Index Chapter 7 7 REPAIRS - FAILURES EEprom Use General Information Data Writing Loading from EEPROM...

Transcription

1 Index Chapter 7 7 REPAIRS - FAILURES 7.1 EEprom Use General Information Data Writing Loading from EEPROM MAINTENANCE FUNCTIONAL TESTS Automatic exposure test Automatic Brightness Control test Cleaning Daily Tests Weekly Tests Monthly Tests Technical Servicing Integrity of cables and connections Leakage current measurement Dust cleaning H.V. Cable head cleaning Contact cleaning Oil check alarm check FUSES INSPECTION Radiographic parameter check

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3 7 REPAIRS - FAILURES 7 REPAIRS - FAILURES 7.1 EEprom Use General Information EEPROM is used only to save data written in the RAM placed on the MPU (MASTER PROCESSING UNIT). The computer, during the normal work, requests the data only to the RAM without ever reading the EEPROM contents. On the EEPROM automatically without any intervention of the user are stored the following data: 1) All the contents of the anatomical progra available to the user 2) All the data inherent to the configuration stage ) All the data inherent to the calibration values of the three X-Ray tubes ( six focal spots) The EEPROM has the function of a not volatile support, in this way it is possible to load automatically all the data concerning a new installation in a new MPU. We advise to write it at the end of the installation so that the data supplied to the computer are stored by the technician. The unit must be consigned and left to the user with a new EEPROM Data Writing BACK-UP, that is the data writing on the existing EEPROM,is done every you arrive at the end of an anatomical program or of configuration and calibration one Loading from EEPROM This operation is necessary every you have to substitute the CPU or the RAM ( average life of this battery is five years) or when in the FIP is shown the writing: ERROR, CALL TECHNICAL SERVICE. The unit switched off we have to do the following: 1) After opening the frontal panel of the power rack, place on right side the switch on PCB 5806 MPU V25. 2)Turn the key switch of the console into the modification position ) By the ON key switch the unit 4) After about five seconds from switching on FIP shows: this means that the reading has been made from the EEPROM. We have then to set the key and the selector in the original positions.

4 page n MAINTENANCE To ensure safety to patient,operator and persons that can enter in contact with this X-Ray system, it is better to check the unit at least every 12 mounts. Often checks are necessary if the unit works in conditions difference than the ones specified in the tables released by the manufacturer. Requested tests are two types: Functional tests that can be performed by user Servicing that must be done by qualified people by proper instrumentation. Manufacturer and installation people declaim all responsibility on any malfunctioning if:: Installation, functionality extension,calibration,maintenance is not done by qualified people and approved by manufacturer. Components directly involved in generator safety are replaced with other not listed in the spare parts list. Electrical installation does not meet the IEC requirements Misuse of the equipment 7. FUNCTIONAL TESTS WARNING! 7..1 Automatic exposure test Before of making any test requesting X-Ray emission,use protective wears, respsect a safety distance and if necessary use personal dosimeter. 1) Close the collimator and if necessary cover it by a lead apron.make one exposure and keep the X-Ray push button pushed, be sure that the AEC is active before of starting the exposure. X-Ray yellow lamp must lit during all the exposure. Warning! Don t care about the alarm at the end of the exposure, this signal inform you that the device is properly working. In latest software versions exposure is stopped instantaneously, this way of operating is correct.. 2) Open the collimator. Make one exposure.in this case the yellow lamp must stay lighted for 0,1 sincerely Automatic Brightness Control test 1) Close the collimator and if necessary cover it by a lead apron. Make fluoroscopy and be sure that the A.B.S. Device is active. The fluoro yellow indicator must be lighted for all the exposure. Warning! Dose shown on the proper display as kv- value must reach the maximum level value. 2) Stop fluoroscopy. Open the collimator. Make a new fluoroscopy.in this case the X-Ray yellow lamp must stay lighted and the dose must reach the mimimum level value. Release fluoro.

5 7 REPAIRS - FAILURES 7.. Cleaning Equipment must be switched off before doing any cleaning action. Clean by using cotton cloth and not abrasive detergents. Do not use any organic solvent or any kind of other solvent. Do not utilize sprays, no detergent must penetrate inside the unit. To disinfect the unit surfaces using water solution based on soap. Do not utilize aggressive detergents based on alcohol Daily Tests 7..5 Weekly Tests 7..6 Monthly Tests Before of starting daily work, make a visual inspection of the equipment and report any evident damage. During the routine work, check that fluoro and radio yellow indicators work properly. Check the cables and electrical connections integrity. Check oil leakage or unusual noises coming from the generator. A.E.C. and A.B.S. tests, previously explained.

