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91
Project logs / Re: Really universal soldering controller
Last post by minkok -
Zener diode need to work in Reverse Bias Region in order to regulate the voltage properly.
First Nowhere is mentioned the kind of the zener nor its power dissipation, not even from you, I meant what was your kind of the zener.
Second, you complain from immediate burning and that speaks for non-propper zener working point or other board fails. Instead of to show your knowledge it is better to come with a solution, and ... Yes 6.2k resistor with BZX585-B36 with 2mA Iz will work. It will work correctly also with the Mod, I publish for the 48V supply ( recommended value is 16k for the extra R - less heated Q1). Definitely, I don't expect to be burned this time!
92
Project logs / Re: Really universal soldering controller
Last post by admaverick -
I mean 36V zener. And I mean to increase the value of R2 to 6.2k. In my opinion, it will limit zener current and will supply enough current to the Q1. You will get not burning and less heating Q1. To be sure , give to me the exact part value of ZD3

Zener diode need to work in Reverse Bias Region in order to regulate the voltage properly.
93
Project logs / Re: Really universal soldering controller
Last post by admaverick -
I mean 36V zener. And I mean to increase the value of R2 to 6.2k. In my opinion, it will limit zener current and will supply enough current to the Q1. You will get not burning and less heating Q1. To be sure , give to me the exact part value of ZD3
What I am saying is yes you do need to limit Zener current but Zener diodes need sufficient current to clamp the voltage properly. I think 1SMB5938BT3G is used here and its Izk@36v is 10ma. Here is a detailed explanation of Izk and Izm here: https://sciencing.com/read-zener-diode-ratings-6160739.html
94
Project logs / Re: Really universal soldering controller
Last post by minkok -
I found it quite weird that when the Zener Diode is 36v, the Pre-Regulator parts explode immediately with 48vac input voltage. But they(pre regulator) works just fine with 24v zener diodes. Q2 runs pretty hot of course but at least it wouldn’t explode for now.
I moded sparky's design. It is not tested, but I expect it to work - not to burn. You can choose the divider of your own will, depending on the Temp of Q1. Initial conditions for ZD3 is not working ( protective purpose ) as in the sparky's design
95
Project logs / Re: Really universal soldering controller
Last post by minkok -
Are you sure about increasing R2? My guts are that 4.7k does not provide sufficient working current for ZD3. I know it sounds counterintuitive but you do want to DECREASE the value of R2 to provide sufficient Izk for ZD3 (plus base current for Q2).
I mean 36V zener. And I mean to increase the value of R2 to 6.2k. In my opinion, it will limit zener current and will supply enough current to the Q1. You will get not burning and less heating Q1. To be sure , give to me the exact part value of ZD3
96
Project logs / Re: Really universal soldering controller
Last post by admaverick -
For sure that needs to be done - 100V Transistor is risky to be used on 48V rail powered by Trf. Not only, but R2 value should also be at least 6.2k and over Look for the right R2 value and this time Q1 will be colder
Are you sure about increasing R2? My guts are that 4.7k does not provide sufficient working current for ZD3. I know it sounds counterintuitive but you do want to DECREASE the value of R2 to provide sufficient Izk for ZD3 (plus base current for Q2).
97
Project logs / Re: Really universal soldering controller
Last post by minkok -
This is Catear’s 48v mod in the picture. MOSFET had been changed to TO-263 packages to withstand higher voltage.
For sure that needs to be done - 100V Transistor is risky to be used on 48V rail powered by Trf.
Several resistors (R2 R47 R51) had been changed to 1206 packaged ones.
Not only, but R2 value should also be at least 6.2k and over
  I found it quite weird that when the Zener Diode is 36v, the Pre-Regulator parts explode immediately with 48vac input voltage. But they(pre regulator) works just fine with 24v zener diodes. Q2 runs pretty hot of course but at least it wouldn’t explode for now.
Look for the right R2 value and this time Q1 will be colder
98
Bus Pirate Support / Self test found 6 errors. v3a
Last post by turtle -
Greetings all still rocking my buspirate v3a pretty much unchanged from the day I bought it.
Firmware v5.10 (r559)  Bootloader v4.4
DEVID:0x0447 REVID:0x3046 (24FJ64GA002 B8)
I just ran the ~ self test and this is what I get:
Code: [Select]
HiZ>~
Disconnect any devices
Connect (Vpu to +5V) and (ADC to +3.3V)
Space to continue
Ctrl
AUX OK
MODE LED OK
PULLUP H OK
PULLUP L OK
VREG OK
ADC and supply
5V(4.98) OK
VPU(0.00) FAIL
3.3V(3.33) OK
ADC(0.00) FAIL
Bus high
MOSI OK
CLK OK
MISO OK
CS OK
Bus Hi-Z 0
MOSI OK
CLK OK
MISO OK
CS OK
Bus Hi-Z 1
MOSI FAIL
CLK FAIL
MISO FAIL
CS FAIL
MODE and VREG LEDs should be on!
Any key to exit
Found 6 errors.

The leds are on, should I just ignore those errors? As it seems like it still works for the little I use it for.
I connect to it with the linux 'screen' command:
screen /dev/ttyUSB3 115200 8N4
Please advise thanks
99
Project logs / Re: Really universal soldering controller
Last post by admaverick -
Sure it can happen if you apply twice the power and not all components changed, what mod have you done on the 5.2?
Have you changed what Catear suggested for his mod 48V and do you have any plan to switch voltages or just want to use it fixed 48v?
This is Catear’s 48v mod in the picture. MOSFET had been changed to TO-263 packages to withstand higher voltage. Several resistors (R2 R47 R51) had been changed to 1206 packaged ones. This unit is not mine, it is someone else’s unit. I found it quite weird that when the Zener Diode is 36v, the Pre-Regulator parts explode immediately with 48vac input voltage. But they(pre regulator) works just fine with 24v zener diodes. Q2 runs pretty hot of course but at least it wouldn’t explode for now. Catear DID NOT modify the valley fill circuit and buck circuit for his 48v version. Maybe he just doesn’t want to do to much of redesigning work. However, sparkybg told me that it is better to connect the valley fill circuit AND buck circuit to a separate 12v winding (either same or different transformer?) Buck circuit should work fine with SEPARATE 12v rail but I am not so sure about the valley fill circuit (if they will work with SEPARATE 12v rail).