Pretty sure I know the answer to this but thought I'd ask here anyways. Got this nice coffee maker from someone since it just died on them. Long story short a surge blew a fuse and MOV in the power supply. I replaced both and tested, machine came back to life! Decided to try to take a video to show a friend and that's when I heard the relay click on and water start boiling in the tank and the display/buttons are now dead again. Did a bunch of testing, couldn't figure out why this is happening, every time I plug it in, the heater turns on via the relay. To try and test more things, I decided to desolder the relay to stop the heater from coming on. Well now some of the buttons at the bottom started lighting up a bit and unfortunately found out what seems like the CPU is running at over 100c (my poor finger 😣). Is there anything I could look at or is this poor board just toast?
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check the voltage regulator cicuit isnt shorted and overdriving the cpu
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Excellent suggestion! Unfortunately I'm really not sure which circuit is for the voltage regulator or how to test for this potential short. I've attached some pictures to show the board itself and from what I've found Vdd is only on pin 11 (pin 1 is directly under the dot). If you could kindly bump me in the right direction to test for shorts, I would be very grateful!
https://imgur.com/a/SPU6GM1Attached FilesComment
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r26 and r27 look a bit toasted,
check all the resistors with a meter
whats on the other side?
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R26 and R27 are fine (4.66k and 4.67k). Testing the rest of resistors will take a long time but I will test them. I've attached an image of the back of the board as well. Looks like the only thing of note is a crystal oscillator and a capacitor (which the CPU is right on the other side of the cap).
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Have you checked the voltage coming from the power supply? looks like it should be +5v (red wire on white plug)Comment
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i didnt think of a seperate psu!
nice that the connectors are labeled!
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Hi, I'm seeing one 9V relay having temperature 40C on its 9V (primary) side. Does that seem right? I switched 2 relays on that board and the temperature was the same (on the same position), so I'm sure it's not a faulty relay. I measured voltage on that relay and it was 9.5V DC, so that looks good. I don't see any other relay on that board having that kind of temperature and they have 9V on them too.
I thought maybe the transistor that is switching this relay keeps switching on/off, so I also checked for AC and there was almost none: 0.3V using mV range. No steady frequency was shown, but... -
Hi everyone!
I have this board that suddenly stopped supplying power to an output that drives an interchanger cleaner motor.
I checked while the board was in place with all wires attached and there's no AC voltage on the corresponding plug X5
This X5 is driven by fuse F8 (tested OK) which comes from the second orange relay
To make sure there are no charcoaled contacts inside the relay, I got a 24VDC power supply and got it ready to manually power up the coil side of these relays.
I respected the polarity, positive to cathode of protecting diode
So provided all... -
I got lucky that when I got home and was about to get some ice out of the ice dispenser I hear and see water running down the outside of the ice dispenser what the heck is going on here
At first I thought that the ice dispenser mold was cracked so I brought a new ice maker because this one has been in there for about 10 years now
Well I put the new one in and wait and I wait for the water valve to open and let water in no such luck well there is a way to check the function of the motor and the water valve on this ice maker just need a jumper wire “L” to... -
I was working on this CNC machine today found no keyboard functioning no control relay powering on
The screen powered on and was giving an operation error but the manual was not very clear about what the error exactly was but with a little bit of troubleshooting and finding out that the control relays not powering on and no keyboard functions we narrowed down to this one switching power supply which of course does not have any indicator LED light they are on the keyboard interface/relay controller board
Found shorted diodes on main controller relays there are 3 of them that... -
Hi everyone,
I'm working on repairing a Pilz PNOZ X4 safety relay module. When I opened it up, I found some of the connector pins detached from their pads. I replaced the connector with individual wires, but the issue remains.
The module is set to dual-channel mode with manual start. In this mode:- Y36-Y37 and Y1-Y2 are bridged.
- 24VDC is applied across A1-A2.
- It monitors two emergency circuits (S11→S12 and S11→S52).
- When both are closed (24V present on S12 and S52) and the start button is pressed (S33 connected to S34), the NO contacts (13-14, 23-24, 33-34)
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