Hello All,
I bought a used Miller Maxstar 200SD and I think it needs one board based on my findings but a second opinion would be greatly appreciated. I bought it for a hobby to learn dc TIG welding, so there is no hurry to fix it. I love to weld and love fixing stuff. I figured this the best place to get some great answers. I am an electrician by trade but information on test points and values are hard to find for these machines. I found and old post on here for test points on a Maxstar 200STX. Everything seems to be the same testing points until I get to the output from the inverter board to operator interface board. It has a 20pin ribbon connector since the SD has a lcd panel on the front. The link to the old thread for the Maxstar STX and my readings below. I will post the values/answers below and maybe someone can give me an opinion or some other pointers. I apologize that this posting is so long. I appreciate everyones help.
Brian
original posting for a Miller Maxstar STX
http://www.mig-welding.co.uk/forum/showthread.php?t=10795
My Miller Maxstar 200SD general info.
Manuf. date 2004
owners manual (electrical block diagram)
http://www.millerwelds.com/service/locate_om.php?manual=O2226T&serial=le374331
currently wired for 120v 60hz for troubleshooting(once fixed it will be set up 240vac 60hz.)
My Test Equip. used:
FLUKE 87V
Symptoms:
Plug in and turn on machine you have no operator interface (no lcd screen for volts/amps/etc. You here a control relay clicking on PC2 power interconnect board. It is almost sound like it is calling on the inverter board to fire up or the next step but it never gets there. I was guessing a PC1 inverter board but I would like to be sure it is not the interface board or boost board or 2 or all bad. If it is one board it is worth it and I know if it is more than that I can not invest anymore time into it.
Place line disconnect switch in On position
1)Check and replace line fuse(s), if necessary, or reset circuit breaker.
This all checks out tested imput voltage
2)Check for proper input power connections and check condition of power cord.
10/4 SOOW cord was visually inspected and ohmed out to validate continuity
3)Check inverter control board PC1 for proper seating.
PC1 inverter board is properly seated
4)Check weld control board PC3 for proper seating.
PC3 weld control/operator interface ribbon connections seated properly.
5)Check boost control board PC10 for proper seating.
PC10 Boost control board is properly seated.
6)Check continuity of Power switch S1 , and replace if necessary.
Continuity of power switch S1 is good.
7)Check bus voltage on power interconnect board PC2 receptacle RC5 replace
PC2 if necessary.
780volts DC on receptacle RC5 on board PC2
Check ±15 volts dc supplies as follows
8)Disconnect plug PLG1 from RC1 on PC1 and check for ±15 vdc. If ±15 vdc is now present,
replace PC3.
This is the step that the STX must have less pins on the plug than the my Maxstar SD. There are 20pins (2rows of 10) that is labeled PLG1 that Plug into RC1 on PC1. This is the step that I need to find out which pins to test to find the +/- 15vdc
9)Disconnect plug PLG5 from RC5 on PC1 and check for ±15 vdc. If ±15 vdc is now present,
replace HD1.
This TESTED GOOD, no voltage present on RC5 of PC1.
10)Disconnect PC1 from PC2, and on PC2 check for ±15 vdc between RC3 pin 5 and RC3 pin 8. If ±15 vdc is now present, replace PC1. If the ±15 vdc is still not present, replace PC10.
I get 19VDC. Does this mean PC10 is good?
11)Check +30 volt dc primary voltage on boost control board PC10
Replace PC10 ifnecessary.
I Dont know where to test specifically on PC10 for this test
12)Check ±15 volt dc primary voltage on boost control board PC10 Replace PC10 if necessary.
I dont know where to test specifically on PC10 for this test
13)Check +15 volt dc buck voltage on boost control board PC10 .
If voltage is present,
stop. If voltage is not present, check resistors.
Before checking resistors, discharge and measure input capacitor voltage .
I dont know where to test for this on PC10
14)Disconnect PC10 from PC2 and check resistors R1, R2, R36, and R37 on PC2. Each
resistor should measure 75K ohms ±10%. If any of the resistors are bad, replace PC2.
These resistors on the Maxstar SD are 150k ohms each. All four check out good and within tolerance.
I need specific test points/locations to questions 8, 11, 12, 13.
