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CCWKen
10-09-2012, 09:22 PM
I bought a Grizzly heat sealer (model H6153) about two years ago and have used it maybe 10 times. On almost the final seal I was trying to make today, it just quit working. Being in the "what have I got to loose" mood, I took it apart and tested various components. I found a diode on the timer board that was loose. It looked like someone went to lunch in a hurry and left one end with nary a touch of solder. I thought great, that's gotta be it! After touching a daub of solder on the loose end and re-assembling, the sealer still didn't work. And the indicator LED doesn't work. But it sounds like the relay is tripping--I can hear a click after the set time. According to the diagram below (supplied with the sealer), the relay (DC-24) can't work if the LED is blown. Or can it?

I bypassed the timer/relay board and just used the lever switch (LS in the diagram) to finish a few seals. The timer/relay circuit is on about a 2" x 2" PCB and I think I can test it stand-alone. It just has pins for AC-in and AC-out for the transformer. (I made jumpers for the connector to bypass the timer/relay. The rheostat for the timer is part of the mounted module. So with AC in, there should be AC out until the timer circuit opens the relay. But it ain't, doesn't output AC or light the LED. Help!

http://img.photobucket.com/albums/0903/CCWKen/Diagram.jpg

Black_Moons
10-09-2012, 10:40 PM
LED's can fry short as well as open.

J Tiers
10-09-2012, 10:41 PM
According to the diagram below (supplied with the sealer), the relay (DC-24) can't work if the LED is blown. Or can it?



According to the diagram, the relay cannot work UNLESS the diode is blown...... it gets DC, but is poled backwards...... should not conduct.... "Grizzly".... said with contempt dripping from every syllable. ;)
Apparently the relay closes when you start it, and then after some time the SCR shorts it and opens the relay. Clearly the diagram is wrong.


OK..... if the relay is closing, there has to be AC to the transformer. If the relay gets power that will happen, unless the relay is bad and no longer makes contact. Being Grizzly, it is perfectly possible that the relay was in some way under rated, and has failed in such a way that it doesn't close the contact.

So........

Your task is to discover if there is voltage across the relay for the set time. And to check that it goes away after the time set. If so, the relay is getting power, but may be bad. If not, but voltage is OK across the SCR, perhaps the LED was not rated well for the coil current and is open. LEDS do fail open reasonably often, other diode types typically fail short.

darryl
10-09-2012, 10:53 PM
If the led is blown 'open', the relay can't work. Because the led is so fragile inside, it probably is open. When you operate LS, you should have dc voltage across the main terminals of CR02 until the zener conducts and latches CR02, which then crowbars the voltage to the relay. If that voltage is there and the relay doesn't click, the led is blown.

jnissen
10-09-2012, 11:15 PM
Pathetic circuit design. The coil current shutting down will provide a large surge of voltage that will easily damage that LED. Depending on what type of LED it is they typically do not like voltage exceeding 3V. I suspect that LED shorted open as others have said. You can replace the LED but it will likely blow again in the near future. I would try a limiting resistor in series with the LED and a shunt diode across the relay coil. If the series resistor added is to high then the coil will fail to properly pull in.

J Tiers
10-09-2012, 11:41 PM
Pathetic circuit design. The coil current shutting down will provide a large surge of voltage that will easily damage that LED. Depending on what type of LED it is they typically do not like voltage exceeding 3V. I suspect that LED shorted open as others have said. You can replace the LED but it will likely blow again in the near future. I would try a limiting resistor in series with the LED and a shunt diode across the relay coil. If the series resistor added is to high then the coil will fail to properly pull in.

That was my knee-jerk response also, but I quickly realized that it won't wash..... the SCR shorting the relay to shut it off will prevent a surge, and even if power is shut down with relay powered, the input capacitor and timing cap through the diode will tend to let it down slowly, with no flyback surge.

