Circuit diagrams of TORO DDC-4

[zulu]

Hi everybody!

I was looking for electronic schematics of a waterproof battery controller. The producer is TORO, the model is DDC-4 (13 years old).
Now I've seen that its name has been changed: DDCWP-4. But I think that they should be rather similar.
Unfortunately, on the internet there seems to be no manual with circuit diagrams (neither for the old model, nor for the more recent).
I was wondering if someone has any useful link to suggest.
Thanks for your help!

 

[73's de Edd]

Sir zulu . . . . . . .

What is the nature of your problem with that controller.

And would it be in this family ?

http://www.amazon.com/Toro-DDCWP-4-9V-Waterproof-Controlled-Controller/dp/B0052D1ZPE

http://www.manualslib.com/manual/738511/Toro-Ddcwp-Series.html?page=2#manual




73's de Edd

 

[davenn]

Sir zulu . . . . . . .

What is the nature of your problem with that controller.

And would it be in this family ?

http://www.amazon.com/Toro-DDCWP-4-9V-Waterproof-Controlled-Controller/dp/B0052D1ZPE

http://www.manualslib.com/manual/738511/Toro-Ddcwp-Series.html?page=2#manual




73's de Edd

nice find !!

 

[zulu]

Sir zulu . . . . . . .

What is the nature of your problem with that controller.

And would it be in this family ?

http://www.amazon.com/Toro-DDCWP-4-9V-Waterproof-Controlled-Controller/dp/B0052D1ZPE

http://www.manualslib.com/manual/738511/Toro-Ddcwp-Series.html?page=2#manual

73's de Edd

Thanks for your interest!
Yes, my controller looks like the ones that can be viewed via the links you posted.
Briefly, when I connect the 9V battery I can navigate through the options of the controller without problems (and I can modify the settings as I wish). But to activate the sprinklers I need to plug in the 24V AC transformer. Doing so, the display crashes: all the symbols appear on the display, stay there for a few seconds and then begin to slowly disappear until the display gets completely blank.
Last time at that point I disconnected the transformer, reset the controller and got back to the situation before connecting the transformer: everything worked fine. But then, once again, plugging in the transformer resulted in the display's crash.
So, I've opened the box, replaced the 3 capacitors (one of which slightly bent) and made the diode test in an area that seems a bit burnt. No anomalies: values in a normal range.
After this, I made another test. The controller worked fine for a couple of minutes. Then, I unplugged the transformer and, after a few minutes, plugged it in again. The display crashed.
Finally, opened the box, I found out that one of the new capacitors was bent (both above and on top). The worse is that this bent capacitor replaced the old bent capacitor.
So, perhaps the new capacitor (470 microfarad -16V) was faulty before its use. Or perhaps some other components are bad (like resistors) and made this capacitor broken.
Could it be a matter of the entry voltage? On the board, where the transformers' wires need to be connected it is specified 24V AC. My tester measured 27.5V
Could it be that if a resistor (or something else) doesn't work as it should, that capacitor has to work with an overvoltage?
What if I replace it with another of the same capacitance but a higher voltage (say 35V)?

 

[73's de Edd]

Sir zulu . . . . . .

Ahhhhh so . . .Most honnable apologies, didn't notice your comeback until just now.

With those types of controller valves they just require a pulse of power to activate as either being on or off.
The back up pair of 9 V alkaline batteries can give 9-18 V at up to short 5 amp bursts of power
The valves are switched sequentially, so that additionally minimizes INSTANT current needs.

With your units loss of its memory /brains and its age being in the 11 year range, i believe that it you will check out the board, your units standby battery . . .icht bin " KAPUT ."

That agrees with your problems, in the drop of power and memory with the AC power apply situation.

Send board closeup photos for us in case you have trouble pinpointing it.

