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Re: G1 won't do a warmstart
|
Freimut
Warning big read lots info to give to you on this! OK after some long research its one of 2 things.? This issue has been seen before and its either of the 2 below.? Mainly this info is from Rene and good old Tom Hilton...bless him (bless them both) some more.? /g/Gemini_users/topic/17926148#26106 /g/Gemini_users/topic/17926357#26711 U3, MCP809-450 voltage supervisor.? Its a voltage detector to tell the system (CPU) if pwr is ok and stop if voltage is not as you get corrupt data.....this is the core bit "corrupt data".? If you get corrupt data....on reboot (or shutdown)...you will be forced into a Cold Start Only!?? How do you get corrupt data...read on. This is from Rene and Tom on this exact problem: "The voltage supervisor has the important task to shut down Gemini in
case of a power loss." (I'll add in here power interruption...aka brownout...)"
If it doesn't work, coordinates and time at shutdown are not saved, meaning
that only a Cold Start remains possible."
"It has the second task to check if the internal +5V voltage has
established at startup. As long as the main processor is waiting for its
power good signal, only the one dot is displayed. If it stays forever,
either the voltage does not reach the nominal value or Q3 is defective.
With your description I suppose the latter."
So what they are saying is that U3 can cause corrupt data. ? Now here's the key!You mentioned you had WD resets!?? A WD reset is a catch all to stop looping program or errors unresolved.? It us usually caused by a U3 problem.? As said U3 is a voltage supervisor that checks pwr on and down status as well as monitor brownouts and stop CPU data processing if there is a low power. What happens is this IC goes faulty causing the WD message and interfering with the things it was supposed to protect!? Well kinda but not quite yes it does go faulty can causes these issues. I would strongly urge you to replace U3 regardless? of anything else as first step.?? Since you said you had WD resets.....replace U3.? Since you said you are not seeing "warm start options"....again leads me to U3 as this has been seen before.? Ok all that said....what else could it be..........It Could also be the SRAM IC you replaced! Since you said you replaced it I'm unsure what SRAM IC you used.? So I'll write what I know so you can compare. The type of SRAM fitted is quite specific in speed and low power standby current draw.? "-70LL" SRAM only!? I have tried "-45LL" and it failed to enter standby lo power.?? You must fit the correct SRAM IC or you will have issues!?? This I know!? I need to know the part number of SRAM you fitted? The SRAM generally used is 128K x 8 must be low power standby SRAM....that is its standby current draw must be in order of 2.5 - 6micro Amps.? Many of the SRAM offered are not low power versions so be very specific what IC is fitted.?? Message me on this if you want.?? As said I've tried other SRAM and it won't work mainly the manner of the Chip Enables work (/CE1 and CE2): UPD431000AGE-70LL UPD431000AGW-70LL CY62128BLL-70SC So check your SRAM ensure it is low power standby versions and only use the above chips due to the manner CE works.?? That said the PCB does have some latitude to change how CE is sent to the SRAM as it has D12 (fitted) and U21 (Not fitted, was MCP810-475, goes to pin 22 /CE1 and pin 32) on the PCB. So please check your SRAM version as this has a huge effect. OK lots for you to Absorb.? Its a complex issue but I'm pretty sure its U3 and the SRAM fitted could be effecting! Get back on the type of SRAM you fitted and replace U3! cheers, do get back.... Brendan |
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