CCWKen
10-10-2012, 12:12 AM
I left the module out in the shop along with my camera. I'll shoot a picture of the PCB tomorrow but I don't think there is a SCR. I'm not great at following traces but I think the diode I soldered is in place of the SCR shown in the diagram. One end of the diode was held by friction only. So bumping the unit probably broke the connection. I'm surprised it worked as long as it did. I could identify/match all the other diodes and the transistor but not a SCR and the loose diode was unaccounted for on the diagram. It's as though the Zener end to the CR02AM may have been miss-drawn or there was a design change.

Keep in mind that I can hear the relay click after a time cycle. The cycle starts when the arm is lowered to make a seal. And I can very the time it takes to click by adjusting the pot. That's what's confusing. Perhaps the relay and LED are bad but I don't see how the relay can work if the LED is open. I'll shoot a pic of the component side and flip (reverse) the trace side pic and study it more. I guess you can't rely on the supplied diagrams.

Thanks a bunch!

CCWKen
10-10-2012, 12:20 AM
I just looked at a data sheet for CR02AM. That's NOT what's on the board. I think it will look clear in the morning. Thanks again guys.

darryl
10-10-2012, 01:53 AM
I can't believe I missed the polarity of the led- yes it does seem like it's in there backwards. However the relay will still work, since a reverse connected led will act like a zener at some voltage. I've checked some that zener at about 5 volts. And no, it will not light when conducting current in that direction. But I believe it will flash briefly when the scr is latched, from the energy stored in the relay inductance. It might be very brief-.

The led won't like conducting in the reverse direction, since it will be dissipating more heat than it would in the forward direction for the same current level. Not sure, but a 24 volt relay could be drawing about 40 ma or so, which is not outrageous for an led, so it's possible that the led is ok. I don't see its value in the circuit though unless by chance it does flash for long enough to be seen as an indicator.

But of course I'm making these musings based on the circuit as shown, which does show that CR02 is an SCR, the led is in there apparently backwards, etc.

Ken, you said that you finished a few seals using LS per the diagram- that does show that the circuit is working, does it not?

dp
10-10-2012, 02:20 AM
I can't believe I missed the polarity of the led- yes it does seem like it's in there backwards.

The drawing is wrong, I think.

The relay suggests it is a 24 vdc device - you should be able to measure 24 or so vdc when the relay is energized. You can short out the LED and the circuit will still work, btw. I presumed this was a one-shot monostable circuit meaning it does not turn on and off forever - it turns on briefly when LS is toggled and then goes off. If this is the case then the test points available should quickly reveal the problem. The 25uf cap should show a charge ramp then a collapse in voltage. The relay coil should show a one-time pulse that is the duration of the rc time constant of the control potentiometer and the 25uf capacitor. The transistor is certainly a PNP and is a current amplifier for the zener/scr trigger circuit. The SCR clamps the voltage across the relay and will swallow the back emf. The diode between the transistor base and emitter is a spike limiter just in case there is any back emf from that relay. The SCR is turned off not by commutation of the gate voltage but by removing power.

There's a zillion ways to make a one-shot including a diac in place of the SCR so there may be a two-wire device in that position now along with other changes.

J Tiers
10-10-2012, 08:16 AM
Well, we already know there is one error on the schematic... the LED. That puts the whole thing in question.

The SCR, if present, would be turned off by the AC input.... the 4.7 uF (hard to read, is it 47uF?) is small, and the current was no doubt expected to drop below the SCR holding current as teh AC goes thru the zero point.

If they changed the circuit, that may not have worked out so well....... but I'd be surprised if a diode were in place of teh SCR.... it would either have no effect, or else would never let the relay work, depending on polarity.

ALL OF THE DISCUSSION IS TOTALLY MOOT UNTIL AND UNLESS WE HAVE AN ACCURATE SCHEMATIC...... WHICH EVIDENTLY GRIZZLY DID NOT SUPPLY (AND WHY IS THAT NOT SURPRISING?)

Barrington
10-10-2012, 09:16 AM
Don't want to appear argumentative but...


The transistor is certainly a PNP

The C458 is certainly an NPN !


one-time pulse that is the duration of the rc time constant of the control potentiometer and the 25uf capacitor

Duration is a function of the time constant of the pot+R and 10uF cap, but not equal to it. The pulse duration cannot be estimated without knowing the zener voltage.