73's de Edd

 

[zulu]

Very glad to read your reply, no matter the time since the last one.
In the meantime my controller got another problem: failing to turn on the displays, regardless the kind of power supply connected (24VAC and/or 9V battery).
I measured voltage values twice, beginning with only the 24VAC and then with the 9V battery. Also, to make out the circuit's logic, I drew on the front-side photo of the board the tracks visible on the opposite side. I then wrote the voltage values on the same photo. And this process was carried out twice: one photo for 24VAC connected and another one for 9V battery connected.
I would like to upload these 2 photos, besides some cleaner photos (without drawings) to let you say whether there can be anomalies on the board (mostly in terms of voltage values).
I think it's all written on the photos. Additional information could be: the U2 IC is marked "C2ZD", it should be a voltage regulator and no datasheet is available (from the chinese website). The 3 electrolitic capacitors have been replaced as well as the internal lithium battery, the 2 main resistors (R5 and R51) and the relay.

I noticed that the transistors communicating with the COB (Q2, Q3, Q4...) don't have any voltage. Is it because the central unit is faulty and doesn't send them any signal?
Is it for the same reason that the AC voltage stops at the pin n.8 of the relay (nearly 28V)? The relay's coil doesn't receive any pulse, so 28V can't go on and reach the D9 rectifying diode. I also checked vias for continuity (even in the relay's area) and there seems to be no continuity's problem.

Instead, the 9V incoming power does arrive at the COB (crystal's pins showed 0.43V and 1.56V), but from there it should go to the displays. However there is no voltage between the COB and the displays.
Is all this enough to state that the faulty component is the COB?
If so, I guess this problem has due to a short circuit at the relay's area (likely the pin n.8 involved). So, I think that if more than 27 volts have gone through all the board's tracks, reaching the central unit (that ordinarily works at about 1V, more or less), I don't know how many hopes I still have to see the central unit in good shape.
What do you think?

 

[73's de Edd]

Principessa zulu . . . . . . .

That will be one wicked board to " read" due to its being double sided with cross connect vias.
Can you associate the loss of display with any prior circuit or parts changing just before its loss ?
Your unidentified RV1 will be of no real consequences to know, since its related to overvoltage protection on that supply line.
As you can see, the R5 series resistor in the 24 AC power supply source has run hot in its overall lifetime.

Initial test:

In a power off condition and no 24VAC presence, test and see if possibly zener diode ZD1 or D10 have failed
to a short condition.

I see that you have already covered my mention of changing the "coin cell" on board memory battery.
Did the display functions work after its change out ?


73's de Edd

 

[zulu]

Thanks for your suggestions!

.
Can you associate the loss of display with any prior circuit or parts changing just before its loss ?
.

No, I didn't notice circuit's parts or components (existent or replaced) changing (thermally or in other ways) before the displays' issue.
Actually, I forgot to mention RV1, the varistor marked "CNR 10D560K". No resistance values in both directions. I know it should have infinite values. So my tester shows 1 with no reaction. Low resistance should indicate a defective varistor. Maybe the absence of reaction could indicate a complete absence of resistance. But, as you wrote, it's not relevant for the overall problem.

In a power off condition and no 24VAC presence, test and see if possibly zener diode ZD1 or D10 have failed
to a short condition.

My little digital multimeter shows these D10 resistance values:
Red lead A, black lead K (2k scale): .643
Red lead K, black lead A (200k scale): 46.1

For the same diode the test diode mode shows these values:
Red lead A, black lead K: 635
Red lead K, black lead A: 1

About the ZD1 diode. It's not easy to visually distinguish between anode and cathode because there isn't the classic black strip, as you can see in the photo below. But I simply noted down the values in both directions and I got these results: my ohmmeter showed no resistance and in the test diode mode the multimeter's display gets stuck on 1

So, while D10 seems to be OK (low resistance and high resistance, as I wrote earlier), the zener shows no values in both directions. Doesn't that mean the diode is shorted? If so, I guess it should be replaced. But I don't have any datasheet of this zener nor any visible code outside, then how could I know the exact values of a new zener?

