Plasma Cutter Advice

[bsmith]

I have a 1997 Thermal Dynamics PakMaster 100XL that just died on me. My nearest service center for TD (BOTCO) says these two circuit boards appear dead,
Part 9-7601 pcb assembly logic control $540
Part 9-7604 diode bridge 3 phase with server $392
and that with labor the repair would be around $1,200
I held off the repair because a new TD Cutmaster 100XL can be bought from CyberWeld for $2055. BOTCO, my LWS, wants $3,000 for a new TD 100XL
I need a powerful plasma cutter about once a month to cut stuff like 1" T1 steel. My usage is fairly low and I hate to have to spend another two grand to get back to where I was before. Wish I could fix the one I had for no more than $800, or is even that too much to throw at a 10 year old unit?
Should I,

1) Try to obtain the circuit boards cheaper elsewhere and take my chances installing them myself and if this is wise where would I buy these boards at the best price?

2) Try to find another repair facility that would do everything needed at a price $800 or below. Tell me if you know of such a place.

3) Forget about fixing the old TD PakMaster 100XL unit because the newer model equivalents in TD and other brands are so much better and just buy a new unit

What do you guys think?

[Rvannatta]

I have a 1997 Thermal Dynamics PakMaster 100XL that just died on me. My nearest service center for TD (BOTCO) says these two circuit boards appear dead,
Part 9-7601 pcb assembly logic control $540
Part 9-7604 diode bridge 3 phase with server $392
and that with labor the repair would be around $1,200
I held off the repair because a new TD Cutmaster 100XL can be bought from CyberWeld for $2055. BOTCO, my LWS, wants $3,000 for a new TD 100XL
I need a powerful plasma cutter about once a month to cut stuff like 1" T1 steel. My usage is fairly low and I hate to have to spend another two grand to get back to where I was before. Wish I could fix the one I had for no more than $800, or is even that too much to throw at a 10 year old unit?
Should I,

1) Try to obtain the circuit boards cheaper elsewhere and take my chances installing them myself and if this is wise where would I buy these boards at the best price?

2) Try to find another repair facility that would do everything needed at a price $800 or below. Tell me if you know of such a place.

3) Forget about fixing the old TD PakMaster 100XL unit because the newer model equivalents in TD and other brands are so much better and just buy a new unit

What do you guys think?

Looks to me like it is time to dump that one. when circuit boards are failing 2 at a time, its time to move on.

I have a good sized plasma which I've had for a year now, but certainly don't have enough information to judge which brands are best (if indeed some are better than others).

[cruizer]

Well, if you lost your bridge, then how would your depot know if the logic board was blown, unless they stuck another bridge in to test it, and they wouldn't do that for fear of taking out another bridge.

Now if your bridge is indeed blown, you'd either be running on single phase , or you'd be blowing a breaker every time you started the machine up.

What was it doing before you took the unit in for repair?

T-dyne Tech

[bsmith]

The machine is setup for single phase power. That was a feature I was looking for in a high capacity machine. The machine was not tripping a breaker. It would power up with a fan running, but it would not start an arc. The technician made his judgment on the status of the boards merely by inspection of them. I have not taken them back out of the machine to see for myself, but he said there was enough black marks to indicate blown boards.

[Rvannatta]

The machine is setup for single phase power. That was a feature I was looking for in a high capacity machine. The machine was not tripping a breaker. It would power up with a fan running, but it would not start an arc. The technician made his judgment on the status of the boards merely by inspection of them. I have not taken them back out of the machine to see for myself, but he said there was enough black marks to indicate blown boards.

a 100 amp machine is one heck of a machine to run on 1 phase. You must blink the lights have way back to the generation plant.

[cruizer]

What was the ac power light doing, was it / or is it blinking after around 8 seconds or a steady light after this time frame?.

I'd think about taking the unit somewhere else for another inspection. Can't see the bridge being blown and still actually powering up in single phase. Logic board maybe, I've had traces blow, easy fix for a repair shop.

I'd really like to know what the AC indicator was doing and if the temp light was on.

I've repaired many machines that another repair shop deemed them to have failed.

