ott
New Member
Posts: 4 
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Post by ott on May 19, 2015 21:56:55 GMT -5
Had flashing red light problem. No -15V. Replaced regulator. Now, pushing ON/STANDBY flashes to steady green but no display and power relay does not activate. A/B speaker indicators work and remote turns unit on/off. Checked for start-up voltages and all OK. Manually activating power relay brings up all voltages, but still no display. Almost looks like CPU failure, but why now? How can I verify the failure point?
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Post by mastertech on May 19, 2015 22:42:38 GMT -5
On the main board locate connector CP555. See if there is any voltage on pin 7. Am I correct you have the main power relay jumped to be always on?
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ojf
New Member
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Post by ojf on May 20, 2015 18:31:21 GMT -5
No voltage on the Protect pin. I've only manually engaged the power relay to see if all power supply voltages come up - and they do.
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Post by mastertech on May 20, 2015 19:14:58 GMT -5
No voltage on the Protect pin. I've only manually engaged the power relay to see if all power supply voltages come up - and they do. What do you mean "manually"? You have the relay cover off and are pressing on the contact arm? If there is no voltage on the protect pin either plugged in or with the relay on then it is going into protect, which is why the display never comes on. There should be around +5v on that line during normal operation. |
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ott
New Member
Posts: 4
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Post by ott on May 20, 2015 20:28:59 GMT -5
Yes, cover off pressing contact arm. I have NO voltage on pin 7.
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ott
New Member
Posts: 4
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Post by ott on May 20, 2015 20:44:03 GMT -5
Sorry, common connection came off. I DO have +5V on pin 7.
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Post by mastertech on May 20, 2015 21:21:15 GMT -5
Are you able to do voltage tests directly on ic201 on the CPU board with it assembled(minus cover of course) and powered? Do you have access?
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ott
New Member
Posts: 4
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Post by ott on May 21, 2015 10:24:06 GMT -5
That is not readily doable.
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Post by mastertech on May 27, 2015 11:59:52 GMT -5
I would probably need tests right on that CPU to see what is going on. Trying to test in other locations would be leaving possible problem areas.
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