Apart from this difficulty, now taking into consideration the 9Vdc values written on the photo of my last message, how could a defective zener affect the functioning of the other components?
Looking at the voltage route (always 9Vdc), it seems that the ZD1 is not involved at all. The current arriving from the battery stops at D10 cathode on the left of D11 but keeps flowing on the right reaching C8 and then the other components, as you can see in the photo.
Perhaps I'm wrong but if you look at the yellow line (tracks of the opposite PCB side), starting under the upper key, you can see that it continues the track arriving from C6, C5, L1 and RLY1, exactly the relay where nearly 28VAC arrive. Knowing that to activate sprinklers I need the AC incoming, the greenish-blue curve that I drew, leaving from ZD1, arrives down right near the Q19 square and then crosses all the transistors (namely all the sprinklers' lines that in my case are 4). Does it then bring the current to the sprinklers?
Does all this mean that ZD1 is involved in the circuit only for bringing current to sprinklers?

Looking further at the circuit, in particular at ZD1 connections (following the yellow path), we can see other 2 routes.
The first one involves D21, Q21, Q22, Q27, Q23 on the right (including the relay which is further on the right) and from Q23 the track comes back to the left (Q26 and so on).
The second route reaches R51 (on the right) and C10-Q2 (on the left). The track finally ends to SEN (water sensor).

Evidently, these components solely dipend on the AC power supply. But Q22 and Q26 have 2 poles with DC power supply (9V battery). Under Q26 and R52 there are tracks full of direct current as well. In these cases it's not easy to determine the relationship between AC and DC without schematics.

I'm just concerned about the importance of ZD1 with reference to the main issue: the display's failure.
We have to consider a fixed point: with 9VDC power supply the controller should turn on the displays and be able to program all the functions. That isn't happening.
The COB, as shown in the photo, receives more than 1V (crystal's pins have 0.43V and 1.55V) but then there is no voltage between the chip and the displays. On the other hand, you can notice that the transistors communicating directly with the central unit (at least Q2, Q3 and Q4) don't have any voltage. Is it so because they would need to get current just from the COB? Or is it the opposite (they should bring current to the COB)?
Perhaps, more likely the first one.
Anyway, I can't see a key role for the ZD1 regarding the display's issue. Am I wrong? If not, would then it be worth to replace the zener?

I see that you have already covered my mention of changing the "coin cell" on board memory battery.
Did the display functions work after its change out ?

No, unfortunately the displays still remained out of work.

 

[73's de Edd]

Mme zulu . . . . . . .

I just saw that the zener was just being against the HOT running R5 resistor and thought it might justify a checking out.
It is only associated with the derived DC power supply of the 24VAC supply line.

You would have to confirm it, with a power down testing, but I would consider that R5 resistor as being in series with the AC input / OR / being in the DC line after creation of the DC supply.

Looking at the 24 VAC line, it looks like the right bus is the basic ground buss while the left buss comes up and is routed through the power relay to a series inductor L1 and then into diode D9's anode and then +DC is thereby created on its cathode to then flow up and create the initial DC supply for the unit across C7 main filter capacitor. .

I can't see the foil paths well enough to surmise on companion C8.

Evaluating your current DC battery operation:

D12 rests across your 9V battery connection for reverse polarity battery installation.
The +9 routes on up via the ORANGE path to D11 diode ( that item also isolates battery DC power from the Line DC power supply) where it is
directionally steered up to the ORANGE path to the SUPPOSED NEGATIVE of
C8 . . . . .thats questionable ?
Maybe you can fill me up on that situation.

The other thing of interest is the negative terminal of the battery, what main foil buss does it connect into ?
On the AC derived DC supply, its the far right foil of the PCB.

I can see that the relay can be keyed on by either Q22 or Q27.
If you bridge between the very top collector connection of Q27 to its bottom left base connection with a 1k resistor, the relay coil should activate.


Waiting for any feedback.


73's de Edd

 

[zulu]

I just saw that the zener was just being against the HOT running R5 resistor and thought it might justify a checking out.
It is only associated with the derived DC power supply of the 24VAC supply line.

