Manuale d’uso / di manutenzione del prodotto XPS H233 del fabbricante Dell
Vai alla pagina of 89
'HOO'LPHQVLRQ ;36+DQG;36+6VWHPV 6(59,&(0$18$/ ®.
.
'HOO'LPHQVLRQ;36 +DQG;36+6VW HPV 6(59,&(0$18$/ ®.
Information in this manual is subject to change without notice. 1997 Dell Computer Corpor ation. All rights reserved. Reproduc tion in an y man ner whatsoev e r wit hout the written perm i ssion of Del l Co mput er Co rporat io n is strictl y forb idden .
v Contents Chapter 1 System Ov erv iew . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 System Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 Advanced Expansion Subsystem . .
vi Chapter 3 Beep Codes an d Err or Me ssages . . . . . . . . . . . . . . . . . . 3-1 POST Beep Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1 System Error Messages . . . . . . . . . . . . . . . . .
vii Advanced Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-7 Peripheral Configuration Submenu . . . . . . . . . . . . . . . . . . . . . . . . . .A -8 Chipset Configuration Submenu . . . . . . . . . . . .
viii Figure 4-14. Microprocessor-Fan Assembly Removal . . . . . . . . . . . . . . . 4-14 Figure 4-15. Card-Guide Assembly Removal . . . . . . . . . . . . . . . . . . . . . . 4-15 Figure 4-16. Control-Panel Board Removal . . . . . . . . . . . . . . . .
ix Table A-8. Security Screen Categories . . . . . . . . . . . . . . . . . . . . . . . . . .A-12 Table A-9. Power Screen Categories . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-13 Table A-10. Exit Screen Categories . . . . . . . . . . . . .
R ead This First W arnings, Cautio ns, and Notes Throughout this manual, there may be blocks of text printed in bold t ype or in italic type. These blocks are warnings, cautions, and notes, and they are used a s follows: NO TE: A NO TE pr o vides helpful information about using the computer sy stem.
System Over vie w 1-1 Chapter 1 System Overview T he Dell Dimension ® XPS H233 and XPS H266 systems are high-speed, single-processor computer systems that use an Intel ® Pentium ® II micro- processor with MMX ™ technology . These Dell ® systems incorporate an ISA expansion bus as well as a high-performance PCI local bus.
1-2 Dell Dime nsion XPS H233 and X PS H266 S ystem s Serv ice Manu al S ystem Features In addition to the standard features found in a traditional PC, the Dell Dimension XPS H233 and XPS H266 systems .
System Over vie w 1-3 Figure 1-1. Computer Orientation CAUTION: T o avoid possible data or f ile structure corruptions, the reset button shoul d only be use d when th e syste m cann ot be reboo ted by press - ing <Ctrl><Alt><Del>.
1-4 Dell Dime nsion XPS H233 and X PS H266 S ystem s Serv ice Manu al Figure 1-2. Desktop C om put e r Featur es microprocessor fan system board secondary hard-disk drive bracket card guide assembly and primary hard-disk drive power supply 3.
System Over vie w 1-5 Figure 1-3. Mini T ower Computer Features expansion-card slots microprocessor fan system board secondary hard-disk drive bracket card guide assem bly and primary hard-disk drive power supply drive bays (typical) 3.
1-6 Dell Dime nsion XPS H233 and X PS H266 S ystem s Serv ice Manu al F i g u r e 1 - 4 . B a c k -Panel Featur es (T ypical) Advanced Expansion Subsystem This computer system of fers an advance d exp.
System Over vie w 1-7 Chapter 2, “Using Configuration Software,” in the Refer ence Guide and the “Confi guri ng E xpa nsion Cards ” sec tion in the on line System User’ s Guide (located in the Dell Accessories folder ) provide instructions for using the ICU to configure legacy ISA expansion car ds.
1-8 Dell Dime nsion XPS H233 and X PS H266 S ystem s Serv ice Manu al C omputer Service The following subsections provide service-related information about the computer . Power Supply The 200-W powe r supply can operate f rom an AC power sour ce of 1 15 V AC at 60 Hz or 230 V AC at 50 Hz .
System Over vie w 1-9 DC Power Distribution Figures 1-5 through 1-9 provide the following information about DC power distribution: • Power-supply cable identification • T ypical DC power connectio.
