HP Forum Archive 14

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19bII no power Message #1 Posted by Mike H on 23 Oct 2004, 11:29 p.m. I recently acquired an HP 19BII that will not power up. The voltage across the batteries reads 4.15 V when installed in the calc, but each measure 1.5+ V individually. Otherwise, the battery cover is in good shape and the calculator looks good. Has anyone seen this problem before, or know of any thing to try? Thanks Mike

Re: 19bII no power Message #2 Posted by Vieira, Luiz C. (Brazil) on 23 Oct 2004, 11:54 p.m., in response to message #1 by Mike H Hi; Do you have the means for measuring the current consumption? I mean, if you have a multimeter (the one you used to measure the voltage across the batteries and with them in place), can you use it to measure the current as well? If the batteries voltage drops to 4.15 (less .35), then the calculator circuitry is draining more power (current) than it should, OR one of the batteries is not good (if they are fresh units, the first is mostly likely to happen). I know that in some circumstances, internal software/firmware loop may cause the equipment to consume more power than in normal operation, mostly if it has I/O ports or devices that consume power. The HP19BII has an IR output, and if by any reason there's an active SW loop triggering the IR, that would be the reason for the voltage drop as well. I'd suggest removing the batteries and keep the [ON] key pressed for some time. OR try the [ON][upper-left][upper-right] reset key sequence, if you have not yet tried it out. Maybe one of these procedures can bring it back to normal operation. If not... well, I'd not consider that for now, but burned IC's would cause this as well. Let us know if you succeed. Luiz (Brazil) Edited: 24 Oct 2004, 12:00 a.m.

Re: 19bII no power Message #3 Posted by Randy on 24 Oct 2004, 9:50 a.m., in response to message #2 by Vieira, Luiz C. (Brazil) The most common and fatal failure in any of the clamshell machines is fracturing of the plastic heat stakes that hold the case halves together. A simple test: With known good batteries installed, place the open unit on a flat surface in front of you. With one hand, press lightly on the raised part of the display bezel as shown here: Then try turning it on with the other hand. If it works, it has suffered the usual clamshell failure. The plastic heat stakes have broken and allowed the back and front case halves to separate causing a loss in connection between the keyboard connector and logic board. You can confirm this by peeling away the keyboard surround overlay (a reversible process) and looking at the heat stake heads. Several will probably fall out or be attached to the overlay. The ones that cause the contact problem are shown here: There is no good or simple way to repair once the stakes break.

Re: 19bII still no power Message #4 Posted by Mike H on 24 Oct 2004, 12:16 p.m., in response to message #3 by Randy Luiz and Randy, thanks, but still no luck. I attempted the reset as described by Luiz and nothing. I tried direct pressure...nothing. I then removed the cover and checked the heatstakes, all OK. At one piont when I removed and re-installed the batteries, the calculator did make a soft buzzing noise, but did not power up. Any other suggestions would be greatly appreciated. Mike

Re: 19bII still no power Message #5 Posted by Randy on 24 Oct 2004, 3:11 p.m., in response to message #4 by Mike H Buy a replacement... as there's not much you can do to repair it. Once you pop the heat stakes to see what is wrong, you can't reclose it.

Re: 19bII still no power Message #6 Posted by Mike H on 24 Oct 2004, 6:25 p.m., in response to message #5 by Randy I did not open the case, I simply peeled back the plastic sheeting to expose the tops of the heatstakes, none are broken.

Re: 19bII still no power Message #7 Posted by Vieira, Luiz C. (Brazil) on 25 Oct 2004, 1:09 a.m., in response to message #6 by Mike H Hi, Mike; have you found a way to measure how many (mili)Amps are drained by the circuits? Just for checking purposes. Luiz (Brazil)

Re: 19bII still no power Message #8 Posted by Randy on 26 Oct 2004, 8:20 p.m., in response to message #7 by Vieira, Luiz C. (Brazil) Luiz, I don't think he really cares to fix it unless it will make him $$$. You see, he is just another eBay bottom feeder coming here for help. Here's the calculator we've been trying to help him with. At least he didn't list it for $100.00. I suspect if I dug deep enough, I could find where he bought it but I don't care to waste the time as his eBay history is full of such examples as this purchase: 32S 50th and then it's resale: this way Then to come here and use the free classifieds to promote his eBay sales is nothing short of shameful. Give people like this an inch and they will take the preverbal mile. I'm done wasting my time with this type of person, this is the second one for me this week. Here's the other one. The only problem is, you never know were the next one is going to appear. :-( Edited: 26 Oct 2004, 8:29 p.m.

