23-05-2015, 05:28 PM
(This post was last modified: 23-05-2015, 05:32 PM by boater sam.
Edit Reason: correct name
)
I have it set up as you suggest. Have limited X shift control, dependant on X-Y on channel 2 setting.
No sweep, there is no sign of trigger, int or ext, single shot is lit permanently.
Link 110/46 goes from 0.04v to 9.8v and link 110/43 goes from 9.2v to 3.5v, with X posn from end to end.
Tested TR73, 74, 64, 65, 66, 68 69. all seem ok, gain of TR64 (FRB749) is 95 others are in the 400 to 600 range but most are BC 239C
D85 is on the reverse of the pcb, no access. I could not establish whether it was OK so I have lifted the transistor leg and bypassed with another diode. Made no change.
Found a few more voltages.
D68 cathode 2.8v which seems correct pre trigger.
TR73 base -7.8v emitter -7.5v
TR74 base -6.8v Collector +6v
TR75 base 16.6v emitter 6.28v collector 16.2v
TR76 base 0.58v collector 9.8v
D73 anode 6v
It would look like the TR73, TR74 bistable is not switched either way?
Mark, I know why you passed on one of these, its terrible to work on.
No sweep, there is no sign of trigger, int or ext, single shot is lit permanently.
Link 110/46 goes from 0.04v to 9.8v and link 110/43 goes from 9.2v to 3.5v, with X posn from end to end.
Tested TR73, 74, 64, 65, 66, 68 69. all seem ok, gain of TR64 (FRB749) is 95 others are in the 400 to 600 range but most are BC 239C
D85 is on the reverse of the pcb, no access. I could not establish whether it was OK so I have lifted the transistor leg and bypassed with another diode. Made no change.
Found a few more voltages.
D68 cathode 2.8v which seems correct pre trigger.
TR73 base -7.8v emitter -7.5v
TR74 base -6.8v Collector +6v
TR75 base 16.6v emitter 6.28v collector 16.2v
TR76 base 0.58v collector 9.8v
D73 anode 6v
It would look like the TR73, TR74 bistable is not switched either way?
Mark, I know why you passed on one of these, its terrible to work on.
Boater Sam.
