krister,
sounds like you are more than qualified
since it worked when you heated it,i will assume the problem was a "feed through" that went intermittent (a plated hole that connects multiple layers of the board ) and a connection that restored when the board flexed.
i have not been back to the shop, since i replied to you. i would think this might just be a matter of plain old dc voltage troubleshooting. looking at an rj45 connector, i was taught to remember ":1326" one data pair is between pins 1 &3, the other is between pin 2 & 6. the others are all ground (or poe). i have been doing this too long, i forget which ones light the led,
when i go to the shop in the am i will see if i can take a cover off my sc545-ex, i believe the network circuit is similar enough for our purposes. we have a pile of service manuals, but i don't think i have yours. if i do, i will pm you . a picture and a schematic would probably help us both at this point
not to overlook the obvious, did you resolder the rj45 connector?
well, the last thing I tried before I replaced the Realtek chip was a reflow of the entire mainboard.
Did not make any difference either.
There has been a problem with temperature on this machine for a long time.
The company that had the machine before my friend had a heatfan blowing warm air from underneath all the time.
They had around 35-45 Celius inside the black metal box where the boards are.
The people that do this kind of stuff does not understand what heat does to electronics and the components.
So my friend bought it "broken" and did not have so much problem with it last summer.
But last autumn and really this winter the problem started to escalate!
Just before we did the reflow and replaced the realtek chip the machine would print anywhere from 1 inch to 5 inch and stopped with message "now processing" on the display on the machine and "no connection" in versaworks.
Very similar to others that I have read that have had this issue.
They have replaced the mainboard and the problem is gone.
Replacing the mainboard for $2000 + custom fee and VAT is not an option for us right now.
The thing that made me thinkt that it really was the realtek chip was that when we made the chip a bit cooler with freeze spray (around 15 celsius) the machine stopped working and when I made the chip warmer again (about 35-40 Celius) it started to work again. (I use a FLiR cam to check the temp on the chip)
The difference with the old chip and the new chip is that the leds where lit and flashed even thou the machine stopped working.
I think thou that we could see a difference on the activity led that it flashed far less when the machine stopped working.....
There is one thing that I came to think about yesterday, capacitors! very well known problem with aging electronics, especially since the previous owner liked to keep the machine very warm.
So I will check every capacitor tomorrow, may one of them died when I replaced the realtek chip.
I´ll will get back tomorrow when I know more.
