_ FCO TA78-I004, Excessive soft errors writing tapes in GCR +-----------------------------------------------------------------------------+ | _ _ _ _ _ _ _ Level of Urgency Page_1_ | || | | | | | | | +--+ Of_20_ | ||d|i|g|i|t|a|l| FCO | I| | ||_|_|_|_|_|_|_| +--+ | |_____________________________________________________________________________| | | | FIELD CHANGE ORDER Number: TA78-I004 | |_____________________________________________________________________________| | Applicability: | | All TA78s not at Rev. "H" which do not have this FCO installed and | | experiencing problems with GCR Write, tape interchangeability, and other | | errors. This FCO implements the follow ECOs: M8950-SH009, M8950-SH010, | | TU78-SH034, TU78-SH036, TU78-SH037. | | | This revised FCO supersedes Rev. B released 30 July 1987. It | | || has been revised to correct errors in the text on pages 3, 4, | | | 11, 12, 15, 16, 17. | |_____________________________________________________________________________| | Problem/Symptom: | | Excessive soft errors while writing tapes in GCR, and the inability to read | | tapes written on another tape drive. | |_____________________________________________________________________________| | Quick Check: | | Label on the inside of front door, and the Preamp module has a shield. | |_____________________________________________________________________________| | Compatibility/Prerequisite FCO: N/A | Est. Time to Install: | | | 3.5 hrs | |___________________________________________________|_________________________| | Special Tools or Test Equipment: See page 2 | | | |_____________________________________________________________________________| | FCO Parts Information | | Order by Quantity: Part Number: Description: | | EQ-01455-01 1 29-26253 See page 3 and 4 | | FA-04741-01 1 FCO Document | | | |_____________________________________________________________________________| |EQ Kit Variation System/Option Applic: N/A | |_____________________________________________________________________________| | Approvals | |_____________________________________________________________________________| | CSSE Engineer | F.S. Product Safety | F.S. Logistics | | Leo Carlin | Steve Caccia | Ed Duggan | |____________________|__________________________|_____________________________| | CSSE Manager | F.S. Microfiche Libraries| Affected Population: | | Curtis Smith | | 3,000 | |____________________| |____________________________ | | MicroMedia Pub. | EP-FSNVX-LB VAX | Initial Kitting: | | Ray LeBlanc | | 3,000 | |____________________| VAXnotes |____________________________ | | Revision: | STARS | Hardcopy Publication: | | C | | 3,000 | |____________________| |_____________________________| | FCO Release Date | | Parts Availability: | | 4-APR-88 | | July 1987 | +-----------------------------------------------------------------------------+ _ _ _ _ _ _ _ | FCO TA78-I004 | | | | | | | | | |d|i|g|i|t|a|l| | PAGE 2 OF 20 |_|_|_|_|_|_|_| | | _______________________________|_________________________________________ Special Tools and equipment required: Continued from page 1. ----------------------------------------------------------- o Dual Trace Oscilloscope and two 10x probes o Digital Volt Meter (DVM) o 1/4" Nut driver (29-10664) o 7" extender for nutdriver (29-11625) o #1 Phillips screwdriver (29-11001) o 5/16" slotted blade screwdriver (29-10960) o Xcelite Handle (29-10562) o Potentiometer adjustment tool (29-26130) o Skew tape (29-19224) o Master output tape (29-11691) o Soldering iron and solder (29-26127 , 29-10569) o Solder removal tool (29-11549) o Scratch tape o Head positioning fixture (29-26160) (use if head, 29-23767, needs to be replaced) o Read Gain/Write Current Adjustment Box (29-26619) o TA78 Service Manual (EK-0TA78-SM-001) o TU78 Technical Manual Volume 2 (EK-2TU78-TM-002) _ _ _ _ _ _ _ | FCO TA78-I004 | | | | | | | | | |d|i|g|i|t|a|l| | PAGE 3 OF 20 |_|_|_|_|_|_|_| | | _______________________________|_________________________________________ FCO Kit Contents: Continued from page 1. ---------------------------------------- Vendor Digital Item P/N P/N Comment Qty. ---- --------- -------- ------- ---- FCO Kit 114840-01 29-26253 1 (Package) Write PCBA 115131-01 29-26254 1 Preamp PCBA 115141-01 29-26255 1 Preamp Shield 114688-01 1 Preamp Bracket 114687-01 1 Cover, test point 114689-01 1 Cable, Write 115326-01 1 PCBA to Preamp PCBA Preamp Hardware 600-2605 Screw 6-32 x 5/16 4 600-0403 Screw 4-40 x 3/16 2 600-0600 Washer #6 Flat 8 600-2608 Screw 6-32 x 1/2 4 _ _ _ _ _ _ _ | FCO TA78-I004 | | | | | | | | | |d|i|g|i|t|a|l| | PAGE 4 OF 20 |_|_|_|_|_|_|_| | | _______________________________|_________________________________________ FCO Kit Contents: Continued from page 1. ----------------- Vendor Digital Item P/N P/N Comment Qty. ---- ------ ------- ------- --- Read PCBA Caps. 130-6805 10-00014-00 Capacitor 68pf 9 Read PCBA Caps. 130-3315 10-00023-00 Capacitor 330pf 9 M8950 PCBA Caps. 143-1521 10-13466-29 Capacitor 1500pf 9 Label (TX78U) 114838-01 36-27464-01 1 Revision Label 36-15946-00 for Drive 1 Revision Label 115157-01 for Read PCBA 1 FCO Document 115158-01 FA-04741-01 TA78-I004 1 Brady marker(s) 114841-01 for M8950 18 A2TB1 Hardware 615-0323 90-00001-04 Standoff 2 656-0023 90-07927-00 Lug 1 600-0604 90-06020-01 Screw 6-32 x 1/4" 2 _ _ _ _ _ _ _ | FCO TA78-I004 | | | | | | | | | |d|i|g|i|t|a|l| | PAGE 5 OF 20 |_|_|_|_|_|_|_| | | _______________________________|_________________________________________ TX78 UPGRADE FCO Installation Procedure for TA78-I004: ------------------------------------- NOTE This document is written on the premise that the reader/FCO installer is extremely knowledgeable of the TU78 and/or TA78 tape transport system and related maintenance procedures. This document must be read in its entirety prior to installing this FCO. Purpose: -------- This FCO is designed to improve performance of the TU/TA78 drive in the areas of: o GCR read and write o PE read o Internal electrical drive noise Design Changes and Implementation: ---------------------------------- 1. Circuit changes to correct design problems on the Preamp PCBA. 2. Write driver circuits and AMTIE circuits on the Write PCBA have been redesigned and the grounds re-structured. 3. Two capacitors will be changed in each channel (18 total) on the Read PCBA. _ _ _ _ _ _ _ | FCO TA78-I004 | | | | | | | | | |d|i|g|i|t|a|l| | PAGE 6 OF 20 |_|_|_|_|_|_|_| | | _______________________________|_________________________________________ 4. The gray flat write cable will be replaced by one with keyed locking connectors. 5. The Preamp PCBA will be shielded to reduce noise susceptibility. 6. [Master's only] One capacitor will be changed to improve PE read (instantaneous speed variations). 7. One ground cable will be shortened to reduce noise. This FCO will include the replacement, addition, or modification of components listed below. Replace Modify ------- ------ Write PCBA Read PCBA Preamp PCBA M8950 (master units only. Qty. =9) Cable (Write PCBA to A2TB1-9 Ground Cable Preamp PCBA) Preamp PCBA) Preamp_PCBA_bracket Special Instructions: --------------------- o All old hardware that is removed from the drive is to be returned to the local logistics stockroom to be scrapped. It cannot be returned for credit. Prerequisites: -------------- o Start/stop ramps, vacuum pressures, capstan perpendicularity and head skew must be properly adjusted as per the TU78 Technical Manual Volume 2 or the TA78 Service Manual. o The forward/reverse ratio check should be performed as per the instructions provided with the head positioning fixture (29-26160). It is also available as Tech Tip TU78-TT-61 and TA78-TT-08. _ _ _ _ _ _ _ | FCO TA78-I004 | | | | | | | | | |d|i|g|i|t|a|l| | PAGE 7 OF 20 |_|_|_|_|_|_|_| | | _______________________________|_________________________________________ INSTRUCTIONS: ------------- 1. Run the functional diagnostics for your tape transport system in PE and GCR. Ensure that there are no hard drive errors prior to installing this FCO. 2. Power the unit down at the main power controller (874-E). ************************************************************** * "WARNING" * * * * INSURE THAT ALL MAIN A/C BREAKERS ARE TURNED OFF * * ON ALL POWER CONTROLLERS BEFORE PROCEEDING. * ************************************************************** 3. Remove the sheet metal cover on the back of the drive to gain access to A2TB1. 