4pm filter trouble (solved)

Hi,

I Just finished my 4pm filter and i have an issue, if someone Can Help:

After assembly i tested the +5 and -5 as described in the guide and all is fine. Problem is when i put all the ic on, the 7805 regulator burn my finger. If i remove the 74hc595 bottom left, no more Problem.

I came to this conclusion because i have two leds i soldered above it to Light up the case. When i firSt plug in the power, the leds Light up then go dimmer and shut off. I can hear a very subtle noise coming fron my power adapter if i use the 74hc595… Then it stops and thats when the 7805 is too hot…

I bought a New 74hc595 waiting for it. But i felt like asking to you for some idea, Thanks…

You have a short somewhere. Use you meter in “beep” mode and check +5 and GND, they should NOT beep.

I checked and tooK some time to clean everything and no more overheating 7805. No shorts either…

But when i touch the 74hc595 the 5v breaks and do not pass tô pins at the bottom of the ic.it is still there on pins 10 and 16 but not going to the other pins thus breaking the 5v connection further. The socket seems Good so maybe the ic is bad ? If i tap the ic with my finger the ic works sometime, the two leds near the socket Light up when ok, pins 6/7 sending the 5v to them…

I wonder if some short before the cleaning damagéd the ic? I Will try the new one once i receive it and report back.

Ah yes, the LEDs on the 4-pole board! At first I though you meant that you had added additional LEDs.

How do you know that the socket is good?

I made a continuity test between each pin from the upside of the socket to the solder below.

Then i dont think it has to do with the socket itself as when it happens, i can mesure 5v on pins 10 and 16 only. 0v everywhere else on 74hc595…

I can mesure 5v on ic6 so i am pretty sure something is wrong with that 74hc595.

Then i received 2 74hc595 from reichelt for the filter board and controller board. The one i used for the filter isn’t looking like the other one, i can barely read What is written on it and the upper face is like burnt/shiny…

The 5v is broken exactly at 74hc595. With the controller board connected with no screen yet, the leds go off when it happens, which is normal from What described above.

But i am no texhnician so i May be completely wrong :frowning:

Can someone explain This please :

If i test the filter alone plugged, and i pass my finger or some metal object around the 74hc595 or the 2 leds above, it Works on and off randomly.

then if i plug the controller board it Works normally even if i pass my finger or touch the 74hc595 on the filter …

is it some électromagnetism going on or what ? is it a sign of a bad 74hc595 ic on the filter?

i Am starting to Wonder if the problem is the psu …

Édit: did a test, the DC connector is fault. damn reichelt…

could be a sketchy chip (not a 595 but something else) I’ve never seen a 595 fail with a power rail short internally so it could be something else altogether. Have you tried the questionable 595 on the control board?

Well i don’t know what to do now. I received the new 74hc595 to replace the one on my filter board, it is doing the same.

Now when i connect the two board together, it works. I can navigate the menu and play the shruthi. But no resonance or almost none…

I am trying to calibrate the filter and i don’t hear it self oscillating, instead i hear a faint resonance and some noise …

I did set the controller board to 4pm and all, but something is wrong with the filter.

Can someone help please ?

I took some pictures of my filter in case. Thanks very much for your time.

your 220p caps are soldered wrong, you have them in the 2 holes that are bridged together, they need to be either one closest to the ICs and the middle or the one closest and the outside one

I think there is a problem with the connection between the control board and the filter board. Check the solder joints at the 6 pin connector of the control board. Or maybe you cut the stackable (arduino) headers to short?
And: The two LEDs on the filter board are supposed to light only at a certain (high) resonance level.

altitude, you fckin ROCK YEAH ! I owe you a HIGH FIVE dude, thank you !

It works great now, what a mission !

common mistake, been guilty of that my self…

My god, am i stupid ? i am now trying to assemble the transparent case that came with 4 screws, am i supposed to assemble it with only 4 screws ?

i don’t get it …

EDIT: just checked, missing the 12 m3 x 12 in the bag … sad … I didn’t pay attention until now :frowning:

Contacted Olivier, great support :slight_smile:

cj55, I understand now the weird behavior of those two leds when the controller board isn’t connected and not set to 4pm. I thought about some voodoo and whatnot, but now it works at high resonance indeed.

The 4pm filter sounds HUGE !

Hey MI community - I have very similiar problem with my 4PM - Its almost working - I, connect the boards (I also have SMR filter and It works very good) hook it up to IC - everything comes up nicelly - I press encoder - I hear the “Lets Jam” note, change filter type to 4pm and its dead - no more sound - checked for short - no short, checked the volages - they’re good - 7805 get super hot very fast. I will post photo - just need to ask someone with decent resolution on their phone to make it - please help. [edit] - 7805 is not getting hot when its only 1054 and powered on - again… and my 220 are in the right spot (but Ive used wima’s)…

@headbite are your second pin headers from Control board to filter board connected?

Yes - also put some extra tin on it to make shure the connection is good - im afraid some the IC or their bases can be down - heated all today but the problem remains - when all the chips are in - and the power is plugged on 7805 gets hot super fast (short somewhere probably?) - but I dont know - I did all the metering and no short and the voltages are great - how can I check the bottom row of IC’s ?