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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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LE40R88BDX/XEU, not quite the usual cycling with relay clicking on
startup as this one does start up but then locks up and power cycles after varying amounts of time. Checked the power supply, which appears to have been built with decent caps in this example, rather than the usual junk, anyway all the voltages 'scope clean as do all the ones I checked on the main board. I have replaced the eeprom (24C256) and performed a factory reset which apparently allowed it to work faultlessly for an hour until it locked up watching Freeview and reverted to the original problem. However, turning off the digital watch dogs in the options table does at least allow it to stay powered, albeit with Freeview (integrated digital tv for those not in the UK ![]() As it appears to work in this state I'm going to leave it like it, as it's being used with a satellite box anyway and HDMI seems to work fine. Unless anyone has any ideas? I don't have access to a newer firmware file and for some reason this particular mainboard revision isn't appearing at the usual suspects, maybe it's just too old now ![]() |
#2
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On 19/06/2014 13:58, Lee wrote:
LE40R88BDX/XEU, not quite the usual cycling with relay clicking on startup as this one does start up but then locks up and power cycles after varying amounts of time. Checked the power supply, which appears to have been built with decent caps in this example, rather than the usual junk, anyway all the voltages 'scope clean as do all the ones I checked on the main board. I have replaced the eeprom (24C256) and performed a factory reset which apparently allowed it to work faultlessly for an hour until it locked up watching Freeview and reverted to the original problem. However, turning off the digital watch dogs in the options table does at least allow it to stay powered, albeit with Freeview (integrated digital tv for those not in the UK ![]() As it appears to work in this state I'm going to leave it like it, as it's being used with a satellite box anyway and HDMI seems to work fine. Unless anyone has any ideas? I don't have access to a newer firmware file and for some reason this particular mainboard revision isn't appearing at the usual suspects, maybe it's just too old now ![]() Or is it just coincidence and an intermittant fault brought on/cleared by close handling?. |
#3
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On 19/06/2014 16:38, N_Cook wrote:
Or is it just coincidence and an intermittant fault brought on/cleared by close handling?. I did wonder that, in particular heating the board changing the eeprom, but prodding, freezing and heating seems to make no difference, whereas a reset does. I'm thinking a failed bga connection or maybe faulty dram. The main chip does run quite hot... |
#4
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"Lee" wrote in message
... On 19/06/2014 16:38, N_Cook wrote: Or is it just coincidence and an intermittant fault brought on/cleared by close handling?. I did wonder that, in particular heating the board changing the eeprom, but prodding, freezing and heating seems to make no difference, whereas a reset does. I'm thinking a failed bga connection or maybe faulty dram. The main chip does run quite hot... Not sure if this relates to yours, but I have seen on some recent vintage Samsungs the cable between the main board and power supply develops a burned and intermittent connection at the power supply side. A close examination of the connections would reveal if this is the case. Mark Z. |
#5
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On 22/06/2014 01:59, Mark Zacharias wrote:
"Lee" wrote in message ... On 19/06/2014 16:38, N_Cook wrote: Or is it just coincidence and an intermittant fault brought on/cleared by close handling?. I did wonder that, in particular heating the board changing the eeprom, but prodding, freezing and heating seems to make no difference, whereas a reset does. I'm thinking a failed bga connection or maybe faulty dram. The main chip does run quite hot... Not sure if this relates to yours, but I have seen on some recent vintage Samsungs the cable between the main board and power supply develops a burned and intermittent connection at the power supply side. A close examination of the connections would reveal if this is the case. Mark Z. It looked ok at first glance, but I will examine it more closely. Thanks. |
#6
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"Lee" wrote in message
... On 22/06/2014 01:59, Mark Zacharias wrote: "Lee" wrote in message ... On 19/06/2014 16:38, N_Cook wrote: Or is it just coincidence and an intermittant fault brought on/cleared by close handling?. I did wonder that, in particular heating the board changing the eeprom, but prodding, freezing and heating seems to make no difference, whereas a reset does. I'm thinking a failed bga connection or maybe faulty dram. The main chip does run quite hot... Not sure if this relates to yours, but I have seen on some recent vintage Samsungs the cable between the main board and power supply develops a burned and intermittent connection at the power supply side. A close examination of the connections would reveal if this is the case. Mark Z. It looked ok at first glance, but I will examine it more closely. Thanks. We've also seen wireless modules and jog assemblies cause this type of thing. Sheesh. For the days when basic troubleshooting was enough. Too much purple magic in this new stuff. Mark Z. |
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