4. Remove the clear plastic cover from the A2TB1 terminal block by removing the two 6 X 32 5/8 inch screws. See Figure Figure 1. 5. Locate the white 8 inch ground wire. It connects A2TB1-9 to ground. 6. Disconnect both ends of the ground wire. 7. Leaving the terminal lugs on, cut the wire in two specified lengths as per Figure 1. _ _ _ _ _ _ _ | FCO TA78-I004 | | | | | | | | | |d|i|g|i|t|a|l| | PAGE 8 OF 20 |_|_|_|_|_|_|_| | | _______________________________|_________________________________________ Figure 1: A2TB1 Ground Cable _ _ _ _ _ _ _ | FCO TA78-I004 | | | | | | | | | |d|i|g|i|t|a|l| | PAGE 9 OF 20 |_|_|_|_|_|_|_| | | _______________________________|_________________________________________ 8. This will leave you with two pieces. One that is 1 1/4 inches long, and a second that is 6 3/4 inches long. Put the longer one aside. You can use this to prepare for your next FCO or if you damage the 1 1/4 inch wire. 9. Strip 1/8 inch of the insulation off the end of the 1 1/4 inch piece. 10. Install the supplied terminal lug (90-07927) to the stripped end of the wire. Use the crimping tool that is part of your F-S tool kit. 11. Test the integrity of the crimp by pulling on the terminal lug to ensure it has been crimped correctly and then check it with a DVM to ensure continuity. 12. Reinstall one end of the 1 1/4 inch wire to A2TB1-9. 13. Position the other end of the 1 1/4 inch wire over the hole of the left hand standoff that the plastic cover was originally mounted to. 14. Screw the (supplied) standoff (90-00001-04) into the original standoff. 15. Ensure that the terminal lug is located in between the old and the new standoffs. 16. Screw the other (supplied) standoff (90-00001-04) into the right hand side standoff. 17. Mount the plastic cover back on being sure to use the two (supplied) 6-32 x 1/4 inch screws (90-06020-01). Note that the original screws will be too long. 18. Reinstall the sheet metal panel that you removed in step 3. 19. Perform the next instruction if the drive is a master. If not, then proceed to step 26. 20. Remove the 9 (nine) M8950 PCBAs from the formatter. 21. Check the revision levels of the M8950 PCBAs. If they are Revision S1 then reinstall the M8950 PCBAs and proceed to step 26. If they are Revision R or below, then continue to the next step. 22. Remove and replace the following capacitors on each of the 9 (nine) M8950 PCBA's. See Figure Figure 2. Remove Add ------------ ------------ C38 (3300pf) C38 (1500pf) 1 per M8950 PCBA _ _ _ _ _ _ _ | FCO TA78-I004 | | | | | | | | | |d|i|g|i|t|a|l| | PAGE 10 OF 20 |_|_|_|_|_|_|_| | | _______________________________|_________________________________________ Figure 2: Replacing Nine (9) Capacitors _ _ _ _ _ _ _ | FCO TA78-I004 | | | | | | | | | |d|i|g|i|t|a|l| | PAGE 11 OF 20 |_|_|_|_|_|_|_| | | _______________________________|_________________________________________ 23. If you have a M8950 PCBA that is Revision N or less, then mark the handle "P3" with the supplied brady markers. If it is Revision R, then scratch out the "R" on the handle using a screw driver tip and inscribe an "S", or if available use brady markers to describe these modules as S1. If they must be scrathched, they will be re-marked should they be returned for repair, but the marking must be done carefully. The part number for the brady markers for the letter "S" is 36-19209-19. (Brady marker part numbers are 36-19208-01 through -10 for numbers 1 to 10 and 36-19209-01 through -26 for letters A to Z.) 24. Reinstall the M8950 PCBAs and power up the drive. Check P.E. Gains (See page 14). 