Haitian molding machine board thermal problem - Page 1
Forum section: electronics / repair

author: boobo-oobo
author_rank: Newbie
timestamp: March 08, 2015, 06:35:42 pm
content: Hello.I have a problem with a motherboard from a Haitian molding machine. The molding machine works, its powered on, 24/7. It only goes off when there's a power outage. And then its impossible to turn in back on. We took the board out and I've hooked it up to a power supply, by then it had cooled down and powered up on my table. If it works for 10-15min, and you restart it, it wont power back on. When waiting for some time, or force cooling the main processor part of the board it will eventually power on. When it doesn power on the board just hangs, like it doesnt boot propperly. On start up there's a beep in about 5-10 sec after power connected, that doesnt happen. Also i can see on the power supply, when its booting fine it will draw on start up a bit more current, 0.01-0.05A more than when it hangs. I cant figure out what could be the problem. Cant see any bad solder joints, caps look fine . . . Could the problem be in the main processor itself?The motherboard is a Techmation2386 development board i guess. I've found some used ones for sale online, but i don't know what do i need to transfer the software or if its even possible.IMG_0051byElektroservis Hreš?an, on FlickrIMG_0049byElektroservis Hreš?an, on FlickrPowered on:IMG_0053byElektroservis Hreš?an, on FlickrIm not sure what am i searching for here, any tips and ideas what to check, measure, test?

author: Daxxin
author_rank: Regular Contributor
timestamp: March 08, 2015, 06:39:08 pm
content: Have dallas nvram ..how old this machine? maybe the battery inside is low and cant boot properly

author: Paul Moir
author_rank: Frequent Contributor
timestamp: March 08, 2015, 08:10:31 pm
content: This looks like it is around 10 years old? If so and it's been on 24/7 I wouldn't trust the electrolytics especially in the PSU section where they're hot. Looks won't necessarily show a problem. You could test them but if you want to keep the machine running for some time I would plan on replacing them. Any idea of brand?Those SMD caps are popular troublemakers too.You could try shooting things with cold spray to see which is the troublemaker.

author: boobo-oobo
author_rank: Newbie
timestamp: March 09, 2015, 09:29:30 am
content: Quote from: Daxxin on March 08, 2015, 06:39:08 pmDont know the exact age, but its around 10 years old. Will check the Dallas and replace it if neccesary. Thanks.IMG_0056byElektroservis Hreš?an, on FlickrQuote from: Paul Moir on March 08, 2015, 08:10:31 pmYeah, the board is something like 2003-2004. Im in the process of getting an ESR meter to check the caps more accurately, not for this but in general, but those caps could be the issue, true. Two brands on the board, Rubycon and Vlsom.IMG_0055byElektroservis Hreš?an, on FlickrIMG_0057byElektroservis Hreš?an, on FlickrDo you recommend to replace all of them as a precaution, the electrolytic ones?

author: Paul Moir
author_rank: Frequent Contributor
timestamp: March 10, 2015, 05:25:24 am
content: Looks like they were smart and put some nice Rubycons where they mattered. As far as I can tell, those el-cheapo ones aren't stressed out so they're likely good. But all are easy to check with an ESR meter. It'll even work in-circuit to a degree.It's hard to say if those capacitors are still good. Would have to see which model they are and what voltage they're operating at and what the environmental temperature is like. However 10+years on with 24/7 operation and presumably 40ish operating temperature is going to be near the max lifespan for just about any aluminium electrolytic. Rubycons are known for often exceeding their specifications but if you need reliability you're going to want to replace them. Or at least test them so you can have some confidence.What really worries me are the SMD mount electrolytic capactors. They aren't the most reliable things in the world and sometimes they leak and wreck the PCB.But start with the Dallas chip first. It baffles me why they used that one with the built-in battery (12C887, right?) when they have an external battery nearby. It's near it's life span too (10 years guaranteed retention).