1-10 Dell Dime nsion XP S H233 and XPS H266 S ystems Servic e Manu al Figure 1-6. DC Power D istribution 3.3 VDC P2 secondary hard-disk drive (uses Y-cable) +5 VDC –12 VDC GND +12 VDC +5 VDC +5 VDC GND GND J9D1 –5 VDC –5 VDC +5 VDC +12 VDC power supply PWRGOOD P1 3.
System Over vie w 1-1 1 DC Power Connector Pin Assignments The power-supply output voltages can be measured at the back ( wire side) of the DC power connectors without disconnecting them.
1-12 Dell Dime nsion XP S H233 and XPS H266 S ystems Servic e Manu al Figure 1-8. DC Power Connectors P2, P3, P4, P5, and P6 Figure 1-9. DC Power Connector P7 1234 +5 V DC (red) common (black) common (black) +12 VDC (yellow) P2, P3 , P5, P6 12 3 4 +5 VDC (red) common (black) common (black) +12 VDC (yellow) P4 45 6 +3.
System Over vie w 1-13 System Board The subsections that follow provide service-related infor mation about system board components. Figure 1-10 . System Boar d Featur es Main Memory The four SIMM sockets can accommodate one or two pairs of EDO SIMMs.
1-14 Dell Dime nsion XP S H233 and XPS H266 S ystems Servic e Manu al System Board Jumpers See Figure 1-1 1 and T able 1-2 for jumper settings and descriptions.
System Over vie w 1-15 T able 1-2. System-Board Jumper Descriptions Jumper Settings Description A, pins 1-3; B, pins 1-6; C, pins 1-3 (microprocessor speed) The microprocessor ’ s internal speed i s 233 MHz . The microprocessor ’ s internal speed i s 266 MHz .
1-16 Dell Dime nsion XP S H233 and XPS H266 S ystems Servic e Manu al I nterrupt Assignments T able 1-3. Interrupt Assignment s IRQ Line Used By/Available IRQ0 Generated by system timer . IRQ1 Generated by I/O c ontroller to indicate full keyboard output buffer .
System Over vie w 1-17 D MA Channel Assi gnments T able 1-4. D MA Channel A ssignmen ts DREQ Line Used By/Available DREQ0 Default audio DMA channel assignment DREQ1 Default audio DMA channel assignmen.
1-18 Dell Dime nsion XP S H233 and XPS H266 S ystems Servic e Manu al T echnic al Specifications T able 1-5. T echnical Specifications Micropr ocessor Microprocessor type . . . . . . . . . Intel Pentium II microprocessor w it h MM X technology Microprocessor speeds .
System Over vie w 1-19 System Cl ocks System clock frequency . . . . . . 66 MHz (matches external proce ssor speed) Diskette/communicatio ns ports frequency . . . . . . . . . . . . . 24 MHz (de rived from system clock) Memory SIMM sockets . . . . . . .
1-20 Dell Dime nsion XP S H233 and XPS H266 S ystems Servic e Manu al Ports Externally ac cessible: Serial (DTE) . . . . . . . . . . . . 9-pin connector Parallel (bidirectional) . . . . 25-hole connector PS/2-style keyboard . . . . . . 6-pin mini-DIN c onnector PS/2-compatible mouse .
System Over vie w 1-21 Power DC power supply: W attage . . . . . . . . . . . . . . . . 200 W Input voltage . . . . . . . . . . . . 90 to 135 V AC at 60 Hz or 180 to 265 V AC at 50 Hz Heat dissipation. . . . . . . . . . 778 BTUs (fully loaded system without monitor) System battery .
1-22 Dell Dime nsion XP S H233 and XPS H266 S ystems Servic e Manu al Environmental (continu ed) Maximum shock: Operating . . . . . . . . . . . . . . left side (for mini tower orientation) and bottom half-sine pulse with a change in velocity of 50.8 cm/sec (20 inches/sec) Storage .
Basic T roubl eshooti ng 2 -1 Chapter 2 Basic T roubleshooting T his chapter describes basic troubleshooting procedures that can help you diagnose a computer system problem. These procedure s can often reveal the source of a problem or indicate the correct starting point for troubleshooting the system.
