FeelTech / Kuman FY6600 DDS Function Arbitrary Waveform Generator repair

[CapLeaker]

Some Got it as a X-Mas present from wifey. Lasted about 30mins and then it was absolutely dead.
Checked the PSU and it was loaded down to next to nothing. Unplugged the main board from the PSU and all is O.k. on the PSU. Ahh! Main board problem!
Took the main board out and find a short at T2 (78L05) regulator between the input and GND pin. Took that out including the cap that is next to it and still have a short. I also measured shorts between C53 and C57. Took these out, took the 2 IC's under that heat sink out and still a short! Running out of options I decided to go old fashioned way hunting a short. Feed Power! Fed 5V 1.2A on the shorted line, doused half of the board with alcohol and success! SMD cap C81 bubbling! Replaced that with another cap the same size I found on a TV main board, put that in, soldered in all the parts I had taken out, reassembled it and I've got a working Function Generator.

So in short: If you have a Feeltech / Kuman FY6600 that doesn't work and the PSU is good, check C81 on the main board. It is under that little heat sink that is on top of of the 2 IC's.

Merry X-Mas!

[eccerr0r]

Was that heatsink specifically for those two ICs? Weird... expecting a SOIC8 and SOP8 to dissipate that much heat is not a good sign...?

[CapLeaker]

Yes. The funny thing is that the heat sink only covers the both IC's only to 75% and there was no thermal paste either.

[CapLeaker]

I decided to open her up again and read the Winbond 25Q16JV SPI flash.
https://www.eevblog.com/forum/repair...nal-generator/

My firmware version is 3.2.1

Enjoy!

[CapLeaker]

... forgot the schematics to that thing.

[CapLeaker]

Now I have to figure out how to read the STM32 in the head unit. That is where the actual firmware is. The stuff on the Winbond doesn't look like firmware.

Did anyone try to copy and flash an STM32 before?

[sam_sam_sam]

Originally Posted by CapLeaker

Took the main board out and find a short at T2 (78L05) regulator between the input and GND pin. Took that out including the cap that is next to it and still have a short. I also measured shorts between C53 and C57. Took these out, took the 2 IC's under that heat sink out and still a short! Running out of options I decided to go old fashioned way hunting a short. Feed Power! Fed 5V 1.2A on the shorted line, doused half of the board with alcohol and success! SMD cap C81 bubbling! Replaced that with another cap the same size I found on a TV main board, put that in, soldered in all the parts I had taken out, reassembled it and I've got a working Function Generator.

This is very interesting in how you found the shorts that were on this board
This was very interesting reading I enjoyed it Thanks for sharing this

[CapLeaker]

Yeah, that old trick saved my butt a few times.

I've managed to get the 3.3 firmware, some .FYbi file for the STM32 from the manufacturer. Now I have to figure out how to update that Function Generator.

[stj]

ask your source, stlink / serial uses HEX files.
they may have written a special bootloader - possibly using the usb port.

[CapLeaker]

Originally Posted by stj

ask your source, stlink / serial uses HEX files.
they may have written a special bootloader - possibly using the usb port.

That's the problem. FeelTech doesn't provide that unless that is something brand new. Nothing is available from their website. All they say is: send it in.

[CapLeaker]

This is supposed to be the version 3.3 firmware for the STM32 on the FY6600 that I've managed to download from FeelTech.

[stj]

that's encrypted binary with a custom header.
install the pc remote-control software and see if it has an upgrade option in it somewhere.

[CapLeaker]

Back to this puppy. Had to grab an old windblows machine and really install that software. Nope, you can't upgrade the Firmware through the PC-software v. 5.5 and that is the latest. Maybe I'll try the software from the newer FY-6800 later on and see what that does.

[bcgelandewagen]

Originally Posted by CapLeaker

Some Got it as a X-Mas present from wifey. Lasted about 30mins and then it was absolutely dead.
Checked the PSU and it was loaded down to next to nothing. Unplugged the main board from the PSU and all is O.k. on the PSU. Ahh! Main board problem!
Took the main board out and find a short at T2 (78L05) regulator between the input and GND pin. Took that out including the cap that is next to it and still have a short. I also measured shorts between C53 and C57. Took these out, took the 2 IC's under that heat sink out and still a short! Running out of options I decided to go old fashioned way hunting a short. Feed Power! Fed 5V 1.2A on the shorted line, doused half of the board with alcohol and success! SMD cap C81 bubbling! Replaced that with another cap the same size I found on a TV main board, put that in, soldered in all the parts I had taken out, reassembled it and I've got a working Function Generator.

So in short: If you have a Feeltech / Kuman FY6600 that doesn't work and the PSU is good, check C81 on the main board. It is under that little heat sink that is on top of of the 2 IC's.

Merry X-Mas!

I have experienced a similar issue where turning on the unit I can hear relay clicks but no display on the led screens. The Red power LED and green channel LEDs seem to be on but faintly. Do you know the value of the C81? I downloaded the schematics but i did not find the value. I'm not very good at troubleshooting I am still learning along.


Thank you,

[CapLeaker]

yours has a different problem than mine had. Mine was totally dead, as one of the voltage rails was shorted to GND. Not sure what problem yours has. Maybe give it a good visual under the microscope. Check all the voltage rails, 12, 5, 3.3, 1.2V. There is a TTL, maybe read it out.