You would have to confirm it, with a power down testing, but I would consider that R5 resistor as being in series with the AC input / OR / being in the DC line after creation of the DC supply.

Perhaps I am wrong but I think that the R5 resistor should be in series with the AC input. Some connections in the photo are just covered by the lines I drew. The right pole of R5 is connected to the D10 anode, while the left pole to nothing. Following the yellow path on the right, earlier than the ZD1, the foil path meets C6, C5, L1 and the relay. Isn't that a second route of the 24VAC (the other one is traced on the reverse side: from L1 the 24VAC reaches the D9 anode and, at the same time, the common terminal on the bottom left of the PCB) ?

D12 rests across your 9V battery connection for reverse polarity battery installation.
The +9 routes on up via the ORANGE path to D11 diode ( that item also isolates battery DC power from the Line DC power supply) where it is
directionally steered up to the ORANGE path to the SUPPOSED NEGATIVE of
C8 . . . . .thats questionable ?
Maybe you can fill me up on that situation.

The other thing of interest is the negative terminal of the battery, what main foil buss does it connect into ?
On the AC derived DC supply, its the far right foil of the PCB.

Sorry, it was just an oversight. After D11 the DC flows up towards the positive of C8.
It seems that the negative terminal of the battery is connected to the ground buss. I am going to upload the 2 photos with the adjustments.

I can see that the relay can be keyed on by either Q22 or Q27.
If you bridge between the very top collector connection of Q27 to its bottom left base connection with a 1k resistor, the relay coil should activate.

Connecting the 9V battery, since Q27 has no voltage, I have to bridge base-collector of Q22 (6.64V arrive at Q22 base) and I suppose I should keep the 24VAC supply on in order to see the effects of the relay coil's activation on the AC line and the derived DC.
Looking at the resistors left at home, I only found a couple smaller, in series, than 1k: 270+330. Could I use 600 ohms instead of 1000? If not, I will buy it on Monday.

 

[73's de Edd]

You are just fine on that selection of series connected resistors.
What I really need to confirm is if the 9v battery is connected, is if it's apparent 7v loaded / or / weakened value appears across pins 1 and 16 of the relay coil.
With all of the vias of this board, it's quite hard to confirm from afar
THEN if even you cannot confirm the supply line source, it's a simple matter to monitor one and then the other pin with one of your 270 ohms to ground and see where the lowest drop on a terminal is. . . . .which will be connected to the main battery + power supply line.
. Of course the other relay coil terminal will be the switching transistor connection.


73's de Edd

 

[zulu]

All right, not the most beautiful bridge but at least Q22 base-connector's connection (through a 600ohm resistor) is OK.
Current flowed towards Q27 and then pin n. 16 (2.50V). Instead, Q23 has only 0.07V on its collector, so pin n. 1 has consequently the same low voltage.
As a result, the AC is still stuck at pin n. 8 but I measured 1.30V at the positive pole of C7 and then 1.13V at D9 cathode (I don't know where that voltage comes from but it's something related to the AC incoming since it disappears with only 9V supply connected). The trip ended before R3 (marked 105, 1Mohm if I'm not wrong). Actually, 1.13V is not exactly the range of voltage that should arrive there, I suppose.

But I'm focused on the pin n.1 of the relay.
Before it there are Q23, R60 and Q26 in series. Q23 is marked 1p, while Q26 2f.
This is an analogous situation to the one of Q27 (1p) and Q22 (2f) in series with pin n. 16
There are nearly 7V available at Q26 base. What if I bridge Q26 base and collector?
Surely the pin n. 1 will get more volts than now and perhaps the relay will be able to let the AC flow up, reaching L1 inductor and D9 anode.
In that case, would you advise to use a resistor to make the base-collector bridge? If so, how much big?
By the way, what if I take out the 600Ohm resistor for connecting Q22 base-collector and I replace it with a simple wire (then with no resistance)?

I've just updated the photo with the last adjustments: voltage values are partly in violet and orange. I hope you can figure out something with all those lines!

 

[73's de Edd]

Mme zulu . . . . .

