Many thanks for that hint - very important - helped me very much for a future project.

By the way:

This way I test my ramtrons before soldering them to the pcbs:

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We use Yamaichi sockets like those for development boards at work. Those buggers cost a fortune!

Yes, but they're so worth it.

The older I get the less I understand the desire to find the absolute least expensive everything. The saying "you get what you pay for" holds more and more true the older I get.

--
Rob Anthony
Pinball Classics
http://LockWhenLit.com
Quality Board Work - In Home Service
borygard at gmail dot com

Interesting thing i just discovered with early date code FM1608s. When using them in the 5101 adapter and a WMS game. If you power cycle quickly by toggling the power switch twice in a quarter second or so, you scramble the RAM contents and the software will factory default.

Most of my used pulls are date codes around 2006-2011. I have come across just a couple from 2004 or so and it appears to only be these ones from 2004 and earlier that can have this issue. I could not replicate RAM failure in sega whitestar or WPC MPU by flipping the switch twice, so it might be only certain games and how the power off cycle works. I have not seen a FM1608 with a date code before 2004 in my batch, not sure what the first date codes are for this device.

I found this line in the datasheet.

-=-=-=-=-

Removed Power Down Sequence diagram and associated timing parameters.
Date codes 0435 and later are not affected by brownout conditions. Updated
footer to comply with new Datasheet Change Procedure. Removed applications
section.

-=-=-=-=-

I will probably be setting aside any date code earlier than 0435 for the moment until i do more testing. This might be something to worry about when getting FM1608s that are remarked. The date code will be a mystery.

Hmmm add a small cap to ride it out.

That is what i was thinking. I need to find an old data sheet that has the power down sequence diagram. I am sure it is out there.

So far only WMS 6-7 MPUs using a dip28 FM1608 dated before 0435 appear to effected by this in my early testing. Early date codes don't have problems that i can replicate so far in WPC, White Star, DE or early bally.

FM1608 datasheet July 2000

FM1608 Rev July 2000.pdf

Interesting developments with using FM1608 and FM1808

I have found FM1608s on a 5101 dual CE dip adapter setup will not work properly in WMS system 3-4 games if you power cycle willy nilly. If you are writing to the RAM when you power down (say adding credits and turn the game off) the next time you power up the RAM will clear to default settings. FM16W08 on a surface mount adapter does not have this problem. I suspect the wide voltage rating has something to do with it. Perhaps reset timing and the fact the +5v that powers the RAM in system 4 stages through the reset delay.

As stated a few posts above. Early date code FM1608s do not work properly in system 6 either. Rapid power cycling will clear the ram. FM1608 with 0435 ish or later date code, this issue goes away.

In my latest batch of FM1608(8k x 8)s i also found a a couple FM1808(32k x 8)s mixed in. FM1808 is drop in replacement for 6264/FM1608. It works fine every system i have tested it in so far with no worries about changing jumpers. AND!!! FM1808 on the 5101 dual ce dip adapter does not corrupt the RAM in a system 3-4 game if you power cycle during a ram write event.

I also found some FM1608s labeled FM1608M. The dye revision on these is "A", FM1608s pretty much all have dye revision "M". So far these behave exactly like FM1608. Perhaps a military graded part???

That being said. I believe FM1808 may be an equal or possibly superior part number over FM1608. Just make sure it is NOT FM18L08 as that is a 3.3v part and will not work.

I realize this is a thread necro, but I didn't see any reason to junk up the forums with another post related to the same subject.

I have a few FM16W08 laying around from a bulk "don't know what this stuff is" buy a few years ago and a few breakout boards. I'm wanting to use them as NVRAM in some MCR arcade boards (Tron, Satan's Hollow, Spyhunter, Tapper, Timber, etc). At first I was thinking it would be a 1-1 and grounding the other 2 address lines... wrong (or my FM16W08's are boo-boo'd).

Do you, or anyone else, have a quick schematic for these?

You also need a pullup resistor on /CE for MCR system or the RAM corrupts and/or fails to boot. 10k resistor between VCC and /CE

Here is the quick schematic

Have fun ...

6116-ADAPTER (resized).JPG

and a suggestion for your layout:

6116 layout (resized).JPG

Awww, I was so close too. Didn't think about the pull-up. Still should've at least tested right, so I guess there's something wonky with atleast one of my NVRAMs. I'll have to redo the thing with the pull-up and a different FM16W08.

Thank you!

quite old thread .. but as I created my DIY 5101 adapters based on information published here I though its OK to reactivate it.
Below pictures and schematics of Version1 and 2; more information and needed infos for DIY on my side https://lisy.dev/fram5101.html
have fun
Ralf

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