Spectra S1+ Breast pump - No suction

[redwire]

Re: Spectra S1+ Breast pump - No suction

This is how the circuit looks to me. To turn on the pump motor, Q9-C should go to ground. You could try tap a 1k resistor to GND and see if the mosfet Q7 turns on.

[caphair]

Re: Spectra S1+ Breast pump - No suction

I’m now wondering if Q9 does drive Q7 if there’s maybe a break to Q9 to Q7 gate within the PCB. I measure 57Mohm from those two points.

Also my meter has a duty cycle option that I probed the bottom left pin of Q9 (base?) and can see duty percentage change as I change the speed of the vacuum motor through the up/down controls

Bottom right pin of Q9 connects to ground so maybe it’s supposed to be grounding the voltage of Q7 gate to turn the motor on?

[caphair]

Re: Spectra S1+ Breast pump - No suction

These parts would have resistors inside:
Q9, Q12 SOT-23 marking NF, NPN digital transistor KRC106S or DRC2124X
Q11 SOT-23 marking PF, PNP digital transistor KRA106S

Q8 SOT-23 marking AO7? likely N-ch mosfet driving the solenoid.

My take on the pcb board:
Q9 drives Q7 for the motor.
Q12 drives Q11 for... braking?
Q10 drives Q8 for the solenoid.

It seems to have motor current-sense R32/R45 back to the MCU.

So would Q9 be the suspect for the motor not turning on?

[redwire]

Re: Spectra S1+ Breast pump - No suction

These parts would have resistors inside:
Q9, Q12 SOT-23 marking NF, NPN digital transistor KRC106S or DRC2124X
Q11 SOT-23 marking PF, PNP digital transistor KRA106S

Q8 SOT-23 marking AO7? likely N-ch mosfet driving the solenoid.

My take on the pcb board:
Q9 drives Q7 for the motor.
Q12 drives Q11 for... braking?
Q10 drives Q8 for the solenoid.

It seems to have motor current-sense R32/R45 back to the MCU.

[caphair]

Re: Spectra S1+ Breast pump - No suction

R21 and R30 do not connect to the top pins of Q9 or Q11.

The 0-4v fluctuation is consistent with the clicking, as well as small fluctuations with the main power ~11-8-11.5v

Pin 3 of Q11 goes up to the drain pins of Q2 (top right of the board) which happens to be the same ic as Q7.

[momaka]

Re: Spectra S1+ Breast pump - No suction

Top of Q9 does not connect to Q7 or any other leads.

Top of R21 connects to the Source pins of Q7
R21 and R30 are in series and bottom of R30 is connected to the Gate of Q7

Do any of the resistor leads of R21 or R30 connect to top pin of Q9? If not, what about Q11? I'm curious what drives Q7.

I've attached pics to show the operations of Q9-12 when powered on and off.

Seems like Q9 possibly cycling whatever's plugged into connector SOL? Looks like maybe an actuator. But that's the clicking I hear when powered on without suction pump.

Hmm. So the 0-4V fluctuation is consistent with the clicking?
Can you trace where the Emitter/Source pin of Q11 goes to? (Should be pin 3, the one on the right when the SOT-23 device is viewed with the single pin at the top, and two at the bottom.)

[caphair]

Re: Spectra S1+ Breast pump - No suction

Top of Q9 does not connect to Q7 or any other leads.

Top of R21 connects to the Source pins of Q7
R21 and R30 are in series and bottom of R30 is connected to the Gate of Q7

I’ve attached pics to show the operations of Q9-12 when powered on and off.

Seems like Q9 possibly cycling whatever’s plugged into connector SOL? Looks like maybe an actuator. But that’s the clicking I hear when powered on without suction pump.

[momaka]

Re: Spectra S1+ Breast pump - No suction

L1 = .794v
L2 = 11.84v

U4 = 11.4v input 5v output

Tests made with the battery not power adapter.

Those look OK, I suppose, particularly U4.

Try the device with the power adapter instead of the battery. Perhaps L1 then might have a different voltage.

As a test, could I ground the gate of Q7 to see if the motor will turn on? Or would that potentially cause an issue somewhere else

It may cause a problem, depending on how the MOSFET is driven. If the Q7 is driven directly by the MCU (which I doubt it would - it's a poor practice, though I have seen it), then you'll be forcing the MCU output pin responsible for driving Q7 into a state that it shouldn't be in, and that can cause it to burn out. On the other hand, if there is a single-ended buffer driver with resistor and transistor to drive Q7, then shorting Gate to ground may be OK.