Thanks. And... Message #9 Posted by Vieira, Luiz C. (Brazil) on 27 Oct 2004, 1:02 a.m., in response to message #8 by Randy Hi, Randy; I'd like to thank you for your warnning. I'd rather sending you an e-mail for private thanks, but I think your constant transparency and willing to help that's been shown here in every post of yours lead me to post an answer here as well, because you deserve a transparent answer. Thank you again. I'm not following e-bay mostly because of difficulties on transportation, delivery and, if applicable, devolution of faulty, wrongly announced equipment when dealers are not in the same country. So, I'm not aware of these facts. Best regards, Randy. Luiz (Brazil) Edited: 27 Oct 2004, 1:38 a.m.

Shameful (edited) Message #10 Posted by Mike H on 27 Oct 2004, 5:09 p.m., in response to message #8 by Randy Randy, I have had several personal emails from you in the past and have always respected your opinion. And yes I do buy and sell calculators on ebay for profit. I search ebay for really good deals and sell them at market value. I see no difference than you fixing a calc for set price regardless of the money or time you have invested. If you had an opportunity to purchase a 32S 50th for $60, what would be the selling price in your new store? Some type of HP calculator has been on my desk since 1982, I use it almost daily. I have offered my input into this forum and well as advice to those I could help. To slander me in this forum, is not in keeping with your true character. "Thank you" to you and Luiz for your time. Edited: 27 Oct 2004, 5:33 p.m.

(deleted post) Message #11 Posted by deleted on 27 Oct 2004, 9:00 p.m., in response to message #10 by Mike H This Message was deleted. This empty message preserves the threading when a post with followup(s) is deleted.

19BII Message #12 Posted by Mike H on 28 Oct 2004, 8:33 a.m., in response to message #11 by deleted The 19BII in question is not, nor ever planned to be sold on ebay. I agree with you that this forum should not be used for individuals to make money. Rather to share in the enjoyment and knowledge base of HP calculators. I had hoped to fix it and give it as a Christmas gift; it is in very nice condition. Since it appears the repair is beyond my capabilities, the calculator is now on its way to you, quid pro quo. To you Randy, Luiz and any others I may have offended, I offer my sincerest apology. This forum is comprised of some very fine and generous individuals, and I enjoy reading the post, even though many are beyond my comprehension. Mike Edited: 28 Oct 2004, 12:00 p.m.

Re: 19bII no power Message #13 Posted by Forrest on 27 Oct 2004, 12:03 a.m., in response to message #2 by Vieira, Luiz C. (Brazil) Luiz, I have two 28S calculators. One works and the other wont turn on. The pressure doesn't work. I tried to measure the current and thru the working one, I cannot get a measurement (less than 1/1000 amp). Through the one that wont work I am reading 0.022 amps. What is the suggestion - waste basket? I bought the non working one with the understanding that it worked. Not too disapointed though because I did get excellent manuals. Forrest

Re: 19bII no power Message #14 Posted by Vieira, Luiz C. (Brazil) on 27 Oct 2004, 1:32 a.m., in response to message #13 by Forrest Hi, Forrest; first of all: never give up an (original) HP device! :-) Now for the facts: as you see, others like Randy have many good, applicable techniques and suggestions, and I guess that if you followed the ones Randy posted here and the calculator still does not respond, chances are you have a faulty IC. I had in hands an HP41 that had average current drain when the batteries were installed and about a current consumption 5 times higher than average when turnned on. The display was too dimm, and this sympton lead me to check the LCD driver. After replaced, the calculator returned to normal. This sort of maneuvre is not possible in the HP28 because of this: (Hewlett-Packard Journal, August 1987, p.26) The hybrid IC's (upper image) contain the LCD drivers: no way to replace any. And the excessive current consumption when the calculator is turned off worries me, because either a faulty electrolytic capacitor or the small IR LED driver (SMD transistor/FET?) may cause it. Even After Randy's precise explanations, I'd at least save it for future experiments. I have one HP28S and I'd like having another, broken one for spare parts... Better yet, having two working units! As I always say: hope you succeed. Let us know if you want to go ahead and open it. Best regards. Luiz (Brazil) Edited: 27 Oct 2004, 1:51 a.m.

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