05-11-2013, 10:36 PM
Eric
Try to do what we are asking you to do.
1. Desolder the transistors you want to check. Attention: semiconductors are VERY sensitive to the long heating so do NOT apply solder heat for long time. Best, grab a lead you are desoldering with needlenose pliers or a large tweezer, so to sink the heat from the iron tip. Note the way the leads go into the board.
If the board is a copper laminate, do not overheat the laminate or it will delaminate.
2. Do measure the power supply 10V and 9V voltages as I asked you before.
3. If indeed the power is 9V and you do see those zero volts relative to GND it is possible the transistors are shorted.
What I am trying to figure out is what caused several transistors to go short.
4. Measure from Q3.E to GND, see if it is shorted.
5. When you say "short", do you mean 0 Ohm or close, or just conductivity of a few hundred Ohm?
Try to do what we are asking you to do.
1. Desolder the transistors you want to check. Attention: semiconductors are VERY sensitive to the long heating so do NOT apply solder heat for long time. Best, grab a lead you are desoldering with needlenose pliers or a large tweezer, so to sink the heat from the iron tip. Note the way the leads go into the board.
If the board is a copper laminate, do not overheat the laminate or it will delaminate.
2. Do measure the power supply 10V and 9V voltages as I asked you before.
3. If indeed the power is 9V and you do see those zero volts relative to GND it is possible the transistors are shorted.
What I am trying to figure out is what caused several transistors to go short.
4. Measure from Q3.E to GND, see if it is shorted.
5. When you say "short", do you mean 0 Ohm or close, or just conductivity of a few hundred Ohm?
![[-]](https://philcoradio.com/phorum/images/bootbb/collapse.png "[-]")
