Today's haul: Macintosh LC 475, AppleCD 300e Plus, Apple Personal LaserWriter printer, a SCSI scanner, a Performa Plus CRT, and a bunch of cables. The LC and CD drive both work fine. I had to put a new PRAM battery in the LC, and replace the Connor drive with my Quantum Maverick Prodrive to get it working. I paid £0.99 for this lot. That's about $1.60. At the moment its all very yellow and dirty, but hopefully not for much longer.
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LC 475, AppleCD 300e Plus, Personal LaserWriter, more
- Thread starter joshc
- Start date
Update: The printer does not want to power on at all. I would take a look in the PSU, as it might be the fuse or some leaky capacitors, but its really not worth my time. (It's a printer, so its evil, and therefore needs to be killed violently.) }
I did take the cover off though, for some photos:
I did take the cover off though, for some photos:
Some problems with the Personal Laserwriter series printers may be resolved by the following:
General preventative maintenance on a newly acquired vintage PLW printer:
1. Pull the cover and inspect for critters, dead or alive.
2. Outside but not in sunlight (dawn or dusk best), remove toner cartridge, keep it relatively level and upright. Using a shopvac on blow, blow out the printer mechanism and complete paper path vigorously, including all sides of the rubber foam roller in the door assembly, and blow out the toner cartridge gently. Too much air in the wrong place and you start to blow fresh toner out of its storage area. Inverting the cartridge even for a moment can result in toner pouring out of openings at both ends, so don't.
3. When not in use for long periods, remove paper from the paper tray and store paper covered, or develop the discipline to blow off the top sheet before use. Dust and dander that collects on the top of the first sheet gets carried onto the drum. Yes, crap on the top sheet can make even a new toner cartridge go bad. If it lodges under the squeegee and lifts it you get a streak that requires removing the drum and cleaning the drum, transfer roller, squeegee, and door rubber roller of excess toner. PITA, and a dirty job.
4. If status lights misbehave reseat all connectors, disassembling as required. Many screws so either maintain tight screw discipline or take photos as you go. The cable connectors fortunately are all different sized.
5. Consider inspecting and changing the surface mount electrolytics on the laser assembly and the scanner motor assembly. These are the same general type and age and more highly stressed than the infamous ones on the SE/30. If you can get the printer working by cleaning them and want to keep the printer, it is definitely worth changing them before they leak more and rot the board.
6. Consider (only for a good working keeper unit) replacing all of the electrolytics. Yes, I mean all of them. A majority of the radial leaded ones leaked fluid in all the four printers I have inspected.
7. Avoid fluids on photosensitive drum and rollers contacting the drum, help them retain whatever electrostatic properties that remain. This includes not talking when the cartridge door is uncovered to avoid spotting the drum. Any cotton balls used on the drum should be fresh and dry, and try to avoid fingerprints.
Won't power on
1. Substitute another power cord, or connect the original one to something else to verify AC is delivered to the end.
2. Verify with an ohmmeter that the power switch and the interlock switch work.
3. Reset the circuit breaker (or as appilcable, check fuse) if any inside the power supply.
4. Only if you are qualified to work on hot circuits, verify output of bridge rectifier and surge limiting NTC thermistor charges the big and deadly rail capacitor (in the US, to 160 VDC).
5. If your model of the power supply has the HA16107P IC, replace the small 47 uF electrolytic that connects to pin 1. This cap is a #$@! fix for a design problem in the IC involving rate of power application. When old the cap lets the DC power comes up too fast for pin 1 of that particular IC. Make sure the potentially fatal big rail cap has discharged. There are bleeder resistors, but they can fail.
6. Substitute power supply from a compatible parts unit (there are several kinds of mechanically incompatible supplies here in the US models, so look for a parts donor that has an identical rear panel layout).
7. Reverse engineer the schematic of the hot side of the switcher (at least two different versions of US and one or more international units) then just debug it. But make sure the bleeders have discharged that rail cap first.
Dirty prints
1. Try another toner cartridge (or even better, many). If any single one works great, the printer electronics are probably ok but there remains the interesting problem of recovering the original cartridge provided it still has appreciable toner. If any new cartridge misbehaves remove it and try debugging with other older cartridges, because a bad HV board can sometimes really crap up quickly an otherwise good cartridge.
2. Remove any air ionizer or anti-static neutralization blower devices from the vicinity of the printer. Over time and use subsequent prints may then clean up.
