Re: OKI 590 Dot Matrix Printer w bad power supply.
Anyone want to throw me a bone and identify the startup capacitor on my board?
Jluxster
Member
Last Activity: 07-15-2020, 11:51 AM
Joined: 06-03-2019
Location: Watertown
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Re: OKI 590 Dot Matrix Printer w bad power supply.
Ok. So what I'm hearing is that the caps on that part of the board are the issue, and that I just need to check the resistors with my meter. That makes sense.
In past PS repair, some times one blown cap meant many others blown downstream. Based on the part of the board this is, is that likely the case here?
I'm trying to talk myself into bothering with the repair.Leave a comment:
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Re: OKI 590 Dot Matrix Printer w bad power supply.
Hmmm.
Any need to replace the resistors is that is the case?Leave a comment:
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OKI 590 Dot Matrix Printer w bad power supply.
Got this OKI ML-590 dot Matrix printer DOA with a note on it saying "no power".
Sure enough. Does not power up. No lights, no startup sounds. I've ruled out the plug switch and fuses, no interlocks on the model that prevent power on. The PS is definitely getting power from the wall.
Removed the cover and had a good listen. No noise of any kind from the power supply, and no bulging caps (though perhaps one of you Jedi masters can spot one the photos are good resolution).
On closer examination I see some charring below a set of three light blue... -
Konica Minolta 3730DN Missing colors streaks and gaps in Magenta toner
I had this and managed to resolve it, so I thought I would post the solution here for anyone else who has this same model.
Symptom: one or more colors print blurry and with gaps or streaks in across the page.
Cause: The waste toner became overfilled, and toner spilled out onto the LED bars that form the image on the OPC drum. (the LEDs that draw the image were blocked by toner).
Solution: I used a stick with a kleenex on the end to gently rub away all of the toner from the LED bars. These bars are located along the bottom of the machine below each... -
Re: Lexmark 654dn power supply dead fans on part # 40x4355
Here are the images after repair.
Thanks for all the posts....Leave a comment:
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Re: Lexmark 654dn power supply dead fans on part # 40x4355
Well, last night I replaced the bulged cap and the two large caps, and the unit now functions with no problems. Startup and post.
Good prediction in naming the small cap as the likely culprit.Leave a comment:
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Re: Lexmark 654dn power supply dead fans on part # 40x4355
Hmmm, OK, this board has a ton of 35V and 50V caps on it. Perhaps one of them is the culprit.Leave a comment:
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Lexmark 654dn power supply dead fans on part # 40x4355
Hey all,
Working on another failed Lexmark LVPS power supply. The printer gradually had more and more trouble making it to the post screen until finally no power on at all. I'm replacing the two large caps, and the one small 100uf 35V cap that shows a small bulge. That is the only visible cap issue, but I hear a faint fast clicking that tells me caps are probably the issue.
Have a look at this board and let's make predictions about what's wrong with it, I'll post my repair results and we can see what the issue was.
Thanks!... -
Re: Lexmark 544dn power supply clicking sound model 40x5409
So. I replaced the two busted 2200uF caps. And the PS was still not powering the unit on. In the end I gave up and recycled the unit. So, one repaired, and one failed repair.Leave a comment:
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Re: Lexmark 544dn power supply clicking sound model 40x5409
OK, tonight I opened the second power supply on the second unit which I will name Wanda to keep it from getting confused with the other identical power supply from the first post. Wanda is the, same model. Symptoms: dead no power on no lights, fan twitching and making a faint chirping sound.
Finding the voltages:
I went to find the line voltage for 5V out and accidentally picked the 120V in instead, and somehow shorted it to ground. Oh well, glad it was only $5 since now the leads are both melted on...Leave a comment:
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Re: Lexmark 544dn power supply clicking sound model 40x5409
Also, only hearing the cyclic buzz when the PS is powered on.Leave a comment:
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Re: Lexmark 544dn power supply clicking sound model 40x5409
And to answer the second question. Fan is working properly after replacing the cap.Leave a comment:
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Re: Lexmark 544dn power supply clicking sound model 40x5409
Hi guys. To clarify:
1) BEFORE replacing the big cap it made a loud clicking sound and the 24V fan was sort of twitching. Otherwise the printer was completely dead.
2) AFTER replacement the printer powers on and works great. BUT I hear a low buzz from the power supply about once a second.
My worry was that there may be another bad component on the board somewhere which caused the large cap to fail. Not sure if there is a good way to know for sure.Leave a comment:
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Re: Lexmark 544dn power supply clicking sound model 40x5409
Alright. I am repairing a second lexmark printer with the same issue tonight. I'll check the Voltage before and after changing the capacitor.
Gotta warn you, this multi meter is the $5 ebay kind, but it should give us an idea. Any help in identifying the 5V and the 24V output? There are two cable bundles coming out, I'm guessing one is each...Leave a comment:
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Lexmark 544dn power supply clicking sound model 40x5409
Lexmark Laser printer 544dn , loud fast clicking sound from the power supply, no power, but the 24V fan on the case was twitching and chirping, no power shown on LED indicators.
I have replaced the large 450V capacitor, as it appeared to be the source of the clicking. Old capacitor was visually fine, no bulging that I could see.TaDa!
Good news: now the unit powers on and works properly.
Bad News: the power supply now makes an ominous cyclic buzz about every second or so.... Which makes me think that I didn't really solve the problem after all. Which is why... -
Re: New Members - please post your introductions here
Hey gang,
I live on the Boston area, and I am an amateur repairer of laser printers. I came across some with PS issues and I'm attempting some repairs. But it'll be my first time back to electronics since I gave up on making home stereos many years ago. I'll post some photos and project specs once my posting privelagea are enabled.
I came across this while doing research to repair a power supply.Leave a comment:
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