wtm@uhura.neoucom.EDU (Bill Mayhew) (12/09/90)
The most likely result of plugging the monitor cable into the 3b1 motherboard upside down is blowing out the fuse in the monitor. If you are lucky, you may replace the fuse and be back in business. If not, the monitor is hosed, and it is time to start poking around at electronic flea markets.... There are several different 3b1 monitors. Depending on what you have, there is either a small tubular glass fuse or else a soldered-in fuse. The former type of fuse looks like an older style automotive fuse. The latter type fuse looks like a 1/8th watt resistor with a thin plastic skin over it. Before proceding, heed safety precautions. Initiate a shutdown procedure on the 3b1 and park the disk drive with the diagnostic utility if required. Good luck on this without the video monitor! Barring that, treat the system very gently to avoid jarring the winchester disk heads with subsequent damage to the magnetic surfaces. Next, power off the system and unplug it from the wall. Allow the system to rest for 20 minutes before attempting repair on the monitor. Time is required for any static electric charge on the CRT to dissipate. What the static charge may or may not cause a lethal shock, you could be startled, cause damage to the CRT and thus risk injury from imploding glass fragments. Even if the system has been turned off, you should treat eveything as if it were still a live circuit, just in case. There are two screws on the back of the monitor, which when removed, will allow the back of the case to slide off. Trace from where the braided shielded power/signal cable from the motherboard enters the monitor. One of the two thickest traces should eventually lead to the fuse. Replace clip fuses with units of same type and rating. It is probably easiest to piggy-back a new soldered-in type fuse (of same rating) on top of the old fuse without removing the old fuse. Refer work to a person wlith competent soldering skills. Check carefully for errant specks of solder and remove after you finish. Last, visually inspect the monitor for dust, foreign objects, etc. before replacing the cover. There is apparently no fuse on the motherboard monitor power (12v from J9), so the monitor itself is the place to look for truouble. Good luck. ==Bill== -- Bill Mayhew NEOUCOM Computer Services Department Rootstown, OH 44272-9995 USA phone: 216-325-2511 wtm@uhura.neoucom.edu ....!uunet!aablue!neoucom!wtm via internet: (140.220.001.001)