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Sanyo MBC-550.

prime

Experienced Member
Joined
Sep 20, 2009
Messages
153
Location
Coventry, UK
Whilst we're on the subject of the Sanyo, does anyone happen to have the schematics for the machine ? or documentation of the hacks required to upgrade beyond 256K ?

Cheers.

Phill.
 
You might want to check out some of the Soft Sector magazine issues. I have heard that one issue has a memory upgrade to 720K, and an issue that I have tells about a modification to the power supply to get the computer to work properly with extra memory and the graphics board. From what I have read in Soft Sector, DOS might need to be patched for extra memory.

Last week I saw a Sam's Photofact for the Sanyo on Ebay, but I don't know if it is still there.
 
There is indeed a soft sector article about piggy backing memory chips up to 512 k and you do have to patch the OS which is also described step by step. I attempted just buying higher capacity memory chips to replace the older ones but the patch didn't work for me in this manner. Someone else said they had done this with success.

I have the full run of soft sector magazines but not in an electronic format.


Whilst we're on the subject of the Sanyo, does anyone happen to have the schematics for the machine ? or documentation of the hacks required to upgrade beyond 256K ?

Cheers.

Phill.
 
Been a loooooonnnnnggggg while since I was on the forums here and luckily my login still works. I found two copies of Soft Sector in storage in good condition - Aug and Sept 1987. Anyone is welcome to them for the price of postage which is probably about 2 bucks for US first class mail in a larger envelope. Email me.
 
I'd be happy to buy the magazines. Is paypal ok?

Also, I have the schematics from the sams photofact in pdf if anyone wants them.

E-mail me at bigbadbrad at gmail for setting up either of these!
 
I'd be happy to buy the magazines. Is paypal ok?

Also, I have the schematics from the sams photofact in pdf if anyone wants them.

E-mail me at bigbadbrad at gmail for setting up either of these!

Emailed you Brad. Almost missed the replies as the forum doesn't send a notice. Good thing I checked back.
 
What are the headlines of the magazines?

July 87 is PC Pyrotechnics, Grappling With Graphics
Aug 87 is A Birthday Special - Anniversary Issue

I used to have all of them but traded them and the 555 years ago. I'm also listed in some of the letters to the editor but not in these two issues. Only vintage machines I have now are a C64 and C128D, IBM PC, PC XT and an NEC lunchbox portable. All of them have been boxed for a number of years and due to come from storage soon though I will likely sell or trade them after I go through them. Just no time for the new stuff let alone the old. I also have gobs of IBM PS/2 parts laying around here from an era where I had gotten loads of them and either sold, traded or parted (and scrapped the rest).
 
What type of RAM is need? 4116? My 550-2 is stock and it needs a memory upgrade. I am really interested in this memory upgrade. I hope someone can provide infomation how to perform it.
 
Are you looking to perform the upgrade to 256k or a higher memory? If you are just looking for the 256k I can give you the instructions from the manual, if you want a higher memory amount I do not know how to do that. I do not know the specific number for the chips right now, but if someone else doesn't respond to that I can take a look at the chips in my computer.
 
I used

http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_41398_-1

Which work fine. They are actually higher capacity than you require but I installed them in my machine to bring it to 256 and they work fine.
Yep in most systems that use 4164s, you can use 41256s as drop in replacements, as long as the extra address line (pin1 IIRC) is pulled either high or low so that it is stable. I believe most 41256 chips do this internally. The only case where this may not work is where the target system expects 4164s with a 128 cycle refresh, as all 41256s are 256 cycle refresh.

I'm going to pdf the page from the manual if you need them. I am also going to pdf the soft sector magazine than instructs a larger 512k upgrade and palce it on my site

Excellent, I'd be interested in that too.

Cheers.

Phill.
 
Ok 4164 is the standard upgrade chip.

If you are interested in going beyond 256k there is a techniqure in the softsector magazine on my website you can checkout. Apparently you can even go beyond 512K as several add on boards were available at one time to do so.

Anyways check out:

www.eriscreations.com/sanyo/

here are the 2 pages from the manual about the standard upgrade to 256k from 128k

sanyo_manual_page_6-10.jpg

&

sanyo_manual_page_6-12.jpg
 
Last edited:
Thanks very much digress. I will need this. Apparently my 550-2 was never upgraded at all. Quite valuable in it's current state but I will need more memory in this machine to make it useful.
 
Ok 4164 is the standard upgrade chip.

If you are interested in going beyond 256k there is a techniqure in the softsector magazine on my website you can checkout. Apparently you can even go beyond 512K as several add on boards were available at one time to do so.

