STOP!!!!! TURN OFF THE POWER!!!! YOU ARE DESTROYING THE DRIVER
TRANSISTORS!!!! NEVER EVER EVER RUN A VECTOR MONITOR WITH THE OUTPUT
TRANSISTORS UNPLUGGED!!!!
Now that I have your attention, please test your monitor by unplugging the
YOKE. This removes the load from the outputs and thus you are very unlikely
to blow them. Now you can check for things like center voltage (should be
"0") and how much off that might be for each channel.
If you wish for a load that will give you a clue as to what is happening,
then you could use a couple of 15 watt light bulbs (115VAC) - one for each
axis. This should be a low enough current draw that the outputs, etc. will
be safe.
John :-#)#
At 11:15 PM 12/05/2002 -0400, Curtis H. Wilbar Jr. wrote:
>I have a G08 deflection board that's driving me nuts...
>
>Blew main fuses first, then while troubleshooting blew one of the deflection
>fuses.
>
>I have now been working on the deflection board with no deflection transistors
>connected (keeps from blowing fuses).
>
>The only thing I found wrong other than some cracked solder joints
>(which I fixed before blowing the fuses) was one of the ECO jumpers
>on the bottom was shorting to another trace through melted wire
>insulation. Fixed that.
>
>Have not reconnected to deflection transistors because voltages at IC600
>are so wrong. Most voltages should have been near 0 except for a
>couple a 4.2, one at 7.5, and then the +9 and -9 supply voltages.
>
>The only correct voltages were the supply ones.
>
>I removed IC600 (expecting that it is probably bad, shorted somewhere).
>There are no shorts between the +9 or -9 supply lines and any other leads.
>
>Rechecking the voltage at the pads for IC600, many of them are now at
>0/near 0 like they should be. The supply voltages are still correct,
>however pins 2 and 18 still measure -8V when they should be (in theory
>with IC installed) at 4.2V. That's a total of 12V of difference...
>
>I then wondered if something up with Q600 or Q700 could be "Backfeeding"
>into pins 2 and 18... so I removed them. pins 2 and 18 still at -8V !
>
>The only other voltage I see wrong is the collectors of Q600 and Q700
>should be 34-35V, but they are at 60+ V.
>
>I don't want to reinstall IC600 till I'm sure everything else is under
>control, as if it is still good (???) I don't want to blow it.
>
>Anyone got any ideas... I've stared at the schematic till I'm blue, and
>I still can't understand why pins 2 and 18 are so far off in voltage.
>
>the supply voltages of +63, -63, +9, and -9 all check fine with a DMM.
>
>Hopefully someone out there has some ideas... I'm pretty baffled.
>
>-- Curt
>
>---------------------------------------------------------------------------
>** To UNSUBSCRIBE from vectorlist, send a message with "UNSUBSCRIBE" in the
>** message body to vectorlist-request@synthcom.com. Please direct other
>** questions, comments, or problems to neil@synthcom.com.
---------------------------------------------------------------------------
** To UNSUBSCRIBE from vectorlist, send a message with "UNSUBSCRIBE" in the
** message body to vectorlist-request@synthcom.com. Please direct other
** questions, comments, or problems to neil@synthcom.com.
Received on Sun May 12 20:44:32 2002
This archive was generated by hypermail 2.1.8 : Fri Aug 01 2003 - 00:34:02 EDT