Repair Fence Energizer SS-1000E Fi-Shock

[R_J]

I was just reviewing and I don't see if you ever measured the resistance of those two 360Ω 10 watt resistors.
You seem to have 230vac going into each end but only 50vac coming out the other ends

[eccerr0r]

Might be a measurement problem, RMS voltage, etc. If it were really 50V, the two 10W resistors would be roasting or roasted in the past to burn open.

As for testing the DB3 I don't think most people have equipment to test these things. Need a curve tracer or perhaps a high voltage (~ 50V) zener tester and see if it (correctly) shorts out when the breakover voltage is met.

Provided the resistors haven't decreased in value, I can't see how the DB3 could fry.

I still vote for leaky C2.

[redwire]

Oh it's a 220VAC powered European version
Here in North America, there is no hot+neutral at 220VAC, how is the fencer then grounded?

About 5 second pulses and 330VDC on the main cap.

If C2 was leaky, the SCR/DIAC would never trigger and just remain off?

I think the main cap C1 16uF 400V might be low value or open. OP is measuring only around 50V on the DC bus, not 330V yet the big resistors are not burning up. He might be measuring mains pulsing DC (AC ripple) everywhere if C1 is low value.
*OP, note C1 is dangerous and there is a shock hazard if it holds a charge. I would check voltage with a multimeter to make sure it's discharged before going near it to measure capacitance.

I tried a Spice simulation and it's kind of funny, the diac pulsed once and then the circuit just sat there doing nothing afterwards. This is with ST and Littelfuse models.
It appears to be saying the holding current of the DB3 diac keeps it on after triggering once. The SCR then stays off because it needs much more gate current to turn on.
In other words, the diac turns on and stays on forever from the steady uA's available from the 2MEG resistor. Holding current spec for DB3 I couldn't find.

[stormy1777]

ok, was curious if it is C2, and replaced with [email protected], but still same symptoms, no light turns on when unit is energized to 220vac.

Here are more interesting findings relating to the coil:

1) When b1 and b2 connectors are disconnected to the COIL, the voltage is stable at 6VAC or jumping from 400mVDC to 1.2VDC.

2) when b1 & b2 are connected from main board to coil, the voltage drops to 0.4VAC, or 0.04VDC, which is basically ZERO... it drops compared when the coil is not connected to main board.

3) Testing the coil with RESISTOR mode in DMM, shows 0.003 ohm or something very low, just pullged to the B1 & b2 wires..

is it possible to coil is somehow shorted?? I have no experience with such things, but that's what logic tells me

will need to find more time to research this but thought to update all those wonderful curious folks who showed interest

Stormy.

[stj]

one of the diodes could be bad under load.

[eccerr0r]

Testing the coil requires specialized hardware, known as a ring tester. I haven't seen many coils go bad however without some serious overheating. But it looks like you do have an LCR meter which should have a ring tester! If so, what's the Q on the windings (make sure you disconnect the output too!)

That is very weird that C2 didn't fix it, unless it too is leaky. Does your LCR meter report leakage? The effective parallel resistance needs to be higher than 20MΩ.

As I figured, you should be able to make a relaxation oscillator to test the DIACs https://www.androiderode.com/how-to-test-diac/ ... And yes this should oscillate without the transformer/inductor there! As long as the source voltage is higher than the breakover plus the SCR gate voltage, it should oscillate.

[budm]

You need to check the DC Voltage between its two legs to make sure it is charged up the firing Voltage of the DIAC or not as I suggested earlier.

[stormy1777]

Originally Posted by budm

You need to check the DC Voltage between its two legs to make sure it is charged up the firing Voltage of the DIAC or not as I suggested earlier.

between "its two legs", what is "it" in this reply? sorry


I put a brand new [email protected], somewhat unlikely that it too is bad.. but I'll keep at it and narrowing other things.

As for the DIAC, I think that page provides two methods to test? I'm going to go with "HOW TO CHECK WITH DIGITAL MULTIMETER", which basically says to test in DIODE mode both ways, then it says:

"Verification: If you get reading in forward bias as 0000 or ‘OL’ or any small value and in reverse bias as 0000 (or) low values the DIAC can be FAULTY and needs replacement."

Regarding the diodes being bad, didn't take them off circuit yet, they are i think IN5400; one measures 0.5V and other 0.475V in diode mode, and reverse is both zero, so maybe replace the 0.475V one? I think i have one of these around somewhere, that also measures 0.5V.

General question, in many cases it seems that these tests are good, but not 100% since they are not truly under load.. are there ways to measure this truly? under load? can i test the diode when the unit is energized? assuming I'm protected (gloves, eye googles, boots, helmets and other protective shields) ?

Thanks.

Stormy.

[budm]

Put the dc Volt meter probes to the two legs of the 22uF cap to measure the Voltage on the cap.

[stormy1777]

Originally Posted by budm

Put the dc Volt meter probes to the two legs of the 22uF cap to measure the Voltage on the cap.

Sorry, missed your original suggestion, rereading, I see it!! ok, energized the board, without B1&B2 (coil) connected, and it took C2 about 30 minutes!!!!! to climb all the way up to 30VDC, then it came back down to ~26VDC and up to 30VDC, it seems to want to stay up there. Volts across D3 seem to match that of C2 at any given time (not measuring both at the exact same time, but 2-3 seconds apart).

Measured V across, R5 (it drops to 0 VDC), and R3 jumps all over, like 9VDC, but never zero.

Maybe R5 should not be zero? maybe it is bad? although it measures 220Ohm as it should based on color coding i think it is red, red, brown, gold (220).

