Trouble with THC voltage

[barnfabmetalworks]

Hey Everyone,
I'm having issues with my THC voltage on my Powermax 85. I've got a StarLabs 5 by 10 table with CandCNC controls on it. I Had some issues with my DTHC IV card with loss of the 5volts DC to run the PWM for the hypertherm 2 weeks ago. After sending it back to CandCNC and having it repaired, I got it hooked up today and it now works but now I'm not getting any voltage from the hypertherm. I can push the test button on the PWM switch and get 125 volt read out (which I couldn't get before the repair) but it stays at 0 on Mach when I run my plasma. Any help or suggestions would be greatly appreciated!

Walter,

[BTA Plasma]

Walter if you want us to service this directly you should let us know. If you are not getting any voltage from the Hypertherm chances are you cable from PWM to hypertherm is bad OR your jack is not plugged in all the way.

[tcaudle]

You can measure the volts coming OUT of the Hypertherm on the plug of the Stereo cable (part of the MIC-01 cable) . Pull the pulg and use a DVm and measure from the tip (+) to the next ring (-) . Fire the torch in the air and you should see about 3.2VDC . Also check the voltage divider option jumper on the PWM. they go out set to the lowest value 7:1) since hooking one up set to 50:1 on a unit with our RAV voltage divider could put to much voltage in and damage the input circuit. Having it set to 7:1 and have the Hypertherm on 50:1 would result in about 14 volts showing at the screen instead of 130

[jimcolt]

Thanks guys....you beat me to it! Jim Hypertherm

[barnfabmetalworks]

Hey guys,
Well I had checked out my voltage coming of the plasma and nothing, so dropped it at the local welding repair place for Hypertherm and it turned out that the board had also gone bad on my PM85. Well just got it hooked back up this week and no read out from my DTHC IV card, seemed to loose the voltage that supplies the PWM since the test button wouldn't do anything along with trying a different PWM and cable. Talked to CandCNC and they are sending me another one. Any thoughts to what could have damaged these cards. I have the table on its own ground rod separate from the building ground. I also unplug every thing whenever I leave my shop, and I've never had the plasma or table hooked up during a thunderstorm.
Thanks for your input!
Walter,

[acourtjester]

Remember seeing those bumper sticker "s*** happens" somethings happen for a reason and other are just the luck of the draw.
Retired from Electronics install and repair on main frame computer, to Medical diagnostic equipment ( CAT and MRI Scanners).
You never know when things will fail, some never do, like everything else you just live with what comes your way

[motoguy]

Just went through the dead hub/bad DTHC IV card/dead voltage divider/main board on my PM85 as well. Same deal...always physically unplug all components during inclement weather, etc.l

My PM85 is still under warranty, but nobody in state could look at it for a month. Divider board is around $150, main board is $800+. I'd buy the divider board outright if I could get it fixed quickly, but I don't want to gamble on the expensive main board.

I ended up just buying/installing a RAV-02 board from CandCNC, and installing it in my PM85. The HT techs actually recommended this, and assured me (after I asked repeatedly) that the addition of the 3rd party card will not affect the warranty on the unit. Talking to the 2 Hypertherm techs, Hypertherm thinks CandCNC controls are wiping out Hypertherm boards. They claim equal odds on it being the divider board, main board, or both.
CandCNC claims they've gone round and round with Hypertherm about this, and (according to CandCNC) HT agrees the CandCNC circuit should not be causing problems.

For some reason or another, Powermax units under CandCNC controls seem to be killing divider boards/main boards, though. Perhaps the PM units are having this issue across the board, with other controls too. Maybe it just seems like a lot of CandCNC/PM failures, because there are so many CandCNC controls out there. I'm curious how often they take a PWM/DTHC board/hub with them (or vice versa). We never did figure out the culprit on mine... I bought a new hub (once it arrived we determined I had DTHC IV board issues), had my original hub replaced under warranty, and just upgraded to Linux since the box had to go back for DTHC IV card testing/repair/replacement anyway.

At this point I've got a (less than) 2 year old PM85, still under warranty, which I can't get repaired in less than a month or two. I guess I could ship it out of state, but that leaves the choice of an additional 2 weeks (at least) of downtime, or $500 overnight/$300 2-day shipping each way. Or find an out of state repair shop than can fix it quickly, and take it to them.

As such, I've had to cobble a workaround (mounting RAV-02 board in the PM85 case) so I can keep working. At least one other HT owner had the same problem. He said he bought a new PM85, and sold his old one after the warranty repair. :/ I don't have an extra $4k lying around for that option.

[barnfabmetalworks]

That pretty much sums up to the T what is going on with mine Motoguy. Every part ends up being 2 weeks of down time. If this was my full time job I'd have to buy 2 machines to keep running. How are you liking your linux upgrade so far, and has the RAV-02 been holding up? That seems like a lot cheaper part to keep on hand then the hypertherm stuff, especially if the warranty is out!
Thanks,
Walter

[motoguy]

And another one...

https://m.facebook.com/groups/264356800 ... 6125431340

[motoguy]

That pretty much sums up to the T what is going on with mine Motoguy. Every part ends up being 2 weeks of down time. If this was my full time job I'd have to buy 2 machines to keep running. How are you liking your linux upgrade so far, and has the RAV-02 been holding up? That seems like a lot cheaper part to keep on hand then the hypertherm stuff, especially if the warranty is out!
Thanks,
Walter

RAV-02 card is holding up fine, but it's only days old at this point. Mounting location / wiring routing was the biggest hassle with it (and not a terribly large hassle).

