sci.electronics.repair@googlegroups.com

Google Groups

Lucifer <LuciferMorningstar@bigpond.com>: Mar 05 08:32AM +1100 On Mon, 4 Mar 2019 12:09:19 +0100, Look165 <look165@numericable.fr> wrote:     >> There are two LEDs on the main board to show power on each >> CPU. The LEDs for CPU two are not lit.   >First check there are physically 2 CPU.   There are, and two lots of RAM.   >Either on the board ans in the BIOS (and activated).   No BIOS. It's an Apple.

John-Del <ohger1s@gmail.com>: Mar 05 04:32AM -0800 On Monday, March 4, 2019 at 4:32:19 PM UTC-5, Lucifer wrote:   > There are, and two lots of RAM.   > >Either on the board ans in the BIOS (and activated).   > No BIOS. It's an Apple.     The next step is determining if both CPUs are fed from the same source, or if there are two separate buck converters on the board for each. You might be able to see two identical converter circuits in the same proximity to each CPU.

bje@ripco.com: Mar 05 12:43PM > No BIOS. It's an Apple.   Was this an ebay special?   Make sure you put a fresh battery in (probably cr2032), there may be no bios but it still has nvram for configuration settings, backed up by the battery.   A flakey battery (or dead) might screw things up quite a bit. On some Sun servers, the machine won't even power up.   One other thought, you said something about 12GB ram, kind of an odd amount.   I think that machine is picky about the type and what slots are used. You can use different sized chips but the pairs have to be matched.   On that machine the slots are arranged like this:   1 5 2 6 3 7 4 8   the ones in slots 1 and 2 have to be matched. (first pair) the ones in slots 3 and 4 have to be matched. (second pair) the ones in slots 5 and 6 have to be matched. (third pair) the ones in slots 7 and 8 have to be matched. (forth pair)   To make life simple, if you know for a fact you have 4 identical simms, just use them in 1-2-3-4 and leave 5-6-7-8 empty.   I'm not sure if the mixed sizes or placement will cause the led not to light on the one cpu but this is just basic troubleshooting.   Odds are it's "something else" including a bad cpu but the battery and simm placement is a good starting point.   -bruce bje@ripco.com

Peter Jason <pj@jostle.com>: Mar 05 07:57AM +1100 On Mon, 4 Mar 2019 08:32:56 -0000 (UTC), gregz >after it's fully dried. I kept thinking some kind of thick stable grease. >Silicone with TFE nope. Got kit ordered.   >Greg   What about the conducting stuff they use for CPUs on motherboards?

John-Del <ohger1s@gmail.com>: Mar 04 02:51PM -0800 On Monday, March 4, 2019 at 3:57:56 PM UTC-5, Peter Jason wrote:   > >Greg   > What about the conducting stuff they use for CPUs > on motherboards?     I assume you mean heat conducting stuff? Way too viscous, but I don't know if it will creep (prob not).

gregz <zekor@comcast.net>: Mar 05 08:22AM >> Greg   > What about the conducting stuff they use for CPUs > on motherboards?   My experience shows it dries up. Sure is messy.   Greg

"Gareth Magennis" <soundserviceleeds@outlook.com>: Mar 04 10:24PM "Phil Allison" wrote in message news:340084f5-a421-404c-910f-c06582dd55d2@googlegroups.com...   Gareth Magennis wrote:     > And this could have shorted the parallel 4kV diode between 3 & 2?   > Or did the opposite occur?   ** I only mentioned the possibility of valve arcing for completeness - cos it is another scenario that would cause similar damage.   Fix you Engl, come back when you have.   BTW   When the Krauts stuff something up - they do a thorough job of it.         .... Phil       *******************************************     I have fixed the Engl.   Some of the 35v ELectro caps on the pre-amp cathodes were shorted, so all 10 got replaced. Kind of confirms a large global overvoltage happened I think, along with the burnt cathode resistor on V5.   The 6l6 heaters all survived, but I guess they are somewhat more resilient.     The Engl tech reckons V5 shorted internally. Not quite sure how this would short the OPT diode to put HT on all the heaters, but who knows the real sequence of events.   I don't know what the customer did, he has only said he replaced the mains fuse with the correct one, but is otherwise keeping schtum.     I still don't have the schematics for this amp, maybe putting the protection diodes on the heater circuit instead of ground was a big design mistake. I have moved them to ground.       Cheers,     Gareth.

