Repair of KS94 Temperature Controller manufactured by PMA

I recently repaired a KS94 Temperature Controller manufactured by PMA. The power supply in the KS94 had failed. The Switch-Mode-Power-Supply's Switching Transistor was shorted. Because the transistor was shorted, I removed the Switching Transformer to make sure it was still good. With my DMM set to resistance mode, I found that the primary winding was shorted to another winding. I drew a schematic of the SMPS to determine if this was a correct function of the Switching Transformer. It was not. The primary winding shorted to the secondary winding. This Switching Transformer was custom manufactured for this application and was not available for purchase. The Switching Transformer was a sealed epoxy unit, so rewinding it would be near impossible without destroying it in the process of disassembly.

The owner of the KS94 Temperature Controller needed it back quickly for an urgent production run, and a new KS94 unit was weeks away if purchased. Thus, another solution had to be worked out.

Ron Abts had me work out the necessary voltage requirements for the KS94 Temperature Controller. Then he went to our parts department and pulled two power supplies off the shelf. The one power supply would produce the proper voltages for the CPU Logic Circuits and the Analog Circuits. The second power supply would make the required isolated voltages for the 4-20mA output. I installed the power supplies, and tested the KS94 Temperature Controller good. The PT-100 Temperature Sensor Circuit worked and the 4-20mA output tracked the Temperature Sensor's changes good.

There are three output relays in this KS94 Temperature Controller. I tested them as part of the KS94 tests. I found them to have high contact resistance, so I replaced them as well.

The KS94 Temperature Controller is in the customer's machine and working.

Repair of AF-300E$ General Electric / Fuji Electric Inverter Drive

A company in New Mexico sent us a Switch-Mode-Power-Supply/IGBT Firing Board from a General Electric / Fuji Electric AF-300E$ Inverter Drive. This AF-300E$ runs a 200 Horse Power Motor. The company only sent the boards in for repair because the drive was to too large to ship to us.

The part number of the Switch-Mode-Power-Supply / IGBT Firing Board is EP-3603A-C2-Z4. The Switch-Mode-Power-Supply Board had a blown trace and external smoke residue covering the board's conformal coating. I cleaned the board and drew a schematic of the blown trace circuit and found that it was the ground path for the High Voltage Bus Monitoring Circuit.

I then tested all the components on both the Power Supply Board and the IGBT Firing Board with my DMM. All the IGBT Pre-driver Transistors on the IGBT Firing Board were shorted.

Judging from the smoke residue and the shorted IGBT Pre-driver stages, we concluded that most likely the IGBT's in the drive were also shorted. I made the repairs to the SMPS Board and the IGBT Firing Board. I drew a schematic of the IGBT Firing Circuit to find out how they were being fired. Then powered up the board with 460VAC. I then tested the IGBT Firing Circuit and the Bus Monitoring Circuit with input signals. Each circuit functioned correctly. In addition to testing these two circuits, I tested good the voltages of the SMPS Circuit. These tests had to be done before mating the boards to the drive. Otherwise the drive would be blown again.

Because we knew that there had to be damage to the drive itself, Ron Abts flew out to the company in New Mexico to check out the drive. He found that the IGBT's were in fact shorted and a 600 Amp Bus Fuse was open. He also found that there was a problem with the Three-Phase-Bridge-Rectifier Circuit. This circuit was made up of four each parallel per line phase of Dual-Diode-Power Modules. Some of the diodes did not measure correctly with his DMM. He also found that the Main Contactor Pre-charge Resistor was open. He partially disassembled the drive to get the IGBT and Dual-Diode-Power Module part numbers. He phoned these part numbers back to the shop so that we could get an early jump on getting them in. He then recommended that the drive be shipped to us, so that the repairs to the drive could be completed. The company agreed and shipped us the drive.

Upon receiving the drive, I started the disassembly process to get down to the IGBT's so that I could replace them. This drive is huge. The current carrying members are large flat metal bars. And so I had to be very methodical in the disassembly of the drive, so that I could re-assemble it correctly. One part not re-installed or installed in error would mean the destruction of the drive again. And wiping out all the effort placed into the repair of the drive.

Once I got down to the IGBT's and Three Phase Bridge Power Modules, I was able to test them. The drive was using three parallel Dual-IGBT's per motor phase. The U phase IGBT's were not shorted, but failed to conduct on my IGBT Tester. The V and W phases were shorted through and through.

I tested the Main Contactor and found the contact resistance to be too high. I disassembled the Main Contactor and cleaned the contacts. I then replaced all the damaged power modules while Ron Abts and Charles Green worked the new pre-charge resistor into the drive. Once the drive was completely re-assembled, we ran the drive unloaded and viewed the IGBT Firing Signals and U,V,W Outputs with a Fluke Oscilloscope. All looked good. We then ran a motor.

