I had a problem like that with a vector monitor. There was a transistor that was leaking a little bit when used but otherwise tested good with the diode check. What a pain in the butt those are to track down (especially when you have to hold a phone to your head as you get instructed on what to do next :)) Usually you can use the other half of the circuit as a reference, but this was in a shared part board :( Jon At 08:21 AM 01/21/2000 -0800, you wrote:
Any of you building the flyback meter kit might find this interesting:
Had a student build one on the bench, and after assembly the thing didn't work quite right. The two red LEDs were on, and when the test coils was used, the display only went to the second yellow LED. Parked it in the "Look at later" box for a month and today pulled it out and took another look at. All parts looked and tested good, Diode check showed all diodes happy, no shorts, ICs exchanged with a working unit-OK. Took out scope and turned on the unit. The output of the test signal was WAY too high. The clamping diode wasn't working, YET the @$#%#@$% thing passed the Diode test! The !@$# Diode tests good out of circuit! Sheesh, what sort of parts is DS using these days? Magic? I'm sure we left the smoke in the diode...
Oh, well just thought you'd be amused...
John :-#)#
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games) http://www.flippers.com "Old pinballers never die, they just flip out."