Dynasty 350 ... dead

[arvidj]

Years ago I purchased a new Dynasty 350, SN# LJ030801L. I used it a couple of times and then life intervened and it has been sitting in my heated Minnesota garage, plugged in but turned off, for at least two, very likely more, years.

Yesterday I actually wanted to use it so I turned it on, expecting it to come to life exactly as it was when I last used it. Regretfully absolutely nothing happened. The display did not come on nor did the chiller or any other signs of life.

I did check to ensure there was single phase power at the outlet. I plugged the Lincoln Power Mig 300 [also unused for several years] and it came to life without any problems. I then plugged the ESAB 875 plasma cutter [you guessed it, unused for several years] in and the power light came on.

Concluding that the outlet was good I removed the cover from the Dynasty 350 and measured the voltage from the black to the white wire on the outlet side of the switch on the back of the 350 with it turned off. About 245 volts ... what I had expected. Also as expected there was no voltage on the welder side of the turned-off switch.

I then turned the switch on and read the expected 245 volts on the welder side of the switch and followed the cables down what I believe to be called the "power module" and measured the same voltage at the end of the cables, suggesting the "power module" has input.

Based on the total lack of activity from any part of the machine I speculate that over time the "power module" has converted itself [for reasons totally beyond my imagination as 'sitting unused in the garage' should not have provided incentive to convert anything] into simply "a module", lacking the all important 'power' adjective.

At this point I stopped because I ran out of knowledge about what to test next.

Given that it was running fine when it was shut off several years ago I did not expect this behavior. Yesterdays intent was to fix something else, not the welder. I'm in the act of booking a trip to Frustration City.

Any suggestions on "next steps" would be appreciated.

Arvid

[sledsports]

Being that it has been plugged in all that time it would be "my guess" that its been hit by lightning. Cruizer would be able to fix it.

[arvidj]

Being that it has been plugged in all that time it would be "my guess" that its been hit by lightning.

Thanks for making a guess but I do not think lightning is the issue.

The switch on the back was off which isolates both hot leads from the breaker box. The neutral is not connected at the plug, which leaves only the ground physically connected to the breaker box.

I made a 25 foot 6 gauge uber extension cord that has a 50 amp plug on one end and three 50 amp sockets and two 30 amp sockets on the other end. All three devices were plugged into the extension cord. All have been turned off for several years yet only the Dynasty seems to have issues. Also nothing else in a house full of electronics [I develop software for a living and the term 'multiple PC' fits well] have had any issues in the last 20 years. I did have a surge suppressor give up its life about 25 years ago, but that was a errant city utilities backhoe and not lightning.

As you suggest, hopefully Cruizer can offer some insight into what to check next.

Thanks,
Arvid

[cruizer]

Pretty darn tough not to have any display, though not near my company display so have to wait till Monday, by the way "technically" once you turned the switch to on with power in place, you would have never have gotten 245

[arvidj]

... by the way "technically" once you turned the switch to on with power in place, you would have never have gotten 245

I don't understand this statement.

With the switch off, when I measure the voltage between the black and the white wires on the back of the switch I get the expected 240 volts. When I measure the voltage on the terminals on the opposite side of the switch [all three have black wires so it is difficult to describe distinction other than 'directly across the back of the switch from the black and white wires] I get nothing. This is expected as the switch if off.

When I turn the switch on I still get the 240 between the black and white wires and now get the expected [the switch is on] between the previously 0 black and black wires. This is what I expected given that the switch is on.

I then followed the two black and black wires down to the power module and measured 240 between the terminals on the power module. This suggests to me that the switch and wires are working correctly ... i.e. switch not defective and wires not open.

I appear to be missing something if I am not to expect 240 volts across what appear to be the input terminals of the power module.

Thanks,
Arvid

[cruizer]

And your serial # is? There is no block other than the filter (CE only), wires run straight to A1,A2,A3 on the side input/output board. Should be a1 - black, a2 white, a3 red

On the switch top to bottom will be black. white, red. problem I m having is if that board is smoked, the orange caps beside the inputs will be smoked. and smoke will be rizing from it as soon as you put power to it so we know the mods/interconnect are ok

It may be that PC5 is damaged or molex plugs on it are loose or corroded, maybe remove and reseat them. Molex plugs tend to corrode and not make contact if not powered on alot. Dielectric grease is whats normaly applied

[arvidj]

And your serial # is?

Years ago I purchased a new Dynasty 350, SN# LJ030801L. ...

Arvid

There is no block other than the filter (CE only), wires run straight to A1,A2,A3 on the side input/output board. Should be a1 - black, a2 white, a3 red. On the switch top to bottom will be black. white, red.