The SCR clamps the voltage across the relay and will swallow the back emf.

Strictly 'swallow the back emf' may be a litle misleading - there is no large back emf generated because the relay coil current is allowed to decay relatively slowly.


The diode between the transistor base and emitter is a spike limiter just in case there is any back emf from that relay.


The diode between the transistor base and collector is to discharge the timing capacitor.


The SCR, if present, would be turned off by the AC input.... the 4.7 uF (hard to read, is it 47uF?) is small, and the current was no doubt expected to drop below the SCR holding current as teh AC goes thru the zero point.
The switch is operated by the sealer arm, so the SCR remains on until the arm is released.


The OP states the relay can be heard operating but there is no AC output. Maybe the LED has failed to high resistance so there's just enough current to move the armature and make a click on release but not enough to force the contacts together ?

Whatever -

1: Just short out the LED. - Then, if function is restored:-

2: Add a new LED and series resistor (1.5k - 2.5 k) across the relay coil and everything may well be good.


Cheers


.

dp
10-10-2012, 11:31 AM
Don't want to appear argumentative but...



The C458 is certainly an NPN !

That's what I get for posting when I should be sleeping. I redrew the circuit yesterday indicating an NPN and said PNP anyway.

The transistor is an emitter-follower circuit pulled up over time by the (10uf!) cap and variable resistor. BTW, I've drawn it as a two-pin device because it is probably a bad thing to wire it as shown in the OP's circuit because the wiper can go open circuit. Just me being picky. And while I left out the series resistor (prevents presenting zero resistance at the end of the POT travel), it needs to be there for a working circuit. This is for analysis.

Anyway - at turn-on the voltage at base of the transistor is zero as the 10uf capacitor will just begin to charge. As the base voltage goes up so too does the emitter voltage but while it is less than the zener voltage of that diode the SCR will remain off and the relay will be pulled in. The LED should indicate current. At the moment the zener voltage is reached the SCR will latch on and the voltage available to the relay will drop to near zero - the saturation voltage of the SCR. That is less than the forward voltage across the LED which ensures the relay is off - no current at all which is probably why the LED is in series with the relay coil. Once latched it doesn't take much current to keep a relay closed. The series resistor at the top of the diagram is limiting the current through the SCR. The only way to shut off the SCR in this circuit is to remove power. The diode in the rc circuit is there to ensure the 10uf capacitor discharges completely between on cycles.

http://metalworkingathome.com/images/one-shot.jpg

CCWKen
10-10-2012, 01:48 PM
Here's a couple of shots of the timer module. The pins at the bottom of the component side are AC in/out. The left two pins are AC input. The right two pins power the transformer (heater) and is AC out. Just so no one is confused (me) I reversed the trace side so it matches the component placement. The glass diode on the right (below the cap) is the one that was loose.

http://img.photobucket.com/albums/0903/CCWKen/Module-Comp-Side.jpg


http://img.photobucket.com/albums/0903/CCWKen/Module-TraceSide.jpg

Barrington
10-10-2012, 05:14 PM
LOL ! - rather different to the diagram.

The LED is connected in series with a 39k resistor across the 120vac output - not a recipe for a long and happy life...

Looks to me like this:-
http://i564.photobucket.com/albums/ss82/MrBarrington/sealer1.png

Unfortunately the diode that was loose appears to be a zener regulating the power supply voltage. When it became disconnected the voltage may have risen to a level which damaged something.

As the LED and ac output appeared to fail at the same time, the LED may actually be ok. First step is to apply 120vac across the output terminals to see if it lights.

The transistor type shouldn't be critical - what is the part number ?

Cheers

.

dp
10-10-2012, 06:48 PM
LOL ! - rather different to the diagram.

Yah - not even close to the published diagram.



The transistor type shouldn't be critical - what is the part number ?

Cheers

.

I'd be tempted to drop a Darlington in there for the current gain. Other than the VR zener there are no other avalanch devices, so lots of current gain would appear useful.

