Fixing motor driver for Rollo

Thread Starter

opxy

Joined Jan 2, 2013
10
Hi all electronics freaks out there,

I have broken motor driven rollo winder. It is exactly this one:
http://www.lottgmbh.com/uploads/media/Eck41009_R-23300A_Aufputz.pdf
(It is in German language but you can get an idea what it is)

As fixing things is my hobby and quite a lot of fun, I'm trying to fix it and also learn something from it :)

I started with drawing circuit schematic in Eagle (please take a look at the attachment) and trying to figure out how does it work. Spent almost full day doing that :)

Before continue let me start with few facts:

1. SV1 is connector that is connected to microcontroller board
2. Line 12 on SV1 is PIC Vref
3. Line 8 and 9 are PIC output for controlling motor motion

I asume motor motion is controlled this way:

L8 | L9 | Motor motion
-------------------------
1 | 1 | Stop
1 | 0 | Forward
0 | 1 | Backwards
0 | 0 | Stop
..............................

4. SV2 is connector for light (sun) sensor - unused as I don't have it

5. VT06 and VT07 are power Mosfets P & N
Datasheet: http://www.vishay.com/docs/65922/si4564dy.pdf

6. U3 is quad OP-AMP
Datasheet:
http://www.ti.com/general/docs/lit/getliterature.tsp?literatureNumber=slos066t&fileType=pdf

7. Output (drain) of the VT06 and VT07 is connected to the motor (not drawn on attached schematic)
It is 24V motor Model FS-398PH-18110 (http://www.neuhold-elektronik.at/datenblatt/N0070.pdf)


Now my questions!:)

1. Take a look at the OP-AMP 1IN+, 1OUT and SV1 line 4.

I don't understand for what this is used. SV1 line 4 is probably INPUT, but why transistor (and circuit around it) VI02 and VT01 are there? Do you think it may be some kind of "current sensor" ? If so how does it work?

2. I also don't understand why VT02 is there? It looks as it doesn't have any function.

3. I think there must be some kind of protection if motor (rollo) is stucked, but I just can't find it.

If anyone could help me explain this two parts of the circuit or at least give me some hint, I would be very thankful.

If you need any additional details please let me know. If needed I can also draw second bord with PIC and measure all resistors values.

Regards,
Gregor

P.S: Happy new year 2013 !:)
 

Attachments

R!f@@

Joined Apr 2, 2009
9,918
To understand the functions I need to see the PIC circuit.

How about you measure the DC voltages and post it.

What are the symptoms?

Can you confirm that the MOSFET/S are not shorted.

An in circuit diode check on them MOSFET's are needed after disconnecting the Motor completely.
 

Thread Starter

opxy

Joined Jan 2, 2013
10
R!f@@,

Thank you for the reply.
I'm at work right now so I can't draw the schematics for microprocessor board. But I will do it when I get home.

For now I'm only adding photo of the board as attachment (SV1 line one is first line on the left)

About the symptoms:
- Motor doesn't turn at all
- Microcontroller is probably working as the control LED is responding
- I measured DC voltage on SV1 line 8 & 9:

On line 9 I get 3,7V when button in pressed
On line 8 it is always 0V no metter what button I press.

From this I may assume that there is something wrong with MOSFET VT07.
Do you know some easy way how to test it? Should I take it out of the circuit.

- I also measured voltage on 12V and 5V voltage regulators (with out motor connected)

12V regulator:
Input: 24V
Output: 11,77V

5V regulator:
Input: 11,77V
Output: 3,7V

But they both get VERY hot: cca 80°C.

As I know they have some protection integrated if they are too hot they shutdown. I need to measure if this actually happens.

That is all I can say for now. I need to do more measurements when I get home.

As I said I would be very glad if you could describe me how to measure P & N MOSFETS.

Regards,
Gregor
 

Attachments

R!f@@

Joined Apr 2, 2009
9,918
Since the regs get hot you have a shorted component.

See the droop in 5V. This output is loaded too much and this loading is causing the 12V reg to heat up.

The input of 5V Reg is from the out put of 12V one.

By the way u mislabeled the out puts of the Regs in diagram. 12V should be 5V & vice versa.

You have a shorted component in the 5V line or the Regulator is giving you trouble. (7805).

I can show you how t deal with it if you could show me the PCB of the control Assy. Nice ones, close up. I need to see it to show you how to deal with it.

U need a Digital Meter with a Diode check function. If you know hot to check diodes first try to check those Zener diodes for dead short. Then go for the diodes and then the Transistors. Leave them Mosfet for now.
 

Thread Starter

opxy

Joined Jan 2, 2013
10
Hi R!f@@,

Again, thank you for your answer.

I actually took MOSFET VT07 out yesterday before I saw your post. I tested it and it looks ok.

Also thank you for warning me about mislabeled reg. In next version of drawing I will change it.

In attachment is close-up of the circuit. VT07 is missing as it is desoldered. Also RED cable from motor fail off and I didn't solder it back yet.

If there is shortened element on 5V line I asume it may be
Transistor VT05, VT04, VT02, VI02 or diodes VD11 and VD09.

I actually don't know if VD11 & VD09 they are zener or normal diodes. I asume they are just normal diodes.

If I look to diodes I would say VD18 and VD11 could not couse short circuit or?

I will not try to measure all diodes and let you know for the results.
 