The three external wires coming from the plug to the switch are indeed color coded and attached in that order. All three of the wires from the switch to the side input/output board [i.e. the internal wires] are black. I am assuming that the connections move "across" the back of the switch in that the top black is "black", the next "black" is white and the bottom "black" is red.

The problem I'm having is if that board is smoked, the orange caps beside the inputs will be smoked. and smoke will be rising from it as soon as you put power to it so we know the mods/interconnect are ok

No smoke or signs of component distress anywhere, nor any evidence of "overload" or shorting. Its on a 50 amp breaker and I am assuming any short capable of tripping the breaker would quickly make itself known.

It may be that PC5 is damaged or molex plugs on it are loose or corroded, maybe remove and reseat them. Molex plugs tend to corrode and not make contact if not powered on a lot. Dielectric grease is whats normally applied

I will try reseating all of the Molex connectors on all of the boards and see what happens. If that gets the boat to float I will then apply the dielectric grease [very familiar with it from the combination Minnesota winter road salt plus moisture and old cars with less than perfect electrical connector weather protection].

If not then maybe there are some test points on PC5 that I can measure voltages? This would not be an attempt to troubleshoot specifically what might be wrong on PC5 but to get a sense about PC5's health as a complete board.

I'll let you know what happens after I get home this evening.

Thanks very much for the guidance,
Arvid

[cruizer]

PC5 handles all the auxillary control, hense the curiousity of no display. Even if the machine was on fire, there would still be a display. Just has me wondering if PC5's connectors are corroded.

[arvidj]

I unplugged, sprayed contact cleaner into, and then replugged every molex I could find on all the boards and still nothing.

I again measured the voltage at terminal A1 and A2 on PC1 - POWER MODULE and it was 245. So power makes it to the board and that is where it ends. No display, nothing to suggest the auxiliary outlet has power, nothing.

The fire you mentioned would at least be a change from the current behavior ;-)

If there were some test points on PC1 that I could measure to validate that it is working correctly I would be happy to test them. The obvious follow-on would be test points on PC5 as that is connected to T2 which is where, at a minimum, the auxiliary power comes from.

There is a fuse on PC5 that is good.

Next thoughts?

Arvid

[arvidj]

As a follow on question ...

Assuming I can track this down to a specific board ... where does one go to get reasonably priced replacement parts? Preferably refurbished but if not then new.

Thanks,
Arvid

[cruizer]

I'm almost thinking that if your trying to fire this thing up in a cold garage, that its having trouble determining that input voltage. If that interconnect board is damaged, there will be obvious signs, and crackle pop noises and smoke will rize from it. so it still points to the auxillary board as being the culprit. A Miller shop with a CST tech will diagnose the machine properly, however no Miller CST tech, don't bother with them.

[arvidj]

I'm almost thinking that if your trying to fire this thing up in a cold garage, that its having trouble determining that input voltage.

The garage is a minimum of 45 F. all the time. It was 45 when I first tried it and since I have been working on the welder the temperature has been 68 F.

If that interconnect board is damaged, there will be obvious signs, and crackle pop noises and smoke will rise from it. so it still points to the auxiliary board as being the culprit.

No pop or crackle or signs of distress. If I turn it on and then off I measure a decaying voltage [35 volts and decreasing rapidly when I measure it, no idea what the peak voltage was] across both C4 and C20. To this neophyte this bodes well for the PC1 board and as you suspect hints that PC5 is the culprit.

Thanks for the guidance and more testing after I get home,
Arvid

[arvidj]

I dropped the welder off at the LWS today for repair.

The assumption is made that large amounts of cash will be required to retrieve it sometime in January.

[Tryagn5]

warranty....

I dropped the welder off at the LWS today for repair.

The assumption is made that large amounts of cash will be required to retrieve it sometime in January.

Since that machine logs hours and starts, your the orginal owner, and you say it has low hours, i would be pushing miller to at least cover the parts. Dynasty 350's are known for board probelms, and it would seem to be good customer service to replace known faulty parts under a good will warranty. If they refused becuase of its age, that would be the last miller product that i would buy. Simply put you bought a cadillac of welders which should provide years of service.
Kevin

[cruizer]

The above is true, least wise your tech can ask. Often there are oodles of test boards kicking around at Miller. Bonus is that they are very pleasant to deal with. However, it all depends on the facility you took it too. List prices for items are often significantly inflated at some shops. As well as, un needed parts are added.

I hear horror stories all the time from customers, ie a engine driven welder comes in with a report that he's got a failed generator, which infact turns out to be a broken wire. A whopping 10 minutes of work. I t-shoot lots and lots of supposedly expensive problems that turn out to be simple fixes.

Can't take the hassle much more so I'll be booking it from this job in a few months, so likely no more tech support from me.