Help me draw this circuit's diagram

[mosfet66]

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Sir mosfet66 . . . . . .

I tell you whuts . . . . .since your fotie-grafs definition/focus was being somewhat less than perfect on the reeee-sis-tom-er-fers marked values.
But . . .HEY . . .I CAN make out the series drive resistor to the Mosfet gate as being 1 K.

However . . . . . . since YOU are able to see ALL of its parts . .you will be able to fill us in..

This would be the first stage towards generating a schematic for your circuitry . . . . .

Get an ohmmeter and check out Zero ohm paths of the "hidden" foil paths under the LM324 of the red circled points.
The Red Star looks like it connects to pin 7, but does it connect to any other LM324 pin also ?
Plus also check every pin of the LM324 to see if there also might also be OTHER hidden interconnects to other pins on it, to be sure.
Seeing my yellow arrows and the fact that the output of an LM324 op amp OUTPUT section is being directly connected to its NON INVERTING input,
with pins 8 to 9 tells me that particular section is being used for a voltage referencing or halving function.
The left mystery ceramic ? capacitor is probably used as a summing function and is up in the 10-47 nf range and is VERY likely unmarked.
While the right ? is probably the frequency determining C portion of a R/C oscillator and you just might find its value marked on its other hidden side.
(Or that COULD possibly be a like film reee-sistor, that just got mounted upside down ? )
You seem to have the speed pot connected with 4 wires, do I have it correct, with one wire possibly being a redundant connection ?
Plus, with it having trim resistors on either end of it, is suggestive of an optimally "sweet spot adjustment range".

Give some feedback on that requested info . . . . .

Your reference . . . . . . .Marked up:

73's de Edd



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I'm finally here, i solved the circuit by testing it, the problem i've now is you told me that the left ? could be a capacitor, but testing with the ohmeter i received a 200K value, so could it be just a resistor? Same thing with the right ? that gave me a 100K value instead.

 

[73's de Edd]

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Sir mosfet66 . . . . . .

The ohmmic test needs to be performed with the caps out of circuit, as you probably are receiving "phantom" resistance shunts produced from within the IC or adjunct components circuitry.

To fully interpret this units design, we also need to know any and all inter connections that are being obscured by the presence of the flat pack I.C. sitting right on top of their foil paths and hiding them.
Plus, as mentioned, just about all of the resistors values are too blurred, so as to be read.

73's de Edd

 

[mosfet66]

...


Sir mosfet66 . . . . . .

The ohmmic test needs to be performed with the caps out of circuit, as you probably are receiving "phantom" resistance shunts produced from within the IC or adjunct components circuitry.

To fully interpret this units design, we also need to know any and all inter connections that are being obscured by the presence of the flat pack I.C. sitting right on top of their foil paths and hiding them.
Plus, as mentioned, just about all of the resistors values are too blurred, so as to be read.

73's de Edd

Here's a new pic with values and paths updated

 

[mosfet66]

I managed to test the capacitor on the left side, and as you can see I wrote the value in the pic. The problem is I now don't know what the ? is in the circuit. I tested it as a resistor and obtained a 100Kohm Value and testing as a cap I received a value of 5.7nF (?) , but to me it doesn't seem a resistor at all. What it can be? Furthermore, if they are both caps, how can I find their polarity?

 

[Alec_t]

What it can be?

Looks like a ceramic cap to me. Both caps are unlikely to be polarised.

 

[davenn]

Looks like a ceramic cap to me. Both caps are unlikely to be polarised.

agreed

 

[CDRIVE]

If we're taking votes I feel more than sure it's a ceramic cap too.

BTW, why does that board look less than factory made?

Chris

 

[73's de Edd]

Sir mosfet66 . . . . . .


I think it will be a universal "given" that the brownish/grey component to the left is going to be a layered ceramic SMD, but the center bottom one and and its white ceramic substrate is going to be a bit more " iffy" in its confirmation .

