a model number or anything similar that might give everybody an idea of the details of its operation. A schematic exists somewhere. I read through the thread and see no such reference.

There could be a wealth of information in the manual, especially if there are some built in diagnostics which could be implemented with the little tone generator.

Are there no sensors on the unit? I would expect that there would be associated with freezing and thawing. It could be programmed to not operate the fa or pumps without valid sensor input.

You received it from a friend as "faulty". Can you provide any other information on that? For example, was it ever working? Did some event occur, after which, it became faulty? That kind of thing.

Did you verify good quality +5 and +12 power?

If I understand correctly, you removed some transistors from the board. How are they marked and have you tested them now that they are off of the board. They may simply be drivers for the PIC to operate the relays, but you have an opportunity to evaluate them separately now.

You said that the PIC gets hot - did you mean warm or too hot to leave your finger on the chip?

....just some thinking

 

[Ashly90]

have you tried opening the buttons and cleaning the contacts?

Yes and they seem to be working as if I go between ground and live side on the button with power to it the voltage goes from around 5 down to 0. I’m guessing this means their working?

 

[Ashly90]

In a sense, I admire your fortitude...especially if it is successful. Would you mind of I asked some questions?

First, can you offer up the name of the unit as in a model number or anything similar that might give everybody an idea of the details of its operation. A schematic exists somewhere. I read through the thread and see no such reference.

There could be a wealth of information in the manual, especially if there are some built in diagnostics which could be implemented with the little tone generator.

Are there no sensors on the unit? I would expect that there would be associated with freezing and thawing. It could be programmed to not operate the fa or pumps without valid sensor input.

You received it from a friend as "faulty". Can you provide any other information on that? For example, was it ever working? Did some event occur, after which, it became faulty? That kind of thing.

Did you verify good quality +5 and +12 power?

If I understand correctly, you removed some transistors from the board. How are they marked and have you tested them now that they are off of the board. They may simply be drivers for the PIC to operate the relays, but you have an opportunity to evaluate them separately now.

You said that the PIC gets hot - did you mean warm or too hot to leave your finger on the chip?

....just some thinking

That’s for the questions,
1) sure it’s a Rothenberger plumb freeze eco, sorry didn’t realise I didn’t give the name.
2) im guessing it will have sensors but the fans are running on start up. Not sure if that helps.
3) it was working a few years ago, he then gave up plumbing and recently found it in his garage. Been sat a few years. He bought it second hand and was working fine but did notice someone had changed one of the buttons as it’s shorter than it should be.
4) I have a good 5/12v
5) I have no idea how to test the transistors sorry, but they are c9013 h908 and c9012 h908
6) it gets warm but I can keep my finger on it. It just gets to that temp very quickly ( within a few seconds )

 

[DrG]

That’s for the questions,
1) sure it’s a Rothenberger plumb freeze eco, sorry didn’t realise I didn’t give the name.
2) im guessing it will have sensors but the fans are running on start up. Not sure if that helps.
3) it was working a few years ago, he then gave up plumbing and recently found it in his garage. Been sat a few years. He bought it second hand and was working fine but did notice someone had changed one of the buttons as it’s shorter than it should be.
4) I have a good 5/12v
5) I have no idea how to test the transistors sorry, but they are c9013 h908 and c9012 h908
6) it gets warm but I can keep my finger on it. It just gets to that temp very quickly ( within a few seconds )

plumb freeze eco gives nothing at the Rothenberger site https://rothenberger.com/gb-en/technical-downloads but it looks like they do have manuals and other technical data for download....if we can zero in on the model.

The transistors look like a run-of-the-mill NPN (edit: the c9013 anyways) https://makerselectronics.com/product/c9013-npn-small-signal-transistor

 

[narkeleptk]

Here is a good video on basic testing of a transistors.

 

[Ashly90]

All of the transistors have a reading of 004. I’ve attached a image of the serial no and other info on the machine

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