enoughstatic
- Mar 13, 2015
- 3
- Joined
- Mar 13, 2015
- Messages
- 3
Hello,
I have a Tektronix 2246 Oscilloscope that worked great for about 3 years and started performing intermittent on start-up... and is now only producing a solid beam of light.
Please note that this particular symptom / problem is not[/i] the same as the "Tektronix 2246 - No Beam!" post found in this forum. Rather, a different issue!
The Problem: After about 3 years of using this scope, it started developing a strange problem. Sometimes it would not start up successfully. I would occasionally get no LEDs lit up on the front panel. When this happened, I would just see a solid mean of light concentrated (at one random point on the CRT). Occasionally, I would receive an error message on the front panel screen: "Part Number 160-3493-00" (see photos).
However, it would start up about 80% of the time. But as the months go by, it would fail more often. Before it failed completely, I ran the self-diagnostics. They all passed. Every function on the scope seemed to work great when it started up successfully.
Steps I took once it failed completely:
1. Checked all power supply voltages: good (within specified DCV and AC ripple/noise)
2. Referencing the Troubleshooting Hints By Diagram in the Maintenance section of the Service Manual:
a) For Measurement Processor:
1. U2501 for RESET condition: good
2. ?SYS_RESET? at U2504E pin 10: good
3. RESET for U2521: good
4. CLKs at U2501: good
5. INTR line: bad when unit won't power up (50% duty cycle); or good when unit powers up
6. ?INTA?: unclear (must check again)
7. KERNAL test: TBD (waiting on new digital scope to arrive!)
b) I replaced the following ICs:
1. U2400 (8-bit microcontroller)... this is the "Part Number 160-3593-00" that occasionally displayed when faulty start-up.
2. U2501 (8-bit microcontroller)... was thinking that this might have been a problem. I carefully removed this one and socketed it. I preserved the old IC without damaging it.
Where I am now:
I sold my old Tek TDS220 scope a couple weeks ago and am about to receive a Rigol MSO (4-ch, with 16-digital ch bus for logic analyzing).
Any experience or suggestions would be greatly appreciated, as I really like this scope.
I have a Tektronix 2246 Oscilloscope that worked great for about 3 years and started performing intermittent on start-up... and is now only producing a solid beam of light.
Please note that this particular symptom / problem is not[/i] the same as the "Tektronix 2246 - No Beam!" post found in this forum. Rather, a different issue!
The Problem: After about 3 years of using this scope, it started developing a strange problem. Sometimes it would not start up successfully. I would occasionally get no LEDs lit up on the front panel. When this happened, I would just see a solid mean of light concentrated (at one random point on the CRT). Occasionally, I would receive an error message on the front panel screen: "Part Number 160-3493-00" (see photos).
However, it would start up about 80% of the time. But as the months go by, it would fail more often. Before it failed completely, I ran the self-diagnostics. They all passed. Every function on the scope seemed to work great when it started up successfully.
Steps I took once it failed completely:
1. Checked all power supply voltages: good (within specified DCV and AC ripple/noise)
2. Referencing the Troubleshooting Hints By Diagram in the Maintenance section of the Service Manual:
a) For Measurement Processor:
1. U2501 for RESET condition: good
2. ?SYS_RESET? at U2504E pin 10: good
3. RESET for U2521: good
4. CLKs at U2501: good
5. INTR line: bad when unit won't power up (50% duty cycle); or good when unit powers up
6. ?INTA?: unclear (must check again)
7. KERNAL test: TBD (waiting on new digital scope to arrive!)
b) I replaced the following ICs:
1. U2400 (8-bit microcontroller)... this is the "Part Number 160-3593-00" that occasionally displayed when faulty start-up.
2. U2501 (8-bit microcontroller)... was thinking that this might have been a problem. I carefully removed this one and socketed it. I preserved the old IC without damaging it.
Where I am now:
I sold my old Tek TDS220 scope a couple weeks ago and am about to receive a Rigol MSO (4-ch, with 16-digital ch bus for logic analyzing).
Any experience or suggestions would be greatly appreciated, as I really like this scope.