2-2 Dell Dime nsion XPS H233 and X PS H266 S ystem s Serv ice Manu al E xternal V isual Inspection The external visual inspection co nsists of a quick inspection of the exterior of the computer , the monitor , the keyboard, any peripherals, and ca bles.
Basic T roubl eshooti ng 2 -3 8. Inspect the exte rior of the comp uter , including all controls, indicato rs, and user-accessible data storage devices for any signs of physical damage. Does the inspection reveal any problems? Ye s . Refer to the appropriate procedure in Chapter 4, “Removing and Replacing Parts.
2-4 Dell Dime nsion XPS H233 and X PS H266 S ystem s Serv ice Manu al 4. While the boot r outine is running, observe the computer for any of the following: • Diskette-drive and hard-disk drive a ccess indicator activity These indicators light in response to data being transferred to or from the drives.
Basic T roubl eshooti ng 2 -5 2. Remove the com puter cover . NOTE: For your safety and pr ot ection of th e system, observe the guidelines listed in “Pr ecautionary Measur es” in Chapter 4. 3. V erify th at the si ngle-e dge contact (SEC ) cartr idge, SIMM s, and e xpan- sion cards ar e fully seated in their sockets or connectors.
2-6 Dell Dime nsion XPS H233 and X PS H266 S ystem s Serv ice Manu al Expansion Subsystem” in Chapter 1 for information on the Device Manager and the ICU.
Beep C ode s and Er ror Mess age s 3-1 Chap te r 3 Beep Codes and Error Messages T his chapter describes beep c odes and system error messages that can occur during system start-up or , in the case of some failures, during normal system operation. In some cases, the system may display error messages a nd emit beep codes simultaneously .
3-2 Dell Dime nsion XPS H233 and X PS H266 S ystem s Serv ice Manu al T able 3-1. POST Beep Codes Beep Code Error Probable Causes 1 Memory refresh fa ilure. Defective system board. 2 Memory parity error . A SIMM is faulty . Replace all of the SI MMs. Defecti ve system bo ard.
Beep C ode s and Er ror Mess age s 3-3 S ystem Error Messages Some system e rror messages indicate a fatal e rror , in which case the system cannot usually be rebooted until an appropriate hardwa re change has been made.
3-4 Dell Dime nsion XPS H233 and X PS H266 S ystem s Serv ice Manu al CMOS Battery State Low System battery not maintaining conte nts of NVRAM. System battery at or near depletion of its charge. CMOS Checksum Failure NVRAM checksum value changed since NVRAM contents were saved.
Beep C ode s and Er ror Mess age s 3-5 Diskette Boot Failure System cannot boot from diskette in drive A. Di ske tte in dr ive A does not contain boot- able operating system, or bootable operating system is corrupt. DMA #1 Error Error condition occurred in DMA channel 1.
3-6 Dell Dime nsion XPS H233 and X PS H266 S ystem s Serv ice Manu al Invalid Boot Diskette System cannot boot from diskette in drive A. Diskette in drive A contains no operating system. Diskette in drive A is faulty . Drive A interfa ce or power cable faulty or improperly connected.
Removi ng and Re placing Parts 4-1 Chapter 4 Removing and Replacing Parts T his chapter provides procedures f or removing and replacing components, assemblies, and subassemblies of the computer . Unle ss otherwise noted, each procedure assumes the following: • The computer cover has alre ady been removed.
4-2 Dell Dime nsion XPS H233 and X PS H266 S ystem s Serv ice Manu al C omputer Cover Figure 4-1. Computer Cover Removal T o remove the computer cover from a desktop or mini tower system, follow these s teps: 1.
Removi ng and Re placing Parts 4-3 F ront Bezel Figure 4-2. Front-Bezel Removal (Mini T ower Chassis) Figure 4-3. Front-Bezel Removal (Desktop Chassis) T o remove the front bez el, follow these steps: 1. Press the thr ee tabs along the edge of the front bezel.
4-4 Dell Dime nsion XPS H233 and X PS H266 S ystem s Serv ice Manu al D riv es The following subsections explain how to remove the front-panel inserts, drive cage, and the various types of drives in the drive bays.
