Hi folks,
I also ordered a Kaleep branded 858D+ from amazon germany (only 36.66€ at the moment!) and it came with a MK1841D3 chip.
I successfully did the following hardware changes:
- Rewired internal earth connection, because between power connector and gun nozzle I had around 20 Ohms.
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Wired earth directly to the case, to the front plate and to the gun.
Crimped the earth cable in the gun to the nozzle metal it was only twisted around as you can see in some other pictures in this thread.
- Added a heatsink to the TIP122 because it got really hot when the fan was running on lower speed. Is this usual?
- Soldered a adapter board based on wguibas great board
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and installed an ATMEGA 328P.
The only problem I had was that the two 10K resistors for VREF=2.5V were somehow to high, the VREF pin pulled the voltage to 2.14V.
So I changed the values to 1K and now I have a VREF of 2.5V
- I added a small buzzer (
eBay auction: #222121496866) to the board because I like how the Hakko soldering stations beep when they have reached the setted temperature and to get an accustic feedback when the gun was correctly placed in the cradle. Because of that, some changes in the custom firmware were necessary.
So here is my own custom firmware V1.47 based on V1.46 from madworm: * - Added an output (arduino pin 18, hardware pin 27 on a 168P/328P) for a buzzer which will beep on the following events:
* Power on (high beep)
* Set temperatur reached (only one time after removing gun from cradle and after changing temperature with the key buttons) (high beep)
* Put gun correctly back in cradle (low beep)
* Setted timeout reached (low beep)
* Keypress (comment out "#define KEYBEEP" in youyue858d.h to disable) (very high beep)
* - Added a multiplicator entry (TPL) to setup menu for stations with samsung or MK1841D3 chip
* For stations delivered with atmel chip set multiplicator to 10 (=1, default), for stations with MK1841D3 set to 21-24 (=2.1-2.4)
* (According to the forum on some stations a value between 2.3-2.4 is correct, on my station with MK1841D3 2.1 was correct)
* Possible values 10 to 40 (= multiplicator 1.0-4.0)
* This change avoids a seperate firmware version (thanks wguibas!) for stations delivered with non atmel chips
* - Added raw ADC value monitoring to the overtemperature shutdown process, because when you fiddle around with the multiplicator
* and set it wrong, temperature input may overflow which results in no shutdown on too high temperatures.
* Station will shut down and show "°C ERR" when analog input for temperature reaches 1000 (analog input is 10bit so max value is 1023)
* - Changed standby display from "---" to "STB" because in my opinion it looks nicer :-)
* - Added a delay time entry (DEL) to the setup menu which kicks in when the fan_off temperature is reached (default 45°C)
* to avoid fan off-on-off-on-off bevaviour because temperature rises to fan_on temperature again after fan was switched off.
* Delay will only be active if a temperature of 100°C was reached.
* Possible values 0 to 60 seconds
* - Changed back max temperature to 450°C and shutdown temperature to 500°C because (depending on cal poti setting) 500° can lead to overflow of temp analog input.
* (If you set the cal poti to 100°C = 0.5V like me, this gives you 2.25V at 450°C.)
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Thanks to madworm, wguibas and all others here in this thread for a lot of useful information, the custom firmware and the adapter board which saved a lot of time!
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Attached my firmware V1.47 (based on madworm's V1.46) as source and as compiled hex for the ATMEGA 328P and 168P.
Before first heating process, set "TPL" in setup menu according to your hardware: - Original Youyue with atmega: 10 (=multiplicator 1.0) according to madworm
- Yihua with samsung chip: 19 (=multiplicator 1.9) according to wguibas
- Kaleep with MK1841D3: 21-24 (=multiplicator 2.1-2.4) 2.1 was correct for my station with 220V, wguibas figured out 2.3-2.4 for the 110V version.
You may also need to adjust the low and high limits of the fan, in case of my Kaleep station it was low 120 and high 320raihei