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- iPad screen - bar in middle - anyone found a fix? - 4 Updates
- Germanium Diode Data sheets - 3 Updates
| Tim R <timothy42b@aol.com>: Apr 06 06:45AM -0700 When I worked for a paper mill we had a machine lose memory, lightning storm I think. The Allen Bradley PLC had an EEPROM backup so we uploaded the program from it. Counterintuitively to the maintenance section, "upload" to A-B means upload FROM the PLC, not TO the PLC. So we loaded the empty program into the EPROM, erasing it. Not a problem, we had another EEPROM safely locked in a cabinet in the office. Of course we repeated the same mistake on our only backup. |
| Ralph Mowery <rmowery28146@earthlink.net>: Apr 06 10:15AM -0400 In article <0d2dd651-6068-4804-81b0-e54f8772146e@googlegroups.com>, timothy42b@aol.com says... > Counterintuitively to the maintenance section, "upload" to A-B means upload FROM the PLC, not TO the PLC. So we loaded the empty program into the EPROM, erasing it. > Not a problem, we had another EEPROM safely locked in a cabinet in the office. > Of course we repeated the same mistake on our only backup. Where I worked we had lots of the AB PLCs. Seems to me that they did many things backwards from more normal thinking,or what other companies were doing. What I really hated about them was if a card went bad you had to shut down the whole PLC system. Something difficult to do and keep the process from going bad. Much perferred some of the other equipment where you could hot swap the bad card. When there are 30 to 50 cards involved and each one has 8 to 16 production items on it, it can make a mess out of production. |
| John Robertson <spam@flippers.com>: Apr 06 07:44AM -0700 On 2017/04/06 6:45 AM, Tim R wrote: > Counterintuitively to the maintenance section, "upload" to A-B means upload FROM the PLC, not TO the PLC. So we loaded the empty program into the EPROM, erasing it. > Not a problem, we had another EEPROM safely locked in a cabinet in the office. > Of course we repeated the same mistake on our only backup. Ouch. I have done similar mistakes. That is why I have both on site and off site backups these days. John :-#(# -- (Please post followups or tech inquiries to the USENET newsgroup) John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games) www.flippers.com "Old pinballers never die, they just flip out." |
| John Robertson <spam@flippers.com>: Apr 06 12:06AM -0700 Has anyone here taken apart an iPad (original - cellular) screen to repair the problem of a fat (1" wide) band fully across the middle of the screen? The band runs horizontally in the normal (narrow side horizontal, button down) position. I have extracted the screen from the iPad, but am a little reluctant to continue tearing it down to find the potential connection issue without knowing what I am facing. Can't find anything so far on line for servicing the actual LCD display. I plan on digging into it in the near future but hope that someone here has done so already and can provide some advice. Thanks! John :-#)# -- (Please post followups or tech inquiries to the USENET newsgroup) John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games) www.flippers.com "Old pinballers never die, they just flip out." |
| Clifford Heath <no.spam@please.net>: Apr 06 05:57PM +1000 On 06/04/17 17:06, John Robertson wrote: > I have extracted the screen from the iPad, but am a little reluctant to > continue tearing it down to find the potential connection issue without > knowing what I am facing What makes you think it's a connection issue? More likely a problem with a driver chip, and the panel is toast. Clifford Heath. |
| ohger1s@gmail.com: Apr 06 04:34AM -0700 On Thursday, April 6, 2017 at 3:07:03 AM UTC-4, John Robertson wrote: > (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games) > www.flippers.com > "Old pinballers never die, they just flip out." Other than the plug that mates the display to the board, there are no other serviceable connections. Try a little contact cleaner in the socket or clean the ribbon (if that's what it uses). Any other connection on the screen proper is going to be of the bonded variety and not serviceable. |
| John Robertson <spam@flippers.com>: Apr 06 07:42AM -0700 On 2017/04/06 12:57 AM, Clifford Heath wrote: > What makes you think it's a connection issue? > More likely a problem with a driver chip, and the panel is toast. > Clifford Heath. I wasn't sure if it was a connection issue or not, but it does flicker. Indeed it could well be a driver chip that is built into the screen and I imagine that is irrepairable. I just haven't poked inside one of these displays before and it is for one of my grand-daughters. It appears I have nothing to loose by trying to open the screen up further so wish me luck! I have tried reseating the connector to the motherboard so have eliminated that as a suspect. If I have any success I will report back - silence means the screen is toasted and I won't waste anyone's reading time further. John :-#)# -- (Please post followups or tech inquiries to the USENET newsgroup) John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games) www.flippers.com "Old pinballers never die, they just flip out." |
| isw <isw@witzend.com>: Apr 05 08:38PM -0700 In article <et7aec1rp5ld0augksedkba1ue0ab91rea@4ax.com>, > use any of the other germanium diodes). Is there any advantage or > disadvantage to either of them? > Also, why dont they use Silicon Diodes? (Mumble) years ago, I needed some germanium diodes for an amplifier I was designing (it was the conduction drop over temperature I specifically needed, for thermal compensation). Found some 1N34s in a catalog, and ordered a few. Which didn't work. Took a while, but I finally got data sheets and (by that time) was not very surprised to find specs of 0.7V forward drop and tempco matching silicon, not germanium. So in answer to your question, I'd say some of them do. Isaac |
| oldschool@tubes.com: Apr 05 10:48PM -0400 On Wed, 5 Apr 2017 23:29:38 -0400, Ralph Mowery >1n60. Somewhere around 75 volts insted of 25 volts. >The germanium has a junction voltage of about .3 volts and the silicon >.7 volts. Better sensitivity at low voltages. Sounds good to me! |
| Phil Allison <pallison49@gmail.com>: Apr 05 08:56PM -0700 Ralph Mowery wrote: > 1n60. Somewhere around 75 volts insted of 25 volts. > The germanium has a junction voltage of about .3 volts and the silicon > .7 volts. Better sensitivity at low voltages. ** FYI: AAZ15 Ge 0.11V @ 50uA BAT46 Schottky 0.15V @ 50uA 1N4148 Si 0.45V @ 50uA MBR745 Schottky 0.12V @ 50uA. That last diode is rated at 7.5A, the other are all small signal types. .... Phil |
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