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GWatPE

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Joined: 01/09/2006
Location: Australia
Posts: 2127

Posted: 10:29pm 16 Feb 2010

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I had recently repaired a WEA controller. This was a 4 stage diversion loading, with a single LM324, and a few handfulls of passives and transistor drivers and output switches. I replaced the burned up LM324 with a TL074. All worked again, with no mods. I never traced the cct, as it would be much easier with a micro.

Gordon.

become more energy aware

adonis
Regular Member

Joined: 13/02/2010
Location: Sweden
Posts: 42

Posted: 11:35pm 16 Feb 2010

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thanks Oztules. i will try to understand all of that, the hystersis thing is one of many terms i never heard of before... but i have some good books, and there is always wikipedia.

/jonathan

oztules

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Joined: 26/07/2007
Location: Australia
Posts: 1686

Posted: 03:26am 17 Feb 2010

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yep 324 and the 074 are pin for pin , and share similar output characteristics.... ie have voltage on the output pin without the need for pull ups.

..........oztules

Edit: I much prefer the lm324 than a pic. @24cents or less to replace and many times tougher than a micro... (>30v and lives) and no need to reprogram, and 5 mins to replace and get going. For the 324 to blow, the micro would be in silicon heaven as well.... and much sooner I would think. The 324 can take continuous short circuit on the outputs.... so I assume a supply rail problem? or a blow back from a blown driver tranny perhaps.Edited by oztules 2010-02-18

Village idiot...or... just another hack out of his depth

GWatPE

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Joined: 01/09/2006
Location: Australia
Posts: 2127

Posted: 05:27am 17 Feb 2010

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Hi oztules,

could not find any problems with any components, except for the LM324. burnt the board as well as the chip. The IC was socketed, burnt up as well. Not something I normally approve of. Repaired the board with a machined pin socket as a last resort. I think the battery may have sulphated, and during a storm, too much power and the voltage went too high. May have been a dry joint somewhere, as I had to go over most of the board just to be sure all was going to work.

Gordon.

become more energy aware

kalamidas
Newbie

Joined: 19/02/2010
Location: Greece
Posts: 21

Posted: 09:06am 19 Feb 2010

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Hello From Greece

I've made the controller and i have a problem.
my controller swicth on the relay at 14,5v and off at 14,4 no matter the trim pots ajust it has only 0,1v
hysterisis if the word is correct.

kalamidas
Newbie

Joined: 19/02/2010
Location: Greece
Posts: 21

Posted: 09:10am 19 Feb 2010

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and somthing else
because i am new with this
in the same board i checked 4 different tl084 all of them
had diferent read outs with diferent op's active.
did you find problems with bad ic's?

Downwind

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Joined: 09/09/2009
Location: Australia
Posts: 2333

Posted: 09:25am 19 Feb 2010

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Hi kalamidas

Welcome to the forum.

What value resistor are you using for R1.

There has been an error in the information in the past and R1 should be 10K.... NOT 12K.

Check this and let us know.

Pete.

Sometimes it just works

kalamidas
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Joined: 19/02/2010
Location: Greece
Posts: 21

Posted: 09:45am 19 Feb 2010

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the r1 is 10k the trim pots is 10k
the r2 is 12k

kalamidas
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Joined: 19/02/2010
Location: Greece
Posts: 21

Posted: 09:48am 19 Feb 2010

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Hello Pete
thanks for the swift responce

the r1 is 10k the trim pots is 10k
the r2 is 12k

regarding the tl084 did you find bad ic's or
i hit a bad batch.

adonis
Regular Member

Joined: 13/02/2010
Location: Sweden
Posts: 42

Posted: 10:24am 19 Feb 2010

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hello kalamidis.
are you able to read the +,- and out voltages on OP3 at some different battery voltages? maby 12, 14 and 15V?
this might help troubleshooting.

kalamidas
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Joined: 19/02/2010
Location: Greece
Posts: 21

Posted: 10:35am 19 Feb 2010

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ok i will reply in 6 hours
thanks for your time.

adonis
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Posts: 42

Posted: 12:34pm 19 Feb 2010

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hello again. the best would probably be to do the same readings that Pete did earlier in this thread, on page 3, where he went from 11 to 16V and then back. that way we will have something to compare with.