25. Run the data reliability test for your tape system to ensure the data integrity before continuing to the next step. 26. Power down the drive at the main power controller (874-E). Remove the Read PCBA (29-23762). ************************************************************** * "WARNING" * * INSURE THAT ALL MAIN A/C BREAKERS ARE TURNED OFF * * ON ALL POWER CONTROLLERS BEFORE PROCEEDING. * ************************************************************** 27. Check to see if the vendor part number on the Read PCBA is 107856-01 or 107856-02. If it is 107856-01, then continue to step 28. If it is 107856-02, then replace the Read PCBA and go to step 32. 28. Remove and replace the following capacitors on the Read PCBA. See Figure 3. Remove Add --------------------- ------------------------- (150pf) C139, 239, 339, (330pf) C139, 239, 339, 439, 539, 639, 439, 539, 639, 739, 839, 939. 739, 839, 939. (33pf) C142, 242, 342, (68pf) C142, 242, 342, 442, 542, 642, 442, 542, 642, 742, 842, 942. 742, 842, 942. 29. Change the vendor part number to 107856-02 using the supplied label. 30. Replace the Read PCBA and apply power to the drive. 31. Run the data reliability test for your tape system to ensure the data integrity before continuing to the next step. There should be no hard errors. _ _ _ _ _ _ _ | FCO TA78-I004 | | | | | | | | | |d|i|g|i|t|a|l| | PAGE 12 OF 20 |_|_|_|_|_|_|_| | | _______________________________|_________________________________________ 32. Power down the drive at the main power controller (874-E). Remove the cable that connects the Preamp PCBA to the Write PCBA. ************************************************************** * "WARNING" * * INSURE THAT ALL MAIN A/C BREAKERS ARE TURNED OFF * * ON ALL POWER CONTROLLERS BEFORE PROCEEDING. * ************************************************************** 33. Remove the Write PCBA (29-23763). 34. Remove the Preamp PCBA bracket assembly. Retain the 4 (four) screws, lock washers, flat washers and lower flange. These will be used to mount the new Preamp bracket. 35. Install the new (supplied) Write PCBA (29-26254). 36. Mount the Preamp PCBA (29-26255) onto the Preamp bracket (supplied) using the four (4) 6-32 x 1/2 inch screws and four (4) #6 washers, but do not tighten fully at this time. 37. Mount the Preamp PCBA/Preamp bracket assembly that you have just assembled into the drive using the original hardware that you saved when you removed the original Preamp bracket assembly. Ensure that the head is properly engaged into the plug before tightening screws. Now tighten hardware from step 36 and this step. 38. Attach the Preamp shield (supplied) onto the Preamp bracket assembly using the four (4) 6-32 x 5/16" screws and four (4) #6 washers. 39. Attach the Preamp test point cover onto the Preamp shield using the two (2) 4-40 x 3/16" screws. 40. Install the new cable (Write PCBA to Preamp PCBA) in the same configuration as the original cable. The cable ends are labeled as to their destination and keyed for orientation. 41. Power up the drive. 42. Check P.E. Gains and run the functional and data reliability tests for your tape system to ensure the data integrity before continuing to the next step. There should be no hard errors. 43. Mount the label (TX78U) inside the drive front door on the bottom left. 44. Fill in the supplied revision label as "changed to" H3. The "changed from" should be the present revision of your drive. Also, fill in your name and the date. 45. Mount the revision label on the back door to the right of the existing label. 