Epson Perfection 4990 Photo Repair

[Cliff43J]

My Epson Perfection 4990 Photo after many ears of light service suddenly will not turn on. Dead as a door nail. Does someone have some troubleshooting guide as to what I need to check and how to do it? I have a multimeter, but when I took off the top of the bed, I was at a loss as to where to put the leads, etc.. I have my fingers crossed that it is a relatively simple test and repair as I do really like this scanner. Thanks for the help.

 

[MattKing]

Welcome to Photrio.
I would advise to check the power plug.

 

[Cliff43J]

Matt, did that right off the bat before posting. Even changed outlets. Nothing.

 

[koraks]

Ouch. Sadly, troubleshooting a problem like this through the internet together with someone with only limited knowledge of electronics is virtually impossible.

My initial guess would be that it's possibly/probably a problem with the power supply. This is probably not a user-replaceable or 'field serviceable' part or module. I'd have to open up my 4990 to see, but given the locations of the various plugs, I'd assume that most of the electronics are combined on one mainboard assembly.

Guiding you through the process of poking around may at best give some insight into the nature of the defect, but you'd still be stuck repairing it. The most likely outcome would be that the easiest fix is to exchange the mainboard with a known-working one from a donor scanner. But if you had a spare and working 4990 sitting there, you would have already been using it anyway...

Yes, there's a slim chance that there's a fuse incorporated in the circuit just before the power supply. However, in my experience, they are usually not there or of a non user-replaceable type these days.

Do you have anyone near you who's experienced in electronics repairs? HAM enthusiasts are always a good option - if you know of any, it's time to pay them a visit and bring a token of gratitude (a.k.a. 'bribe' ).

 

[Kino]

Here is the service manual for the 4490 (close enough?); I don't know if it is a "pay" service, but you can view the pages through the watermark:

EPSON PERFECTION 4490 PHOTO SERVICE MANUAL Pdf Download

View and Download Epson Perfection 4490 photo service manual online. Color Image Scanner Photo Automatic Document Feeder. Perfection 4490 photo scanner pdf manual download.

www.manualslib.com

One simple test I would perform is to see if the inline power transformer has gone bad.

Are you getting any voltage out of the transformer plug?

 

[koraks]

That's for a 4490. The 4990 is a different machine. The 4990 has an internal power supply, so there's no external adapter/'transformer'.

 

[Kino]

That's for a 4490. The 4990 is a different machine. The 4990 has an internal power supply, so there's no external adapter/'transformer'.

Ok, but regardless, a simple test of the transformer is still valid.

 

[koraks]

No, because the 4990 doesn't have an external transformer. It has an internal power supply and that's likely an SMPS. Yes, I'd personally start measuring there, but if someone doesn't know where to look or what they're doing, I'm not going to direct them to do measurements on a circuit that has a lethal voltage on it. Keep in mind that every SMPS starts with rectifying incoming AC with a decently sized buffer cap on the HV DC; the charge in that is sufficient to kill under unfortunate circumstances.

 

[Cliff43J]

Ouch. Sadly, troubleshooting a problem like this through the internet together with someone with only limited knowledge of electronics is virtually impossible.

My initial guess would be that it's possibly/probably a problem with the power supply. This is probably not a user-replaceable or 'field serviceable' part or module. I'd have to open up my 4990 to see, but given the locations of the various plugs, I'd assume that most of the electronics are combined on one mainboard assembly.

Guiding you through the process of poking around may at best give some insight into the nature of the defect, but you'd still be stuck repairing it. The most likely outcome would be that the easiest fix is to exchange the mainboard with a known-working one from a donor scanner. But if you had a spare and working 4990 sitting there, you would have already been using it anyway...

Yes, there's a slim chance that there's a fuse incorporated in the circuit just before the power supply. However, in my experience, they are usually not there or of a non user-replaceable type these days.

Do you have anyone near you who's experienced in electronics repairs? HAM enthusiasts are always a good option - if you know of any, it's time to pay them a visit and bring a token of gratitude (a.k.a. 'bribe' ).

I am not seeing a fuse. There is a small circuit board containing the on/off switch and a flat cable with pin connector on the end. I have a feeling that this board may be the issue as the power light is not going on, and it is part of this small circuit board assembly. With the flat connectors with 4 or 5 pins is it the two outside pins that are the power supply? I think so. If so, I need to test those first. I am used to working on commercial and house wiring, but this small stuff is new to me. If it's not that then I shall buy a new scanner...nuts...

 

[koraks]

I have a feeling that this board may be the issue as the power light is not going on

That's possible, but the little board is not likely not the power supply, and it's just as likely (even more so) that the defect is in the power supply itself. The little light is just a pilot light; it won't go on if there's no power, but that in itself does not mean the problem is located close to it.
My guess is that the power supply itself is in the long enclosure along the side of the scanner, on the side where the transport locking mechanism also is. There's a long metal enclosure you can see through the glass with some ventilation holes in it. The power supply is probably inside it.
You could open the device up and start measuring around, but that's a rather haphazard endeavor without knowing what you're looking at.

 

[David Reynolds]

I have used a company in Massachusetts who reconditions, fixes and repairs Epson printers and scanners. Here is a link to their website. They did a great job on my Epson R2400 printer (20 years old) and mentioned they would work on my 4990 Photo scanner. (luckily it hasn't needed work)

MA Printer Services

CTS Services, Inc. is the Market Leader in Providing Expert Printer Services. Call today: 508-528-7720

www.ctsservices.com