I was just going to rely in its circuit design positioning between pins BUT . . . .see ***.

Take a look at my add on of the "hidden" paths of the foils being covered under the IC and confirm, even better, take ohmmeter and connect to pin one and use the other probe to check to ALL of the other pins sequence for a short . . . eg . . . .direct connection.

Then step up to make reference to pin 2 and the same continuity testing . . . . then 3,4,5,6,7,8,9,10,11,12,13 and 14 . . . . .whew . . . (but, hey, at least the possibilities diminish towards the end !)

***
THE OTHER quirk now, is that the definite fact that the driver output from the IC is feeding via a 1K resistor to the power FET gate.
Now this IC is definitely not the common 555 with its mere 8 pins, needing to make it a 556 dual unit with a proper 14 pins complement.

THAT then makes the 1K input resistor be connected to a / either pin 7 or 14 power rail connection of the 556 IC, even if you flip the IC pin indexing around 180 degrees .

Soooooooo, this IC used, must NOT be the suspected 556, which would connect to the 1K gate drive input thru either a pin 9 or a pin 5 interfacing.

About 8 other 14 pin possibilities are coming from off the top of my head, but none of them would interface the required pin 7 output, even shifting across to single and dual one shots, hex inverters or arrayed gates, of which, their 7 and 14 power pins rule out them from being a possibility..

Inspect the I.C. top to see if its part number is visible . . . .or if they have wet sanded it off . . . for "proprietary" info reasons.

Lastly look for the I.C. indexing dot to see if I have made proper pin indexing assignments.

Thats it for now . . . . .

Aside . . . . for CDDRIVE . . . .

Looking at that bike size, its tie on point and the length of that pipe.
All factors considered, that eventually somewhat shortened
"drag stick" should have assimilated to having a 37 degree tapered end
at the end of the trip..

Good show ! . . . .and ingenuity .

Techno addenda:
Whoooooooa Nellie,
I just checked back to your second photo and found out that I could definitely detect the pin 1 divot marking in the N case, with there even being an additional banded end marking.
Using some " NASSER" image enhancing techniques I then come up with LM 324 with a " new old stock code date" and the marking of Sally Jean Johnson of the
3rd shift of "Tejas Instrumentations" as having done the final marking and QC test of the unit.
I wasn't yet considering in a quad op amp IC in the game plan, but its second op amp output is a pin 7.
Will see how they are using it now.


73's de Edd
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[CDRIVE]

Edd, I had a drag stick duct taped to the blacktop end of the 10' thin wall. It was quite a bit shorter and very pointy by the time I got home!

Chris

 

[mosfet66]

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Sir mosfet66 . . . . . .



I think it will be a universal "given" that the brownish/grey component to the left is going to be a layered ceramic SMD, but the center bottom one and and its white ceramic substrate is going to be a bit more " iffy" in its confirmation .

I was just going to rely in its circuit design positioning between pins BUT . . . .see ***.

Take a look at my add on of the "hidden" paths of the foils being covered under the IC and confirm, even better, take ohmmeter and connect to pin one and use the other probe to check to ALL of the other pins sequence for a short . . . eg . . . .direct connection.

Then step up to make reference to pin 2 and the same continuity testing . . . . then 3,4,5,6,7,8,9,10,11,12,13 and 14 . . . . .whew . . . (but, hey, at least the possibilities diminish towards the end !)

***
THE OTHER quirk now, is that the definite fact that the driver output from the IC is feeding via a 1K resistor to the power FET gate.
Now this IC is definitely not the common 555 with its mere 8 pins, needing to make it a 556 dual unit with a proper 14 pins complement.

THAT then makes the 1K input resistor be connected to a / either pin 7 or 14 power rail connection of the 556 IC, even if you flip the IC pin indexing around 180 degrees .

Soooooooo, this IC used, must NOT be the suspected 556, which would connect to the 1K gate drive input thru either a pin 9 or a pin 5 interfacing.