3. Rock the toner cartridge along the long axis, but do not invert nor tip more than 30 degrees end to end. About 20 tilts. Then blow off excess or spill outside but out of sunlight with the shop vac. This rocking triboelectrically builds static charge into the two part toner causing the fusible pigment particles to more tightly adhere to the non transferring magnetic iron carrier particles. This is where the bistable print/no print comes from. Without this charge, any residual charge on the drum can attract some toner and you get that general gray background. After charging you may have to disassemble the drum and clean both drum accumulated and spilled excess toner (this is why you do not want to exceed the angle limits) that exceeds the squeegee's ability to remove. Rocking is also useful to get the final use out of a nearly empty toner cartridge by end to end leveling of remaining toner, but the intent here is quite different. This two part toner charging is not discussed generally on the various internet printer fix-it web pages but is evident after patent searching.
4. Reinsert the cartridge and leave the printer on idling for several hours, letting it periodically cycle. When you hear it cycle up during idle it is magnetically and mechanically stirring the toner, and the static charge you induced by rocking will be more evenly distributed.
5. Don't vacuum toner, and don't blow cartridges unless you have access to an outside work area suitable for dirty cartridge work at dawn or dusk.
6. Cotton balls work well to remove small amounts of excess toner from the drum without scratching. For everything else, use a shopvac that can blow. A drum that cleans up nice but then dirties again on an otherwise good printer may need disassembly to clean the squeegee, along with a cleaning of all rollers that contact the drum. I have sucessfully disassembled and recovered drums under subdued incandescent lighting indoors. Uncertain how much UV they can take. Sunlight is harmful. So is exposure to static eliminator airstream (at least temporarily the drum will not print at all, uncertain about recovery time).
7. It may take dozens of test print pages for a printer to clean up (this means for the charge distribution on the toner, drum and rollers to stabilize and squeegee cleanup to complete) after an electrostatic upset either from recharging the toner or from a repaired high voltage board. So don't write off your printer or cartridge too soon.
Scanner malfunction:
1. Replace all of the SMT electrolytics on the scanner board, clean the board carefully and avoid touching the mirror surfaces. The caps are stressed when accelerating the mirror head up to speed. The caps, a bad driver IC and capacitor goo damage, are prime suspects when you can hear the motor first trying to get to speed but then shutting down and aborting a print.
2. Replace the scanner board with another from a donor parts unit, but only if the replacement is not wet with capacitor goo.
Seriously bad or no printing, intermittent print quality or new cartridges go bad quickly:
1. Check that the HV wires to the door hinge area from HV board are plugged on securely.
2. Change all of the electrolytics on the high voltage board.
3. Check for exploded or cracked HV board transistors destroyed by bad electrolytics.
4. If a spare is available, swap in another HV assembly.
5. There are high voltages on the HV board during operation, but very limited energy storage that incorporates bleeders to discharge things upon shutdown. If a bleeder fails the stored energy is less than the SE/30 case so there is more static shock risk pulling clothing out of an electric dryer than working on the HV board. The switching power supply mentioned earlier, however is quite dangerous if the largest electrolytic cap retains rectified AC primary mains energy due to a failed bleeder resistor and a non-operating switching transistor.
Mystery status lights where no trouble is subsequently found in paper path:
1. Blow clean all paper path optical sensors and actuator levers
2. Remove and reseat all connectors, disassembling as necessary to get to them.
Feed problems:
1. Photograph carefully the exact position of the feed roller assembly cam so you can correctly replace it. Then remove the roller assembly and either Rubber Renue the feed bands, or carefully reverse them to expose the other surface. A tacky surface is critical, because top sheet paper pickup must occur and top only sliding initiate before the cam force increases enough to engage several sheets and carry multiple sheets into the feed rollers.
2. Deglaze by abrasion, or replace the cork friction pad that separates sheets.
Sheets jam or distort into top output tray but not into side tray:
1. Replace the top tray rubber output rollers that have become reduced in diameter about their middle sections with age and pressure. With reduced waist diameter they cannot uniformly keep up with the fuser feed rate and the paper distorts to make up the difference.
2. Easier still, just use the side output tray only.
Horrible loud mechanical grab/slip noise when printer tries to start up a print:
1. Check for critters or other foreign material jamming the paper path gear train.
2. Check if compound gear/clutch that drives toner cartridge drum and stirring mechanism is cracked. If it is, you either need, or maybe you have just now discovered, a spare parts donor unit.