46. Perform the following adjustment procedure. _ _ _ _ _ _ _ | FCO TA78-I004 | | | | | | | | | |d|i|g|i|t|a|l| | PAGE 13 OF 20 |_|_|_|_|_|_|_| | | _______________________________|_________________________________________ Figure 3: Replacing the 150pf and 33pf Capacitors _ _ _ _ _ _ _ | FCO TA78-I004 | | | | | | | | | |d|i|g|i|t|a|l| | PAGE 14 OF 20 |_|_|_|_|_|_|_| | | _______________________________|_________________________________________ READ GAIN/WRITE CURRENT ADJUSTMENT PROCEDURE: --------------------------------------------- The Read Gain/Write Current Adjustment Box allows the field engineer to accurately and conveniently adjust both the PE read gains and the GCR write current. The procedure for adjusting the write current allows adjustment to be performed as per ANSI standards. The Adjustment Box is not intended as a debug tool, however it's failure to operate properly indicates the need for corrective maintenance. a. Read Gain In the Read Gain mode, the box simply compares the peak signal amplitude with an internal reference. The LED's indicate if the signal is too HIGH or too LOW. A narrow window, where neither LED is on indicates ideal adjustment. b. Write Current (Three parts) 1. The box must calibrate itself to the particular drive by finding the "Calibration" point. This is done by increasing the write current to beyond the 100% saturation point while watching the LED's. 2. A standard reference point, known as the "95% Output" point must be determined. This is done by decreasing the write current to below the 100% saturation point while watching the LED's. 3. The final current setting, known as the "115% Current" point must be determined. This is done by removing the "clip- lead" from the Write PCBA (as indicated in the procedure), which provides a specific multiplication of the write current obtained in the previous step. _ _ _ _ _ _ _ | FCO TA78-I004 | | | | | | | | | |d|i|g|i|t|a|l| | PAGE 15 OF 20 |_|_|_|_|_|_|_| | | _______________________________|_________________________________________ INITIAL SET-UP: --------------- 1. Power down the transport. ************************************************************** * "WARNING" * * INSURE THAT ALL MAIN A/C BREAKERS ARE TURNED OFF * * ON ALL POWER CONTROLLERS BEFORE PROCEEDING. * ************************************************************** 2. Connect the Read Gain/Write Current Adjustment Box as follows (see Figure 5 and Figure 4). a. Connect Red Wire to, U13 pin 3 on the Preamp PCBA. (Regulator +VDC) b. Connect Green Wire to, U14 pin 3 on the Preamp PCBA (Regulator -VDC) c. Connect Black Wire to, Ground wire on the Preamp PCBA d. Connect White Wire to, Test point 1-9 as applicable during the adjustment. See legend on adjustment box. 3. Power up the transport. 4. Load a master output tape to BOT and place drive off-line. 5. Set the AGC switch (located on the Read PCBA) to the right or "Off" position. 6. Set the MIA PCBA switches as follows; TU/TA78 S1-S4 to the right, U196 all switches forward. 7. Using a DVM, measure across TP2 (+), and TP24 (-) on the Write PCBA. If necessary, adjust R103 on the Write PCBA until this voltage is equal to 4.5V + or - .1V. _ _ _ _ _ _ _ | FCO TA78-I004 | | | | | | | | | |d|i|g|i|t|a|l| | PAGE 16 OF 20 |_|_|_|_|_|_|_| | | _______________________________|_________________________________________ READ GAINS ADJUSTMENT: ---------------------- 8. Place switch "S3" on the MIA PCBA to the left (1600). 9. Set the Read Gain/Write Current Adjustment Box into READ GAIN mode. 10. Connect the Adjustment Box white lead to TP1 on the Preamp PCBA. 11. Place the drive on-line. The tape should now be moving forward writing an all 1's pattern in PE mode. 12. Adjust track one on the Read PCBA by watching the "High" and "Low" LED's on the Adjustment Box. If the "Ready/High" LED is on, rotate the potentiometer to the left. If the "Low" LED is on, rotate the potentiometer to the right. Both LED's will be out or flickering with approximately the same intensity when the adjustment is correct. 13. Perform this adjustment on all 9 tracks. 