Removi ng and Re placing Parts 4-5 Drive Cage Figure 4-5. Drive Cage Removal NOTE: The drive cage is the same in both the desktop and mini tower comput- ers. The drive cage in the mini tower computer is mounted 90 degr ees clockwise fr om the one shown in Figur e 4-5.
4-6 Dell Dime nsion XPS H233 and X PS H266 S ystem s Serv ice Manu al 5.25-Inch Drive Figure 4-6. 5.25-Inch Drive Removal T o remove a dr ive from a 5.25-inch drive bay , follow these steps: 1. Remove t he front bezel. 2. Remove t he drive cage and drives as an assembly .
Removi ng and Re placing Parts 4-7 Upper 3 .5-In ch Dr ive Figure 4-7. Upper 3.5-Inch Drive Removal The upper 3.5-inch drive uses a drive bra cket between the drive and the right side of the drive cage. T o remove a drive fr om the upper 3.5-inch drive bay , follow these steps: 1.
4-8 Dell Dime nsion XPS H233 and X PS H266 S ystem s Serv ice Manu al Lower 3.5-Inch Drive (Mini T ower Computer O n l y ) Figure 4-8. Lower 3.5 -Inch Driv e Remova l (Mini T ower C o m p u t e r Only) The lower 3.5-inch drive attach es to the left side and bottom of the drive cage.
Removi ng and Re placing Parts 4-9 3.5-Inch Diskette Drive Figure 4- 9. 3.5-I nch Dis ke tte Dri ve Remov al T o remove the 3.5-inch diskette drive, follow these steps: 1. Remove the front bezel. 2. Disconnect the power and interface cables from the back of the 3.
4-10 Dell Dime nsion XP S H233 and XPS H266 S ystems Servic e Manu al Primary Hard-Disk Drive Figure 4-10 . Primar y Hard-Disk Dr ive Removal T o remove the primary hard-disk drive, f ollow these steps: 1. Remove t he front bezel. 2. Remove t he two mounting scre ws.
Removi ng and Re placing Parts 4-1 1 Secondary Hard-Disk Drive Figure 4-1 1. Secondary Hard-Disk Drive Assembly Removal T o remove the secondar y hard-disk drive, follow these steps: 1. Remove the front bezel. 2. Disconnect the power and interfac e cables from the back of the second- ary hard-disk drive.
4-12 Dell Dime nsion XP S H233 and XPS H266 S ystems Servic e Manu al 5. T o r emove the secondary hard-disk drive from the drive bracket, remove the scr ew fr om the side of the hard-disk drive, and then pivot the bracket away from the drive. Figure 4-12.
Removi ng and Re placing Parts 4-13 P ower Supply Figure 4-13. Power Supply Removal T o remove the power supply , follow these steps: 1. Disconn ect the AC power cable at t he power sup ply . 2. Disconnect the DC powe r cables from the POWER and J7M1 connec- tors on the system board (see Figure 4-17).
4-14 Dell Dime nsion XP S H233 and XPS H266 S ystems Servic e Manu al M icroprocesso r Fan Assembly Figure 4-14 . Microproces sor-Fan As sembly Removal T o remove the microprocessor f an assembly , follow these steps: 1. Disconnect the micropr oce ssor fan cable from the J8L1 connector on the system board (see Figure 4-17).
Removi ng and Re placing Parts 4-15 C ard Guide Assemb ly Figure 4-15. Card-Guide Assembly Removal T o remove the car d guide assembly , follow these steps: 1. Disconnect any cables connected to full-length expansion cards, and r emove these expansion c ards.
4-16 Dell Dime nsion XP S H233 and XPS H266 S ystems Servic e Manu al C ontrol Panel Board Figure 4-16. Control-Panel Board Removal T o remove the control panel board, f ollow these steps: 1. Remove t he front bezel. 2. Remove t he card guide assembly .
Removi ng and Re placing Parts 4-17 S ystem Board Comp onents Figure 4-17 shows the locations of components on the system board. The sub- sections that follow explain how to remove various s y s t e m b o a r d c o m p o n e n t s .
4-18 Dell Dime nsion XP S H233 and XPS H266 S ystems Servic e Manu al Expansion Cards Figure 4-18. Expansion Card Removal T o remove an e xpansion card, follow these steps: 1.