General preventative maintenance on a newly acquired vintage PLW printer:
1. Pull the cover and inspect for critters, dead or alive.
2. Outside but not in sunlight (dawn or dusk best), remove toner cartridge, keep it relatively level and upright. Using a shopvac on blow, blow out the printer mechanism and complete paper path vigorously, including all sides of the rubber foam roller in the door assembly, and blow out the toner cartridge gently. Too much air in the wrong place and you start to blow fresh toner out of its storage area. Inverting the cartridge even for a moment can result in toner pouring out of openings at both ends, so don't.
3. When not in use for long periods, remove paper from the paper tray and store paper covered, or develop the discipline to blow off the top sheet before use. Dust and dander that collects on the top of the first sheet gets carried onto the drum. Yes, crap on the top sheet can make even a new toner cartridge go bad. If it lodges under the squeegee and lifts it you get a streak that requires removing the drum and cleaning the drum, transfer roller, squeegee, and door rubber roller of excess toner. PITA, and a dirty job.
4. If status lights misbehave reseat all connectors, disassembling as required. Many screws so either maintain tight screw discipline or take photos as you go. The cable connectors fortunately are all different sized.
5. Consider inspecting and changing the surface mount electrolytics on the laser assembly and the scanner motor assembly. These are the same general type and age and more highly stressed than the infamous ones on the SE/30. If you can get the printer working by cleaning them and want to keep the printer, it is definitely worth changing them before they leak more and rot the board.
6. Consider (only for a good working keeper unit) replacing all of the electrolytics. Yes, I mean all of them. A majority of the radial leaded ones leaked fluid in all the four printers I have inspected.
7. Avoid fluids on photosensitive drum and rollers contacting the drum, help them retain whatever electrostatic properties that remain. This includes not talking when the cartridge door is uncovered to avoid spotting the drum. Any cotton balls used on the drum should be fresh and dry, and try to avoid fingerprints.
Won't power on
1. Substitute another power cord, or connect the original one to something else to verify AC is delivered to the end.
2. Verify with an ohmmeter that the power switch and the interlock switch work.
3. Reset the circuit breaker (or as appilcable, check fuse) if any inside the power supply.
4. Only if you are qualified to work on hot circuits, verify output of bridge rectifier and surge limiting NTC thermistor charges the big and deadly rail capacitor (in the US, to 160 VDC).
5. If your model of the power supply has the HA16107P IC, replace the small 47 uF electrolytic that connects to pin 1. This cap is a #$@! fix for a design problem in the IC involving rate of power application. When old the cap lets the DC power comes up too fast for pin 1 of that particular IC. Make sure the potentially fatal big rail cap has discharged. There are bleeder resistors, but they can fail.
6. Substitute power supply from a compatible parts unit (there are several kinds of mechanically incompatible supplies here in the US models, so look for a parts donor that has an identical rear panel layout).
7. Reverse engineer the schematic of the hot side of the switcher (at least two different versions of US and one or more international units) then just debug it. But make sure the bleeders have discharged that rail cap first.
Dirty prints
1. Try another toner cartridge (or even better, many). If any single one works great, the printer electronics are probably ok but there remains the interesting problem of recovering the original cartridge provided it still has appreciable toner. If any new cartridge misbehaves remove it and try debugging with other older cartridges, because a bad HV board can sometimes really crap up quickly an otherwise good cartridge.
2. Remove any air ionizer or anti-static neutralization blower devices from the vicinity of the printer. Over time and use subsequent prints may then clean up.
3. Rock the toner cartridge along the long axis, but do not invert nor tip more than 30 degrees end to end. About 20 tilts. Then blow off excess or spill outside but out of sunlight with the shop vac. This rocking triboelectrically builds static charge into the two part toner causing the fusible pigment particles to more tightly adhere to the non transferring magnetic iron carrier particles. This is where the bistable print/no print comes from. Without this charge, any residual charge on the drum can attract some toner and you get that general gray background. After charging you may have to disassemble the drum and clean both drum accumulated and spilled excess toner (this is why you do not want to exceed the angle limits) that exceeds the squeegee's ability to remove. Rocking is also useful to get the final use out of a nearly empty toner cartridge by end to end leveling of remaining toner, but the intent here is quite different. This two part toner charging is not discussed generally on the various internet printer fix-it web pages but is evident after patent searching.
4. Reinsert the cartridge and leave the printer on idling for several hours, letting it periodically cycle. When you hear it cycle up during idle it is magnetically and mechanically stirring the toner, and the static charge you induced by rocking will be more evenly distributed.