Given the measurements you did here:
https://www.badcaps.net/forum/attach...6&d=1600025667
See if the top (single) pin of Q9 connects to Q7 Gate. Also check what R21 and R30 connect to, as these appear to be related to the Gate circuit of Q7. One of them might be a pull-up resistor (possibly R21?) Check and report back.

Sometimes my meter in continuity mode beeps suggesting connection to Q7 other times it doesn't. Not sure why that is

Typically that is caused by capacitors in the circuit charging up from the multimeter. With a discharged capacitor of sufficiently large capacitance, the multimeter will momentarily show low resistance (and often beep in continuity mode) when the probes connect to the capacitor leads. As the cap charges to the test voltage of the multimeter, the resistance will keep increasing until it goes high / out of range (hint: as a bench experiment, try measuring the resistance across electrolytic caps of different capacities with your multimeter to see how the resistance changes.)

Again, I suspect Q7 is driven by Q9, but I could be wrong.

Not sure where Q11 and Q12 tie with this... though one possibility is that Q11 (NPN BJT, and looks line "NF" references to KRC106S) driven by the MCU... which then drives Q11, which is possibly a PNP or P-ch MOSFET, which then drives something else... through R36 and R38??

[CapLeaker]

Re: Spectra S1+ Breast pump - No suction

tell the owner to get oldskool and use her boyfriend/husband's hand

next time i'll tell wifey that there is no suction. lets see what happens!

[caphair]

Re: Spectra S1+ Breast pump - No suction

Couldn't trace all pins of Q9-Q12 but attached a pic showing what I found. Guess I was wrong as none seem to connect directly to Q7. Sometimes my meter in continuity mode beeps suggesting connection to Q7 other times it doesn't. Not sure why that is

[caphair]

Re: Spectra S1+ Breast pump - No suction

L1 = .794v
L2 = 11.84v

U4 = 11.4v input 5v output

Tests made with the battery not power adapter.

It’ll take me some time to trace how Q9-Q11 connect.

As a test, could I ground the gate of Q7 to see if the motor will turn on? Or would that potentially cause an issue somewhere else

[momaka]

Re: Spectra S1+ Breast pump - No suction

Resistance between S and G is 4.78k

That means driver chip is likely not shorted.

If I try soldering low-ESR caps in parallel do I need the same values?

No, just similar capacitance values or somewhere in the ballpark (up to +/-50% will probably be OK.) Since device is operated at 12V, you don't really need anything higher than 16V-rated caps... but if you don't have 16V-rated caps, you can of course use higher-rated voltage caps.

I'm curious is Q9 Q11 and Q12 are ok as they seem to be connected to Q7 but can't find any datasheets on them. They're marked NF1E (Q9 Q12) and PF2G (Q11)

How exactly are they connected to Q7. Try tracing their pins and see which go to ground, which to 12V, and which to (if any) other voltage rails. We still don't know if the issue is power or logic -related. So that's why we need to establish that everything is getting power (and clean power too), then we can try to troubleshoot the issue if it turns out to be logic-related.

With that said, check the voltage output between ground and the pins of the two "100" inductors (you may have to try measuring to each side of the inductor, because if it's for a buck regulator, that may throw off the readings on your multimeter a bit.) Also check the voltage input and output on the TO-223 regulator (looks like it's a 1117 of some sort.)

[caphair]

Re: Spectra S1+ Breast pump - No suction

Try measuring the resistance between Source and Gate, then report back what you get. Make sure battery and power source are both removed when doing these measurements, so they don't impact the reading. If you get low resistance (I'd say under 200 Ohms), there may be something shorted somewhere, and you'll probably have to track back from the Gate pad for the MOSFET to the controller that turns it On.

That aside, have you tried running the device on batteries? Reason I ask is because I just noticed there are several buck-type regulators from the main 12V power adapter for some of the lower voltage rails inside. I also noticed that some of the SMD electrolytic caps are Samyoung (I think, based on their logo), so those may be worth checking at some point too... or you can just solder a few regular low-ESR leaded eletrolytics with them in parallel to make sure the switching buck regulators are not having problems (which could be a potential problem why the controller is not making the MOSFET turn on.)

Resistance between S and G is 4.78k

I've tried running it with the 12v the battery that it comes equipped with and same results

If I try soldering low-ESR caps in parallel do I need the same values?


