Grid 1520 Battery Backplane

[retinull]

Hello fellow GRiD enthusiasts, I just bought my first 1520 yesterday! I love the aesthetics of almost all of their models.

The one I bought was in working order, for a few minutes. I plugged it in, turned it on, then left to go help my wife with the new baby. After a few minutes I started smelling burning plastic, which is never good. I quickly raced downstairs and turned it off and pulled the PSU. I thought it might have been a blown CAP in the PSU (when I removed it it stunk really bad) and I had another one in good working order. Anyway, I had some free time today and made a DOS 3.3 disk and tried booting from that. The only thing it does is turn on, and go to the bios flash screen, then it counts the base memory and the extended memory. It just sits at that screen and does nothing else. I did take the top cover off just to peak at it and found that the battery backplane had fried. Before I start tearing it apart further, do any of you know if that could be what is causing it to not boot beyond memory check? I don't want to go messing with a bunch of already brittle parts unless I have to. But, I probably will end up tearing it down just to see if there's anything else wrong with it.

Does anyone have a spare parts unit with the battery backplane in it available for purchase? Or a whole spare unit? Depending on what else may be wrong anyway... It seems all GRiD laptops for sale on ebay are about $300+ for any non working model.

Any and all help is very much appreciated! Here's a couple photos of the battery backplane that sits right behind the PSU.

 

[0xDEADBEEF]

I think your battery backplane is probably OK. You do have a blown cap. And the computer does not boot because HDD is crapping out.
Mine sometimes gets stuck at post as well because I have bad HDD. Now, I would replace the blown out cap (and others) and try few more times. Maybe HDD will spin up and boot.
Also, try booting with HDD disconnected and floppy disk?

 

[FGrid]

Firstly you should look into the dallas rtc battery issues with gridcase units.
The backplane should not be giving issues with booting, you can plug in an appropriate rated barrel jack and it will boot the same I'm sure.

I would not purchase spare parts before you fiddle around inside.
From my experience nothing is brittle inside the gridcase besides the keyboard blue connectors and the RAM that uses sipp pins which is really scary to unplug and plug back in in fear of breaking.

I would start with unplugging HDD and see how if boots past that then, then maybe ram removal.
But most peoples issues are with the Dallas RTC.

The burning might have occurred from the rubber protective strip thats on it dissolving. You might want to clean that up with alcohol and replace it with something new that will protect the solder points.
Goodluck

 

[FGrid]

Sorry my reply was halted by needing to be reviewed by moderation first. Didn't mean to repeat what 0xdeadbeef said.

 

[0xDEADBEEF]

So was mine, so was mine. ;-)

 

[retinull]

Definitely will do. Thank you both for the great help! I just need to find the time now... Maybe I'll burn some midnight oil and sacrifice some sleep. Thanks again!

 

[0xDEADBEEF]

BTW, you may want to consult all the hardware service guides/diagnostics manuals for 15XX series here https://flecom.net/yahoo-groups/RuGRiD-Laptop/files/
Like https://flecom.net/yahoo-groups/RuGRiD-Laptop/files/63_GRiDCASE-1500-No-Boot-Procedure.pdf
One thing they suggest is checking 12V and 5V on modem pins after removing the modem card.
Also, according to manuals you can boot from floppy by pressing I for internal or E for external during boot but I am not sure it works, since I tried it myself and it didnt.
Also, I maneged to boot my 1520 using 128KB EPROM which I burned with DOS 3.3 image I found on interwebz https://archive.org/details/gri-dcase-1520 MS-DOS 3.30 (D27010) 300-850-00.BIN

 

[nasaguy]

On a 15XX series you should be able to press F once you hear the POST Beep to Boot from Floppy or press H to boot from Hard Drive. Also, if the Hard Drive has errors the computer will appear Dead and the Plasma will not light. If you remove the Hard Drive or jumper it from Master to Slave the Plasma typically will light and proceed to POST. If your Hard Drive is the only issue keeping you from passing POST it will most likely timeout after approximately 100 seconds and then the screen should light. Once you hear the Beep, press F and boot from a GRID DOS Floppy so it doesn't retry the Hard Drive. If you are lucky you may be able to see Drive "C" (just not boot from it). If so, from Drive A: the DOS SYS command can be used to transfer DOS from A to C and get C in a bootable State. If that doesn't work and you think your C drive is Toast, you can try FDISK and FORMAT or CNRFMT for Low Level Formatting if your drive is a Conner. Most likely you will not be able to boot from a non GRID supported Hard Drive unless you update the EPROM.