"Gareth Magennis" <soundserviceleeds@outlook.com>: Mar 04 10:42PM "Gareth Magennis" wrote in message news:GAhfE.28020$LG6.15778@fx04.am4...       "Phil Allison" wrote in message news:340084f5-a421-404c-910f-c06582dd55d2@googlegroups.com...   Gareth Magennis wrote:     > And this could have shorted the parallel 4kV diode between 3 & 2?   > Or did the opposite occur?   ** I only mentioned the possibility of valve arcing for completeness - cos it is another scenario that would cause similar damage.   Fix you Engl, come back when you have.   BTW   When the Krauts stuff something up - they do a thorough job of it.         .... Phil       *******************************************     I have fixed the Engl.   Some of the 35v ELectro caps on the pre-amp cathodes were shorted, so all 10 got replaced. Kind of confirms a large global overvoltage happened I think, along with the burnt cathode resistor on V5.   The 6l6 heaters all survived, but I guess they are somewhat more resilient.     The Engl tech reckons V5 shorted internally. Not quite sure how this would short the OPT diode to put HT on all the heaters, but who knows the real sequence of events.   I don't know what the customer did, he has only said he replaced the mains fuse with the correct one, but is otherwise keeping schtum.     I still don't have the schematics for this amp, maybe putting the protection diodes on the heater circuit instead of ground was a big design mistake. I have moved them to ground.       Cheers,     Gareth.       *************************************************     One other thing, V5 is driving the effects send and return loop, so this is available to the outside world.       Gareth.

Phil Allison <pallison49@gmail.com>: Mar 04 11:38PM -0800 Gareth Magennis wrote:     > I still don't have the schematics for this amp, maybe putting the protection > diodes on the heater circuit instead of ground was a big design mistake. > I have moved them to ground.   ** That the HV diodes connect to the heater line ( instead of chassis ground ) likely did not cause the failure, but it sure caused all the damage.   FYI:   A tech working for the maker / importer is NO use to you when it comes to bad design problems. I see a lot of them these days in tube amps and have to modify circuits to effect a reliable repair.   I don't give a hoot what the amp maker or even the customer thinks of this cos *** I *** am the one liable for a repeat failure both financially and in terms of reputation.       .... Phil

three_jeeps <jjhudak@gmail.com>: Mar 04 09:22AM -0800 On Monday, March 4, 2019 at 5:50:17 AM UTC-5, Clifford Heath wrote:   > Sooo, you're looking for your Brother's keeper?   > :)   > Personally, I wouldn't keep a Brother. HP all the way.   Yea, I used to think that way until the last two HP printers (one laser, one inkjet) had continuous annoying failures (laser printer had phantom paper jams with less than 10,000 copies) and the inkjet AIO ate ink (<200 pages with the XL cartridges, was incredibly slow, and eventually lost its mind after 2 years.) The Brother replacement was a little more expensive than a comparable HP, but I get 400+ pages on ink cartridges that in total, are $30 less than the HPs. Yes, color images (e.g. photos) are not quite as good, but since color photos are less than 1% of my printing, the brother is a much better tradeoff. Also, firmware and sw updates on the HP were an exercise in patience and futility. One click on the brother and the updates download and install flawlessly. HP printers are not your fathers HP, no way, no how.

Ralph Phillips <ralphp@philent.biz>: Mar 04 11:55AM -0600 On 3/3/2019 1:41 AM, Spare Change wrote: > Brother.   > Any pointers to any Brother service apps would be greatly appreciated.   > Thanks.   USUALLY - that's the Maintenance tab in the printer driver.   It's not immediately accessible in Windows 10, but if you go Win-R --> Control --> Devices and Printers --> Pick "printer Properties" from the right-click menu, and check the "Maintenance" tab. (If there isn't one, check all the tabs for a Maintenance button. I don't have a Brother, so I can't verify here.)   RwP

"Ron D." <ron.dozier@gmail.com>: Mar 04 10:45AM -0800 HP is getting like everyone else. price is more important than quality. I own a HP P2015dn B&W laser printer and i like it a lot. It was only about $250.00 on sale.   I wanted networking and the "possibility" of a straight paper path which is has. Once they discontinue the rollers and the toner your out of luck or you have to rely on aftermarket stuff. Forget answering questions about older stuff.   The firmware updates are no longer available. Most parts aren't either.   I have about 32,000 pages on the printer with a self done clean and replace rollers.   I also had to do the easy-bake oven repair on the printer where you bake the formatter in the oven for a while.   One change I would like and can probably do myself is to make the manual paper tray less fragile by incorporating a magnetic catch. If I used it more often, I would fix it.

You received this digest because you're subscribed to updates for this group. You can change your settings on the group membership page. To unsubscribe from this group and stop receiving emails from it send an email to sci.electronics.repair+unsubscribe@googlegroups.com.