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Re: Ye Beta24 build

PostPosted: January 31st, 2018, 6:40 pm
by zhanqian
Hi Ti, obee, cobretti

Sorry, I think it's due to my poor English, I can't explain it well, I post the schematic and the source code below.
The soft start resistor is connected in series to the AC to transformers, and all the relay I used are normally "opened".
The delay 2 seconds is for avoid the rush current. Is the procedure OK?

Re: Ye Beta24 build

PostPosted: February 1st, 2018, 2:05 am
by amb
OK, the code makes it all clear now. It's good.

Re: Ye Beta24 build

PostPosted: February 1st, 2018, 7:58 am
by obee
zhanqian wrote:Hi Ti, obee, cobretti

Sorry, I think it's due to my poor English, I can't explain it well, I post the schematic and the source code below.
The soft start resistor is connected in series to the AC to transformers, and all the relay I used are normally "opened".
The delay 2 seconds is for avoid the rush current. Is the procedure OK?


With the schematic, it's much clear.

About the code, you may consider using interrupt instead of a forever loop.

https://www.arduino.cc/reference/en/lan ... interrupt/

I am not sure you are using Arduino kind of mcu or not. If you do, see if your arduino supports interrupt, it might be a little bit better.

Re: Ye Beta24 build

PostPosted: February 1st, 2018, 7:00 pm
by zhanqian
Thanks, Ti

Hi obee,
The power button have already used the GPIO and the Timer interrupt, it changes the power status variable "beta24_power_on" in the interrupt. The power on and power off procedure takes "long", therefore it is not suitable to put into the interrupt routine.

I didn't use the Arduino, the controller board I use is some kind of common in the market in China, it's base on the STM32F103 processor, and it's cheap :D .

Re: Ye Beta24 build

PostPosted: March 13th, 2018, 6:51 am
by zhanqian
Hi Ti,

I got one of my board setup finished.

In the Input stage bias setup, R7 and R8 are about 4.10v, R9 and R10 are about 4.03v,
In the VAS stage, the R11 and R13 are about 143mv, not about 130mv. I decided to move on, finish the rest of the setup.
After finished all setup, the R45,R46 , R47,R48 are about 40mv, the DC offset is between -0.3mv and 0.1mv. The R11 is 81.6mv, R13 is 173.2mv.

Is the setup OK? Or should I mind about the VAS stage R11 and R13 voltage are not correct?

Re: Ye Beta24 build

PostPosted: March 13th, 2018, 8:06 am
by amb
It’s all good!

Re: Ye Beta24 build

PostPosted: March 13th, 2018, 8:52 am
by zhanqian
Sorry Ti, I didn't see your reply when edited.

OK, get it, move to another board. :D

Re: Ye Beta24 build

PostPosted: March 15th, 2018, 6:38 pm
by zhanqian
Ti, I have some problem in the other channel setup.

When I finished step 9(null the DC offset), found R45 and R46 is 0mv, and remains 0mv even if I turn VR2 fully clockwise.
I try tweet VR4, but need to tweet a lot to make R45 and R46 40mv, then the DC offset is about 300mv, can't be reduced.
I tried reflow almost all the solder joints, do it initial setup again, but no luck.

One thing is strange, in the VAS stage balance setup, the voltage of R11 and R13 are about 80mv and 180mv, I need adjust VR4 a lot to make R11 and R13 about 130mv,
and the voltage of R11 and R13 are not stable, change between 125mv and 132mv continually, which didn't happened in the first channel.

Re: Ye Beta24 build

PostPosted: March 15th, 2018, 10:52 pm
by amb
Try swapping Q1/Q3 (or Q2/Q4, but not both) to see if it makes any difference. This has been discussed in other people's β24 build threads, you should search/browse for additional answers and information.

Re: Ye Beta24 build

PostPosted: March 16th, 2018, 4:57 am
by Pieterh
I had a similar problem with one board. You can check this here: initial-set-up-issue-beta24-board-t3689.html

Besides checking solder joints, it was advised to measure all measureable components and compare values between your 'bad board' and your 'good board'.