6 page n Technical Servicing For a scheduled servicing program of the unit follow this table: Inspection Frequency Every 6 months or every that a PCB having the function of adjusting and/or controlling the radiographic parameters Controlling activity description Correctness of radiographic parameters must be checked: value average value during the exposure MAs accuracy value If one or more of the above mentioned parameters are not in the prefixed limits make anew adjustment (for ) or a new calibration of the trimmers concerning the signals on the card CCB pcb 580 Check the operativity of the posemeter, both the correctness of adjusted s both the safety for dose too low Moreover make all the tests that are non expressly mentioned but requested by law in the country where the unit is installed Every 12 months Every 6 years or any that it is necessary Activity of checking of all functionality and cleaning as per the procedures written in this paragraph Substitution of the Dallas (socket with battery of the RAM) on the cardmpu pcb When the battery is off or the memory is kept away from its socket, all the contained are lost, the you have to proceed to reload it when repositioned in the socket and in the MPU as explained at the paragraph often present chapter Regular maintenance includes: Check of the integrity of cables, insulating, covers preventing the contact with live parts. Control of correct functional working of the unit ( tests as written in previous paragraph) leakage current measurement Measure of the earth resistance between the protective earth and every accessible conductive (metallic) part of the unit. Dust cleaning of all critical parts of the unit Control,cleaning and silicon substitution of the high tension cables terminals Control and cleaning of relay and contractor contacts Check of the oil level of the HT transformer Alar check Fuses control Radiographic parameters check Calibration All tests and controls not here directly mentioned that can be useful to a correct generator working. We recommend to do all these tests at least once a year, any way more frequent tests make the generator use safer.

7 7 REPAIRS - FAILURES Integrity of cables and connections Switch off the unit, open the power rack and make a visual inspection of the connections: cables, look for interruption or lost of insulation of the wires,check that the cable fixing is well done (steady). PCBs, check that the connectors of the PCB are well connected. Open the control console and make the same as above mentioned Leakage current measurement 7.4. Dust cleaning Use an appropriate instrument to perform this test. Refers to the test methodology showed in the standard I.E.C Switch generator off. Open the rack, using a brush clean all the dusty surface, YOU MUST NOT UTILIZE LIQ- UID CLEANING PRODUCTS ON PARTS THAT CAN BE UNDER VOLTAGE WHEN THE GENERATOR IS ON, USE ONLY A BRUSH. You had to clean also PCB havin g vertical surfaces. Open the control desk and clean it H.V. Cable head cleaning Contact cleaning Switch the generator off: Take out the cable head Discharge the cable head: using a conductor short, one at a, the pins with the nearest ground Look at the cable head If needed clean the cable head If needed open the pins Test isolation of positive side, of negative side and also check the conduction between ground pole and the screen If needed cover the cable head with silicon grease Put the cable in the receptor Do the same with the other cable head Switch the generator off and also all the other machines linked to it. Open the generator rack, most of relays are present on G.T.B. Look at the boards to select the relay that had to be cleaned. Take out the protective cap, clean with an appropriate spray. Close the relay. Dismount the frontal part of the contractor, clean the contacts or change them if needed. Mount the contractor again. Close the rack.

8 page n Oil check Switch off the generator. Open the generator rack. Check the High Voltage transformer oil level using the cork placed on the cover. Oil level must be at 1,0 1,5 cm from the internal side of the cover Check with a visual inspection the bottom of the rack in order to see the absence of oil. If evidence of oil, check the transformer to locate the oil outgoing point. If the loosing point is critical change the damaged component Inform the constructor. Clean all parts with oil, if needed, fill up the H.V. Tank with new oil. Close the generator rack alarm check Switch the generator off. Open the rack. Check of printer circuit board CAB and QUAD DRIVER Switch the generator on. Warning, Warning!, Because of in the back of the rack are located the electrolytic capacitor with high energy stored, every that the generator is switched on without the lateral panel, be careful to avoid: contacts, to be very near with every part of the body and the capacitor terminals or any non isolated toold. Before to touch the caps terminal be sure that those caps are fully discharged Open the GTB panel; put jumper jp8, the red led DL19 must become lit, alarm 'GENERAL SAF. must be showed on control desk FIP and a bleep must come on. Reset the alarm con using the reset key, the bleep stops and the red led had to came off; put jumper jp9, the red led DL14 must become lit, alarm 'GENERAL SAF. must be showed on control desk FIP and a bleep must come on. Reset the alarm con using the reset key, the bleep stops and the red led had to came off ; put jumper jp7, the red led DL1 must become lit, alarm 'GE- NERAL SAF. must be showed on control desk FIP and a bleep must come on. Reset the alarm con using the reset key, the bleep stops and the red led had to came off Switch the generator Off. Inverter supply check Take out the on signal of the contattor LB placed behind the GTB panel, the on signal is breaked by a breaker (Si off) placed on the omega rail. Switch generator on. the bleep had to came in and the alarm message 'PWS SAFETY' must be showed on the FIP. Reset, switch generator off, close Contactor Si, switch generator on. Make an exposure with 80 kv, 100, 0,100 s., no one alarm must be active during this exposure. Switch generator off. Inverter led check Switch on generator Check for correct status of all the following leds: PCB 5800 Quad Driver : DL7, DL8, DL9 on LD4, LD6, DL, DL5, DL1, DL2 off