Removi ng and Re placing Parts 4-19 SIMMs Figure 4- 19 . SIMM Re moval T o remove a SIMM, push outward on each of the SIMM socket’ s metal tabs (see step 1 of Figure 4-19), a nd rotate the SIMM in the direction of the arrows (see steps 2 and 3 of Fi gure 4-19) until i t is released from i ts socket.
4-20 Dell Dime nsion XP S H233 and XPS H266 S ystems Servic e Manu al SEC Cartridge and Heat Sink Assembly Figure 4-21. SEC Cartridge and Heat Si nk Removal 1. Slide the retainer bar toward the front of the computer to remove it, being car eful not to damage the SIMMs next to the heat sink supp ort.
Removi ng and Re placing Parts 4-21 firmly seat the assembly . Up to 25 pounds of force is required to sea t the SEC cartridge. Slide the retainer bar ba ck into position on the heat sink support. Battery Figure 4- 22 . Batt er y Remov al The battery is a 3.
4-22 Dell Dime nsion XP S H233 and XPS H266 S ystems Servic e Manu al S ystem Board Figure 4-23 . Syste m Board Re moval 1. Disconnect any cables attached to the I/O panel on the back of the comp uter .
Removi ng and Re placing Parts 4-23 Figure 4-24. System Board Mountings 8. Place the syste m board on a level surface. Protect the surface with an antistatic bag or other protective material. 9. Remove the SEC cartr idge and heat sink as sembly as described in “SEC Car tridge and Heat Si nk Assembly” f ound ear lier in thi s chapter .
4-24 Dell Dime nsion XP S H233 and XPS H266 S ystems Servic e Manu al Figure 4-25 . Guide- Brack et Assem bly Removal T o install a replacement system board, install the guide bracket assembly for the SEC cartridge. The assembly is keyed for correct insertion (see Figure 4-25).
Syste m Setu p Pro gram A-1 Appendix A System Setup Program T his appendix describes the system setup program, which is used to change the system configuration information stored in C MOS and NVRAM on the sys- tem board. T o enter the system setup program, follow these steps: 1.
A-2 Dell Dime nsion XPS H233 and X PS H266 S ystem s Serv ice Manu al Main Screen Figure A-1. Main Screen T abl e A-1. Mai n Scre en Categor ies Category Function System T ime Resets time on system’ s internal clock. System Date Resets date on system’ s internal calendar .
Syste m Setu p Pro gram A-3 Secondary IDE Slave Identifies the second drive attached to the sec- ondary EIDE interface, usually a CD-ROM or tape drive. See the “Device Configuration Sub- menu” subsection in this appendix. Boot Options Displays a submenu.
A-4 Dell Dime nsion XPS H233 and X PS H266 S ystem s Serv ice Manu al IDE Device Conf iguratio n Submenu Figure A-2. IDE Device Configuration Submenu T able A- 2. IDE Device Configuration Submenu Categories Category Function IDE Device Configuration Configures individual EIDE drives.
Syste m Setu p Pro gram A-5 Boot Option s Submenu Figure A-3. Boot Options Submenu T able A-3. Boot Options Submenu Categories Category Function First Boot Device Determines which devi ce the system tries to boot from first.
A-6 Dell Dime nsion XPS H233 and X PS H266 S ystem s Serv ice Manu al Fourth Boot Device Determines which device the system tries to boot from if it cannot boot from the devices selected for First Boot Device, Second Boot Device, and Third Boot Device.
Syste m Setu p Pro gram A-7 Advanced Screen Figure A-4. Advanced Screen T able A-4. Adva nced Scre en Cate gories Category Function Processor T ype Displays type of microproce ssor installed. Processor Speed Displays internal speed of the microproce ssor .
A-8 Dell Dime nsion XPS H233 and X PS H266 S ystem s Serv ice Manu al Peripheral Configura tion Submenu Figure A-5. Peripheral Configuration Submenu T able A- 5. Perip heral Configuration Submenu Categories Category Function Primary PCI IDE In terface Configures the primary EIDE interfac e on the system board.
Syste m Setu p Pro gram A-9 Parallel Port Interfa ce Configures the built-in parallel port on t he system board. Set this category to Auto Con- figured (the default) or to Disabled, or select a specific port designation, I/O address, and I RQ line for the port.