I am now seeing your new voltage readings, which you have taken on pins 1 and 16 of the relay .
It looks like Pin 16 of the relay will be the dominant power pin, of which, one would normally expect almost 7 volts of DC supply being across it, but something seems to be pulling it down.
Now if we look across to companion pin 1, it's so low, that it looks like there is a short to ground somewhere along that foils path.
So how about going into a power removal situation, of both the 9 V battery and the 24V AC supply.
That will then let you take a safe ohms reading from pin 1 of the relay down to the negative terminal of the 9 V battery connector.

Now . . . . .Do we have a short or defective component on that line ?

Also you have done a superb job on the photographic coverage and side annotations, but could you take another photo of the board just like the one that we are working with.
Down in the area just below the circle LCD display, there are parts in shadows that can't be made out.
Of course, that area is of no interest now, since basically, we're interested in the top right quadrant of the whole board for this present problem.
Your current composition of the board is just filling a complete picture frame, top to bottom, which is excellent and the vertical alignment is perfect, with your picture not being tilted.

Can you you go outdoors and take advantage of that full sky lighting, and take the photo but not being in the direct sunlight, as that would create shadows.
I can then take that photo and 4X it and be able to see every little part and also cross reference to your marked up one as is being necessary..

73's de Edd

 

[zulu]

Finally, I managed to key the relay, following your tips about pin 16.
As there was too few voltage across it, I made this reasoning: the near positive terminal of 9V battery has about 7.6V (I replaced the old battery with a new one), enough to give sufficient power to pin 16. So I tried to make a bridge between the positive terminal and the track in front of that terminal (which I scratched a bit to uncover the foil path) that brings to pin 16.
It seems that now the AC crosses the relay, arriving at L1 and, on the front side PCB track, stopping at C5 (the first of the 2 capacitors in series), while continuing its route on the back side PCB track in 2 directions: up to the rectifying diode (D9) and down to C, the common terminal (bottom left of the PCB).

So, starting to measure alternating voltage values from the beginning, I updated the photo. At the relay I checked both AV and DV. All contacts have a voltage value, except for pin 6. Is it normal? If not, I guess it's not due to the relay itself because I replaced it after the displays' issue.
I've always thought that the whole problem was born after a short circuit happened in the relay area, probably between pin 8 and another one (perhaps the companion 9). Well, if this happened, 28V arrived everywhere (or almost but surely at the COB) causing a "little" problem.

But now let's continue with the AC route. As I said, L1, after the relay, and C5. There, it stops but I suppose that the aim of C5 and C6 in series is just that.
So, D9 comes and on its cathode we have 36.3Vdc, nearly the same voltage in R3 and the close left pin of R5 (whose connection to R3 I now show with a greenish-blue mark on the photo). At that point great job for R5: voltage drops from 36V to about 12V. From there to the close D10 and ZD1 (which is in a short condition) and then down to the "operational area" (the hole near Q19), supplying the necessary voltage to the various transistors. But I'd like to get back later on this point as I wish to know your opinion about a possible solution involving the "operational area".

About ZD1. Considering the voltage value before the zener (approximately 12V) and the path after it, what are the right values (in terms of W and V) that ZD1 could have in my PCB?

Now, let's go straight to the IC marked "C2ZD". I have found the datasheet of a series of voltage regulators (see this link:http://www.sii-ic.com/en/semicon/datasheets/power-management-ic/voltage-regulator-ldo/s-812c/). There is no final "D" but only the other 3 letters (only a chinese website shows all the letters but there is no datasheet available). If it is the same component as mine (despite that "D"), is that working efficiently? I only know that before the COB, R1 has 5.1V and the crystal has 1.9V and 4.5V on its pins. Then after the COB, all the displays' pins have about 1.7V but nothing appears on the LCD, as the last time, no matter the voltage arriving at the COB.
The C2ZD is just a voltage regulator: this time output 8.1V from 11.9V, while the last time 3.73V from 7.25V (due to the smaller power of the 9V battery). By the way, the last time crystal's values were 0.43V and 1.56V with no voltage across displays' pins.