how do you know that your controller does not work? have you checked the actual relay connection or are you just looking at the leds? because i think that 1kohm might be a bit to high resistants before some leds:
if you have a potential in the OPoutput of around 6,5V (wich seems to be the case), and the led "eats" around 2V, you can calculate the current using ohms law over the resistor. I=U/R=4,5/e3=4,5mA. this might not be sufficient as some leds requires around 20mA to glow strong. one easy way to check on this is to connect another reststor in parallell with the one before the led (no need to solder, just hold it there and make sure there is a connection). if you use another 1kohm in paralell you get a total resistance of 1/(1/1000+1/1000)=500ohm giving you twice the current.
but if the problem is the relay not swiching you dont need to do this.

how does the 4 TL084 differ? the OP3 has a kind of memory, so when you pull one out and replace it with another one it may give different outputs even if the circuit is not incorrect. the best way to compare them should perhaps be to connect them at a battery voltage of 11V and then rise the voltage to around 13V before checking the output potential.
the outputs of OP1 and 2 should not be affected of when the tl084 is connected though, so if they differe much between different tl084's there is something wrong i think.

oh, i probably should mention that i dont really know much about electronics, this is mostly guesses, but i hope quite good ones. if someone spots a critical mistake in this post, please correct me before Kalamidas gets home and burns his chip...

Downwind

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Joined: 09/09/2009
Location: Australia
Posts: 2333

Posted: 12:56pm 19 Feb 2010

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One can only expect a construction fault as many have built this circuit and it has worked as per designed.

As the crystal ball is broken on the forum we can only help you with the information you provide for us to work with.

I reject the theory there is a faulty batch of chips as it can happen but very unlikely to get several all the same.

AS you said you are new to this and mistakes are easy to make even to those of us that should know better, we still make them too.

Please give some voltage readings of the opamp pins so we have something to work with.

Do a reading at 12v supply input and one at 15v input
and post the readings.

As i listed the voltages i received per pin earlier in this thread you should be able to check your voltages pin for pin against mine to see where the difference is.

We will work out what is wrong but will need your input and if you dont understand what we ask you to do than say so or we will go around in circles and acheive nothing except wasted time.

If you can post some photos of your board might help too.
Top and bottom shots of the board be good.

I understand where Adonis is comming form in his post above but would not consider that to be the problem area in this case. (still good to have the input though)

Pete.

Sometimes it just works

kalamidas
Newbie

Joined: 19/02/2010
Location: Greece
Posts: 21

Posted: 05:40pm 19 Feb 2010

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ok i'me home the readings of op3 are

12v 13.5v 15v
+1.35 +1.39 +7.22
-7.34 -7.35 -1.62
out1.35 out 1.35 out 6.32

kalamidas
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Joined: 19/02/2010
Location: Greece
Posts: 21

Posted: 05:44pm 19 Feb 2010

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i've compared the readings of page 3 at 12v with mine
and the only diferance is that op2 out reads 7,2v with
op3 - 7,2
hope that helps Pete

adonis
Regular Member

Joined: 13/02/2010
Location: Sweden
Posts: 42

Posted: 06:00pm 19 Feb 2010

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your readings seems to be as they should. maby -in should not be high at 13,5v, but if you have not got it to work you probably have not adjusted that one.
measure the resistance over the transistor when op3 is high, that resistance should be close to zero.

kalamidas
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Joined: 19/02/2010
Location: Greece
Posts: 21

Posted: 06:06pm 19 Feb 2010

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what can you sai about the active op2 out at 12v
from what i've read so far this should be 1.6v not 7.2?

kalamidas
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Joined: 19/02/2010
Location: Greece
Posts: 21

Posted: 06:10pm 19 Feb 2010

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i've turn the low trimpot clockwise to the end and the
op2 falls to the desired 1,4v thanks very much.
but i still have the problem with hysterisis it is only 0.1v.
the relay activates at 14,5 and deactivates at 14,4

adonis
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Joined: 13/02/2010
Location: Sweden
Posts: 42

Posted: 06:13pm 19 Feb 2010

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yes, it should be low above the "cut in again" voltage. can you not turn the low trimpot to make that happen? this might be the problem.

adonis
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Joined: 13/02/2010
Location: Sweden
Posts: 42

Posted: 06:14pm 19 Feb 2010

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ok. i was to slow

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