>>>>> It now boots, but after about 4 or 5 secs it starts constantly rebooting,
>>>>> output below, along with board LEDs going fron steady green to red then
>>>>> green, then red then green etc. The reset button has no effect.
>>>>>
>>>>> At first I thought it was the power supply developed a problem, so I've
>>>>> tested with another PSU - same thing. I've disconnected everything
>>>>> and still same problem.
>>>>>
>>>>> Anybody any suggestions at all as to what I might check for? If I'm quick
>>>>> I
>>>>> can get maybe a couple of redboot commands executed, if anything will give
>>>>> any diagnostic info.
>>>
>>> ...snipped...
>>>>>
>>>>> RedBoot>
>>>>>
>>>>>>> TS-BOOTROM, Rev 1.02 - built 16:55:24, Sep 14 2004
>>>>>>> Copyright (C) 2004, Technologic Systems
>>>>>>> TS-7200: Rev A PLD detected, options ( MAX197-ADC )
>>>>>
>>>>>
>>>>>
>>>>>>> TS-BOOTROM, Rev 1.02 - built 16:55:24, Sep 14 2004
>>>>>>> Copyright (C) 2004, Technologic Systems
>>>>>>> TS-7200: Rev A PLD detected, options ( MAX197-ADC )
>>>>>
>>>>> ....repeated over and over
>>>>>
>>>> If it is rebooting whilst being held static at the reboot prompt, it must
>>>> be hardware. It definitely sounds like power brown-out triggering the
>>>> reboot.
>>>>
>>>> Can you monitor the output of the onboard regulator?
>>>
>>> Good point. I'll check.
>>>
>>> It's a bit wierd. After a quick power cycle it starts the constant reboot
>>> cycle after about 3 to 4 secs. If it is powered down for a while and then
>>> powered up. the reboot cycle starts after about 5 to 7 secs. It could be
>>> something heating up and failing.
>>>
>>> The 3.3v and 1.8v regulators are linear on the 7200, so will be
>>> dissipating heat.
>>
>> Ok so grabbing some Freezer spray, and guess what spray the 1.8v reg. and
>> the beast works. So now I know what needs replacing. I've not done SM
>> repair before, but there's got to be a first time for everything - need a
>> finer solder tip etc.
>>
>> Thanks Jacques
>>
>
> Good luck, SMC repairs are bit like neurosurgery, only more fiddly. ;)
>
> It's pretty rare for integrated electronics to fail like this, especially
> in a non definitive way.
>
> Were you able to establish whether the regulator was failing to regulate.
> the output was sagging or the output disappeared completely?
>
> I'd still suggest looking for a PCB fault in that area. The heat of the
> component and the contraction due to your spray could be causing that
> small physical movement that is critical.
>
> Try reflowing the solder of the contacts of that chip and any associated
> cmpts., eg capacitors.
>
> I'd recommend a closer look before opting for surgery. The fault may not
> be the chip itself.
Thanks for the tips and recommendations. I'll check this over and do the
reflow first before trying surgery.
In 2001 I had an X86 SBC that blew an on board regulator - but luckily it
was in warranty and was repaired by the manufacturer. Not that I knew it
was one of the onboard regs until I got it back from being repaired - the
repair was pretty obvious.
cheers
Jim
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