Earlier I mentioned the "operational area" because I got an idea but I don't know if it's feasible. If you look at the last photo, I drew a red rectangle on the right, a hypothetical component or device whose name and possible existence are unknown to me. Before, there are 12-13V coming. This voltage should get into this device which would provide 4 different lines as output, each sequentially activated for an amount of time.
So, 12-13V arrive but firstly only the line 1 gets the current for 1 hour (just an example of time). At the end, it's the turn of the line 2 and so on until the line 4.
I would connect each output line (using insulated wires) to a small piece of track after the transistor emitter because it's there that the DC should be, flowing then down until the terminal contact. In this way, I would bypass the COB signal to the transistor base. I simply would not need it. And I would successfully solve the whole problem, activating each sprinkle line simply by connecting the 9V battery (to key the relay) and the 24VAC (then reduced to 12-13VDC).
It looks like a signal splitter combined with a timer. I'm afraid it doesn't exist or, at least, it would cost too much.

Otherwise, is there a way to apply the logics I've just explained?
I just need a sequential start of the sprinkle lines for 1 hour each, that's all. If we can modify the final part of the circuit to accomplish this need, we definitely solve the problem. What do you think? Could we take advantage of the power arriving at the operational area to sequentially activate the 4 lines?

Here are the electrical specifications regarding the station output power:
- 24 VAC
- 6 VA (0.25 amps) per station maximum
- 6 VA (0.25 amps) pump start/master valve
- 12 VA (0.50 amps) total load

Following are the 3 photos. Unfortunately I didn't take the chance to get a shot of the PCB in the sunlight but I managed to take a better photo of the bottom left quadrant, as you suggested. I hope it will be fine for a quick understanding of the operational area.

 

[73's de Edd]

Mme zulu . . . . .


To be sure that I catch all, I am going to fill in between your entrys.

It seems that now the AC crosses the relay, arriving at L1 and, on the front side PCB track, stopping at C5 (the first of the 2 capacitors in series),
>>>Pass back the marked on voltage rating on that C5 capacitor<<<<
while continuing its route on the back side PCB track in 2 directions: up to the rectifying diode (D9) and down to C, the common terminal (bottom left of the PCB).

But now let's continue with the AC route. As I said, L1, after the relay, and C5.
There, it stops but I suppose that the aim of C5 and C6 in series is just that.
>>>Pass back the marked on voltage rating on that C6 capacitor<<<
So, D9 comes and on its cathode we have 36.3Vdc, nearly the same voltage in R3 and the close left pin of R5 (whose connection to R3 I now show with a
greenish-blue mark on the photo).
At that point great job for R5: voltage drops from 36V to about 12V.
>>>That explains the heat associated with the discoloring of both the nearby PCB as well as the color bands on R5 as its dissipating right at 2W in the drop. <<<
From there to the close D10 and ZD1 (which is in a short condition)
and then down to the "operational area" (the hole near Q19), supplying the necessary voltage to the various transistors.

About ZD1. Considering the voltage value before the zener (approximately 12V) and the path after it, what are the right values (in terms of W and V) that ZD1 could have in my PCB?
>>> It looks like ZD1 might be right at its limits as it is <<<

