Does anyone have any tips on how to troubleshoot ROHS {lead free} circuit boards - Page 1
Forum section: electronics / repair

author: ELye
author_rank: Newbie
timestamp: October 27, 2015, 05:25:01 am
content: My wife's OKI dot matrix printer stopped printing half-way through a page. It has 3 interfaces: serial, parallel and USB. On two separate windows laptops the usb printer is recognised but no test print comes out. I tried the windows printer troubleshooting download and it found no problem within windows. The test print for the printer works so this rules out the power supply and mechanism. The only thing left is the circuit board and when I saw that it was Lead-Free, I immediately suspected tin whiskers. I examined the board with 5x reading glasses but nothing noticeable. I couldn't find any Dave videos troubleshooting tin whiskers. I don't have the circuit diagram or scopes or a degree in Electronics. I may have to replace the board if washing it with dishwashing liquid and drying on the clothes linefails to fix this.

author: Stonent
author_rank: Super Contributor
timestamp: October 30, 2015, 03:46:15 am
content: I'm not sure why you're washing it. That won't get rid of tin whiskers.Doing a board reflow in the oven could help.Some of these articles might help.https://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=reflow+laserjetI had a Laserjet Printer that had a faulty formatter board that I fixed by baking it.Oh! Be careful if the board has connectors on it. If they aren't designed for reflow, they could melt.

author: joeqsmith
author_rank: Super Contributor
timestamp: October 30, 2015, 10:33:20 am
content: Quote from: ELye on October 27, 2015, 05:25:01 amThey still make dot matrix printers? And, lead free to boot?QuoteThen why do you think it's a hardware problem?

author: crispy_tofu
author_rank: Super Contributor
timestamp: October 30, 2015, 11:09:48 am
content: Could it be the printer cable?

author: GreyWoolfe
author_rank: Unknown
timestamp: October 30, 2015, 05:00:05 pm
content: Quote from: joeqsmith on October 30, 2015, 10:33:20 amhttp://www.officedepot.com/a/products/537667/Lexmark-Forms-Printer-2590-Dot-Matrix/?cm_mmc=PLA-_-Google-_-Printers_Scanners_Faxes-_-537667-VQ6-47886840836-VQ16-c-VQ17-pla-VQ18-online-VQ19-537667-VQ20-83661040676-VQ21-&gclid=Cj0KEQjwqsyxBRCIxtminsmwkMABEiQAzL34PeP26sdkIlE5_G0XGKKypM99x1hKPJF2QD2KN-zO-NYaAl-Q8P8HAQOh, yes and they are ridiculous money.

author: merox
author_rank: Regular Contributor
timestamp: October 30, 2015, 06:27:20 pm
content: Quote from: joeqsmith on October 30, 2015, 10:33:20 amSure they still make them, you need them if you need a carbon print of your document (e.g. doctors etc.).Sometimes you can still get Windows 10 drivers for ancient printers (15- 20 years old) because they are still made and in wide use today. Oki makes a lot of them.

author: nctnico
author_rank: Super Contributor
timestamp: October 30, 2015, 07:46:28 pm
content: I'd try a different cable / interface. I doubt lead free is the source of the problem. Something could be broken but a cabling problem is more likely.

author: steve207a
author_rank: Contributor
timestamp: October 31, 2015, 06:40:13 pm
content: Hi I used to work on oki dot matrix printer years ago and the main problem with them was print head the needle wires would get jammed or stuck causing the printer to stop take the head out and examine it the wires should all look level a spray of wd 40 in the mech might helpif i remember correctly you can with very fine pliers tweezers gently move the wire in and out but that may not be on your model Mostly the pcb are very reliable ....all problems were print head or the carriage it runs ongood lucksteveps appologies as didnt read your post correctly as to test print works sorry

author: SeanB
author_rank: Super Contributor
timestamp: October 31, 2015, 07:25:00 pm
content: No comms with USB means either the USB port is bad ( fake FDTI chip in it), the USB A socket has cracked solder joints or the little resistor on the 5V line has cracked or burnt. If the parallel port is faulty it will be either a bad cable ( common now as they are ageing, and the ends tend to break from flexing, and only 1 break in the 26 cores will either have no print or garbled print) or a bad port chip. There is normally a resistor pack there to act as pull up, and a pair of 74LS 373 buffers ( or similar) to buffer the data and control pins.The test for them if the parallel cable is used is to open a DOS window with DOSBOX ( not the abortion that is command.com now, you want the full dos command line) and see if you can print from DOS to LPT1: to see if you echo the keyboard. USB try a known working cable.The description given is very poor, what does not work aside from no print, does the PC recognise the cable being unplugged, does it detect hotplugging on USB of the printer, is the parallel port enabled in BIOS.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: November 01, 2015, 12:20:21 am
content: If tin whiskers were the problem it would most likely be a transient fault, as the whiskers are very fine and tend to burn clear. They do occasionally bring the connected silicon to the graveyard with them. In this case standard troubleshooting techniques looking for burned spots or stuck signal lines would work.If I was going to blame lead free, I would be more likely to blame a cracked solder joint, particularly if your printer came early in the ROHS game. Early in the ROHs world standards and processes weren't mature and marginal joints were more common than you would like. "Sometimes" you can find them with a microscope, but again it is usually more productive to find the problem using standard methods, (localize to a subsystem, then a circuit, then a wire) and then look for the fault that caused the open.

author: Stonent
author_rank: Super Contributor
timestamp: November 08, 2015, 03:48:41 am
content: Almost all dot matrix printers can either speak the EPSON LQ protocol (most common) or IBM ProPrinter protocol (or both).My old Panasonic printer had dip switches on the back to select which protocol it used. In Epson mode it pretended to be an Epson FX80 printer. In IBM mode it pretended to be a ProPrinter X24e.

author: Richard Crowley
author_rank: Super Contributor
timestamp: November 08, 2015, 04:13:19 am
content: Quote from: joeqsmith on October 30, 2015, 10:33:20 amBecause @ELye apparently tested it with the built-in "virtual" printer and verifed that the print function of the operating system was functioning.I agree that there are several more likely suspects before tin whiskers.

author: zoltan
author_rank: Contributor
timestamp: November 08, 2015, 07:24:48 pm
content: Quote from: Richard Crowley on November 08, 2015, 04:13:19 amThose type of printers usually have a "test" button, along with "LF", "FF", etc. So you can test the printer without computer attached.And they are almost impossible to kill. I've seen them in accounting offices where they are used all day long, and still can achieve 10+ years of service. Then just change the hprint head and go for another 10 years.I'd check the cable first. Then boot some linux live CD as see if it prints. Windows can do weird thing with drivers.

author: joeqsmith
author_rank: Super Contributor
timestamp: November 09, 2015, 03:35:23 am
content: Quote from: ELye on October 27, 2015, 05:25:01 amThis should have actually printed a test page on the printer. Sounds like it worked. I suspect they did some Norton 360 auto update...

author: crispy_tofu
author_rank: Super Contributor
timestamp: November 09, 2015, 04:25:12 am
content: Maybe the OP can return to explain his situation

author: Smokey
author_rank: Super Contributor
timestamp: November 09, 2015, 07:59:17 am
content: Maybe he's still in space where you have to worry about tin wiskers......Thats a funny conclusion to immediately jump to with a printer