Ron went back with the repaired drive to install it at the company site in New Mexico. The repaired drive is working in the machine.

General Electric electronic repairs

General Electric parts we can repair;
DS3800NFCF1J FIRING CIRCUIT
DS3800NFEA1C TVS CONTROL BD
DS3800NFEX1C FIELD EXC BOARD
DS3800NFIB1D ANALOG INTF BD
DS3800NFIB1E ANALOG INTF BD
DS3800NFMC1E FAULT FINDER BD
DS3800NFMC1F FAULT FINDER BD
DS3800NFOA1G FAULT OPT BOARD
DS3800NFOA1H FAULT OPT BOARD
DS3800NGMA1A G/P MULTIPLY BD
DS3800NGMA1B G/P MULTIPLY BD
DS3800NGPA1B GAIN PROG BOARD
DS3800NGRA1A REGULATOR BOARD
DS3800NGRA1B REGULATOR BOARD
DS3800NGRA1C REGULATOR BOARD
DS3800NGRA1D REGULATOR BOARD
DS3800NGRA1E REGULATOR BOARD
DS3800NGRA1F REGULATOR BOARD
DS3800NGRA1G REGULATOR BOARD
DS3800NGRA1H REGULATOR BOARD
DS3800NGRA1I REGULATOR BOARD
DS3800NGRA1J REGULATOR BOARD
DS3800NGRA1K REGULATOR BOARD
DS3800NGRA1L REGULATOR BOARD
DS3800NGRB1A REGULATOR BOARD
DS3800NGRB1E REGULATOR BOARD
DS3800NGRC1D REGULATOR BOARD
DS3800NGRC1F REGULATOR BOARD
DS3800NGRC1H REGULATOR BOARD
DS3800NGRD1D REGULATOR BOARD
DS3800NHVB1C HIGH VOLTAGE BD
DS3800NHVD1E HIGH VOLTAGE BD
DS3800NHVE1A HIGH VOLTAGE BD
DS3800NHVE1C HIGH VOLTAGE BD
DS3800NHVF1A HIGH VOLTAGE BD
DS3800NHVH1A HIGH VOLTAGE BD
DS3800NHVH1B HIGH VOLTAGE BD
DS3800NHVJ1A HIGH VOLTAGE BD
DS3800NHVK1A HIGH VOLTAGE BD
DS3800NHVM1C HIGH VOLTAGE BD
DS3800NHVM1E HIGH VOLTAGE BD
DS3800NHVN1A HIGH VOLTAGE BD
DS3800NISA1B SIG ISOLATOR BD
DS3800NISA1C SIG ISOLATOR BD
DS3800NISB1E SIGNAL ISOLATOR
DS3800NISB1F SIGNAL ISOLATOR
DS3800NLBA1D LOAD BALANCE BD
DS3800NLIA1F LOAD INV BOARD
DS3800NMEA1G MOTOR EXC BOARD
DS3800NMEA1H MOTOR EXC BOARD
DS3800NMEA1I MOTOR EXC BOARD
DS3800NMEA1J MOTOR EXC BOARD
DS3800NMEA1K MOTOR EXC BOARD
DS3800NMEA1L MOTOR EXC BOARD

