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1
Repair / Re: Reball "repair" (the Rossman video and such)
« Last post by stojke on Today at 07:32:16 pm »
Each and every customer is fully aware of what an reballing procedure and an chip replacement procedure is.
Then I know why you don't have returns. Because they sell them to another suckers before they die again.

Do they or do they not I do not know nor care. But I do know that those who purchased an repaired laptop from my self , as I sell repaired laptops as well , those who bought reballed laptops returned for system maintenance and purchase of additional devices later on. The shop is open and on the same address for years as it has always been, it is their own flaw not to return and get problems solved.
2
Beginners / Re: High side current sense using differential opamp
« Last post by npelov on Today at 07:28:28 pm »
Yes, that circuit can go lower but is it stable? As I said previously, it's got a lot of gain. I notice you've got C1 to provide some frequency compensation but is it enough? I suspect not. It's extremely likely that circuit will oscillate.
I have no idea if it will be stable. Having mosfet in the loop is very tricky. I thought the low input capacitance would help to stabilize.

Have you thought about using an op-amp which can work up to the positive rail, in a current mirror configuration?

The op-amp only needs to work up to 5V and 5V rail-to-rail op-amps are cheap.

The P-MOSFET could even be swapped for a PNP BJT, which will reduce the accuracy slightly, due to the base current, but it's chaper and possibly make it more stable, since it has less capacitance, than the MOSFET.

That circuit is definitely interesting. I was thinking about two 12V lead acid batteries. The charger would have supply of >=30V. Most of the current sense don't go that far. And this circuit should minimize current - at higher voltages few mA means a lot of wasted power. Zero drift is not required unless precision is needed. Maybe I can use MCP601/MCP602 because its low power consumption (I don't have to burn a lot of current through Rbias and it has low offset current so R1 can be higher.

Thanks!
3
Repair / Re: Reball "repair" (the Rossman video and such)
« Last post by wraper on Today at 07:27:28 pm »
I always had a sneaking suspicion that graphics card failures in iMacs that come good after heating the card might have been due to tin whiskers from lead free solder causing shorts that were then melted during the heat process as they are so fine. Just a theory, I have no proof though.
Tin whiskers, particularly on GPU. When there are tons of other components with finer pin pitch.
4
Other Equipment & Products / Re: Best remote home automation solution?
« Last post by EEVblog on Today at 07:27:26 pm »
Does anyone know if it's actually possible to get a temperature log/graph using the Vera Edge system. Bugger if I can find a way to do it...
5
Sounds like you're taking on too much at the same time.
Start with adding some memory and then some simple (uart) io and build from there. Ignore interrupts for now.
When you make the steps smaller, you will be able to ask more specific questions and we'll be able to give you a more concrete answer.

A quick glance at the data sheet brings back Z80 memories.
The external pins are different using the address latch most notable.
Try to wrap your head around interfacing a single static memory (any size) chip to this CPU, draw the schematic and post it.

[2c]
6
Repair / Re: Reball "repair" (the Rossman video and such)
« Last post by wraper on Today at 07:25:35 pm »
Each and every customer is fully aware of what an reballing procedure and an chip replacement procedure is.
Then I know why you don't have returns. Because they sell them to another suckers before they die again.
7
Repair / Re: Reball "repair" (the Rossman video and such)
« Last post by Synthtech on Today at 07:25:06 pm »
I always had a sneaking suspicion that graphics card failures in iMacs that come good after heating the card might have been due to tin whiskers from lead free solder causing shorts that were then melted during the heat process as they are so fine. Just a theory, I have no proof though.
8
Test Equipment / Re: Hack of Sigllent spectrum analyzer ssa3021X?
« Last post by grants225 on Today at 07:24:19 pm »
Hi everyone,

while I managed to update/unlock some other devices (router, TV box etc)  :-+, my scripting knowledge is close to zero  :--. This definitely will not stop me from trying to upgrade SSA3k I am awaiting to be delivered, but some help/advise would be very helpful, especially after reading some warning posts.

I has read all current thred and still have questions:
1) if I understand Gonzo_the_grate script on #428, it makes backup to usb stick and makes copies of xml files adding 'x'-es in firmware0 and backup?

Code: [Select]
plug in FAT32 formatted USB memory stick (to take a backup).
telnet to SSA30xxX
root/ding1234

cd /   
cp -R /usr/bin/siglent/usr/backup /usr/bin/siglent/usr/mass_storage/U-disk0/SA-backup 
cp -R /usr/bin/siglent/firmdata0 /usr/bin/siglent/usr/mass_storage/U-disk0/SA-firmdata0 
mount -o remount,rw /dev/ubi2_0 /usr/bin/siglent/firmdata0
cd /usr/bin/siglent/firmdata0 
mv NSP_sn_bandwidth.xml NSP_sn_bandwidthx.xml 
mv NSP_trends_config_info.xml NSP_trends_config_infox.xml   
mv nsp_data_b nsp_data_bx   
cd /usr/bin/siglent/usr/backup   
mv NSP_sn_bandwidth.xml NSP_sn_bandwidthx.xml 
mv NSP_trends_config_info.xml NSP_trends_config_infox.xml 
mv nsp_data_b nsp_data_bx 
cd /
sync   
logout

reboot


2) where should be added this licence line? Is it xml file should be edited manually?:

Code: [Select]
<?xml version="1.0" encoding="UTF-8"?>
<nsp_system_info_root>
  <device>
    <system_information>
      <serial_number>
        <chip>SSA3XHAxxxxxxxxxxx</chip>
      </serial_number>
    <license><_3032>TRUE</_3032><_tTG>TRUE</_tTG><_tEMI>TRUE</_tEMI><_tMeas>TRUE</_tMeas><_tCAT>TRUE</_tCAT><_t1HZ>TRUE</_t1HZ><_t3M>TRUE</_t3M></license></system_information>
  </device>
</nsp_system_info_root>
9
Repair / Re: Reball "repair" (the Rossman video and such)
« Last post by wraper on Today at 07:23:50 pm »
Zillions in my book is a synonym for plenty or dozens :-)

https://www.eevblog.com/forum/beginners/getting-started-with-bga-reflow-and-reballing/msg472940/#msg472940
Quote
I'm not an expert in BGA reflow, but I have repaired macbook pros, macbook airs, white iMacs and aluminium iMacs, all with these nvidia chips that develop cracked solder joints, a few dozen Macs in total, with this simple "recipe" I was given:
Zillion is certainly is more than plenty of dozens. But I still won't ever believe you have so much "friends" that they could bring in plenty of dozens of iMacs and PowerBooks. And at the same time you don't do this professionally for living, yet pay off for a right equipment. Not to say that old PowerBooks are completely irrelevant to the problem.
10
General PCB/EDA/CAD Discussions / CircuitMaker Component Libraries?
« Last post by Pack34 on Today at 07:22:22 pm »
I want to get back into some open source work and wanted to ditch Eagle in favor of CircuitMaker. I figured it would be easy to switch between CM and AD between OSHW and my job.

I like to keep my component libraries meticulous. Such as "Resistor 0402 Yageo", "Capacitor 0201 Murata", etc. I can clearly see how to make PCB projects, but for components it seems to be just Octopart listings.

Can you not make an integrated component library in CM? I know it's all supposed to be online and open, which is the point, but certainly I should be able to make an open source component library to support my open source PCB. Is this actually not the case? All components are just floating there in a single library in the cloud?
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