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Jackal66
03-16-2008, 08:33 PM
Hello,
I have a 1976-198? Hobart cyber tig. It has been a great welder, but today it all of a sudden started running wide open. If you are TIG OR STICK WELDING it won't go down . No matter what the control is on. I have checked the remote pedal, tried to run it non-remote on the panel settings.

The Hobart book for it says that: It is either the pickup coils, or the SCR gater circuit. I checked the connections on both of them from the manual and it wasn't anything visibly wrong.

Before calling a repair person, does anyone on here have any suggestions? This is my main money machine right now. It may be 2 weeks before I use it, or it could be every night for a month.

Let me know,

Thanks in advance,
JAckal

tadream
04-01-2008, 09:06 AM
Hello,
I have a 1976-198? Hobart cyber tig. It has been a great welder, but today it all of a sudden started running wide open. If you are TIG OR STICK WELDING it won't go down . No matter what the control is on. I have checked the remote pedal, tried to run it non-remote on the panel settings.

The Hobart book for it says that: It is either the pickup coils, or the SCR gater circuit. I checked the connections on both of them from the manual and it wasn't anything visibly wrong.

Before calling a repair person, does anyone on here have any suggestions? This is my main money machine right now. It may be 2 weeks before I use it, or it could be every night for a month.

Let me know,

Thanks in advance,
JAckal

I guess it's obvious that I've not checked in on the board for a while, seeing the date the original message was posted, so I hope this isn't too late. That machine is WAY out of support these days, but if you've got the book you are ahead of the game (and better off than me). It's not a model that I'm very familiar with, but they all work the same. 95% of the time you won't see anything visible with the circuit. It should have SCR's, a control board for them, a panel pot, foot pedal pot, and a standard/remote switch. It's very unlikely that the switch or either pot is bad, as those will ALMOST always result in MINIMUM output, not maximum. The most likely culprit is the control board (not likely to find one) second most likely is shorted SCRs. (can be found at any REAL electronics store). If it's not already too late, I'll be happy to see if I can help you figure it out, either on or off list. If you do need help with it, sending a copy of the schematic will be a huge help. BTW, I left out one distinct possibility: there should be some sort of current sensor (probably a shunt) on or near the output studs. If the two small wires from this are broken, etc. it would cause this symptom. LMK if I can assist.
Jim

Jackal66
04-01-2008, 09:06 PM
Hello Jim,

Thanks for the reply. I just got the board back from Innovat in Virginia. It was sent to them a week ago with a rush premium payment. Monday the
31st it arrived here and it still doesn't work. I guess from the maintenance manual it says to check the pick up coils but doesn't give a ohm's reading for them.

Are these pick-up coils the same as the shunt coils you are referring to? They are the size of standard glazed donut, and have the output leads running through them before the leads go to the output posts. These coils are wrapped in elec. fiberglass and dipped in varnish. Approx 3 small wires coming out of each.

I will take some pics to show you.

The "gater" board that I sent off, is the main circuit board. There are a few small board in various locations with a few resistors ,etc.

I am kind-of lost on the SCR's. I see some diodes ( I believe ) up in the top on a heat sink type of mount, and some more on the bottom behind the output posts.

I'll take some pics to show you. With a little help on the understanding I should be able to fix it.

Thanks a lot,

You responded at the right time.

Jack

tadream
04-04-2008, 09:08 AM
Jack, read your reply yesterday, but didn't have time to respond (been busy - 2 jobs). Okay, the donuts sound like current transformers which would do the same job as an actual shunt. Not what I would expect, but if the cables to the studs go through them then that's about all they could be. Can't figure why there's more than one unless they are using separate ones for the board and meters. (this is where the schematic would really come in handy for me.) Anyway, they typically only have two wires, but more than likely you won't find a published resistance spec on them. It would be very low anyway. Important test #1: they should have continuity. Disconnect them to make sure you aren't reading anything else. They must have good connection to wherever they are going. Test #2: when you are drawing current out of the machine, they should be putting out some voltage. It won't be very high though. Old shunts typically put out 50mV at full meter deflection, and modern current sensors are typically 1 volt per hundred amps. Not sure what those would do, but I am sure if the one going to the board puts out NOTHING when you have an arc struck, then your machine will try to put out it's max or close to it. Also, if your meter is working, and one goes to it, and they look identical, you might try swapping them and see if that does it for you. As far as the rest of it, I've dealt with Innovat before and they do good work, so for now, I'd trust the board. Check the pot on the front panel. You should have some DC voltage from end to end on it, and a varying voltage between the center and either end as you adjust it. Trace the wires back to the board and make sure you get the same readings there. The SCRs should be mounted in the heat-sinks you referred to before. They stud type look like a large diode, except for they have two small wires coming out of them, (one red, one white) which should go to the board. Disconnect the "pigtail" and check from it to the stud, and make sure there's no short on them. If all of those things check good, then you are likely down to that feedback circuit. Essentially, the pot tells the board how much current you are asking for, and controls the gate timing of the SCRs to put that out. The feedback transformers/shunts, send a voltage to the board telling it what actual output is, and it then regulates up or down so that actual matches what you ask for. If there is no feedback, the board "thinks" it is zero and turns everything wide open. That's why I think they are most likely at this point. Hope this helps, keep me posted, and LMK if you need any deeper looking. Try to see if that schematic is scanable too, as that will make it easier for me too. Good luck!