[Glenn B]

There is a place that rebuilds circuit boards for welders they may have them for plasmas They usually just exchange them for a rebuilt one if they have it. they are about 1/3 to 1/2 what a new one costs. I dont know if you want to put that much money into what you have. I can look up their phone# for you monday if you want it.

[cruizer]

Actually its a 70 amp machine 40% duty

[bsmith]

Cruizer, I believe the light just stays on solid with no blinking. I will test it again tommorow. GlennB, yes, please post a phone number for the company that rebuilds boards. That's good to know for other things besides my plasma cutter problem. Thanks guys for your thoughts on this problem.

[bsmith]

Cruizer, one of my guys has the unit right now and when he picked it up from Botco it was not completely reassembled so he didn't want to try powering it up until he brought it back to my ranch on Monday to let me put it back together. But he said that when he was at Botco showing the problem, the cooling fan was definitely running and he thinks the indicator light was on solid with no period of blinking but he is not completely sure of that.

Do you think it would be worthwhile shipping the unit to you for repair? Sounds like it might be because there is a good chance both boards are not actually bad. But if the two boards are bad as guessed by the Botco tech, would the costs be as high as they quoted or could you save me enough money to make it worth fixing this thing?

[Rvannatta]

Actually its a 70 amp machine 40% duty

I hadn't figured out it was that light a machine. Red and blue rate themselves for output at 60% duty I believe. I have suspected that some of these cutters were 10 lbs in a 5 lb bag and maybe that is why it melted itself down.

[cruizer]

Cruizer, one of my guys has the unit right now and when he picked it up from Botco it was not completely reassembled so he didn't want to try powering it up until he brought it back to my ranch on Monday to let me put it back together. But he said that when he was at Botco showing the problem, the cooling fan was definitely running and he thinks the indicator light was on solid with no period of blinking but he is not completely sure of that.

Do you think it would be worthwhile shipping the unit to you for repair? Sounds like it might be because there is a good chance both boards are not actually bad. But if the two boards are bad as guessed by the Botco tech, would the costs be as high as they quoted or could you save me enough money to make it worth fixing this thing?

Your repair shop is guessing, If a bridge is blown, the input board would roast itself.

If the unit powers up, ie, senses the power, AC blinks for 6-8 seconds, you hear a click inside the machine and then goes to a solid colour. It ain't the bridge. If the temp light cpmes on, at the same time, the logic board is probably hooped. Hover if you hear the click, the AC light is lit solid, and no Temp light on, You have gun problems, an easy fix.

[bsmith]

This is a followup post that might help someone else in a future similar situation. Cruizer explained to me in a PM that little used plasma cutters rarely fail to the catostrophic degree that my LWS said had happened. Black marks on circuit boards that transmit a lot of power are not uncommon and that visual cue alone is not enough to condemn two expensive circuit boards. After speaking with the authorized local service tech, I realized that his knowledge was subpar on the unit in question although he was saying that he was sure that two major boards were bad on the unit and that it was not worth fixing.

So I called the Thermal Dynamics factory to see if I could send the unit in myself for evaluation and possible repair. They don't normally allow that as you have to work through an authorized distributor. Finally, I convinced them to let me ship the unit directly to them and just take my chances that it was economically repairable. Well, lo and behold, there were no bad boards on the unit. The problem was a shorted torch and a bad internal relay switch. The factory was able to repair and ship the unit back to me in perfect working order for $560.

The LWS apologized for the wrong diagnosis of their tech and refunded the $70 they had me pay for the diagnosis that almost made me discard the unit. The moral of this story is sometimes it is worthwhile to challenge the accurracy of a local tech's diagnosis and take the chance on sending a unit to the factory for final evaluation.

I am sure that in most cases across the country certified tech's are mostly correct in their initial assessments. But by getting second opinions as I did from this board, there was enough doubt raised to warrant the bet of paying to ship a 75lb item across the country on the chance it was actually repairable at reasonable cost. Many thanks to Cruizer for encouraging me to investigate further. $560 is not exactly a cheap repair but it is alot less than the $2,500 my LWS offered on selling me a new unit of the exact same model.
Bill Smith

[cruizer]

You mean I was actually right????

Well, after 16 years of troubleshooting, sometimes I know what I'm talking about.

It's great you got things worked out!