Now, let's go straight to the IC marked "C2ZD". I have found the datasheet of a series of voltage regulators (see this link:http://www.sii-ic.com/en/semicon/datasheets/power-management-ic/voltage-regulator-ldo/s-812c/).
There is no
final "D" but only the other 3 letters (only a chinese website shows all the letters but there is no datasheet available).
>>>You remember that we had almost 36VDC raw DC out of the power supply to be filtered by C5, and I don't think that level was used anywhere in circuitry tie ins, but then that supply level went right on to be regulated down to 12VDC by ZD1 and then C6 filters the 12VDC supply.
Now I see that 12VDC is going over to our "mystery" U2 regulator, and I really think that is being either a 9 or 8V regulator chip and is right in line with the standby 9 volt battery supply voltage after it gets filtered by C9.
>>>Pass back the marked on voltage rating on that C9 capacitor<<<
After its filtering by C9 that ~ 8.2VDC supply ends up at blurry Q1 or 7 . . .its just to the left of readable R11.
I'm thinking that little cluster might be a malfunctioning 5V supply regulator area.
Since I have never seen the other side of the board , and since we have had an associated canned elecrolytic with each prior level of voltage regulation , like C5, C8, C9 do you see yet another canned filtr that might be related to this lower voltage supply.
Just down below the questionable Q1-7 there is another questionably legible Q or D3 its left tab is shiny while the right pair seem discolored . . . .put a fingertip to it and see if it is hot . . .when operating.
These parts do not show up in your common generic PNP and NPN transistor list.
With those associated 200k and 1 meg higher value resistors, we might have ourselves a FET instead of a common sil transistor.
Can you pass on their top marking codes ?
Can I also get the full numbers associated with RLY 1 so that I can sort out its terminal layouts and coil specs.

Back at the time when the display failed, did you do a total power down and check out all diodes and transistors in the diode test mode . . . .to confirm all having good junctions ?
Of particular interest is the ones I have just mentioned, along with the cluster in the area to the left of RLY 1.


If it is the same component as mine (despite that "D"), is that working efficiently? I only know that before the COB, R1 has 5.1V and the crystal has 1.9V and 4.5V on its pins. Then after the COB, all the displays' pins have about 1.7V

but nothing appears on the LCD, as the last time, no matter the voltage arriving at the COB.
The C2ZD is just a voltage regulator: this time output 8.1V from 11.9V, while the last time 3.73V from 7.25V (due to the smaller power of the 9V battery). By the way, the last time crystal's values were 0.43V and 1.56V with no voltage across displays' pins.



73's de Edd

 

[zulu]

After its filtering by C9 that ~ 8.2VDC supply ends up at blurry Q1 or 7 . . .its just to the left of readable R11.
I'm thinking that little cluster might be a malfunctioning 5V supply regulator area.
Since I have never seen the other side of the board , and since we have had an associated canned elecrolytic with each prior level of voltage regulation , like C5, C8, C9 do you see yet another canned filtr that might be related to this lower voltage supply.

Good point!
Actually, it's Q1 (I'm going to upload a less blurred photo for that area). There is no transistor on that square, so the voltage ends up there. Even R11 has not been installed, as well as LED 10, LED 11, LED 12 (the 6 small circles in couple) and D13.
Perhaps when you talked about lower voltage, you're referring to the cluster below, Q3, where I measured a bit more than 2V.
Then Q1 cluster has no canned filter, differently from the previous areas.
Having had a look at C5 and C6, it seems that there is no readable code. Anyway, they perfectly filter 28VAC (don't they?): after C5 there is no volt (as well as after C6).

Just down below the questionable Q1-7 there is another questionably legible Q or D3 its left tab is shiny while the right pair seem discolored . . . .put a fingertip to it and see if it is hot . . .when operating.
These parts do not show up in your common generic PNP and NPN transistor list.
With those associated 200k and 1 meg higher value resistors, we might have ourselves a FET instead of a common sil transistor.
Can you pass on their top marking codes ?

The transistor Q3 is marked "1P" (it should be an NPN transistor) and I assure you that it's in a good shape: no discoloring or burnt points and no overheating during power on condition.
Are then normal those voltage values (a bit more than 2V) for that transistor?
Its left pin is directly connected to the COB, the top right pin is connected to Q4 (via the hole on the right of Q4) and to Q24 bottom right pin (just see the greenish-blue route). Finally, its bottom right pin is connected to R10 and then Q4.
As a result, all these components approximately have the same voltage (2V or a bit more). And I measured even lower values on Q2 (1.6V, 0.48V and no voltage on the other pin, the one then connected to the yellow path of the shorted ZD1: could then ZD1 be important for the low values' issue?).
Actually, I'm concerned about these low values because the central unit could even receive an insufficient amount of current to then activate the displays.