Jackal66
04-05-2008, 04:24 PM
Hello Jim,

I have both of the manuals for the Welder on PDF. Adobe acrobat file. IF I could get your email through a personal messsage or something I can send these to you. Then it might be easier for you to Zoom-in on certain areas of the schematic.

The pickup coils are wired in series so both of them have to work to get continuity. They have a jumper wire connecting them. My guess is 1) is for the current limiting. The 2)nd coil is for the high frequency on start only or the "Hot start" circuit. I couldn't get any voltage from the coils at the boards connections while welding. ( It may have been so minimal that my digital meter wasn't picking it up)

The potientiometer checked out o.k.

The SCR's checked strange. I disconnected the small 18ga? wire pigtails both red and white and they both showed full continuity to the mounting stud, as well as each other.

I did not disconnect the large 4 ga. red wire while doing the test.

My testing may not tell you anything.

I sure do thank you for the help.

Thanks,
Jack


PS send me your email and I will send you both manuals they are 3 Mb total.

kirk_wallace
05-23-2008, 02:30 PM
Jackal66, I hope your welder is getting better.

I am also having trouble with my Cyber-TIG 300 (w/ model 120 controller). I get plenty of voltage but it won't produce any current. The gater board was listed as something to check. If you have a known good spare gater, I may be interested in buying it. I have a thread going on HobartWelders.com here:

http://www.hobartwelders.com/weldtalk/showthread.php?t=30405

Kirk, http://www.wallacecompany.com/machine_shop/

ALBERT HUFFMAN
08-24-2008, 09:56 PM
Hello Jim,

I have both of the manuals for the Welder on PDF. Adobe acrobat file. IF I could get your email through a personal messsage or something I can send these to you. Then it might be easier for you to Zoom-in on certain areas of the schematic.

The pickup coils are wired in series so both of them have to work to get continuity. They have a jumper wire connecting them. My guess is 1) is for the current limiting. The 2)nd coil is for the high frequency on start only or the "Hot start" circuit. I couldn't get any voltage from the coils at the boards connections while welding. ( It may have been so minimal that my digital meter wasn't picking it up)

The potientiometer checked out o.k.

The SCR's checked strange. I disconnected the small 18ga? wire pigtails both red and white and they both showed full continuity to the mounting stud, as well as each other.

I did not disconnect the large 4 ga. red wire while doing the test.

My testing may not tell you anything.

I sure do thank you for the help.

Thanks,
Jack


PS send me your email and I will send you both manuals they are 3 Mb total.

Hello i was wondering if you could send the pdf files on the welder i just bought one and they have no paper work thanks AL. Here is email address judyh1@frontiernet.net

Hillbillyvette
03-01-2009, 07:33 PM
Hello Jim,

I have both of the manuals for the Welder on PDF. Adobe acrobat file. IF I could get your email through a personal messsage or something I can send these to you. Then it might be easier for you to Zoom-in on certain areas of the schematic.

The pickup coils are wired in series so both of them have to work to get continuity. They have a jumper wire connecting them. My guess is 1) is for the current limiting. The 2)nd coil is for the high frequency on start only or the "Hot start" circuit. I couldn't get any voltage from the coils at the boards connections while welding. ( It may have been so minimal that my digital meter wasn't picking it up)

The potientiometer checked out o.k.

The SCR's checked strange. I disconnected the small 18ga? wire pigtails both red and white and they both showed full continuity to the mounting stud, as well as each other.

I did not disconnect the large 4 ga. red wire while doing the test.

My testing may not tell you anything.

I sure do thank you for the help.

Thanks,
Jack


PS send me your email and I will send you both manuals they are 3 Mb total.

Hello I am also in need of a manual for my 1970 cyber tig 300. Would you please email me the pdf? I would be in your dedt. Thanks . My email is WHUDDLE@CHARTER.NET

kiroshi
07-28-2009, 08:39 PM
Originally Posted by Jackal66 View Post

" Hello Jim,

I have both of the manuals for the Welder on PDF. Adobe acrobat file. IF I could get your email through a personal messsage or something I can send these to you. Then it might be easier for you to Zoom-in on certain areas of the schematic.

The pickup coils are wired in series so both of them have to work to get continuity. They have a jumper wire connecting them. My guess is 1) is for the current limiting. The 2)nd coil is for the high frequency on start only or the "Hot start" circuit. I couldn't get any voltage from the coils at the boards connections while welding. ( It may have been so minimal that my digital meter wasn't picking it up)

The potientiometer checked out o.k.