General Electric electronic repairs

General Electric parts we can repair;
DS3800NCVA1A CURR LOOP BOARD
DS3800NDAC1A D/A CONVERTER
DS3800NDAC1B D/A CONVERTER
DS3800NDAC1D D/A CONVERTER
DS3800NDAC1E D/A CONVERTER
DS3800NDIB1B DRIVE INTERFACE
DS3800NDIB1C DRIVE INTERFACE
DS3800NDIB1D DRIVE INTERFACE
DS3800NDIC1A CURR ISOL BOARD
DS3800NDIC1B CURR ISOL BOARD
DS3800NDIC1C CURR ISOL BOARD
DS3800NDID1F DRIVE INTERFACE
DS3800NEPA/HSMA MOTOR EXC ASSY
DS3800NEPA/HSMB MOTOR EXC ASSY
DS3800NEPA/HSMC MOTOR EXC ASSY
DS3800NEPA/HSMD MOTOR EXC ASSY
DS3800NEPA1A MOTOR EXC BOARD
DS3800NEPA1C MOTOR EXC BOARD
DS3800NEPA1D MOTOR EXC BOARD
DS3800NEPA1F MOTOR EXC BOARD
DS3800NEPB/DEPB MOTOR EXC ASSY
DS3800NEPB/HSMA MOTOR EXC ASSY
DS3800NEPB/HSMB MOTOR EXC ASSY
DS3800NEPB/HSMC MOTOR EXC ASSY
DS3800NEPB/HSMD MOTOR EXC ASSY
DS3800NEPB1B MOTOR EXC BOARD
DS3800NEPB1C MOTOR EXC BOARD
DS3800NEPB1D MOTOR EXC BOARD
DS3800NEPB1F MOTOR EXC BOARD
DS3800NEPB1G MOTOR EXC BOARD
DS3800NEPC1E MOTOR EXC BOARD
DS3800NEPD/NPCS EXCITER/SNUBBER
DS3800NEPD1A MOTOR EXC BOARD
DS3800NEPD1B MOTOR EXC BOARD
DS3800NEPD1F MOTOR EXC BOARD
DS3800NEPD1H MOTOR EXC BOARD
DS3800NEPF1A EXC POWER BOARD
DS3800NFCD/DFCD FIRING BD ASSY
DS3800NFCD1F FIRING CIRCUIT
DS3800NFCD1G FIRING CIRCUIT
DS3800NFCD1H FIRING CIRCUIT
DS3800NFCD1J FIRING CIRCUIT
DS3800NFCD1K FIRING CIRCUIT
DS3800NFCD1L FIRING CIRCUIT
DS3800NFCD1N FIRING CIRCUIT
DS3800NFCD1O FIRING CIRCUIT
DS3800NFCD1Q FIRING CIRCUIT
DS3800NFCD1S FIRING CIRCUIT
DS3800NFCF1A FIRING CIRCUIT
DS3800NFCF1C FIRING CIRCUIT
DS3800NFCF1D FIRING CIRCUIT
DS3800NFCF1E FIRING CIRCUIT
DS3800NFCF1G FIRING CIRCUIT
DS3800NFCF1H FIRING CIRCUIT

Even more General Electric parts

Even more General Electric parts we can repair;
DS3800HSQE1D SEQUENCER BOARD
DS3800HSQE1E SEQUENCER BOARD
DS3800HSQE1F SEQUENCER BOARD
DS3800HSQE1G SEQUENCER BOARD
DS3800HSQE1H SEQUENCER BOARD
DS3800HUMB1A UNIV MEMORY BD
DS3800HVDB1K VIDEO DRIVER BD
DS3800HXCA1D SERIES 6 MASTER
DS3800HXMA1G EXPANDER BOARD
DS3800HXMA1J EXPANDER BOARD
DS3800HXMA1L EXPANDER BOARD
DS3800HXRA/DXRA S/6 RCVR ASSY
DS3800HXRA1B S/6 RECEIVER BD
DS3800HXRA1C S/6 RECEIVER BD
DS3800HXRA1D S/6 RECEIVER BD
DS3800HXRA1E S/6 RECEIVER BD
DS3800HXRA1F S/6 RECEIVER BD
DS3800HXRB1B C BUS RECEIVER
DS3800HXRB1C C BUS RECEIVER
DS3800HXRC/DXRC S/6 RCVR ASSY
DS3800HXRC1A S/6 RECEIVER BD
DS3800HXRC1C S/6 RECEIVER BD
DS3800HXRC1D S/6 RECEIVER BD
DS3800HXTA1A S/6 XMTR BOARD
DS3800HXTA1B S/6 XMTR BOARD
DS3800HXTA1C S/6 XMTR BOARD
DS3800HXTA1E S/6 XMTR BOARD
DS3800NADA/DADA A/D CONVERTER
DS3800NADA1E A/D CONVERTER
DS3800NADA1F A/D CONVERTER
DS3800NADB/DADB A/D CONV ASSY
DS3800NADB1A A/D CONVERTER
DS3800NADB1B A/D CONVERTER
DS3800NAIA1E CURR LOOP INPUT
DS3800NATA1A ATTENUATION BD
DS3800NBIB1J BRIDGE INTF BD
DS3800NBIB1K BRIDGE INTF BD
DS3800NBIC1H BRIDGE INTF BD
DS3800NBIC1J BRIDGE INTF BD
DS3800NBID1C BRIDGE INTF BD
DS3800NCBA1A COMPONENT BOARD
DS3800NCCB1E CONV COORD BD
DS3800NCCB1F CONV COORD BD
DS3800NCCB1H CONV COORD BD
DS3800NCIB1C CURR ISOL BOARD
DS3800NCIB1E CURR ISOL BOARD
DS3800NCIB1G CURR ISOL BOARD
DS3800NCIB1H CURR ISOL BOARD
DS3800NCIC1C CURR ISOL BOARD
DS3800NCIC1D CURR ISOL BOARD
DS3800NCIC1E CURR ISOL BOARD
DS3800NCID1B CURR ISOL BOARD
DS3800NCLA1B CURR LOOP BOARD
DS3800NCMA1A COMPARATOR BD