5. Don't vacuum toner, and don't blow cartridges unless you have access to an outside work area suitable for dirty cartridge work at dawn or dusk.
6. Cotton balls work well to remove small amounts of excess toner from the drum without scratching. For everything else, use a shopvac that can blow. A drum that cleans up nice but then dirties again on an otherwise good printer may need disassembly to clean the squeegee, along with a cleaning of all rollers that contact the drum. I have sucessfully disassembled and recovered drums under subdued incandescent lighting indoors. Uncertain how much UV they can take. Sunlight is harmful. So is exposure to static eliminator airstream (at least temporarily the drum will not print at all, uncertain about recovery time).
7. It may take dozens of test print pages for a printer to clean up (this means for the charge distribution on the toner, drum and rollers to stabilize and squeegee cleanup to complete) after an electrostatic upset either from recharging the toner or from a repaired high voltage board. So don't write off your printer or cartridge too soon.
Scanner malfunction:
1. Replace all of the SMT electrolytics on the scanner board, clean the board carefully and avoid touching the mirror surfaces. The caps are stressed when accelerating the mirror head up to speed. The caps, a bad driver IC and capacitor goo damage, are prime suspects when you can hear the motor first trying to get to speed but then shutting down and aborting a print.
2. Replace the scanner board with another from a donor parts unit, but only if the replacement is not wet with capacitor goo.
Seriously bad or no printing, intermittent print quality or new cartridges go bad quickly:
1. Check that the HV wires to the door hinge area from HV board are plugged on securely.
2. Change all of the electrolytics on the high voltage board.
3. Check for exploded or cracked HV board transistors destroyed by bad electrolytics.
4. If a spare is available, swap in another HV assembly.
5. There are high voltages on the HV board during operation, but very limited energy storage that incorporates bleeders to discharge things upon shutdown. If a bleeder fails the stored energy is less than the SE/30 case so there is more static shock risk pulling clothing out of an electric dryer than working on the HV board. The switching power supply mentioned earlier, however is quite dangerous if the largest electrolytic cap retains rectified AC primary mains energy due to a failed bleeder resistor and a non-operating switching transistor.
Mystery status lights where no trouble is subsequently found in paper path:
1. Blow clean all paper path optical sensors and actuator levers
2. Remove and reseat all connectors, disassembling as necessary to get to them.
Feed problems:
1. Photograph carefully the exact position of the feed roller assembly cam so you can correctly replace it. Then remove the roller assembly and either Rubber Renue the feed bands, or carefully reverse them to expose the other surface. A tacky surface is critical, because top sheet paper pickup must occur and top only sliding initiate before the cam force increases enough to engage several sheets and carry multiple sheets into the feed rollers.
2. Deglaze by abrasion, or replace the cork friction pad that separates sheets.
Sheets jam or distort into top output tray but not into side tray:
1. Replace the top tray rubber output rollers that have become reduced in diameter about their middle sections with age and pressure. With reduced waist diameter they cannot uniformly keep up with the fuser feed rate and the paper distorts to make up the difference.
2. Easier still, just use the side output tray only.
Horrible loud mechanical grab/slip noise when printer tries to start up a print:
1. Check for critters or other foreign material jamming the paper path gear train.
2. Check if compound gear/clutch that drives toner cartridge drum and stirring mechanism is cracked. If it is, you either need, or maybe you have just now discovered, a spare parts donor unit.
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Thanks wally. I'm afraid your valuable info is a little late - the printer was dumped yesterday. Sad, but there was little else I could do with it. After messing with it I was planning on getting rid of it anyway, as space here is very limited. It just seems that nobody wants these at all. I frequently see old Apple printers on eBay, nobody ever bids on them. In any case, printers are evil, even if they bear the Apple logo.
Ah, well, perhaps it will be of use to someone else then. The PLW models do require much maintenance. I find I need to have several donor units on hand just to keep several printers alive, and the toner cartridges can get dirty at a blink of an eye...
Newer technology higher resolution laser printers use a single component toner so they will have a different set of electrostatic magic incantations no doubt as they age.
Newer technology higher resolution laser printers use a single component toner so they will have a different set of electrostatic magic incantations no doubt as they age.
Nice haul. Was that a car boot sale or something? It's hell here trying to get any old stuff. If you go to the vintage mac section on ebay.ie and filter the results to "Ireland only" you almost always get 0 listings. Ebay.com is like a candy store but then the big bad postman shows you the shipping bill.