CCWKen
10-10-2012, 09:27 PM
Thanks guys. The transistor is S9013 over H 331. I just noticed in the trace pic that one of the transistor pin connections is hidden by the LED but it is connected to the horizontal trace (AC in). Looks like Barrington figured that out already. I've never seen a LED connected across the AC line-out like that. It used to glow noticeably but wasn't very bright. So it's just used as a AC-out indicator which is what it was doing. Smart little LED--It doesn't glow now and there's no AC output. :)

Would I be correct in that since I'm hearing the relay click after the time setting that the relay contacts are toast?

J Tiers
10-10-2012, 09:45 PM
As for the long and happy life..... if that thing EVER lit, it would be dead now......... except that it very likely is an "AC LED", a double, a back-to-back pair in one enclosure, rather similar to the bicolor type.

They will not like the results over temperature..... leakage in what is probably a zener to the transistor base may cause the transistor to be on when it should not be. I have seen that same mistake many times before. A darlington generally has base-emitter resistors and actually might be better there...... even if not needed on a gain basis.

Still no need for a catch diode here, the transistor will trail off in current slowly enough to not have any significant flyback problem.


Don't want to appear argumentative but...


The switch is operated by the sealer arm, so the SCR remains on until the arm is released.



.

It likely is..... I hadn't the least idea how the overall mechanical gizmo works..... since writing that response I have seen reference to a "lever switch", so presumably you turn it on by hitting a lever switch and holding, during which the timed cycle is supposed to go. In that case, there is no need to turn the SCR off, it wants to, as you say, hold off until the lever is released.

I thought I saw a rather small filter cap of 4.7uF maybe a spot on the schematic so might be 47 uF..... The 4.7 would likely not have held up the SCR current, a 47uF may, and if it didn't, the discharge diode would have let the timing cap contribute, with poor results.....

Apparently I saw SOME of the circuit problems and operation and let it go at that.

dp
10-10-2012, 10:06 PM
Thanks guys. The transistor is S9013 over H 331. I just noticed in the trace pic that one of the transistor pin connections is hidden by the LED but it is connected to the horizontal trace (AC in). Looks like Barrington figured that out already. I've never seen a LED connected across the AC line-out like that. It used to glow noticeably but wasn't very bright. So it's just used as a AC-out indicator which is what it was doing. Smart little LED--It doesn't glow now and there's no AC output. :)

Would I be correct in that since I'm hearing the relay click after the time setting that the relay contacts are toast?

If that is the case then the diode connected to the transistor base is a zener diode as that S9013 is an NPN transistor. You should be able to see line voltage across the out pins come and go as the relay flips on and off. There may also be a fuse (thermal or current) on the heater element that has blown.

CCWKen
10-10-2012, 10:30 PM
The fuse on case was the first thing I checked. It's good and I was able to seal bags manually by bypassing the timer module. I just made jumpers for the connector that would connect to the four pins on the module.

Jay - Yes, there's micro-switch (LS in the diagram) on the arm that turns-on AC to the module. As long as the arm is down, AC would be present at the module input. The timer and relay control when AC is output to the heater. When the timer expires, AC output is dropped but AC input would still be present until the arm is raised. It used to work great. Part of the sealing process is to keep the arm down for a short period to maintain the seal while it cools. This usually takes only a second or two.

darryl
10-10-2012, 10:59 PM
That's a completely different circuit. Regardless, if you're hearing that relay clicking, it should be closing the contacts. If you're not getting a closed circuit through the contacts, the relay is bad. It's unlikely that you would hear the click if, say, it was undervoltaged and wasn't closing all the way. The click is the armature touching the pole cap, in which case the contacts are pushed together as much as they ever would be.

The led in this drawing is completely separate from the relay and timer circuit, so even if the led is bad, there's no effect on the rest of the circuit.

The transistor is a pnp. An npn can't work in that configuration.