I'm curious is Q9 Q11 and Q12 are ok as they seem to be connected to Q7 but can't find any datasheets on them. They're marked NF1E (Q9 Q12) and PF2G (Q11)

[momaka]

Re: Spectra S1+ Breast pump - No suction

Try measuring the resistance between Source and Gate, then report back what you get. Make sure battery and power source are both removed when doing these measurements, so they don't impact the reading. If you get low resistance (I'd say under 200 Ohms), there may be something shorted somewhere, and you'll probably have to track back from the Gate pad for the MOSFET to the controller that turns it On.

That aside, have you tried running the device on batteries? Reason I ask is because I just noticed there are several buck-type regulators from the main 12V power adapter for some of the lower voltage rails inside. I also noticed that some of the SMD electrolytic caps are Samyoung (I think, based on their logo), so those may be worth checking at some point too... or you can just solder a few regular low-ESR leaded eletrolytics with them in parallel to make sure the switching buck regulators are not having problems (which could be a potential problem why the controller is not making the MOSFET turn on.)

[caphair]

Re: Spectra S1+ Breast pump - No suction

So with Q7 out of the board it seems to test ok.

I still get the .978 reading both ways where gate and source pins would be on the board.

Not sure where to go from here

[stj]

Re: Spectra S1+ Breast pump - No suction

tell the owner to get oldskool and use her boyfriend/husband's hand

[momaka]

Re: Spectra S1+ Breast pump - No suction

On Q7 I measure battery voltage 11-11.34v (jumps to 11.34 then back to 11v as the little metal box cycles on/off) on gate and all 3 source pins. So this should be turning the mosfet on correct? Vg-Vs 11v-11v = 0v (could be wrong I often struggle remembering how mosfets work)

No, to turn a P-ch MOSFET On, you ground the Gate if Source is connected to the positive output of the PSU.

With Gate Voltage = Source Voltage, P-ch MOSFET will be off.

I think Q7 is shorted Gate to Source I measure .978v in diode mode both ways

Remove out of the board and test. If bad, then worry about the replacement.

I can't recommend any SOIC-8 P-ch MOSFETs off top of my head, but since this is used for relatively low-current switching applications, you don't really need to match the specs exactly. I suspect anything rated for 25V or more and 5 Amps or more continuous will do. Given the power adapter is rated for 12V and 2 Amps, even Rds_on is not important, because 20 mOhms at 2 Amps will generate negligible power dissipation in the MOSFET. And if bad comes to worse, you could also fit a TO-252 MOSFET in place of that SOIC-8. I've done it before a few times now. Doesn't look as pretty, but is secure and works just fine.

[caphair]

Re: Spectra S1+ Breast pump - No suction

http://gs-power.com/products.aspx?CID=P_00001349

See if you can get some from the manufacture

The only problem you might have is if this part is preparatory then you will not be able to get any but I would ask if there is a direct replacement part number for this part it does not hurt to ask ( there might not be one )

*** Disclaimer I will not be held responsible for anything that might happen to you if you do not know what your company policy is about doing something like this or something similar ***

I have used this in the past but I know what our company policy is about using your company email account

****Here is a trick that might get you some where if you have a company email address use it if you can with out getting in trouble with the company that you work for ****

Do this like you are repairing some machine I would not tell them that you are trying to repair the device you have

Or you could try saying that you are trying to pro typing something that this part has the specifications that you are looking for

Interesting so there aren't any similar equivalents out there with same voltage Etc characteristics?

[sam_sam_sam]

Re: Spectra S1+ Breast pump - No suction

http://gs-power.com/products.aspx?CID=P_00001349

See if you can get some from the manufacture

The only problem you might have is if this part is preparatory then you will not be able to get any but I would ask if there is a direct replacement part number for this part it does not hurt to ask ( there might not be one )

*** Disclaimer I will not be held responsible for anything that might happen to you if you do not know what your company policy is about doing something like this or something similar ***

I have used this in the past but I know what our company policy is about using your company email account

****Here is a trick that might get you some where if you have a company email address use it if you can with out getting in trouble with the company that you work for ****

Do this like you are repairing some machine I would not tell them that you are trying to repair the device you have

Or you could try saying that you are trying to pro typing something that this part has the specifications that you are looking for

[caphair]

Re: Spectra S1+ Breast pump - No suction

Can’t seem to find a replacement. Could someone help me with that?