So far I'm really liking the Linux setup. The first day I tried to cut with it (after installing the RAV-02 board) was quite frustrating. I kept crashing the torch and blowing out nozzles. I was very anxious to watch the VAD do it's thing, and eliminate Sheetcam cut rules. VAD just wasn't responding, though. Eventually we determined that my DTHC IV card was overlooked during the upgrade, and my original Rev 1 board does not work with VAD. CandCNC shipped a replacement board yesterday. In the mean time, I'm using cut rules in Sheetcam. Lol

The touch off sequence in Linux is awesome. After being used to the Mach touch off, pause, etc...Linux is blink-of-an-eye fast!

It's still a bit weird to watch Linux cut. It seems more "jerky" than Mach. I think this is due to the (improved) line tracking in Linux. Mach would sacrifice line tracking (rounding off corners, etc) to maintain feed rate. As such, it spent more time near programmed feed rate...it would occasionally just butcher your cut path to do it!

Linux, on the other hand, sacrifices feed rate to maintain line tracking (ie, stays on the designed path better). This leads to a lot more slowing down/speeding up than Mach did. Since I'm used to Mach, this constant change of speed is perceived as "jerky" motion, but it really isn't. The ability to hold true to the programmed cut path, without the machine shuddering, divot producing byproducts of "direct stop" (or whatever it was called) is awesome.

And no more "ports and pins" menu surfing to reset a d E-stop! Hallelujah! Lol Linux is a single button right there in the CommandCNC window. I LOVE THIS!

[tcaudle]

From our perspective the "epidemic" of Hypwertherm divider failures is overstated. When this first started over three years ago we have worked directly with Hypertherm Enginnering (not tech support) and asked them to analyze our circuit and to give us any scenario where our high impedance circuit could cause a failure. The answer was that they say nothing that could cause the failure of an internal voltage divider. The PWM runs on a floating, overload protected, 12V supply that can only supply about 300 ma max. The input impedance at 50:1 (load it puts on the divided voltage line) is over 1 meg ohm. In virtually every case there is no damage to the PWM module, so a bigger question is how can an event occur that damages the internal divider yet leaves the PWM sensitive input circuit unscathed? Even more of a question is that most often its NOT the secondary voltage divider card but the primary divider/filter on the main PCB that fails. That should isolate it even further from any external influence. The numbers we see compared to the total installed base are rather low but from a Hypertherm perspective we represent a higher percentage of units that use the internal divided volts. A lot of other vendors still use another voltage access methods. so the internal divider is not used.
Let me offer this: If you have one of our units that has been working with the internal voltage divider on a Hypertherm and you suffer a divider failure contact us and we will make the RAV-02 divider card available to you at a reduced price. We have never had a case of a failure of the RAV-02 in any Powermax Hypertherm.

[barnfabmetalworks]

Thank you motoguy Sounds like it works pretty awesome, have you tried cutting detailed cuts in thin gauge? On Mach it seems to pause in corners bad and then dive down into the part for me.
Thank you for the response tcaudle, I would be very interested in giving RAV-02 a try. Warranty will cover my hypertherm for another 2 year but I would rather go the rout where no one has to repair anything and I keep on making parts. Do you have a plug and play setup for a PM85 or would I Need to do some wire splicing?

[motoguy]

Tom, Could the below routing of the divider card wiring between the leads be causing an issue? The photo with the red lines is a different user. He found the wiring suspect, and wanted to see if it was standard wiring. The two photos without the red lines are from my PM85, which suffered divider board/main board (unsure which, haven't had to warranty center yet) failure.

[barnfabmetalworks]

Just got my dthc IV and plugged it in (not hooked to plasma just pwm) and I get 125 with the test switch but after turning the test off I get 206 volts? I tried a different cable and I had a different pwm I tried but if I hit the test it will go between 125 and 206. Kinda afraid of hooking up the plasma to it. Any thoughts?
Thanks Walter

[motoguy]

According to the folks at CandCNC, when mine was showing 224/226/whatever volts, that's a sign of an open circuit with NO input. Ie, if the plasma is not hooked to the PWM, and the PWM is hooked to the DTHCIV card, the display will be 2xx volts. Have you hooked it up to the plasma, without firing the plasma? I suspect if you hook it to the (assuming repaired/properly functioning) plasma, it'll read closer to 0v.

[t-tracks]

its been 2 years of you guys using the rav-02, my divider went out on my hyp65 also with candcnc bladerunner, i ordered the rav-02 card to install in my unit but want to see how all u guys are making out with yours.

[tcaudle]

One advantage of the RAV-02 is it has an on-board balanced twin LC filter network for trapping out added noise . You don't give up anything as far as response or accuracy and its a pretty hardy circuit with both input and output overvoltage protection Its lower divide ratio offers much higher immunity from external noise. A standard 50:1 can be effected from only .05 volts of external noise whereas the RAV-02 makes that over .35 volts

[motoguy]

HT ended up replacing my PM85, due to constant 0-30 errors. Not wanting to risk the OEM boards in the HT, I moved my RAV-02 over to the new unit (and bypassed using the HT boards). The RAV-02 has worked flawlessly in both units.

[t-tracks]

and now with ur new unit u dont get 0-30 misfire? i have one about every 15min. and then more often as unit warms up. my rav02 shows up tomorrow.

[t-tracks]

and just to verify this is where we hook up wires for rav02 an also where did u mount yours inside the unit. i plan to just have the one phone jack cable run from the plasma unit to the pwm and use the cpu conector on back of plasma unit for the arc ok an start torch. also with the rav02 do i just need to hook up the 2 wires if i still use the rear plug on my unit for arc ok am torch fire