CCWKen
10-10-2012, 11:09 PM
I scrounged around and found an eye loop to check component values. Here's what I could see.

http://img.photobucket.com/albums/0903/CCWKen/Module-Comp-SideValues.jpg

dp
10-11-2012, 12:11 AM
That's a completely different circuit. Regardless, if you're hearing that relay clicking, it should be closing the contacts. If you're not getting a closed circuit through the contacts, the relay is bad. It's unlikely that you would hear the click if, say, it was undervoltaged and wasn't closing all the way. The click is the armature touching the pole cap, in which case the contacts are pushed together as much as they ever would be.

The led in this drawing is completely separate from the relay and timer circuit, so even if the led is bad, there's no effect on the rest of the circuit.

The transistor is a pnp. An npn can't work in that configuration.

The data sheet says NPN, and the 5V6 is a zener (5.6Vb) as I suspected. The transistor turns on when the voltage across the capacitor exceeds the zener Vb + the transistor Vbe voltages which energizes the relay. The contacts must therefore be NC.

darryl
10-11-2012, 01:29 AM
According to the last diagram, the dc voltage which is clamped by one of the zeners is fed to the relay coil. The other side of the coil goes to the transistor emitter (a positive voltage). When the dc voltage is initially applied, the capacitor in the base circuit temporarily holds the base voltage low, allowing the transistor to conduct and operate the relay. When the capacitor voltage rises, the transistor is forced to shut off and removes the grounding of the relay terminal. The relay at first sees a voltage across it equal to the dc voltage minus the zener voltage and the base-emitter voltage. That voltage then decays at the same rate the capacitor voltage rises. When the power is removed, the capacitor discharges through the other diode, making the circuit ready to time again.

If there was an npn transistor in there, it would not conduct to ground, but it would conduct through the reverse base-emitter breakdown voltage and the zener voltage and the cap. The entire relay coil current would have to be conducted through this path in order for the relay to operate. The capacitor would have to be a large value to allow the relay to remain on for a long enough time, and it isn't.

But if that is indeed an npn, then it's drawn wrong on the diagram- the emitter should be drawn at the bottom and the collector at the top. And you're right- if that's the case, then the relay contacts are NC.

Barrington
10-11-2012, 05:38 AM
In light of new info, revised diagram:-

http://i564.photobucket.com/albums/ss82/MrBarrington/sealer-2.png

Apologies - I was fixated on the relay having only two contacts - I don't remember the last time I saw an NC only type (i.e. not changeover). That meant the driver had to be pnp, but I must admit I wasn't convinced about the base diode...

The LED will go into reverse breakdown on each cycle but the current is limited to only a very few mA (that's why it's so dim) so it maybe it could last a while...

Cheers

.

J Tiers
10-11-2012, 08:00 AM
I
The LED will go into reverse breakdown on each cycle but the current is limited to only a very few mA (that's why it's so dim) so it maybe it could last a while...

Cheers

.

As I mentioned, it very well could be a bidirectional (AC) type. With 39K in series, ir will receive only 3 mA, which is likely to be dim with nearly any ordinary LED.

example... note the "red, red" option along with the various bicolor types.

Even the inexperienced chinese designers are not THAT stupid.

http://media.digikey.com/pdf/Data%20Sheets/Lite-On%20PDFs/LTL-10CxJ.pdf

Barrington
10-11-2012, 09:02 AM
Even the inexperienced chinese designers are not THAT stupid.
I was a little dubious myself, so I've put an ordinary LED in series with 82k on a 240vac supply, and it's been running fine, admittedly only for some 4 hours so far, but...

Cheers

.

dp
10-11-2012, 12:10 PM
Here's a line drawing of Barrington's schematic:

http://metalworkingathome.com/images/heater-timer.jpg

CCWKen
10-11-2012, 02:40 PM
Man, you guys have your stuff together. Thanks for clearing up (correcting) the original diagram. No wonder I couldn't figure out why the relay was working and LED not. I kept trying to match the parts on the board to the diagram provided with the sealer. I checked the newer version manual online and Grizz is still using the same diagram as originally posted. The only thing different is a few color pictures.