About 8 other 14 pin possibilities are coming from off the top of my head, but none of them would interface the required pin 7 output, even shifting across to single and dual one shots, hex inverters or arrayed gates, of which, their 7 and 14 power pins rule out them from being a possibility..

Inspect the I.C. top to see if its part number is visible . . . .or if they have wet sanded it off . . . for "proprietary" info reasons.

Lastly look for the I.C. indexing dot to see if I have made proper pin indexing assignments.

Thats it for now . . . . .


Aside . . . . for CDDRIVE . . . .

Looking at that bike size, its tie on point and the length of that pipe.
All factors considered, that eventually somewhat shortened
"drag stick" should have assimilated to having a 37 degree tapered end
at the end of the trip..

Good show ! . . . .and ingenuity .



Techno addenda:
Whoooooooa Nellie,
I just checked back to your second photo and found out that I could definitely detect the pin 1 divot marking in the N case, with there even being an additional banded end marking.
Using some " NASSER" image enhancing techniques I then come up with LM 324 with a " new old stock code date" and the marking of Sally Jean Johnson of the
3rd shift of "Tejas Instrumentations" as having done the final marking and QC test of the unit.
I wasn't yet considering in a quad op amp IC in the game plan, but its second op amp output is a pin 7.
Will see how they are using it now.



73's de Edd



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I tested all the pins and this is the result. I've also made a prototype, but, obviously, it doesn't work (I mean it doesn't decrease the speed of the motor). The prototype was made using two caps one of 8.2nF and one of 5.6nF.

 

[mosfet66]

If we're taking votes I feel more than sure it's a ceramic cap too.

BTW, why does that board look less than factory made?

Chris

It's not factory made, it's handmade by a technician in my town.

 

[CDRIVE]

It's not factory made, it's handmade by a technician in my town.

Ah, that's why some of the traces are not exactly running at right angles. The board was probably not made from a CAD.

Take a look at what I found. There are two of them on the page. I believe one of them is yours!
http://solorb.com/elect/pwm/pwm2/

Chris

 

[mosfet66]

Ah, that's why some of the traces are not exactly running at right angles. The board was probably not made from a CAD.

Take a look at what I found. There are two of them on the page. I believe one of them is yours!
http://solorb.com/elect/pwm/pwm2/

Chris

Thanks for the link, unfortunately i don't think they're actually the same

 

[CDRIVE]

Marco, "the same" is relative in this case. Since the 324 is a quad OpAmp it's very possible that different amps and different pins were used for different segment of the circuit. This would be especially true if the link I posted didn't use SMD components. In that case the designer would have laid out the physical pin connections quite differently because the R & C components would take up much more real estate. That said there can't be many (if any) significant differences in (electrical function) design when based on an LM324 PWM circuit. Things do tend to get repetitive and somewhat standard SOP.

Also, the values of some R & C values my be different because many designers try to use commonly procured R and C values.

Chris

 

[73's de Edd]

Sir Marco . . . . .

Hmmmmmmmmm . . . .I guess that I got off on the LM556 path since it had been so long since the topic was initiated.
But I do see that my original mark up had LM 324 clearly placed upon it and I cleared its area in my later drawing to create the blank PCB proper
such that I could show the hidden traces below the IC body.

I am now placing my INITIAL " rough" draft of the circuits schematic for you to compare point by point.
Now, by circuit assimilation, I can see that the "second mystery white capacitor" is, in actuality, an upside down mounted 100K resistor R4 (as you measured) that is DC coupling from an output of U1A op amp section to an input of U1D.
U1C section is taking current sampling referencing of any power supply rail voltage loading "sag" and compensating for motor speed correction.

The very bottom "doodling" is just the statement of all of the parts interconnects on the PCB.

Now . . .check it out for any initial schematic errors . . . . versus the PCB proper .

73's de Edd

 

[CDRIVE]

Edd, after seeing the schematic you drew it only confirms the comments I made regarding the circuit link I posted.