Attachments

Thread Starter

opxy

Joined Jan 2, 2013
10
Ok I measured all diodes and transistors (in circuit)
There is no short dead diod (all have inf resistance in one direction).

How ever I find VI02 and VT08 (on schematics is VT01 - mistake) problematic - see measurements. I think I will take it from circuit tomorrow and measure it again

Rich (BB code):
VI02 (specifications: http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/CD00000993.pdf) 
------------------------------
 B | C | E | resistance OHM
------------------------------
 + | - |   |  0,5k
 + |   | - |  1,53k
 - |   | + | inf
   | + |   |  0,5k
   | - | + |  inf
   | + | - |  0,91k

VT01
------------------------------
 B | C | E | resistance OHM
------------------------------
 + | - |   |  1,29k
 + |   | - |  1,3k
 - |   | + |  inf
 - | + |   |  inf
   | - | + |  1,956k
   | + | - |  inf

VT05
------------------------------
 B | C | E | resistance OHM
------------------------------
 + | - |   |  1,29k
 + |   | - |  1,28k
 - |   | + |  inf
 - | + |   |  inf
   | - | + |  inf
   | + | - |  inf

VT04
------------------------------
 B | C | E | resistance OHM
------------------------------
 + | - |   |  1,28k
 + |   | - |  1,31k
 - |   | + |  inf
 - | + |   |  inf
   | - | + |  inf
   | + | - |  inf

VT08 (on schematics VT02 -mistake)
------------------------------
 B | C | E | resistance OHM
------------------------------
 + | - |   |  1,29k
 + |   | - |  1,30k
 - |   | + |  inf
 - | + |   |  inf
   | - | + |  inf
   | + | - |  inf
 
Last edited by a moderator:

R!f@@

Joined Apr 2, 2009
9,918
OK. Remove both MOSFET and check for stable 12V and 5V.

If 5V sags, then remove U3 ans do the test

PS. Keep the uC board removed if you can
 

Thread Starter

opxy

Joined Jan 2, 2013
10
Did you see measurements I sent?

Unfortunately I can not disconnect uC board as they are permanently connected together.

I will try to remove VT06 MOSFET as well and hopefully U3 - It will be quite a task since I don't have hot air soldering tool. If I manage to fix this board I will probably invest in one :)

@bertus: Thanks for correcting "code".
 

Thread Starter

opxy

Joined Jan 2, 2013
10
Ok,

I desoldered both MOSFETs & U3 op-amps. There are still only 3,87V from 5V reg.

What do you think about my transistors measurements?

Regards,
Gregor
 

Thread Starter

opxy

Joined Jan 2, 2013
10
Latest update:

I desoldered following parts:

U3 4xOP-AMP
VT06 MOSFET P & N
VT07 MOSFET P & N

VT01 Transistor
VT08 Transistor (on schematics 02 - mistake)
VI02 Transistor

Voltage on 5V Reg is still 3,8V.

I'm thinking to desolder voltage regulator and actually check if it is working correctly by it self. I'm just wondering if should I use condensators in test circuits or voltage regulator alone would be ok?

Maybe there is mistake on logic bord. I will try to draw schematics today.

Regards,
G
 
78L05 is dead.

When you replace it, put a 1N4001 diode anti-parallel with In and Out to reduce reverse biasing to 0.6V.

Your schematic has the 12V and 5V Nets listed improperly. Hint: Look at the regulators.
 

R!f@@

Joined Apr 2, 2009
9,918
Get a 5V reg.

If you have can a To-220 Package can be installed without a problem. If not get the original package.

Check for voltage before soldering any other component.
 

Thread Starter

opxy

Joined Jan 2, 2013
10
Yesterday I was drawing uC board schematics. It is not finished yet. Today I will continue and will post all together.

Regarding 5V regulator, I'm thinking to do like that:

1. Desolder 5V reg and try it on dev-board (with 12V input from lab power supply)
2. If it will output 5V it is probably ok and something else is broken
3. If it will output 3.8V I will assume it is broken
4. I will connect roll circuit 5V rail to my lab power supply and measure Line 8 and 9 voltages with oscilloscope.

I think I will be able to do this within hour or two.

Thank you both for suggestions!!

Gregor
 

Thread Starter

opxy

Joined Jan 2, 2013
10
Envisionelec you were right about 78L05.

I desoldered 78L05 and put it on dev board, connected Input to 12V power supply and measure output with oscilloscope. In test circuit I didn't use any condensator (I hope it didn't affect measurements too much)

The output was between 3,6 - 3,8V.

What I'm planning to do now is to solder back all components that were desoldered and try to power 5V rail with lab power supply. Do you think this is good idea?

Regards,
G
 

Thread Starter

opxy

Joined Jan 2, 2013
10
It is working!!! :))

Connected to the Lab Power supply (24V & 5V - instead of 78L05).

I will order new 78L05 tomorrow.

@Envisionelec: Can you tell me more about "1N4001 diode anti-parallel with In and Out to reduce reverse biasing to 0.6V" ?

Thank you for help!!

P.S.: I will still draw full circuit and post it - in case anyone else will need it in future.

Gregor
 

R!f@@

Joined Apr 2, 2009
9,918
Reverse bias diode is not typically necessary in this case.

They are mostly used in LAB PSU to protect them from all sorts of wrong connection at the output.

Since your board is fixed load as you see, messing with it ain't a good idea.

If it works, leave it.
 
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