Entering the 68k ecosystem with a Centris 650 - what to check?

[1200XL M.U.L.E.]

Hello everyone! I will be entering the 68k ecosystem soon with a Centris 650 I purchased from eBay. The system comes with a monitor, keyboard, and mouse. What are some of the first things I should I check for when I receive the system? Pre-boot and during first boot?

What are some good hardware-centric system scanners and utilities to run right away that show what is running inside the box?

Here is a link to eBay auction of the system I purchased. The seller was open to my offer, refunded excess shipping charges, and was wonderful to work with. I'm not sure if I overpaid, underpaid, or paid just right but as a potential long-term owner I feel OK with the deal.

Apple Macintosh Centris 650 M1205 Desktop Computer - Tested/Working Condition. | eBay

Mac Centris 650 825-1742-A M1205 SN: XC33IK3ICA2. It will boot up to the desktop. I was told everything was still in working order or it should be. But that appears to be it. Everything else seems good.

www.ebay.com

I wanted a 650 like this because I read in some forums that it has tantalum capacitors which won't leak. The case design was also more appealing than the 800. Watching YouTube videos of that case and looking at images of it made me cringe a bit.

The majority of my computing experience in the 80s and 90s was with the Atari 8-bit, Atari ST, and x32 DOS/Window machines. After the Pentium came out I migrated to a PowerPC iMac followed by an Intel iMac. I am back to using a Windows box because it scratches my gaming itch a bit. I used 68k Macs in Jr. High School and High School, especially Mac SE machines.

I am excited to learn more about my 650!

Thanks!

 

[MrFahrenheit]

Welcome to the 68kmla forums, and to the community, with your 'new' Mac purchase.

The price seems to be pretty decent, considering the inclusion of the keyboard, mouse, monitor, and system (with the CD-ROM drive).

You will need to do a bit of servicing to get it all working properly again. Your first step will be to open it up and remove that PRAM battery on the logic board, which is a ticking time bomb, and ready to explode at any moment. Explode, as in create a chemical reaction and burn a big hole in the board. I've never heard of them actually "exploding". Next, that floppy drive might require a cleaning, or even new gears inside. Lastly, even though the logic board on the computer has tantalum capacitors, the CD-ROM drive does not. The ones on there leak, and will need to be done, likely soon (or already).

The 650 is a nice machine, as you found, and comes with tantalum capacitors which should never need replacing. Depending on what configuration the machine includes, it may have a full 68040 CPU. Usually the 8MB (with ethernet) configuration had the full 68040 CPU.

You'll have to get acquainted with how the Macintosh file system works, and how downloading things on other machines and moving it over can often corrupt a file. Fortunately you have ethernet, which means you could setup a simple FTP server and transfer files via FTP. The big first step will be getting something on there that can be used to transfer stuff.

 

[joshc]

Welcome to the forum

By many measures, the 650 is one of the best 68k Macs you can get. You can make them run at 40MHz, they can take NuBus upgrades, lots of RAM, and they can run many versions of Mac OS. There won't be much you cannot do with it, in the scheme of what you'd expect from a 30 year old computer.

What are some good hardware-centric system scanners and utilities to run right away that show what is running inside the box?

TattleTech

That said, it's not going to tell you a whole lot you can't find out by other means in your case. Your 650 doesn't have any NuBus upgrade cards - as all the NuBus slot covers are still present. But it will tell you which processor is installed and the clock speed it is running at.

You can use Apple menu -> About this Macintosh to see how much RAM is installed and which OS version.

Edit: I see the auction had a photo of that, and it's got 32MB RAM and is running System 7.5. 32MB is sufficient for a lot of things but you may wish to upgrade the RAM later on.

What are some of the first things I should I check for when I receive the system? Pre-boot and during first boot?

Remove the PRAM/clock battery and replace with a new one, or run without one. It's only needed to retain certain system settings between boots and there are solutions to keep settings without a battery.

The reason to remove the battery is that its the big killer of these machines - they leak when left for too long in storage and cause lots of damage when they do.

The case design was also more appealing than the 800.

