Hello, I see some threads on my exact board in the past, so hope this is ok to post here.
I want to learn more about PCB repair and possibly save money repairing my commercial treadmill that I use at home. I design and make solid-state III-V optoelectronic devices for my academic research job and I have made simple low-voltage mixed AC and DC circuits for custom testing of my devices, but it's all very simple breadboard-type stuff compared to a complex PCB. Like RC filters.
The story- I replaced my garage 20A outlet with a GFCI and after testing it out on a halogen lamp, I plugged my treadmill into it. After turning it on, I heard a loud pop and knew I had messed up something. I don't know what I did wrong, maybe a coincidence, but it was working fine before I changed the outlet. I put the old outlet back.
Visual inspection revealed that the bridge rectifier on the motor controller PCB labelled DF06 was blown. This board is ~$200 to have repaired professionally. Here is the album with pics of the board with some markup of my notes:
If I understand the service manual correctly, the board takes 120VAC input and doubles to 230 V. It converts to DC, then inverts to 3-phase AC. The microcontroller applies PWM to the both output voltage and frequency. I have not tested the motor itself, I assume I will have to do that but not sure how yet.
I am making parts list to replace. So far, I am going to replace all the electrolytic capacitors since they're probably 20 years old and should be replaced anyway. And the DF06 rectifier. I think the relay too.
That DPDT relay next to the blown rectifier does not work as I expect. I have tested the relay with the power off, it looks to me that one of the connections that should be closed when de-energized is not closed. You see from my notes that 3 of the 4 connections are open circuit, when I think just 2 should be open and then the other 2 are switched to after 12VDC is applied to coil. Could one of the relay poles failed and caused the bridge rectifier to fry?
All components immediately connected to the DC side of the fried bridge rectifier appear ok.
Will the IGBTs be broken? How do I test the IGBT module? I'm not even sure how to remove it from the board yet.
Thank you.
I want to learn more about PCB repair and possibly save money repairing my commercial treadmill that I use at home. I design and make solid-state III-V optoelectronic devices for my academic research job and I have made simple low-voltage mixed AC and DC circuits for custom testing of my devices, but it's all very simple breadboard-type stuff compared to a complex PCB. Like RC filters.
The story- I replaced my garage 20A outlet with a GFCI and after testing it out on a halogen lamp, I plugged my treadmill into it. After turning it on, I heard a loud pop and knew I had messed up something. I don't know what I did wrong, maybe a coincidence, but it was working fine before I changed the outlet. I put the old outlet back.
Visual inspection revealed that the bridge rectifier on the motor controller PCB labelled DF06 was blown. This board is ~$200 to have repaired professionally. Here is the album with pics of the board with some markup of my notes:
If I understand the service manual correctly, the board takes 120VAC input and doubles to 230 V. It converts to DC, then inverts to 3-phase AC. The microcontroller applies PWM to the both output voltage and frequency. I have not tested the motor itself, I assume I will have to do that but not sure how yet.
I am making parts list to replace. So far, I am going to replace all the electrolytic capacitors since they're probably 20 years old and should be replaced anyway. And the DF06 rectifier. I think the relay too.
That DPDT relay next to the blown rectifier does not work as I expect. I have tested the relay with the power off, it looks to me that one of the connections that should be closed when de-energized is not closed. You see from my notes that 3 of the 4 connections are open circuit, when I think just 2 should be open and then the other 2 are switched to after 12VDC is applied to coil. Could one of the relay poles failed and caused the bridge rectifier to fry?
All components immediately connected to the DC side of the fried bridge rectifier appear ok.
Will the IGBTs be broken? How do I test the IGBT module? I'm not even sure how to remove it from the board yet.
Thank you.