Delta pulse 2 Sniffer, continuous beep issue

[deepseeker3214]

Hello all, i have Delta Pulse 2 that i posted about here in the past, was working fine but it's now beeping continuously i'm suspecting i gave it too much power but not sure, battery about 16v made from lithium 18650 ones but higher current due to parallel setup. The device was fine until today, even with removing an IC each time with most of them the peeping continues. the same battery worked on it before so i'm not sure what could be the cause.
Any help will be much appreciated guys.

[kt315]

check 1N4148 in power line, both. in my sch they are VD8 VD9. i changed 1N4148 on 1N4004 because there were always the problems.

[deepseeker3214]

check 1N4148 in power line, both. in my sch they are VD8 VD9. i changed 1N4148 on 1N4004 because there were always the problems.

I tried unplugging them one pin each and testing with multimeter they seem to be working fine.

[deepseeker3214]

The diodes give reading on one side only so should be working fine, I have noticed that even after running the device without some ics it will work with that non stop beep. Also no components are heating up, I have around 14 to 16 volts ( battery output) on the board. Please help me debug this and fix the issue the md was working fine and started acting like this a day ago.
...It was actually giving some good performance lately with the battery upgrade before he got that issue...to think about it maybe it's like when some people become beautiful and energetic right before they die

[Emersonpaz]

it was the improvement of death. 16v works at the maximum limit of the integrated ones, do you use CD4538BE?

[deepseeker3214]

it was the improvement of death. 16v works at the maximum limit of the integrated ones, do you use CD4538BE?

Yes both CD4538BE, and i knew he was about to die as he started acting young again

[Emersonpaz]

so CD4538BE is not the problem I thought I could have used MM74HC4538 your datasheet is 6v I made this mistake once. What is your delta configuration? TX power pulse wasn't very high? Maybe IRF840 fried.

[deepseeker3214]

so CD4538BE is not the problem I thought I could have used MM74HC4538 your datasheet is 6v I made this mistake once. What is your delta configuration? TX power pulse wasn't very high? Maybe IRF840 fried.

I'm using IRFP 4229, and the potentiometers levels are where they used to be and worked fine before, i'm joining couple of pics to front and back of the board.
https://ibb.co/yByRG1V
https://ibb.co/dMpWBgY

Thank you for your assistance.

[kt315]

you run for the power... so got you the trouble right after you did change IRF740 on IRFP4229?

[deepseeker3214]

you run for the power... so got you the trouble right after you did change IRF740 on IRFP4229?

No i had the IRFP4229 all along since the beginning and it worked good, never got hot or anything and i have heatsink with it as a precaution

[deepseeker3214]

I just tested IRF650B and the same thing continuous beeping sound.
And the same thing even without the mosfet, i'm guessing the fault is way before the mosfet stage.

[kt315]

8. Set pots in pre-set position:

- DEPTH - min, at left side, counter-clockwise
- DISC - min, at left, counter-clockwise
- GEB - middle
- SENS - middle
- T/HOLD - middle

[jakob leo]

NE 556

[Nightryder]

I suspect it's a transistor thing since you checked the ICs. But you have to distinguish between the transistors because some of them are installed as diodes (collector and base are connected)

Also, with this much power, double check your damping resistor and if it's not 2 watts, it's a good idea to replace it.