14. Place the drive off-line and rewind the tape. 15. Move switch "S3" on the MIA board to the right (6250). Switches 1-4 on the MIA PCBA should all be in the same position at this time. WRITE CURRENT ADJUSTMENT: ------------------------- 16. Install a jumper between TP7 and TP24 on the Write PCBA. 17. Connect Adjustment Box wire "Test Point 1-9" (white) to TP5 on the Preamp PCBA. 18. Set the Read Gain/Write Current Adjustment Box into the WRITE CURRENT mode. _ _ _ _ _ _ _ | FCO TA78-I004 | | | | | | | | | |d|i|g|i|t|a|l| | PAGE 17 OF 20 |_|_|_|_|_|_|_| | | _______________________________|_________________________________________ 19. With the tape at BOT, place the drive on-line. The tape should now be moving forward writing an all 1's pattern in GCR mode. 20. Push the reset switch on the test box. The "Ready/High" LED will now be lit. 21. Rotate R103 to the right until the "Ready/High" LED goes out. Ignore the "Low" LED during this step. You have now located the "Calibration" point. 22. Now rotate R103 to the left. The "Ready/High" Led will light up again. 23. Continue rotating R103 in the to the left until the"Ready/High" LED goes out. If you go too far, the "Low" LED will light up. Both LEDS will be out or flickering with approximately the same intensity when the adjustment is correct. This is the "95% Output" point. Do not take more than 30 seconds to perform this step as the calibration may drift. If you take too long or want to repeat the adjustment, go to Step 22. 24. Remove the jumper from between TP7 and TP24. This sets the write current saturation to the "115% Current" point. 25. Recheck the Voltage between TP2 (+) and TP24 (-) on the Write PCBA. An acceptable reading is between 4.3V and 5.5V. Any other reading indicates that you have installed the FCO incorrectly or that you have defective hardware or adjustment box. A reading below 4.3V is an indication of a worn out head. 26. Check the read gains using the read gains adjustment portion of this procedure. Adjust the gains if necessary. This is done to ensure that none of the tracks have changed due to the write current adjustment. 27. Set the AGC switch (located on the Read PCBA) to the left or "AGC" position. 28. Set the MIA PCBA switch S4 to the left. 29. The read gains and the write current are now adjusted. _ _ _ _ _ _ _ | FCO TA78-I004 | | | | | | | | | |d|i|g|i|t|a|l| | PAGE 18 OF 20 |_|_|_|_|_|_|_| | | _______________________________|_________________________________________ Figure 4: Read Gains/Write Current Adjustment Box and Preamp PCBA _ _ _ _ _ _ _ | FCO TA78-I004 | | | | | | | | | |d|i|g|i|t|a|l| | PAGE 19 OF 20 |_|_|_|_|_|_|_| | | _______________________________|_________________________________________ Figure 5: Adjustment Potentiometers Location of Adjustment Potentiometers ------------------------------------------------------------------------ S1 S2 S3 S4 : U196 : MIA =================================================================== TRACKS 2 8 1 9 3 5 6 7 4 [] [] [] [] [] [] [] [] [] READ ==================================================================== REV.U R906 R806 R706 R606 R506 R406 R306 R206 R106 S1 TRACKS 1 2 3 4 5 6 7 8 9 [] [] [] [] [] [] [] [] [] READ ==================================================================== REV. V R906 R806 R706 R606 R506 R406 R306 R206 R106 S1 [ ] WRITE ==================================================================== R103 CNTL M2 ==================================================================== S1 [ ] [ ] [ ] [ ] [ ] CAPSTAN ================================================================== R66 R78 R59 R179 R47 [ ] [ ] [ ] REEL SRV ================================================================== R91 R76 S1 R52 _ _ _ _ _ _ _ | FCO TA78-I004 | | | | | | | | | |d|i|g|i|t|a|l| | PAGE 20 OF 20 |_|_|_|_|_|_|_| | | _______________________________|_________________________________________ LARS USA GIA EUROPE Activity - Contract and Warranty W U Y Non Contract/Non Warranty F F F DEC Option TA78 TA78 TA78 Type of Call M M M Action Taken D D I Fail Area-Module-FCO-Comments TA78-I004 TA78-I004 TA78-I004 Material Used EQ-01455-01 EQ-01455-01 EQ-01455-01 \^ TA78 \\TA78 \\TA78-I004 \\CARLIN \\1988 \\APR \\FCO_DOCS