And now the good news. It's working! :) I couldn't sleep thinking about ways of testing the module and various TP voltages. Anyway, I got back up and found a power cord that fit pins 1-2 and set up an insulated work space with my meter at the ready. When I plugged in the cord, the LED came on then went out. I thought; "what the hell". I tried it several times adjusting the time and it appears to work as it should. The only thing I could think of is that during examination for the component part numbers, I moved or slightly rolled the parts. I figured there must have been corrosion, cold joint or loose connections somewhere so I got the soldering iron out and re-touched all the joints. It's still working and I even tapped the module on the desk. I haven't re-installed the module yet but I'll get to that later today after testing it again.

Having a correct diagram sure helps and I can't thank you enough for your trouble and interest in the problem. Thanks guys!

As far as the LED, it looks like a simple, run of the mill, old-fashioned two-pin red LED. I held it up to the light and it has the usual two triangle format. Doesn't seem to be anything special. I have several applications for the same arrangement I've been putting off for lack of powering a LED without a bunch of extra parts or power supply. I'll see how Barrington's test goes.

Once again, Thank You.
Ken

J Tiers
10-11-2012, 07:43 PM
The double LEDs look about the same, and are ordinary 2 pin devices.......

I suppose they can be used as zeners, but it is an "off data sheet" usage, and one would not do it in a unit covered by any commercial warranty...... or perhaps better said, an experienced western designer would not do that..... It's one of those things that works OK for a while, and then inexplicably stops working with a new shipment of parts.

darryl
10-11-2012, 11:22 PM
Kind of like using the reverse breakdown voltage of a base-emitter as a zener. It's a fairly sharp knee, but the transistor will suddenly become noisier and I think the gain suffers from that as well.

Something I noted from the pictures of the pc board, trace side- looks like the last pin to the right has a poor pc connection. Hard to tell from here, but that would be something to take a close look at.

wigglylines
09-08-2013, 09:20 AM
Good Day Gents,
I also have an issue with the timer circuit like CCWKen's circuit and could not equate the schematic from the sealer manual to what is present on the PCB. Thanks to Barrington for the schematic
all now becomes clearer. However I do have a problem. The pot has a value of 220Kohms. Given the capacitor shows to be 4.7 uf this would give times to reach 5.6v for the zener to avalanche of
21 millisecs when the pot is zero ohms+20Kohm and 240 millisecs when pot is at 220Kohm+20Kohm resistor. Clearly this is incorrect therefore the capacitor must be 47uf. However again this gives timings
of 218 millisecs and 2.4 secs respectively. The sealer is specc'd at 1 to 8 seconds hence something must slow down the charge into the capacitor. If I insert a 100Kohm in series with the pot and 20Kohm then the circuit works but the max/min output timings do not equal to 1 to 8 seconds. Can any of you wizards of the web suggest what might be the problem solution? regards from this side of the pond.

Lew Hartswick
09-08-2013, 10:50 AM
This hole thread reminds me of the three blind men telling what an elephant is like while feeling a different
part of the animal. :-)
...lew...

CCWKen
09-08-2013, 02:09 PM
Just as a follow up, mine is still working. :)

Barrington
09-10-2013, 10:19 AM
wigglylines - we never knew the value of the pot !

Questions:-

1: Has the unit ever worked (and with a 1 to 8 second range) ?

2: Is the pot original or might it have been replaced ?

3: You say the timing cap 'must' be 47uF rather than 4.7uF - are the markings not legible ?

4: Can you confirm (or contradict) the other component values ?

5: With the extra 100k in series with the pot, what is the range of timings ?


Cheers

.

wigglylines
09-11-2013, 01:00 PM
wigglylines - we never knew the value of the pot !

Questions:-

1: Has the unit ever worked (and with a 1 to 8 second range) ?

2: Is the pot original or might it have been replaced ?

3: You say the timing cap 'must' be 47uF rather than 4.7uF - are the markings not legible ?

4: Can you confirm (or contradict) the other component values ?

5: With the extra 100k in series with the pot, what is the range of timings ?


Cheers

.

Good Evening Barrington, Good to have you 'on board', this has been giving me a lot of angst and threatens to destroy my long cherished knowledge.