9 7 REPAIRS - FAILURES PCB 580 CCB : green leds and DL20 must be lit red leds all off yellow leds LD1, LD8, on only during x-ray Power electronics leds Switch generator ON Check for those leds: PCB 5814: _ PCB 5805: supply check, led on means good supply. DL, DL7, DL8 on; DL1 and DL2 off PCB 5820: check fuse F1, F2 and with a voltmeter check the supply voltage. PCB 5822: during normal working, starting tube s spin up, led DL1 e DL2 must be lighted PCB 5810: green leds must be lighted; red leds must be switched OFF yellow led: check specific functionality. Switch off the generator. Close the rack FUSES INSPECTION Check all the fuses, with a visual inspection and, if possible, with an ohm- meter Radiographic parameter check To check the correctness of the radiographic the check of tubes calibration is needed, are tube depending, are tube independent, the parameter to be inspected are:, mean radio, radio, s. On both kv and You can make some adjustment, does not need any adjustment because is quartz controlled, s are automatically corrected by the adjustment of kv and. Adjustment done by factory for kvp and are made during final inspection before delivering; this job is done using an invasive instrument produced by RadCal Corp. And known as Dynalyzer; its job is to measure kvp, e. Please refer to this instrument or on equivalent instrument to make H.W. Adjustment on the generator boards Refer to the following test: Connect all the instrument for the kv e measure, the connection of external instrument is needed, if this is not possible put a scope on kv feedback signal on pcb CCB test point TP5, a wrong interfacing to those signal could introduce noise on the kv signal giving serious consequences at kv regulation level. You can measure Radio on TP2, TP9 or TP8 depending on the needed ratio. Switch generator ON

10 page n.10 ACCURACY TESTS: TEST TEST CONDITIONS LIMIT RESULT UNIT Accuracy intermittent mode small focus Displayed data: 60 kv, 25, 100 make exposure and measure: mean* 57/6 22/ kv, 25, 100 make exposure and measure: mean* 95/105 22/28 60 kv, 75, 100 make exposure and measure: mean* 57/6 67/8 100 kv, 75, 100 make exposure and measure: mean* 95/105 67/8 60 kv, 150, 100 make exposure and measure: mean* 57/6 15/ kv, 150, 100 make exposure and measure: mean* 95/105 15/ kv, 200, 100 make exposure and measure: mean* 57/6 180/ kv, 200, 100 make exposure and measure: mean* 95/ /220

11 7 REPAIRS - FAILURES TEST TEST CONDITIONS LIMIT RISULTAT UNIT Large focus 60 kv, 400, 100 make exposure and measure: mean* 57/6 60/ kv, 400, 100 make exposure and measure: mean* 95/105 60/ kv, 600, 100 make exposure and measure: mean* 57/6 540/ kv, 600, 100 make exposure and measure: mean* 95/ / kv, 800, 100 make exposure and measure: mean* 76/84 720/ kv, 1000, 100 make exposure and measure: mean* 57/6 900/ kv, 200, 100 make exposure and measure: mean* 57/6 180/220 * ignore spike due to the H.V. Cables and the H.V. capacitors perform those radiography if the tube and/or the generator allows it

12 page n.12 TEST TEST CONDITION LIMIT RESULT UNIT 2. repeatability 80kV, 100, 100 large focus repeat 10 exposure using always the same parameters kvp () 76/84 90/110 Any value of kv,, must be within the LIMIT kvp. Continuos mode accuracy 40 kv, 0,5 80 kv, 2, kv, 4 6/44 0,4/0,6 76/84 2/2,5 114/126,6/4,4 kvp kvp kvp KV must be within 5%, must be within 10 %. If kv are not within the limits, before to proceed with the potentiometer adjustment on pcb CCB contact the manufacturer for the authorization. If great difference are found on value, before proceeding to a new calibration, check pcb 5805 supplies, check H.V. Cables pins on the cable heads, and check for the filament. kv accuracy, if kv is not within the limit showed in the table You must make the adjustment on the feedback gain trimpot towards MPU pcb To adjust kv real value use R8 trimpot. To adjust kv red by the MPU and showed on the MPU display use R251trimpot on all the CCB 580 from revision 2 on. This adjutant is not possible on CCB 580 of revision 1.. accuracy, if value is not within the limit You must have a new focus adjustment if the problem is present on both the focus the adjustment had to be done on the gain trimpot on CCB pcb 580. Three channel for,measurement are present on pcb 580, icl, fluoro channel (10Volt 10 ), icm, low radio channel (10Volt 150 ), ich, high channel (10Volt 1500 ). To adjust fluoro value use R2 trimpot. To adjust low radio value use R69 trimpot. To adjust high radio value use R54 trimpot. From revision 2 on no offset adjustment are needed. radio accuracy, all the test must confirm the accuracy of radiography, no adjustment had to be done. s accuracy, because of s are the product of and the only adjustment that can be done is on.

13 7 REPAIRS - FAILURES Calibration Because tube are getting older by the use year by year the tube had to be recalibrated every year. Follow synoptic tables to calibrate the table (section 2). Or put at 1 the value of automatic adjustment coefficient in order to perform the calibration a each exposure.

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