Across D5 (upper right corder) volts typically measure: 2.2VDC

Attaching few photos from this session, including ESR meter of the C2 capacitor (shows 0.5Ohm), and chart shows it well within range, with 1.5Ohm as max for the [email protected] The other meter does not show leakage, just capacitance.

Volts from B1 to B2 without coil board connected comes to about 1VDC when board is fully energized and C2 shows 30VDC.

I suspect that is not good, so need to probably look in that "area"

I'll proceed with more testing later on, like test D5 out of circuit, or maybe replace D1...

Thanks.
Stormy.

[eccerr0r]

Though 2M * 22µF is large (44 seconds), getting to 30V in 30 minutes is way too long. Either that 2M resistor has gone open or something is leaking the charge off the capacitor, and it could be the capacitor itself. This would be the "leakage" we're talking about. This value has nothing to do with the "ESR" that most people talk about on this form - in this case, ESR has almost no bearing on the operation of this circuit due to the low currents we're working with here.

However the parasitic parallel resistance makes a huge difference.

[stormy1777]

It took a very long time to get to 30V, and it seems C1 (that huge capacitor) is in sync with C2 (and D3 the DIAC) climbing up, all that time R5 is showing as ZERO (but R3 is none-zero), is that normal? maybe R5 resistor is "opening" under electrical "pressure"? I just don't know enough about that trigger loop/circuit

On an old LCD power supply board, found a working [email protected] capacitor, so will replace that now .. I think the COIL is not the issue, since the Voltage on B1/B2 is ~1VDC, i'd expect to see something like 30-50VDC, or maybe really high value, or maybe that higher value is done by the coil

I see online-tools for Circuit "design" or "simulators", do you think it would help if I enter all this data into one of these, and it could tell what is expected to show in reality? or that is not the way to go? I've never done it, but do not mind spending time and learning, like i said, in my naive world, this should be like math/computers, i.e. deterministic, given we know all the parts/specs, it should be possible to simulate/calculate, and thus quickly spot the bad component, based on such voltage measurements? maybe too naive or? ahead of my time ???

Stormy.

PS: Being very careful working this project, taking the time, and trying to get it done right

[stormy1777]

oh, looked at few online schematic editors, seems like SCR, DIAC are non-simulatable I bet higher-end systems can do that ok, lets replace C2, again

[eccerr0r]

Wait, the big capacitor should charge up to full DC voltage fairly quickly - should be well over 100 volts within a few seconds. If this is not the case we have a problem there - look at R1, R2, and the two diodes in series.

[stormy1777]

Originally Posted by eccerr0r

Wait, the big capacitor should charge up to full DC voltage fairly quickly - should be well over 100 volts within a few seconds. If this is not the case we have a problem there - look at R1, R2, and the two diodes in series.

We got an ECC Err0r

The big guy is not charging up quickly! it goes about 5VDC ahead of the C2 tiny capacitor and it takes them about 5-10min to get to 35-30VDC respectively, then they start going down very slowly to ~20VDC or sometimes drop immediately to 2-5VDC and slowly start to climb up back to 30VDC range.

This test I did after letting the unit "cool down" (not that it is getting any warm) for 2hrs, i.e. not touching it and disconnected.. however, the COIL was connected to in this test.

I suspect the coil somehow discharges it every once in a while, and maybe it is not charging fast due to one (or two) of the diodes failing under load..

Let me see if i can take out of circuit and maybe replace one if i can find a good match..

I wonder if I need to migrate this post to baddiodes.net forum

Cheers.
Stormy.

[redwire]

With the transformer disconnected at B1/B2, there is no load on the power supply so the main cap C1 should charge right up to 330VDC, fast in about 0.2 sec so OP needs to figure out why current is not flowing. Regardless of the SCR/diac/D4 etc. as they get power from the transformer primary winding. That is why you get maybe 1V when B1/B2 disconnected.

The resistance of the fuse, two power resistors and the two 1N5408 rectifiers is all that is in series with mains. One of these parts is pooched.


RC time constant defined as charge to 63% but for C2 we should go 0 to 32VDC from 330VDC, which is 10% and so the RC time is 4.5 seconds.
There is small leakage current in the diac and 22uF cap and multimeter loading, total about 15% less charging current.

[budm]

What is the resistance and capacitance reading of that 16uF 400v CAP?
Make sure to discharge it first.

[CapLeaker]

The most common things that fail in a fence energizer are: The power input terminals (12V), the big HV capacitor, fuse, MOV (accross the mains power) and the transformer. Just fixed one 2 weeks ago.

[stormy1777]

Originally Posted by budm

What is the resistance and capacitance reading of that 16uF 400v CAP?
Make sure to discharge it first.

Discharged, made sure volt is ZERO, disconnected black wire, so C1 is technically off-circuit; then measured and it shows exactly 16uF by two different meters.

Discharged again, then ESR meter shows 0.03, then quickly drops to 0.00ohms, so i think that is OK, maybe it's too big for this meter..

now, disconnecting B1/b2 and applying 220V, monitoring VDC on C1, noticed it is NOT charging instantly like our friend redwire says..

so, I will invest more time on the early phases of that board, the fuse is OK, b/c it has 230vac across it. next will take the diodes out of circuit and try to find a matching one, that may take time, b/c I'm a Capacitor collector, not (yet) a diode collector

Thanks for your cheering support!! hopefully this thread will help others in the future

Stormy.

[budm]

The reason I have you checked the resistance, NOT ESR, is to find out if has leakage resistance that is bad enough to cause the problem or not.