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[41] Odd display problem
04-21-2015, 01:45 PM
Post: #2
RE: [hp41] Odd display problem
A pity nobody can give a clue.

In any case, I keep looking for it. I've found that, in a a working 41, the display OS1 signal stays at 0.9 V in RUN and SLEEP modes, whereas it shows a triangular waveform, between 0 and 0.9 V (at a frequency of 7 kHz) in STANDBY mode. The 7 kHz frequency is consistent with the 11 minutes timeout, as the LCD driver chips wait for the timeout 9ยท2^19 ~ 4M7 cycles. At 7 kHz such number of cycles means ~11 minutes.

My faulty 41 does not show such triangular waveform, it remains fixed at 0.9 V anytime. I do not know yet if the oscillator is faulty or there is another reason for this behavior (although I am missing the hope on such).

Regards.
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Messages In This Thread
[41] Odd display problem - emece67 - 04-19-2015, 07:45 PM
RE: [hp41] Odd display problem - emece67 - 04-21-2015 01:45 PM
RE: [hp41] Odd display problem - jebem - 04-22-2015, 04:57 PM
RE: [hp41] Odd display problem - emece67 - 04-22-2015, 08:57 PM
RE: [hp41] Odd display problem - emece67 - 04-26-2015, 07:29 PM
RE: [hp41] Odd display problem - emece67 - 04-27-2015, 06:40 PM
RE: [hp41] Odd display problem - emece67 - 04-28-2015, 07:55 PM
RE: [hp41] Odd display problem - jebem - 04-28-2015, 10:16 PM
RE: [hp41] Odd display problem - emece67 - 04-29-2015, 04:46 PM
RE: [hp41] Odd display problem - TASP - 04-29-2015, 05:01 PM
RE: [hp41] Odd display problem - emece67 - 04-30-2015, 10:29 PM
RE: [hp41] Odd display problem - emece67 - 04-30-2015, 11:22 PM
RE: [hp41] Odd display problem - emece67 - 05-01-2015, 07:25 PM
RE: [hp41] Odd display problem - emece67 - 05-01-2015, 07:30 PM
RE: [hp41] Odd display problem - emece67 - 05-01-2015, 11:22 PM
RE: [hp41] Odd display problem - emece67 - 05-03-2015, 12:02 AM



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