RE SMD resistor mounted upside down. There should be a law!

RE the 2.2Ω Vcc decoupling resistor. I don't think it does much. Heck, it doesn't even have a bypass cap associated with it.

Chris

 

[mosfet66]

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Sir Marco . . . . .

Hmmmmmmmmm . . . .I guess that I got off on the LM556 path since it had been so long since the topic was initiated.
But I do see that my original mark up had LM 324 clearly placed upon it and I cleared its area in my later drawing to create the blank PCB proper
such that I could show the hidden traces below the IC body.

I am now placing my INITIAL " rough" draft of the circuits schematic for you to compare point by point.
Now, by circuit assimilation, I can see that the "second mystery white capacitor" is, in actuality, an upside down mounted 100K resistor R4 (as you measured) that is DC coupling from an output of U1A op amp section to an input of U1D.
U1C section is taking current sampling referencing of any power supply rail voltage loading "sag" and compensating for motor speed correction.

The very bottom "doodling" is just the statement of all of the parts interconnects on the PCB.

Now . . .check it out for any initial schematic errors . . . . versus the PCB proper .

73's de Edd



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Ok, comparing the schematic with the pcb, it looks perfect except for the connection between 7 and 5 that is wrong, this is the correct schematic i edited... The only problem now is that i made a prototype that unfortunately doesn't work. I checked every connection, but the motor doesn't start at all. attached you'll find also pics of the prototype.

 

[CDRIVE]

Where's the MOSFET?

Chris

 

[mosfet66]

Where's the MOSFET?

Chris

Hi Chris, I highlighted the mosfet in the circuit. If you need a better pic of the connection just let me know

Marco

 

[73's de Edd]

Sir mosfet66 . . . . . . . .

I made two 1X side by side dupes of your circuits component and foil sides and placed the guesstimated schema just below them .
Your component interconnects, I have marked up in PINK lines.
I checked out your perfboard creation . . . . . and by my green check offs of the pins of the IC . . . . . seems like all connections agree.
My view of the area under the RED star was a bit iffy, so I mainly depended on the foil side for that area for connections and routing confirmation.

Variants noted :

Seems like you had to opt for 46K resistors for the 43.2 Ones . . .no problem . . .as the only critical area with them are the R1-R2 slots, where that C portion amp halves the voltage supply
for use as a a reference. BUT you are STILL providing proper balanced voltage division with the present two 46 K's being used there.

There are some resistor color codes that just appear to be using all black bands to me.
To wit . . . . . the R9 at the very top should be a 1K, and it is one of those that appear all blacks, YET I am seeing the two REDS on the 2.2 ohm that is being just two positions over to its left.

Down at the bottom center, it looks like you had to make up R7 , by using two series resistors, of R7a--b, and to me, that R7a looks all blacks BUT seems like I can see the final RED "K"
band designator of the other R7b resistor.

Do we still have the original working board to compare against, or did it have to donate some of its parts for this construction, like the D1 damping diode and the power FET .

For further troubleshooting and analysis do you have an Old Silly Scope and know how to load, trigger and shoot it ?
Or possibly, you only have a DVM and maybe an older and additional analog metered VOM.

PLUS . . . just in case I have to introduce you to "Mac Gyver" *** testing . . . . .:

Some scrap electronics around that will yield us, a loan of an approximate
1 uF capacitor in the poly family . . . . (Thats being of a type akin to your present C1).
About a 10 uF electrolytic and some test leads with clip ends.( Or hook up wire to make equivalent solder tack on test leads with.)

***
https://en.wikipedia.org/wiki/MacGyver
http://lifehacker.com/top-10-awesome-macgyver-tricks-that-speak-for-themselve-476433796
http://www.cracked.com/photoplasty_1460_20-macgyver-style-tricks-fixing-everything-in-your-life/

Le Perfboard creation . . . . .

73's de Edd