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						 The Commodore PET 
						(Model : CBM 8096)  | 
					 
				 
				
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						 Photos of my CBM 
						8096  | 
					 
					
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						| I obtained this machine from its 
						original owner, it was used in a photo developing and 
						printing business until it was retired - probably in the 
						late '80s. Chris had done a reasonable job of cleaning 
						up the outside before putting it on ebay, it was in good 
						cosmetic condition, with no evidence of the rust that I 
						had seen on some other ebay PET/CBMs.  
						The keyboard was a bit grubby and a look through the 
						cut-outs for the expansion connectors confirmed that it 
						was not quite so pristine inside.  | 
						
						 
						
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						| My first view inside a Commodore PET/CBM 
						computer! To get to the inside of the computer, the 
						lid is flipped up, rather like a car bonnet - the 
						similarity goes even further when you see the lift up 
						support bar at the left. 
						In this photo, the top of the case is overextended - 
						beyond the reach of the support bar and is actually 
						resting on the rear of the monitor housing. The front of the 
						case is raised about 4" off the surface of the desk 
						that it 
						is sat on. To allow the top to be tilted this far back, 
						the keyboard connector has been removed. 
						Since last used, the machine had been consigned to an 
						(apparently very dusty) attic. 
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						| This photo shows the edge of the hinge 
						that allows the upper half of the case and integrated 
						monitor to swing clear of the base. Looking into the 
						base of the monitor you can see the PCB for the monitor 
						and wires between the monitor and the base - brown for 
						AC power from the transformer and the multi-coloured 
						wires for the VDU signals.  | 
						
						 
						
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						As you can see, a good clean was 
						required on the inside - a thick layer of dust was 
						covering everything, but apart from the grime, the 
						inside also appeared to be in very good condition. 
						The large white plug resting on the upper PCB  is the 
						connector for the keyboard interface cable that connects 
						below the monitor, 
						disconnected to allow the case to open fully. The 
						mains transformer is at the rear left, the 8032 
						motherboard is at the lower board and the extra 
						64k RAM card sits on top of it.    | 
						
						 
						
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						| The 64K mezzanine board is attached to 
						the main board and chassis by four cross-head screws and 
						the main board is attached to the base by three screws 
						and three plastic posts. Cleaning of the PCBs and the 
						bottom half of the case is obviously much easier with 
						the boards removed. 
						With the dust etc. removed, you can see that the 
						metal base is in excellent condition, with hardly a 
						blemish on it. There is a small amount of surface 
						corrosion on the transformer and around the spot welds 
						of the hinge support,  | 
						
						 
						
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						| Solder side of the main board | 
						
						 
						
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						| The 64kB expansion RAM board  | 
						
						
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						| The 64kB expansion RAM board  | 
						
						
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						| When the machine was reassembled and 
						powered on, it started up with an encouraging CBM 8000 
						series "chirp" and the screen displayed the "basic 4.0" 
						welcome screen, but only reported "15359 bytes free".
						 A CBM 8096 should report "31743 bytes free", i.e., 
						there appears to be a RAM fault on the main board.  | 
						
						 
						
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						| Having found the faulty RAM, with the chip replaced, the upper 
						16K is now visible and the system correctly reports 
						"31743 bytes free", See the
						RAM fault repair 
						page for the details  | 
						
						 
						
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						 Photos of my CBM 
						8250 Dual Disk Drive  | 
					 
					
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						| The inside of the 8250 disk unit. 
						Although it may not be obvious from the photo, the 
						amount of dust inside the case was even greater than in 
						the PET itself. 
						Again, a good dose of cleaning will be required, 
						particularly inside the drives themselves to make sure 
						that all traces of dust/debris are removed from the 
						drive heads.  | 
						
						 
						
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						| With the drives removed and the case 
						given a good clean, you can see that, like the 8096, the 
						chassis is in pretty good condition with no obvious 
						corrosion present. The power cord is terminated under 
						the rectangular metal shroud in the upper left corner of 
						the photo. The original power cord had been cut off 
						close to the case, although not visible in the photo, I 
						replaced it while I had the drives removed for cleaning.  | 
						
						
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						| After giving them a bit of a clean, the 
						drives looked to be in reasonable condition for their 
						age, but they had not actually been tested at this 
						point. As the photo shows, PET drives have no 
						electronics on them, the signals from the disk sensors, 
						motors, heads and LEDs for both drives are cabled to a 
						common disk control board mounted on top of the right 
						hand drive (drive 0).  | 
						
						
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						| A better view of the read/write heads, 
						drive motors and the worm drive from the head stepper 
						motors.
						 A small amount of corrosion is visible on the head 
						stepper motor mounting, but does not look too serious.  | 
						
						
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						| The underside of the drive, showing the 
						belt drive for the disk motor and the timing wheel fixed 
						to the drive spindle with calibration marks for 50Hz and 
						60Hz. The label shows that the drive is a
						
						Micropolis 1006-IV    | 
						
						
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						| The dual disk controller board is 
						mounted on top of the right hand drive (drive 0).   | 
						
						
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						| Solder side of the dual drive controller 
						board | 
						
						
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						Drives replaced, controller board 
						refitted . . . . . 
						
							it's now looking a little more presentable than 
							when I received it.   
							Let's hope it works ! 
						 
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						| Time passes . . . . . . . 
						 Well, that was a surprise, I don't have 
						any PET disks, other than the Commodore 8250 "Demo" disk 
						that I got with the system. 
						 
						As you can see, the disk can be read - this is using 
						drive 0, but drive 1 gives the same results.   | 
						
						
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