RA-100 schematic

[CBCZ]

Hello, I'm trying to find the schematic for the RA-100 RAM card.

 

I have already found a lot of information about RAM cards in general, schematics of the RA-500 and pictures, but none for the RA-100. Casio made some RAM cards for their calculators and PDAs which look like the same kind of edge connector.

 

The service manual for the HT-3000 I got online and so I can get some information from there, but the scan I have blows.  Its difficult to make out letters because the scan is so lo res.  If I read it correctly the RA-100 must have had only 8K as I see 13 address lines.  

 

I have an HT-700 and want to make a replacement RAM card, maybe use another type that has the same connector or possibly put it inside.

 

I wrote to Casio but haven't received a response yet.  If you have any information such as a schematic on the RA-100 I would appreciate a copy of it.

 

thanks

 

 

[Chas]

This link is for how to modify an RC100 VZ series ROM card (as VZ RA500 ram cards are so hard to get hold of compared with the RC rom cards). The VZs used a very similar design of card to the RA500 cards used in the HT/ HZ series, and likely only differ by different capacity memory chips.

 

It might give you a direction for remaking HT/ HZ RA100 ram cards. Many HT/ HZ owners (including myself) would love to find alternatives to the now sought after and expensive RA100 cards.

 

http://www.warningwillrobinson.com.au/index_files/RA500.htm

[CBCZ]

Hello Chas,

 

I found that site already but it doesn't have what I'm looking for.  I was hoping to find more info on the chip Casio used for the RA-100 so as to make 100% sure anything I make was compatible.  I have read the Ra-500 and the RA-100 are not compatible, though it appears they have the same 45 pin card connector. I'm going to guess that just about any Static RAM from the era will work, just need to get the CE, CS, WE etc right.

 

I got an answer back from Casio which was "no" they don't have it. I'll keep looking for pictures or maybe a dead one.

 

Thanks

 

 

[Jokeyman123]

You might want to try to do some research on the "EZ-CZ" cartridges which were designed as compatible to all the CZ series as a beefed-up version of the RA-!00-I had several way back when, and I'm sure the circuitry (with further circuits for switching between banks) must have been identicalto the RA-100's  in terms of ICs and pinouts. I have no schematics-but might find these cartridges on the web and/or schematics-and cartidges are still available-although pretty over-priced now IMO. I've seen a few on eB****?<":L#@!%! Not allowed to mention specific vendors here....but you know who this is.....

[Chas]

@Jokeyman123 - I'm almost certain that the CZ RA cards are very different to the VZ RA cards. I took  pictures showing my CZ's RA3 card next to my HT's RA100 card, and also put a VZ Rom card next to them. 

 

 

 

Putting the CZ RA-3 next to the HT RA-100, the RA-3 is considerably chunkier:
 

 

 

 

And taking apart the RA-3, we can see that its components are much too large to fit inside an RA-100 case:

 

 

 

 

I still suspect that the RA-100 and the RA-500 are very closely related, and likely only differ by the size of the RAM chip. Putting a VZ RC ROM card next to an HT RA-100 card, other than the height 'bump", the dimensions are identical:

 

 

 

 

 

The edge connectors of the HT RA-100 and VZ RC-110 also appear to be identical (RC is top, RA is bottom):

 

 

 

 

@CBCZ - If there was a way of opening my RA-100 card without damaging the label/ case, I'd be happy to do so to find out what's inside. I suspect that the label has to be peeled off to reveal the screws holding it together. Unless it's held together by snap clips? Let me know if there is a way of getting it apart without damaging the label.

 

 

 

[Jokeyman123]

oops, didn't realize, sorry! Totally different architecture vz vs. cz. 

[CBCZ]

Chaz thanks for those Pictures!

 

I thought the card edge connector might be the same as I used to have a VZ-10m with the card.

 

Last night it dawned on me I had all the info I really need -  just use the same RAM chip in the HT-700,  (HT6264al5p-15) I looked up that chip and found all I need, the data sheet tells me TTL, access time, etc. UPDATE: actually this is not true, see more recent post.

 

Oh and thanks Jokerman for the CZPL note, I have seen that device but thought it was just for the CZ series. 

 

I will post my progress for those who desire an RA-100 and can't get one.

 

CBCZ

 

 

[CBCZ]

I looked up the chips I could read on the RA-100 picture: those chips are 2K RAM, I can't read the other chip but I think its likely a decoder or serves the function of one. I believe they chose those chips as the data sheet says they are special "low profile" chips (HM6117lfp-3) and that makes sense as they are in the narrow card. 

 

So the 8K chip is not going to be a direct replacement because some of the address lines are being used to block select the 2K chips. Though it can't be many as there are just the two chips. The RAM card only has 4K of memory total so the other 4K of the 8K of Main RAM is probably used for system functions. 

 

I missed some important info in the HT-3000 service manual, pages 16-17 discuss the RAM card interface, lines being used, etc.  With that and the datasheets I have enough to begin.  The service manual has a lot of useful information even though the scan is lo res.

 

 

 

 

[mgrunt]

Hi,

How did it go with the RA-100 card survey? Do you already have all the information to make a copy of it? I have a HT-3000 and would also like a RA-100 card or a copy of it. Thank you.