Anyways check out:

www.eriscreations.com/sanyo/

here are the 2 pages from the manual about the standard upgrade to 256k from 128k

View attachment 11088

&

View attachment 11089

I believe 768k was the largest RAM upgrade but most had a switch to bring the available ram to 360k or somewhere in there for programs that had problems with the excess memory and while it's been a long time since I had a 555-2 I believe a memory manager had to be run with the Sanyo version MS-DOS to make use of the 768k. I got rid of my Sanyo in about 1993 before I left central IL when the base there closed. I had another given to me since, around 2000, and I ebay'd that to someone else since it had no DOS disks. My original had a lot of upgrades I did starting with the power supply upgrade from Soft Sector then I added a CGA video board then upgraded the memory with a kit with a switch, then went to 2 800k floppy drives and the aftermarket DOS that supported them, then I built an external enclosure and added two more floppy drives and I also added a serial board and modified a PC joystick to work with the weird Apple style DIP plugin. Eventually I ran my first BBS on it using Fido BBS and since programs were small then I had a couple of file areas, all on floppy. I would swap the floppies each week giving the users a different set of files to download. For the time period I had it the machine was OK but I quickly lost interest when I got a clone AT machine. It ran the BBS only for about 18 months then I was given another clone 286 and changed the BBS over to the clone and sold the Sanyo with all the manuals, software and hardware. I think the biggest annoyance on the machine was the lack of the ALT key and the reset being so easy to hit on the side of the keyboard.
 
That is cool. I have the CGA upgrade card in mine now. Wanted it back in the 80's but it's cool to see the sanyo running some IBM Graphics, even 16 colours on the low res Sierra Kings Quest.

The memory thing would be great to increase for this purpose mainly as some of these games required 384k, 512k and even 640k

according to articles in soft sector they had upgrade boards that would triple the clock speed to 10.74 and could have ram up to 960k

I upgrade using 41256 chips and hacked the dos version I had to try and take advantage of the increased memory using the technique in the softsector mag but it didn't work so it's just 256k.

I also have a speaker volume control installed which is helpful as some programs were quite loud. This is from a technique also in soft sector.

I even have the v20 upgrade microprocessor but it makes several programs incompatbile so I took it back out.

My main interest was making basic games and I made a bunch, I used it as an art computer and have lots of pictures and animation done with the system. Because it had a composite output in b&w it was great for doing graphics & video titles for home videos & movies me and a group of friends used to make in high school.



I believe 768k was the largest RAM upgrade but most had a switch to bring the available ram to 360k or somewhere in there for programs that had problems with the excess memory and while it's been a long time since I had a 555-2 I believe a memory manager had to be run with the Sanyo version MS-DOS to make use of the 768k. I got rid of my Sanyo in about 1993 before I left central IL when the base there closed. I had another given to me since, around 2000, and I ebay'd that to someone else since it had no DOS disks. My original had a lot of upgrades I did starting with the power supply upgrade from Soft Sector then I added a CGA video board then upgraded the memory with a kit with a switch, then went to 2 800k floppy drives and the aftermarket DOS that supported them, then I built an external enclosure and added two more floppy drives and I also added a serial board and modified a PC joystick to work with the weird Apple style DIP plugin. Eventually I ran my first BBS on it using Fido BBS and since programs were small then I had a couple of file areas, all on floppy. I would swap the floppies each week giving the users a different set of files to download. For the time period I had it the machine was OK but I quickly lost interest when I got a clone AT machine. It ran the BBS only for about 18 months then I was given another clone 286 and changed the BBS over to the clone and sold the Sanyo with all the manuals, software and hardware. I think the biggest annoyance on the machine was the lack of the ALT key and the reset being so easy to hit on the side of the keyboard.
 
That is cool. I have the CGA upgrade card in mine now. Wanted it back in the 80's but it's cool to see the sanyo running some IBM Graphics, even 16 colours on the low res Sierra Kings Quest.

You are really lucky to have the CGA board. I had one in my Sanyo that I bought new back in the 1980s but we can't work out where that machine went. I think it vanished along with several other machines during a house move 20 years ago! I wish I could find a CGA board for mine!

Im still looking for one of the versions of DOS for the Sanyo that support the 800K floppies too.
 
ds dos from michtron I believe. I don't have a copy either.

I am also looking for a Sanyo CRT 70 monitor which goes with this machine if anyone comes across one. Hard to find. I saw one for sale in New zealand but they wouldn't let me bid on the auction not being from there and all.
 
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