The displays are currently receiving nearly 2V but nothing appears on them. I guess they just need specific signals from the COB, otherwise they would be defective or with a too low voltage level to work. Is then there a specific pin (or more then one) of the COB which is responsible for sending the right signals to the displays and let them show what they should show?
Could instead the displays be defective? If so, how to detect this condition?

Can I also get the full numbers associated with RLY 1 so that I can sort out its terminal layouts and coil specs.

In the photo below you can see the original relay (white) and the current relay (black).

Back at the time when the display failed, did you do a total power down and check out all diodes and transistors in the diode test mode . . . .to confirm all having good junctions ?

Yes, it was the very first thing. I checked for continuity and no particular issue arose in the diode test mode. Transistors and diodes didn't have bad junctions.

Of particular interest is the ones I have just mentioned, along with the cluster in the area to the left of RLY 1.

Q22, Q27 and Q23 should act on the relay, while, on the opposite, Q2 and Q24 (over than the above mentioned Q3 and Q4) communicate directly with the central unit. Considering the current display's issue, where would you focus on eariler?

A last small point to mention. It seems that it would be possible to activate 2 sprinkle lines at the same time (to be confirmed by testing the autoclave). So I could connect, for example, 2 wires on terminal n.1 and the other 2 on terminal n. 4. Hypothesizing that the COB and/or the displays won't work, I could bridge base and collector (via a resistor) of the 2 transistors commanding those 2 lines (Q12 and Q15 in our example). For the first hour of power on, I could connect the first 2 wires to the terminal n.1. Then I could get back to the controller, turn it off, disconnect the first 2 wires, connect the other 2 to the terminal n.4 and finally plug in the transformer again. I think this procedure would take less than a minute but it would be effective.
The ideal would then be to find a way to avoid the manual switch between the 2 lines. Perhaps by purchasing a dual timer switch (with a dual relay inside, if I'm not wrong)? I've recently seen something like that on the web. It's cheap but it would completely replace the current controller, since it should have a couple of common terminals and input terminals (I should then connect all the wires to this device).
I'm afraid that with a defective COB the only way to automatically switch between lines is an external device, am I wrong?

 

[Dryman]

hi, my toro ddc6 problem....display is off, because puffer capacitor 470micro/16v is damaged and zd1 is damaged...so....controller not working, because Ut is high...controller is good working Ut =max 5V......change zd1 9,1v zener dioda, change 470 mikro damaged capacitor, and u2 stabilizator ic ..lm78l05 pin compatible modding...this u2 not used 5 pin, see this bord place...this 3 pin used 5v voltage sabilizator ic. 9V battery voltage outgoing dioda....9V-0,6V=8,4V going 5V voltage regulator in, voltage regulator out 5V go display driving chip...5V voltage is ok, display is on. 24V alternative voltage go diodae vs one way graetz bridge...on capacitor voltage is x1,42V...so...~36V---- go to resistor R 330ohm. common point resistor and zd1 is good voltage 9V.

 

[Dryman]

hello guys! change zd1 6,8v zener diode, voltage is 6,2Volt common points voltage regulator input. display is on, kontroller switching tranzistors bazis is ok, solenoid valve is working.used 6,8v zener small temerature in R5 rezistor.

 

[dondrusco]

Thank you very much for your investigation and solution.
I have a TORO DDC-6 controller, 10 years old. It had the same symptoms. I have replaced capacitors, but it didn't help. My friend Google didn't found any relevant schema. Just words TORO,DDC and ZD1 returned this page.

My controller had missing the ZD1 diode. It was unsoldered by high temperature. I have replaced it with a 6,8V 0,5W Zener diode, which I soldered it into a small holes next to the SMD. It works on the second attempt. First, I soldered it wrong polarisation and I measured just 0,9V. I know my fault immediately. I put it the right way and controller runs OK.
It spares me 99,95 EUR, because a new Zener diode costs 0,05EUR and a new controller 100EUR.

Tags: TNL Ver:E TNL_V13,