That's right, the 650 case is far better than the 800 one. The only weak spot on the 650 case is a plastic 'strap' that holds the power supply in a bit better, but I've had machines without it and it's not really caused a problem. The plastic strap tends to snap so a lot of 650s don't have it anymore.

Speaking of which, the power supply is the part that you need to keep an eye on - if it works right now, great, but don't expect that it will forever. You can replace the capacitors inside the power supply, but some people carry out an ATX conversion to run off a more modern power supply.

If you want to find out more about the 650, I'd recommend reading through two things, the Apple service manual, and the Apple developer notes.

Another thing you can do with these machines is modify the clock speed to improve the performance - there is a whole thread about that here:

Wombat (650, 800) board overclocking limitations

I had some questions about oscillator swapping (overclocking) the Centris 650 (modified gestalt ID via on-board resistor), Quadra 650 and Quadra 800 boards. Namely some questions regarding the 'limiting factors' mentioned. So according to Marc on the archived clock chipping page: When you run...

68kmla.org

 

[Juror22]

Congrats on your purchase! For years I had turned up my nose at the IIvx and their look-similar Centris and Quadra 650 brethren, but then I got a IIvx from a fellow member here and upgraded it with a Q650 board and I am convinced they are an excellent choice for performance and (so far) reliability.

Based on the description in the listing, there will be a couple things to take care of in addition to checking on the PRAM battery (per MrFahrenheit's excellent suggestion).
You will also want to remove the feet from the monitor as soon as possible, since dissolving foot goo gets everywhere.
It also sounds like the CD is a non-starter, which for these, usually means recapping or replacement, but since you also have ethernet connectivity, you may not need a working CD player.

 

[3lectr1cPPC]

I don’t think it’s been mentioned yet, but the power supply may need to be recapped as well. They’re better than the PSUs in some other models, but they’re 30 years old and fail often due to weak caps. If it’s fine then it’s fine, but if you end up having any system instability related to power, it may need to be done. The CRT may as well need it at some point.
Edit: ah and I just saw that it has been mentioned, ah well.

 

[1200XL M.U.L.E.]

Thank you for the replies, everyone! I appreciate all the information here!

PRAM battery - yes, I have heard of people removing it and relocating it outside the case. Is it solely for maintaining the date and time? I read in a few places that it also maintains some system settings.

Transferring files - I understand that Macintosh files contain metadata that define the file type. This is in contrast to Windows and the like that use file extensions to define the file type. It sounds like this metadata is corrupted when shuttling files around. The best source here would be one that was compressed natively on a Macintosh in Stuff It (.sit) format. Extracting a Stuff It archive seems to preserve the metadata and the Macintosh can recognize the file types. Is that right?

FTP - I was hoping to network the Centris 650 to my Windows box through a small network switch and use static IP addresses between the two machines. Is FTP the best way to transfer files? Is there no way for the machines to see each other as folders or drives? I've never set up a FTP server so maybe this is my hesitation.

RAM - I would like to super-charge the system with as much RAM and VRAM as possible because ... why not? The memory is not terribly expensive. That may be something for next month after I figure out the system better. One step at a time.

Overclocking - I used to overclock my 32-bit x86 machines. It was pretty simple. All I did was replace an oscillator. I took a quick glance at the first page of the overclocking thread. Wow, the forum really went deep into the topic! That might be something I do much further down the line after I stabilize and customize the system to my preferences.

Capacitors - Ooohh, I didn't think of the capacitors that may be inside the CD drive and monitor! They're everywhere, aren't they? How critical is a CD drive for this system? Can I just mount ISO images and run applications from inside there, like Windows? I see some people use adapters and converters to connect to VGA monitors. This is something I need to check out for future.

Thanks!

 

[3lectr1cPPC]

On caps - you can certainly avoid using the CD-ROM drive (I’d recommend a PiSCSI for this) but think of how that poor drive would feel being left to rot like that

 

[macinbot]

Regarding the PRAM battery, there are options for retrofitting them with coin cell style batteries instead of the 1/2 AA:

MacBatt CR2032 PRAM Apple Macintosh battery by Siliconinsider on Tindie

MacBatt CR2032 PRAM Lithium battery replacement for Apple Macintosh computers

www.tindie.com

And a SCSI-to-SD solution like BlueSCSI makes file transfers and local installs A LOT easier.