The circuit is exactly like CCWKen's shown earlier from which you produced your 'life saving' drawing, except that the resistor in series with the pot is 27Kohm and the capacitor is 33uf which explains why the 27Kohm has been increased.

1. I wouldn't really know if they have ever worked as they were given to me to figure out why they stopped working. However if I connect a 750Kohm pot then the extended times is approx 6 seconds but the minimum time is still 218 milliseconds through the 27Kohm resistor into 33uf capacitor to reach 5.6 volts for Zener to avalanch.
2. There is no indication that the pot has been swopped. In any case if the pot is at 0 ohms then the only charging resistor will be the 27Kohm one. This will give a minimum time of 207 milliseconds if into a 33uf cap or if it was a 4.7uf cap then it is even worse being 29 milliseconds.
3. The markings are 33uf @ 25v.
4. The components are exactly as CCWKen's except for the 20Kohm which is now 27Kohms. Red,Violet,Black,Red. and the capacitor at 33uf.
5. With the 100K in series, the timings are approx. 1 second and 2.5 seconds give or take a bit for watching second hand on watch.

Either I don't understand the activity going on at the base of transistor or that something must be slowing down the charge at cap.

Sure am looking forward to an explanation! Perhaps I can request CCWKen to open up his module and give me a answer to the value of the pot?


regards..............wigglylines

Barrington
09-11-2013, 03:35 PM
Don't panic! - The laws of physics do not appear to have failed...

User manual:-
http://cdn0.grizzly.com/manuals/h6153_m.pdf

Page 1, Heating time H6153 = 0.2 -> 1.5 sec

Now the max:min time is actually (220+27):27 = 9.15:1, so the max might be nearer 1.8-2.0 sec, but close enough.

Where does the 1 - 8 second spec come from ?

Cheers !

.

wigglylines
09-12-2013, 03:29 AM
Don't panic! - The laws of physics do not appear to have failed...

User manual:-
http://cdn0.grizzly.com/manuals/h6153_m.pdf

Page 1, Heating time H6153 = 0.2 -> 1.5 sec

Now the max:min time is actually (220+27):27 = 9.15:1, so the max might be nearer 1.8-2.0 sec, but close enough.

Where does the 1 - 8 second spec come from ?

Cheers !

.
Well blow me down with a feather.......

I assumed the spec was 1 to 8 seconds by investigating similar new ones on EBAY who's descriptiona are (two examples)


" Supplied with a UK 3 pin plug
Adjustable timer from 1-8 seconds
All are Impulse Sealers are 'CE' Certified.
ABS (durable plastic) Body"

"Quick, efficient heat sealing - create a custom bag in 2 easy steps
Simple to operate - can process up to 100 seals per shift
Our hand sealers seal poly bags and any thermoplastic material such as polyethylene (PE) and polypropylene (PP) quickly and efficiently.
No warm up time is needed.
Materials up to 30cm wide can be sealed.
Adjustable timer from 1-8 seconds
A signal light and "beep" indicates the heat cycle is complete and the seal is done. Once the timer is set, hand sealers will provide a consistently flat seal.
Supplied with UK 3-pin plug"

plus the fact that the escutcheon is marked 1 to 8. So by association I assumed that the sealers were 1 to 8 seconds.

Anyway, sir, you have been a great help to my own ego and as such should you ever visit the U.K. then e-mail me at
wigglylines@hotmail.com and I will treat you to dinner with The Chief Fairy (a.k.a wife) or a pint or two (do you have pints in the U.S.)

best regards

Pepi_ZA
03-08-2017, 01:31 AM
Good day everyone,

Newbie to the forum and noob(ish) at electronics, but I seem to find my way around.

I have a similar impulse sealer with the same circuit as per the diagram found earlier in the thread.
The issue is however now that when one closes the circuit, the sealing wire heats up and seals the bags, but it does not automatically switch off as before. Could someone point me in the direction of the specific component(s) I need to replace? I have tried to test the components individually with a multimeter, but no luck on finding something obvious.

Thank you in advance!