author: boobo-oobo
author_rank: Newbie
timestamp: March 13, 2015, 10:33:37 am
content: Here's an update.I changed the Dallas chip, caps on the power input, some electrolytic caps near some chips but still nothing. When cooled down it boots normally, second, third etc boot after that nothing.But, i got some compressed air, and managed to pin-point one area. When I blow/cool down the RAM chip, its starts every time :IMG_0062byElektroservis Hreš?an, on FlickrThe problem is that i don't have a soldering iron that can do SMD soldering, and re soldering might do more damage than good. None of the SMD caps looks bad/leaked.Any idea why cooling the RAM chip makes it boot? Bad solder joint, or a bad chip perhaps? I tried pressing in the pins of the chips slightly, maybe a pin has a bad connection, but no change. It just takes a little cold air on the chip and it boots every time. . .

author: Seekonk
author_rank: Super Contributor
timestamp: March 13, 2015, 09:46:56 pm
content: I always lift up socketed chips and reinsert them twice to clean the contact surfaces of corrosion. This likely experiences humidity at that location. Try that with the rom.

author: Paul Moir
author_rank: Frequent Contributor
timestamp: March 14, 2015, 04:16:16 pm
content: No substitution for proper troubleshooting.Looks like you can still get them on ebay. You don't need anything *too* fancy to solder these if you're careful, just a good temperature controlled soldering iron with a small chisel tip. Check out youtube for some SMD soldering techniques (TSSOP especially) and try them out on a scrap board.First thing I would do is reflow the solder on all the pins, just in case there's a break rather than a problem with the chip itself. If that doesn't work, get a hold of some chips and replace it. You can remove the old one by cutting off the pins and then removing them individually. I would probably remove that big connector first just to get it out of the way.EDIT: Looks like the IS41LV16100C is an updated version (silicon change) so those *probably* can be used as a substitution. The -50 is the speed and the letters after that are the temperature rating.

author: boobo-oobo
author_rank: Newbie
timestamp: March 14, 2015, 07:04:31 pm
content: Quote from: Seekonk on March 13, 2015, 09:46:56 pmI did on all socketed chips, but guess whatThe RAM is soldered on the board.Quote from: Paul Moir on March 14, 2015, 04:16:16 pmMy local electronics part store can get them in about two weeks for app. 20$ a piece. In the meantime, we've put the board back in the machine, cause the company needs the machine asap. The machine is on 24/7, so if there wont be any power outages its gonna be ok. Even if there are, some cold air on the chip should bring it back up. When the RAM chips get here we'll take it back off and try to resolder/change the RAM chip. Until then, we waitThanks for all the help so far, really means a lot when you try to troubleshoot something

author: wraper
author_rank: Unknown
timestamp: March 14, 2015, 07:27:45 pm
content: Hmm, this reminds me about one PITA device I have to deal with. There was a similar issue. Reason seemed to be that reset circuity (resistor+ capacitor) worked too fast. Likely problem appeared because PSU was replaced before with different type, power voltages rise times were obviously different. Fixed by replacing those resistor+cap with AVR MCU with few lines of code which generated 1.5 second delay as ultimate solution. Probably here is the same, if reset circuity is made of resistor and some crap Y5V / Z5U capacitor, capacitance will change greatly with temperature by multiple times. Cooling it increases capacitance and therefore reset delay. Or probably capacitor is cracked. I would say, check reset circuity first. There could be some specialized reset IC too which failed and therefore you don't have reset delay = no boot.

author: wraper
author_rank: Unknown
timestamp: March 14, 2015, 07:35:24 pm
content: Just noticed, There is Bios flash IC next to the RAM chips you were blowing on. It could be that at fault. Some part of FLASH memory reads unstable because some cell charge dropped over time what is quiet common. And temperature makes a differende how it reads. I would advise to immediately make a backup of it's contents until it is too late and device stops booting at all. Of course it really sucks that it is soldered into the PCB.

author: boobo-oobo
author_rank: Newbie
timestamp: March 14, 2015, 08:31:18 pm
content: Quote from: wraper on March 14, 2015, 07:35:24 pmI dont think its the BIOS chip, i tried to blow on every chip, capacitor, segment of the board separately, couple of times on the bios but no pattern. Only on that RAM chip (and blowing air from the right to the left on the picture, away from the bios chip) had a pattern of booting up after blowing on it.And good point on the backing up things, but im not sure how to do it. What do i need to get to transfer all the data from the motherboard? Some kind if an developer tool? Does anyone know how to do it?The reset circuit, i also had my doubts on it, but with limited time with the board, i didn't get to figure out the circuit, and cant find a pinout for the main processor.