The SCR's checked strange. I disconnected the small 18ga? wire pigtails both red and white and they both showed full continuity to the mounting stud, as well as each other.

I did not disconnect the large 4 ga. red wire while doing the test.

My testing may not tell you anything.

I sure do thank you for the help.

Thanks,
Jack


PS send me your email and I will send you both manuals they are 3 Mb total."

Hi, im Julian from colombia, some company Hired me to Renew some of this CYBERTIG 120 series machines, my work, most of all, was to reverse-engineer the SCR´r Controller card (HOBART 362732) and turn it to a modern Devices capeable Card, so i did it, i found what devices use to replace the old ones, diodes, Rectifier bridges and the card works pretty well (actually i found wich devices can be modified on the card to improve the power, but off course that shortens the SCR´s life -and its a very difficult part to find-, this card works pretty well on the operative machines on that company.

now, the same company has another machine wich is incomplete, they have the main SCR´s. the power transformers and most of it, they need the SCR´s controller card -wich they already paid me for- and the Control panel (HOBART 362830-3) wich has a few electronic Parts more, and the principal Voltage and current Pot´s.

im having some troubles with this Control panel, cause has a mess of Cables. i was thinking you (Jack off course) to send me the PDF manuals, please!!, my email is juliankaus@hotmail.com.


If you, or anyone else need the Schematics and references from the HOBART 362732 Controller card i would gladly share them with you, just mail me and ask for them, i also have ready to transfer PCB´ layouts, Netlists, component lists and Pictures -i would charge a small simbolic Paypal fee for this last items-.

thanks for your help, and im available if someone needs mine,

greetings, Julian.

jimr1946
05-30-2010, 10:04 PM
Originally Posted by Jackal66 View Post

" Hello Jim,

I have both of the manuals for the Welder on PDF. Adobe acrobat file. IF I could get your email through a personal messsage or something I can send these to you. Then it might be easier for you to Zoom-in on certain areas of the schematic.

The pickup coils are wired in series so both of them have to work to get continuity. They have a jumper wire connecting them. My guess is 1) is for the current limiting. The 2)nd coil is for the high frequency on start only or the "Hot start" circuit. I couldn't get any voltage from the coils at the boards connections while welding. ( It may have been so minimal that my digital meter wasn't picking it up)

The potientiometer checked out o.k.

The SCR's checked strange. I disconnected the small 18ga? wire pigtails both red and white and they both showed full continuity to the mounting stud, as well as each other.

I did not disconnect the large 4 ga. red wire while doing the test.

My testing may not tell you anything.

I sure do thank you for the help.

Thanks,
Jack


PS send me your email and I will send you both manuals they are 3 Mb total."

Hi, im Julian from colombia, some company Hired me to Renew some of this CYBERTIG 120 series machines, my work, most of all, was to reverse-engineer the SCR´r Controller card (HOBART 362732) and turn it to a modern Devices capeable Card, so i did it, i found what devices use to replace the old ones, diodes, Rectifier bridges and the card works pretty well (actually i found wich devices can be modified on the card to improve the power, but off course that shortens the SCR´s life -and its a very difficult part to find-, this card works pretty well on the operative machines on that company.

now, the same company has another machine wich is incomplete, they have the main SCR´s. the power transformers and most of it, they need the SCR´s controller card -wich they already paid me for- and the Control panel (HOBART 362830-3) wich has a few electronic Parts more, and the principal Voltage and current Pot´s.

im having some troubles with this Control panel, cause has a mess of Cables. i was thinking you (Jack off course) to send me the PDF manuals, please!!, my email is juliankaus@hotmail.com.


If you, or anyone else need the Schematics and references from the HOBART 362732 Controller card i would gladly share them with you, just mail me and ask for them, i also have ready to transfer PCB´ layouts, Netlists, component lists and Pictures -i would charge a small simbolic Paypal fee for this last items-.

thanks for your help, and im available if someone needs mine,

greetings, Julian.

I hate to barge in however I saw that you had the manuals and electrical drawings. I jsut bought a Holbart Cyber Tig II I am not sure if it works or not I sure would like to have any infor that you have incase it does not work. I know I need a torch for sure he has the foot switch but that is all I paid 325.00 for the unit he said it worked 4 years back is that too much to pay thanks for any help you can give. Jim

dbman
06-29-2010, 07:34 PM
I hate to barge in however I saw that you had the manuals and electrical drawings. I jsut bought a Holbart Cyber Tig II I am not sure if it works or not I sure would like to have any infor that you have incase it does not work. I know I need a torch for sure he has the foot switch but that is all I paid 325.00 for the unit he said it worked 4 years back is that too much to pay thanks for any help you can give. Jim
Hi,

I have not posted to this group before and it looks to have pretty good info on it.

I have a Hobart Cyber-TIG 120 (300Amp) Welder. I looking for a Schematic and Manual for it.

Thanks for the help.