Silent Scope 1 NVRAM Testing

KevinMullins

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SiLeNtNiNjA1 has been a huge help to me with this issue so far, but I hate to keep bugging just one person and it may turn out to be sometime of an odd problem.

Backstory - Picked up a Silent Scope 1 for cheap, everything boots and checks ok then gets the typical Error 11-P, bought and socketed new pre-programmed NVRAM, still has error 11-P.
Won't go into test menu or anything like that, just the usual reboot after error failure.
Power supply voltages check good.

Stumped I start probing the socket to try and double check my solder work etc. Noted that pin 14 (GND) and pin 28 (VCC) were dead shorted.....well that just doesn't seem right. (?) Even with the board completely removed from the set.

Pins 28 and 26 have continuity which seems expected to enable read and write....but both are shorted to ground (pin 14)?!?

Can anyone with a boardset handy check continuity on their NVRAM socket? Or even if it's not socket check on the backside?

Being a multi-layer board and no schematics this could turn into a pain.
 

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Pm sent, id like to know where to get the nvram chip for silent scope as i have 3 bad error 11-p boards. Ed
 
16.5 ohms is not a short circuit
Did SiLeNtNiNjA1 send you the data file or did you use one from MAME?

SiLeNtNiNjA1 sent me a pre-programmed NVRAM using the file from MAME.

I don't think my older Willem can do these. (at least it's not a chip choice that I can find)
 
if you really want to ill check what the resistance is on mine next time im in the workshop.
ive not really had any problems in programming a new chip for these other than a bad solder joint when I fitted a socket. Its fairly easy to see the traces from the pins on the underside, maybe worth trying to check there is continuity between them
 
if you really want to ill check what the resistance is on mine next time im in the workshop.
ive not really had any problems in programming a new chip for these other than a bad solder joint when I fitted a socket. Its fairly easy to see the traces from the pins on the underside, maybe worth trying to check there is continuity between them

A comparison sure would be helpful, just to eliminate that I'm not on some wild goose chase.
Continuity everywhere else seems to check out good, it was just VCC to Ground that kinda threw me off.
 
Anyone know off-hand if the MAME files will work on the 830 UC boards?
When mine boots it comes up as v1.33 and it does have the revision D rom at location 27P.
I've read tons on UA, UAA, UAB, but not much on UC boards.

Is there a difference between the two NVRAM files found in the SS1 MAME set?
One is named m48t58y-70pc1 and the other is m48t58y.35d
I realize they will always have different checksums and never verify against eachother, but are they essentially the same file?

It's been a while since I doinked with this sort of stuff, just trying to verify if it's a file issue or a board issue before I dig to much deeper.
 
Is there a difference between the two NVRAM files found in the SS1 MAME set?
One is named m48t58y-70pc1 and the other is m48t58y.35d
I realize they will always have different checksums and never verify against eachother, but are they essentially the same file?

FWIW...
According to the MAME source, the ".35d" file is never used. It's listed in one driver, the not actually used (the other file is loaded over top of it).

Code:
 1327      ROM_REGION(0x2000, "m48t58",0)
 1328      ROM_LOAD( "m48t58y.35d",   0x000000, 0x002000, CRC(b077e262) SHA1(5cdcc1b742bf23562f4558216063fea903f045ab) ) // this is set to the JXD, I don't think it's valid.
 1329      ROM_LOAD( "m48t58y-70pc1", 0x000000, 0x002000, CRC(ee815325) SHA1(91b10802791b68a8360c0cd6c376c0c4bbbc6fa0) ) // so just load over it with the US one, we know works.
 
Cool. That would confirm why the .35d file showed up as JZD or something when I opened it with my Willem software. The other was version UAA.
Now just to confirm if the UAA will work for this board.

I was re-reading one of our old threads on this stuff and it seems there was something about the UC version, but I gotta find it again.
 
The resistance of my board is 15.9 ohms.
I'm also sure that the nvram data works with all versions of silent scope 1.
Silent Scope 2 uses a checksum too so does change with each region
 
Awesome. Thanks for checking for me.

Now at least I can poke around elsewhere and figure out why I'm still getting the same error.
(literally no change whatsoever)
 
Got it sorted. Turns out there was something wonky on the newly programmed NVRAM. No idea on exactly what or why.
I dug out my ol' cheap Willem PCB3 programmer and after some research and doinking around and building a quick socket adapter I was able to program it as if it were a 2764 EPROM. Can't "read" them quite properly, but it does the trick to program them at least. Tried a couple versions of the UAA files out there and both worked. Original NVRAM was definitely bad.
 
Yeah, it happens....but it also forces me to dig back into this stuff from time to time and learn something new. (especially with my not so fancy equipment)

On the plus side - Got it all back in, plugged up and everything seems to work great.... including the scope LCD.
Just gotta finish by tweaking on the monitor a bit, it needs a little TLC, probably due for a rebuild.
 
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