A-10 Dell Dime nsion XP S H233 and XPS H266 S ystems Servic e Manu al Chipset Configuration Submenu Figure A-6. Chipset Configuration Submenu T able A- 6. Chipset Configuration Su bmenu Categories Category Function Base Memory Displays the maximum amount of memory available to MS-DOS programs that do not use expanded or extended memory .
Syste m Set u p Program A-1 1 Plug and Play Configurat ion Submenu Figure A-7. Plug and Play Configuration Submenu T able A- 7. Plug an d Play Configuration Submenu Categories Category Function Co n f.
A-12 Dell Dime nsion XP S H233 and XPS H266 S ystems Servic e Manu al Security Scree n Figure A-8. Security Screen T able A-8. Security Screen Ca tegorie s Category Function System Password Indicates whether a system password has been assigned. Setup Password Indicates whether a setup passwor d has been assigned.
Syste m Set u p Program A-13 Power Screen Figure A-9. Power Screen T able A-9. Power Screen Categories Category Function Advanced Power Management Enables or disables all the other categor ies on the Power scre en.
A-14 Dell Dime nsion XP S H233 and XPS H266 S ystems Servic e Manu al VESA V ideo Power Down NOTES: For the W indows 95 operating system, use the Display Pr operties dialog box in the Contr ol Panel to save monitor power rather than using the VESA V ideo Power Down cate- gory .
Syste m Set u p Program A-15 Exit Screen Figure A-10. Ex it Screen T able A-10. Exit Sc reen Categories Category Function Exit Saving Changes Saves any changes you have made, exits the system setup pr.
A-16 Dell Dime nsion XP S H233 and XPS H266 S ystems Servic e Manu al.
Index 1 Index A adapter card, 1-6, 4-18 B back-panel fe atures, 1-6 battery location, 1-13 removal, 4-21 beep codes about, 3-1 list of, 3-2 bezel removal, 4-3 boot routine observing when troubleshooti.
2 Dell Dime nsion XP S H233 and XP S H266 S ystems S ervic e Manu al E EIDE subsystem, 1-7 error messages, 3-3 expansion card configuration, 1-6 removal, 4-18 expansion-card guide, 4-15 expansion-card.
Index 3 battery, 1-13 SIMMs, 1-13 system battery removal, 4-21 system board components, 1-13 removal, 4-22 system board jumpers location, 1-14 settings, 1-15 system error messages, 3-3 system power-su.
.
® Printed in the U.S.A. P/N 8498 0.
Un punto importante, dopo l’acquisto del dispositivo (o anche prima di acquisto) è quello di leggere il manuale. Dobbiamo farlo per diversi motivi semplici:
Se non hai ancora comprato il Dell XPS H233 è un buon momento per familiarizzare con i dati di base del prodotto. Prime consultare le pagine iniziali del manuale d’uso, che si trova al di sopra. Dovresti trovare lì i dati tecnici più importanti del Dell XPS H233 - in questo modo è possibile verificare se l’apparecchio soddisfa le tue esigenze. Esplorando le pagine segenti del manuali d’uso Dell XPS H233 imparerai tutte le caratteristiche del prodotto e le informazioni sul suo funzionamento. Le informazioni sul Dell XPS H233 ti aiuteranno sicuramente a prendere una decisione relativa all’acquisto.
In una situazione in cui hai già il Dell XPS H233, ma non hai ancora letto il manuale d’uso, dovresti farlo per le ragioni sopra descritte. Saprai quindi se hai correttamente usato le funzioni disponibili, e se hai commesso errori che possono ridurre la durata di vita del Dell XPS H233.
Tuttavia, uno dei ruoli più importanti per l’utente svolti dal manuale d’uso è quello di aiutare a risolvere i problemi con il Dell XPS H233. Quasi sempre, ci troverai Troubleshooting, cioè i guasti più frequenti e malfunzionamenti del dispositivo Dell XPS H233 insieme con le istruzioni su come risolverli. Anche se non si riesci a risolvere il problema, il manuale d’uso ti mostrerà il percorso di ulteriori procedimenti – il contatto con il centro servizio clienti o il servizio più vicino.