03-02-2008, 01:58 PM
Join Date: Oct 2007
Location: santa cruz
Total Cats: 0
MS is dead after cleaning with acetone
I built a MSI V3.0 and passed all tests up to and including step 55.
Controlled Megatune gages with Stim pots.
Finished building board to the end.
Washed board with acetone and re-inspected all joints. Everything was spick and span.
Woke up this morning and hooked MS to DB9 cable and Stim and I get nothing. Fresh battery. Nothing. Double checked my cable, jumped pins 2&3 and got echo. Plugged cable back into MS, jumped U1 pins 12 & 13, no echo. If I jump DB9 pins 2 & 3 on the board, I get appropriate echo so I know DB9 cable is connected to MS.
Stuck at test in step 26.g.
Pin 4 of processor shows 32.76hz
Testing on the MAX232 shows
Pin 16 is 4.95
Pin 15 = 0.6 Ω to the middle pin of U5
Pin 11 to CPU Pin12 = ~0.3 Ω
Pin 12 to CPU pin 13 ~0.3 Ω
Power supply testing on U1 pins all succesful.
I have 5 volts between pins 19 (ground) and 20 (+5), there is also +5 on pin 1 and 31 (checked against ground at pin 19), and there is ground potential on pins 2 and 32 (checked against +5V on pin 20). The processor has power on the 40-pin socket but none of the LEDs on the MS respond. Capacitors with polarity and all diodes were triple checked for correct orientation and all checks out.
As I stated before, everything passed testing up to and including step 55. Then I brushed off the flux with acetone, gently blew it off with compressed air and waited approx. 12 hours. Hooked back up and now I donít get response.
Iíve spent several hours searching and troubleshooting and Iíd greatly appreciate any assistance.