Again, Thank You for anyone up to the challenge. Brian
I bought a used Miller Maxstar 200SD and I think it needs one board based on my findings but a second opinion would be greatly appreciated. I bought it for a hobby to learn dc TIG welding, so there is no hurry to fix it. I love to weld and love fixing stuff. I figured this the best place to get some great answers. I am an electrician by trade but information on test points and values are hard to find for these machines. I found and old post on here for test points on a Maxstar 200STX. Everything seems to be the same testing points until I get to the output from the inverter board to operator interface board. It has a 20pin ribbon connector since the SD has a lcd panel on the front. The link to the old thread for the Maxstar STX and my readings below. I will post the values/answers below and maybe someone can give me an opinion or some other pointers. I apologize that this posting is so long. I appreciate everyones help.
Brian
original posting for a Miller Maxstar STX
http://www.mig-welding.co.uk/forum/showthread.php?t=10795
My Miller Maxstar 200SD general info.
Manuf. date 2004
owners manual (electrical block diagram)
http://www.millerwelds.com/service/locate_om.php?manual=O2226T&serial=le374331
currently wired for 120v 60hz for troubleshooting(once fixed it will be set up 240vac 60hz.)
My Test Equip. used:
FLUKE 87V
Symptoms:
Plug in and turn on machine you have no operator interface (no lcd screen for volts/amps/etc. You here a control relay clicking on PC2 power interconnect board. It is almost sound like it is calling on the inverter board to fire up or the next step but it never gets there. I was guessing a PC1 inverter board but I would like to be sure it is not the interface board or boost board or 2 or all bad. If it is one board it is worth it and I know if it is more than that I can not invest anymore time into it.
Place line disconnect switch in On position
1)Check and replace line fuse(s), if necessary, or reset circuit breaker.
This all checks out tested imput voltage
2)Check for proper input power connections and check condition of power cord.
10/4 SOOW cord was visually inspected and ohmed out to validate continuity
3)Check inverter control board PC1 for proper seating.
PC1 inverter board is properly seated
4)Check weld control board PC3 for proper seating.
PC3 weld control/operator interface ribbon connections seated properly.
5)Check boost control board PC10 for proper seating.
PC10 Boost control board is properly seated.
6)Check continuity of Power switch S1 , and replace if necessary.
Continuity of power switch S1 is good.
7)Check bus voltage on power interconnect board PC2 receptacle RC5 replace
PC2 if necessary.
780volts DC on receptacle RC5 on board PC2
Check ±15 volts dc supplies as follows
8)Disconnect plug PLG1 from RC1 on PC1 and check for ±15 vdc. If ±15 vdc is now present,
replace PC3.
This is the step that the STX must have less pins on the plug than the my Maxstar SD. There are 20pins (2rows of 10) that is labeled PLG1 that Plug into RC1 on PC1. This is the step that I need to find out which pins to test to find the +/- 15vdc
9)Disconnect plug PLG5 from RC5 on PC1 and check for ±15 vdc. If ±15 vdc is now present,
replace HD1.
This TESTED GOOD, no voltage present on RC5 of PC1.
10)Disconnect PC1 from PC2, and on PC2 check for ±15 vdc between RC3 pin 5 and RC3 pin 8. If ±15 vdc is now present, replace PC1. If the ±15 vdc is still not present, replace PC10.
I get 19VDC. Does this mean PC10 is good?
11)Check +30 volt dc primary voltage on boost control board PC10
Replace PC10 ifnecessary.
I Dont know where to test specifically on PC10 for this test
12)Check ±15 volt dc primary voltage on boost control board PC10 Replace PC10 if necessary.
I dont know where to test specifically on PC10 for this test
13)Check +15 volt dc buck voltage on boost control board PC10 .
If voltage is present,
stop. If voltage is not present, check resistors.
Before checking resistors, discharge and measure input capacitor voltage .
I dont know where to test for this on PC10
14)Disconnect PC10 from PC2 and check resistors R1, R2, R36, and R37 on PC2. Each
resistor should measure 75K ohms ±10%. If any of the resistors are bad, replace PC2.
These resistors on the Maxstar SD are 150k ohms each. All four check out good and within tolerance.
I need specific test points/locations to questions 8, 11, 12, 13.
Again, Thank You for anyone up to the challenge. Brian
