Tektronix 2335, no trace, no beam
Hi all,
I just bought a Tektronix 2335 oscilloscope, one minute working, the next minute the trace is gone. The beam finder does not work. nothing works. However I do see a flash of a blurry beam when I first turn it on, but that's it. When opened I see small resistor is burned open just to the left of q114 off the emitter on the vert out/HV power pcb. I can't tell what the value is and I don't have any schematics. The big question is this: What else is gone and why? I don't suppose anybody has the schematic for this board?? (same as 2336 scope) Please help if you have ANY ideas!! Bob email: To email remove NOSPAM |
Tektronix 2335, no trace, no beam
Bob Kelly wrote in
: Hi all, I just bought a Tektronix 2335 oscilloscope, one minute working, the next minute the trace is gone. The beam finder does not work. nothing works. However I do see a flash of a blurry beam when I first turn it on, but that's it. When opened I see small resistor is burned open just to the left of q114 off the emitter on the vert out/HV power pcb. I can't tell what the value is and I don't have any schematics. The big question is this: What else is gone and why? I don't suppose anybody has the schematic for this board?? (same as 2336 scope) Please help if you have ANY ideas!! Bob email: To email remove NOSPAM Bob, I believe the resistor you are referring to is R113, 1.6k. If you still need the print, reply to the group and I will email you a scan. Len Johnson |
Tektronix 2335, no trace, no beam - Tek2335-HV.pdf (0/1)
Yes that is the correct resistor, however replacing it doesn't seem to
help. It just burns up again. I pulled Q114 and Q115 and they check out ok. Even during the burn-up I get no trace. Everything else seems to look good. I do have the schematic thanks to a good samaritan, although I don't have the part list, so I can't tell what the transistors are exactly. (can tell pnp npn no trouble) Does anybody have any ideas?? see attached pdf. (I hope attachments are ok) Thanks Len!! I'll take a scan of the part list if you have it. Bob On Sun, 17 Aug 2003 17:26:42 -0000, Len wrote: Bob Kelly wrote in : Hi all, I just bought a Tektronix 2335 oscilloscope, one minute working, the next minute the trace is gone. The beam finder does not work. nothing works. However I do see a flash of a blurry beam when I first turn it on, but that's it. When opened I see small resistor is burned open just to the left of q114 off the emitter on the vert out/HV power pcb. I can't tell what the value is and I don't have any schematics. The big question is this: What else is gone and why? I don't suppose anybody has the schematic for this board?? (same as 2336 scope) Please help if you have ANY ideas!! Bob email: To email remove NOSPAM Bob, I believe the resistor you are referring to is R113, 1.6k. If you still need the print, reply to the group and I will email you a scan. Len Johnson |
Tektronix 2335, no trace, no beam
Yes that is the correct resistor, however replacing it doesn't seem to
help. It just burns up again. I pulled Q114 and Q115 and they check out ok. Even during the burn-up I get no trace. Everything else seems to look good. I do have the schematic thanks to a good samaritan, although I don't have the part list, so I can't tell what the transistors are exactly. (can tell pnp npn no trouble) Does anybody have any ideas?? see attached pdf. (I hope attachments are ok) Thanks Len!! I'll take a scan of the part list if you have it. Bob On Sun, 17 Aug 2003 17:26:42 -0000, Len wrote: Hi all, I just bought a Tektronix 2335 oscilloscope, one minute working, the next minute the trace is gone. The beam finder does not work. nothing works. However I do see a flash of a blurry beam when I first turn it on, but that's it. When opened I see small resistor is burned open just to the left of q114 off the emitter on the vert out/HV power pcb. I can't tell what the value is and I don't have any schematics. The big question is this: What else is gone and why? I don't suppose anybody has the schematic for this board?? (same as 2336 scope) Please help if you have ANY ideas!! Bob email: To email remove NOSPAM Bob, I believe the resistor you are referring to is R113, 1.6k. If you still need the print, reply to the group and I will email you a scan. Len Johnson |
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