Hi all,

a while ago, I bought a not working G1 which had a WD_Reset error and an SRAM_failure. After changing the SRAM and the serial chip all works fine so far with one exception: The G1 won’t do a warmstart nor a warm restart. The HC always shows me a ?cold started at…“ regardless of what I selected at startup. Some ideas?

thanks


Freimut Matheus
N 51°43'10.73'' E 14°39'05.52''

I’m assuming it’s saved all data ok and isn’t giving any errors in the HC on boot? ?

Are there the” ?on the HC ?display or any other messages on the HC display on boot? ?

Is the system time ok?

Are you sure you haven’t changed the system HC to ”reduced menu”. ?Which hides some of the menu operations?

Brendan

开云体育

Hi Brendan,

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:

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

Hi Brendan,

loads of informations….

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, I’ll replace it.

I already get the warm start options and can choose them but it always does a cold start.

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

soooo, thats are my thoughts too… I didn’t get the recommended SRAM chip at that time when I repaired these G1, so I choosed a CY62128ELL-45SXI. The low power standby seems to work with this chip, otherwise it should eat batteries? But yes, I’ll try to get a correct SRAM and swap it.

All in all it’s not that big problem because I use this G1 mostly in the field, so a warm start is only exceptionally possible.

Thanks so far


Freimut Matheus
N 51°43'10.73'' E 14°39'05.52''

Freimut

The CY62128ELL-45SXI is wrong SRAM.?? I've tried it.? It doesn't completely go into low power standby mode and draws ....from memory 180+micro amps...or more....this drops as VBatt drops.? As said it will chew batteries but also wont properly power down.?? Which could easily be causing your issues (allowing data to be entered when it shouldn't) .?? You can probably fiddle with /CE1 and CE2 to force the SRAM into standby (re:lower pwr) and fix this. ? I never got to this.....it was easier to get the specified SRAM.? ?

You said above......"I already get the warm start options and can choose them but it always does a cold start."?? Ok, that changes everything.?

I said above the "-45SXI" SRAM doesn't fully power down in Vbatt mode. ? So it's more than possible for it to read/write corrupt data as it hasn't fully shut down.?? Its possible spurious spikes can cause it to corrupt.? Its possible .....a bad U3 can allow bad data to be written to the SRAM while in power down or when powering down.?

Ok Change U3 but IMHO the new info you mentioned, "I already get the warm start options and can choose them but it always does a cold start."......is also possible from the wrong SRAM for the reasons mentioned.?

I think you also should go back and replace the SRAM with the correct specified. ??

Cheers tell us how you go....

Brendan