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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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HP DeskJet 500
Our church has one of these printers that has worked well for a long time.
It now doesn't. Upon turning on the power, it appears to go through the power up testing, but then when trying to move the head, it powers down. I have checked and watched the power supply and I suspect that it's being told to turn off. I checked ESR on all the electrolytics, and all appear to be fine. I can move the head to the middle, and upon powering up, it will take it home, but then shut down once it gets there. I measured about 5v across the head motor, so I pulled it out and put 5v to it. It does run, but not very smoothly, and sometimes doesn't want to start very well. I don't know if this motor has brushes or not, but it feels like maybe the motor is struggling, thereby shutting down the power supply. If I unhook that motor plug, upon power up, the printer flashes an error. Any more thoughts here? Maybe something I missed? WT |
#2
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HP DeskJet 500
"Wayne Tiffany" writes:
Our church has one of these printers that has worked well for a long time. It now doesn't. Upon turning on the power, it appears to go through the power up testing, but then when trying to move the head, it powers down. I have checked and watched the power supply and I suspect that it's being told to turn off. I checked ESR on all the electrolytics, and all appear to be fine. I can move the head to the middle, and upon powering up, it will take it home, but then shut down once it gets there. I measured about 5v across the head motor, so I pulled it out and put 5v to it. It does run, but not very smoothly, and sometimes doesn't want to start very well. I don't know if this motor has brushes or not, but it feels like maybe the motor is struggling, thereby shutting down the power supply. If I unhook that motor plug, upon power up, the printer flashes an error. Any more thoughts here? Maybe something I missed? Even I would say it's possibly time to retire it. I've found bad solder connections in the power supply of one of those. --- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/ Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/ +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html Important: Anything sent to the email address in the message header above is ignored unless my full name AND either lasers or electronics is included in the subject line. Or, you can contact me via the Feedback Form in the FAQs. |
#3
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HP DeskJet 500
"Sam Goldwasser" wrote in message ... "Wayne Tiffany" writes: Our church has one of these printers that has worked well for a long time. It now doesn't. Upon turning on the power, it appears to go through the power up testing, but then when trying to move the head, it powers down. I have checked and watched the power supply and I suspect that it's being told to turn off. I checked ESR on all the electrolytics, and all appear to be fine. I can move the head to the middle, and upon powering up, it will take it home, but then shut down once it gets there. I measured about 5v across the head motor, so I pulled it out and put 5v to it. It does run, but not very smoothly, and sometimes doesn't want to start very well. I don't know if this motor has brushes or not, but it feels like maybe the motor is struggling, thereby shutting down the power supply. If I unhook that motor plug, upon power up, the printer flashes an error. Any more thoughts here? Maybe something I missed? Even I would say it's possibly time to retire it. I've found bad solder connections in the power supply of one of those. --- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/ Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/ +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html Important: Anything sent to the email address in the message header above is ignored unless my full name AND either lasers or electronics is included in the subject line. Or, you can contact me via the Feedback Form in the FAQs. I thought about the solder and so checked all joints under the microscope - all looked good. I really think the controller is telling it to shut down since it is so repeatable. I can watch the voltage shut off when the head reaches the home position. WT -- Posted via a free Usenet account from http://www.teranews.com |
#4
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HP DeskJet 500
Wayne Tiffany wrote: I thought about the solder and so checked all joints under the microscope - all looked good. I really think the controller is telling it to shut down since it is so repeatable. I can watch the voltage shut off when the head reaches the home position. Considering the cost of cartridges it would be a blessing to retire it ! Graham |
#5
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HP DeskJet 500
On Mon, 26 Jun 2006 12:38:28 -0500, "Wayne Tiffany"
put finger to keyboard and composed: Our church has one of these printers that has worked well for a long time. It now doesn't. Upon turning on the power, it appears to go through the power up testing, but then when trying to move the head, it powers down. I have checked and watched the power supply and I suspect that it's being told to turn off. I checked ESR on all the electrolytics, and all appear to be fine. I can move the head to the middle, and upon powering up, it will take it home, but then shut down once it gets there. I measured about 5v across the head motor, so I pulled it out and put 5v to it. It does run, but not very smoothly, and sometimes doesn't want to start very well. I don't know if this motor has brushes or not, but it feels like maybe the motor is struggling, thereby shutting down the power supply. If I unhook that motor plug, upon power up, the printer flashes an error. I may have a spare motor for this model. If so, then you can have it for the cost of postage from Australia. What is its part number? Any more thoughts here? Maybe something I missed? WT I believe there may be an encoder strip which may need cleaning. - Franc Zabkar -- Please remove one 'i' from my address when replying by email. |
#6
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HP DeskJet 500
Hi!
I really think the controller is telling it to shut down since it is so repeatable. I can watch the voltage shut off when the head reaches the home position. If memory serves, these are just a permanent magnet DC motor--not a stepper type or anything quite that fancy. The positioning is done by way of the encoder strip. In other words, it could well have built up a short circuit by way of either conductive whiskers or something that has broken and changes position just enough to cause trouble. Maybe the components responsible for driving the motor don't start to break down until they've been loaded for a while? When that happens, the controller might just shutdown on overload, instead of burning up. I've never had one of the carriage motors quit, but some of mine have had the spring that holds the belt tightly in place start to back off. When this happens, the printer may make "twanging" or "gritty" noises like gears stripping. If it gets bad enough, the controller shuts down and lights flash. I would think that taking the motor out, cleaning it well and putting it back might solve the whole problem. Even today these printers have a lot of life left in them and the ink can be downright cheap compared to a new unit! William |
#7
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HP DeskJet 500
I considered that but the motor is constructed with the crimp type on the
ends, not fasteners. I have my eye on a newer printer (Hp DJ932C) that is probably available, and if it works, I will tear into the motor on the 500 just to see what's what. WT "William R. Walsh" m wrote in message news:Oc3og.6446$FQ1.3679@attbi_s71... Hi! If memory serves, these are just a permanent magnet DC motor--not a stepper type or anything quite that fancy. The positioning is done by way of the encoder strip. In other words, it could well have built up a short circuit by way of either conductive whiskers or something that has broken and changes position just enough to cause trouble. Maybe the components responsible for driving the motor don't start to break down until they've been loaded for a while? When that happens, the controller might just shutdown on overload, instead of burning up. I've never had one of the carriage motors quit, but some of mine have had the spring that holds the belt tightly in place start to back off. When this happens, the printer may make "twanging" or "gritty" noises like gears stripping. If it gets bad enough, the controller shuts down and lights flash. I would think that taking the motor out, cleaning it well and putting it back might solve the whole problem. Even today these printers have a lot of life left in them and the ink can be downright cheap compared to a new unit! William -- Posted via a free Usenet account from http://www.teranews.com |
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