SECTION 6 – TROUBLESHOOTING
6-1. Troubleshooting Table
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See Section
Use MILLER Testing Booklet (Part No. 150 853) when servicing this unit.
Trouble | Remedy |
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Prior to Serial No. KG164875, no weld | Be sure line disconnect switch is in the On position. |
output; unit completely inoperative – |
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Effective with Serial No. KG164875, |
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no weld output; unit completely inop- |
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erative; PL2 off. |
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| Replace building line fuse(s) or reset circuit breaker(s) if open. |
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| Check for proper electrical input connections (see Section |
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| Check for proper jumper link position (see Section |
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| Check Power switch S1 and replace if necessary. |
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Prior to Serial No. KG164875, no weld | If using remote control, place Output (Contactor) switch S3 in Remote 14 position, and connect re- |
output; fan runs – Effective with Serial | mote control to Remote 14 receptacle RC1 (see Sections |
No. KG164875, no weld output; fan | used, place Output switch S3 in On position. |
runs; PL2 on. |
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| Check, repair or replace remote control device. |
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| Allow a cooling period of approximately 15 minutes. If thermostats TP1 remain open, check continuity |
| and replace if necessary (see Section |
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| Check circuit breaker CB1, and reset if open (see Section |
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| Place Output Selector switch S4 in desired position (see Section |
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| Check optional preflow timer board TD3, and replace if necessary. |
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| Check optional spot timer relay TD2 for proper connections and resistance. Replace TD2 if |
| necessary. |
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| Check continuity of Spot Time switch S8. Check condition of contacts. Repair or replace S8 if neces- |
| sary. |
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| Check SR1, and replace necessary components. If components are replaced, check capacitors C7 |
| thru C10. Replace capacitor(s) if necessary. |
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| Check control board PC1 and connections, and replace if necessary. |
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| Effective with Serial No. KB110695, check resistance and connections of HD1; HD1 is 1600 ohms |
| ± 10% between pins 1 and 3 of plug PLG3. Check input and output voltages. Replace HD1 if |
| necessary. |
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Unit provides only minimum weld | Check position of Amperage Control switch S5 (see Section |
output. |
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| Increase Amperage Adjustment control R1 setting if a remote control is used (see Section |
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| Check, repair or replace remote control device. |
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| Check resistance and connections of Amperage Adjustment control R1; R1 is 1000 ohms ± 10%. |
| Replace R1 if necessary. |
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| Check SCRs in main rectifier SR1, and replace if necessary. If any SCRs are replaced, Check capac- |
| itors C7 through C10 for a short or open, and check for proper connections. Replace C7 through C10 |
| if necessary. |
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| Check control board PC1 and connections, and replace if necessary. |
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| Effective with Serial No. KB110695, check resistance and connections of HD1; HD1 is 1600 ohms |
| ± 10% between pins 1 and 3 of plug PLG3. Check input and output voltages. Replace HD1 if |
| necessary. |
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Unit provides only maximum weld | Check Amperage Adjustment control R1 for proper connections and resistance; R1 is 1000 ohms |
output. | ± 10%. Replace R1 if necessary. |
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| Effective with Serial No. KB110695, check resistance and connections of HD1; HD1 is 1600 ohms |
| ± 10% between pins 1 and 3 of plug PLG3. Check input and output voltages. Replace HD1 if |
| necessary. |
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| Check connections for continuity to shunt device on units with Serial No. prior to KB110695. |
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| Check bypass capacitors C13, C14, C16, C17, C18, and C19 for broken leads, shorts, and leakage. |
| Replace if necessary. |
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Syncrowave 250 |