issues connecting to GPIO

[tmoble]

it's an assembled GPIO MShift. There have been some previous issues, but thought to have them all resolved. Now using a 12V battery to power the board, USB to serial adapter, homemade serial cable. This stuff all worked in the past. Now have 12V on pin1 of the voltage regulator, 0 on Pin 2, but no 5 V on Pin3. Is this expected? there is a fractional volt on Pin 3.

History on this board: this is one of the ones that was dead on first try a couple years ago, had to be returned to B&G for BDM flash. got it back, started build, was able to to access the board and do the S19 load. built the rest, started to assemble into the case but it was too long. Sanded too much off the end, broke the 12V trace to D4, dead. Found a post by another member who had more electronics experience, followed his example to run a haywire from a 12V source to D4. committed classical bonehead stunt by forgetting to power down the board while soldering haywire to D4, slipped, shorted out, fried D4 and MOV1. Parked it for an extended period but finally got going again. acquired the correct D4 and MOV1 parts, installed carefully, bypassed burnt trace from C5 to D4, ran new 12V haywire from +12V on GPO3, OK. No continuity between Ampseal PIN1 and ground pins. powered up, 12V at Vreg Pin1, 0 at Pin2, but no 5V at Pin3, instead have 0.2V. Vreg gets pretty hot quickly, can't leave finger on it for 1 sec. Is it maybe fried too? Emitting an odor now. I can replace it, just a long drive in traffic to Fry's Electronics or wait for Amazon. Does it require any other part of the board to be functional to operate?

[Bernard Fife]

Vreg gets pretty hot quickly, can't leave finger on it for 1 sec. Is it maybe fried too?

tmoble,

It could be, or there could be a short to ground causing it to overheat. Such a short may only show up when the board is at operating temperature, which may be why you aren't seeing any continuity between 12V and ground when cold. However, the simplest thing to do (logistics aside) is to replace the voltage regulator and see if that helps.

Lance.

[tmoble]

Lance, thanks for taking time. My conclusion is the same as yours. I'll try to get one today and see what happens.

[tmoble]

Well, I found this at Fry's, it's an NTE IC-POS VR 5V 1A . V in is 35 max, 15 watt Pd. It's a little short of the 1.5 amp specified, but I'm going to try it. Easy to change, maybe it will act as a fuse if there really is a short to ground somewhere. Always the optimist......

[tmoble]

installed the slightly under-spec VReg, found reasonably correct voltages on all three legs. still no joy, board seems dead. in order to repair the 12V supply trace sanded off the end of the board I used a haywire from 12V supply in an unused section, GPO3. slipped while testing voltages at Vreg, shorted between pin1 and pin2. dead short to ground fried part of the trace leading from AMPSEAL pin1 to the GPO sections. Still had voltage at GPO4, closest to AMPSEAL so used the 12V source on it. Did the same thing again. Great. this time I actually heard a faint snap as the trace fried. Dang. So, haywire direct from AMPSEAL pin1 to D4, voltages good at VReg, but still unable to get response from board.

Getting burned out on this but for some reason thought to look at the computer I built for my son, I didn't recall this but it has an actual physical serial port on com1. eliminated the USB to serial converter, plugged directly into com1. tried all the usual serial comms stuff, no joy. board seems dead. portcheck sees the serial port but no connection. downloader util can't find it, tunerstudio can't find it. Giving up for now, ordered a new board from DITAutotune. Dang and double-dang. Hurted my widdle feewings is what it did.

Probably find out the new board is still too long for the case.