HP 29C died in my hands ....
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03-06-2014, 06:05 PM
Post: #1
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HP 29C died in my hands ....
Hello,
I had this 29C for a long time and I was using it with great care, charging the batteries out of the calculator, using the correct type of rechargeable batteries with correct current rating. Last weekend, when I was in the middle of my calculations, it displayed a "0" at the far right hand side of the display and stopped responding to any key press. This "0" was brighter than anything it has displayed so far. I turned it off and on again but there was a blank screen. Hoping that this may be caused because of the flat batteries, I replaced them with freshly recharged ones. The moment I placed them in, I have noticed that I have left the calculator on, and it immediately displayed that "0" again. Turning it off and on gave the same blank screen. I made sure that the calculator was off, and took the batteries out, waited for a couple hours, and placed the batteries back in. When I turned it on, I had flickering "0"s and when I pressed a key, some segments of some digits were lit and the key-digit combinations were consistent. After reading the posts regarding 25/25C/29C repairs, I have decided to write my experience here, because I couldn't made any resemblance with any article that I have read so far. I would appreciate any input that may shed a light to what is going on with this 29C. I have another 29C which was serviced by the previous owner, therefore I am not sure which components are salvageable. Besides, that one has a daughter board, but this one does not. Also I have a 25C and a 25 willing to donate their parts if needed. Thanks in advance, Onur |
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03-06-2014, 07:10 PM
Post: #2
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RE: HP 29C died in my hands ....
A fried ACT I fear...
Greetings, Massimo -+×÷ ↔ left is right and right is wrong |
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03-06-2014, 09:53 PM
Post: #3
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RE: HP 29C died in my hands ....
Well, I have several ACT chips lying around. I guess the best way is to buy a low profile socket and start testing.
Is there something that I need to pay attention to while doing this? like: iron temperature, wrong ACT causing other failures... /Onur |
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03-06-2014, 10:25 PM
Post: #4
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RE: HP 29C died in my hands ....
(03-06-2014 09:53 PM)Onur ILKORUR Wrote: Well, I have several ACT chips lying around. I guess the best way is to buy a low profile socket and start testing. Based on Eric Smith's invaluable "HP Calculator Chips" site, the donor ACT will need to be either P/N 1820-1596 or 1820-1741. I weep for your loss. Mark Hardman Ceci n'est pas une signature. |
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03-06-2014, 10:48 PM
Post: #5
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RE: HP 29C died in my hands ....
That is a very good list indeed. I am so surprised how I missed it till now.
I think lady luck has changed her mind. I have an AMI 1820-1741 lying around. I don't recall for how long or from where I have it but I think I know already what I am going to do this Sunday afternoon. Mark and Massimo, thank you for your valuable time and input. I will share the result here. /Onur |
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03-06-2014, 10:54 PM
Post: #6
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RE: HP 29C died in my hands ....
One last thing ...
I am usually punished after replacing some ICs by the power supply. Meaning that, I sometimes replace some ICs on a circuit board, but later I realize that the IC is being blown away because of a faulty power supply. I think I need to check the voltage levels of the power supply before I replace the ACT? /Onur |
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