 

[AndiS]

I'll try to answer some of your questions.

Yes the PRAM stores other settings beside the time. It is possible to use most Macs without a working PRAM battery but it is not convenient. You don't have to relocate it out of the case. The easiest way is to get a replacement battery and use it for the next 10 years. Or you get one of the "less explosive" alternatives like MacBatt mentioned above.

Regarding files. It is easy to transfer images and (Mac) compressed files over FTP, HTTP (via browser) or even Diskettes. It is important though to not unpack them on Windows since the file's Ressource Fork that stores important info is lost. This may be fine if you copy a Word Document for example which will in the worst case only loose its icon. But if you transfer any executable file (a programm) it will not run.

Still you can download images from the web, transfer them to the Mac and unpack them there. That's fine. FTP is a perfectly viable option for that.

Overclocking - with this machine replacing some SMD resistors with different values does the trick. There are even mods with variable resistors available that enable you to select the processor speed.

 

[Phipli]

Transferring files - I understand that Macintosh files contain metadata that define the file type. This is in contrast to Windows and the like that use file extensions to define the file type. It sounds like this metadata is corrupted when shuttling files around. The best source here would be one that was compressed natively on a Macintosh in Stuff It (.sit) format. Extracting a Stuff It archive seems to preserve the metadata and the Macintosh can recognize the file types. Is that right?

Incorrectly handled files don't just lose the metadata, they lose an important part of their data called the resource fork, too.

Also complicating things, older (before version 5) versions of stuffit used the resource fork and so a file being ".sit" doesn't automatically mean it is safe to hold on a drive not formatted to work with such things.

 

[rjkucia]

Incorrectly handled files don't just lose the metadata, they lose an important part of their data called the resource fork, too.

Also complicating things, older (before version 5) versions of stuffit used the resource fork and so a file being ".sit" doesn't automatically mean it is safe to hold on a drive not formatted to work with such things.

And that's why you'll often see Stuffit files converted to MacBinary (.bin) or hex (.hqx) - those "flatten" the forks and make it safe to transfer/move. So, you'll often see things like "bunchoffiles.sit.hqx".

 

[AndyO]

I'm not familiar with the Centris 650, but I do use a Performa 630CD every day, so while some hardware details may be different, many of the principles will be the same.

My 630 has an Ethernet card in its COM slot, and is connected to my network. I use a static IP, and Fetch 4 (an FTP client) with QuickFTP (very simple and easy to use FTP server software) on my M1 iMac which is also on the network, to move files around, including documents, but also disk images and software installers saved from internet resources such as macintosh garden.org.

I could use the 630 to grab these using Fetch, but the more modern iMac is faster for downloads, and has more storage space to save them.

I also have a BlueSCSI DB25 (https://androda.work/product/bluescsi-v2-db25/) which is a SCSI drive replacement, using a microSD card, for file transfers between my other old Macs - mostly PowerBooks - and the 630, and also to back up the 630, and provide an alternative means to boot it if necessary (just for peace of mind and convenience). There are other similar SCSI devices such as ZuluSCSI, but the benefit is that you can create multiple 'hard drives' on microSD cards for a huge amount of storage or operational flexibility.

I have also recently replaced the hard drive in the 630 with a compact flash card using an adapter plugged in to the IDE cable in place off the drive, and this has made it much smoother to use, and faster to boot.

The PRAM battery saves a few system settings and preferences, so I went ahead and replaced mine. It's a different type than in the 650, I think, but it is worth getting a new one. These things last for years, and tend to cause problems only after they are depleted and left in storage. In active use I have never had a PRAM battery explode or leak, but then I have never kept one for more than 10 years!

I have left my 630 at 20Mb RAM, which doesn't seem like much, but running Mac OS 8.1 seems sufficient since up to OS X, Mac OS was more memory efficient than Windows, and I have no interest in overclocking since it really doesn't seem to need it with period appropriate software, and as it is, it is one of the most stable systems, old and new, that I have used in a long time.

VRAM is not expandable in the 630 though, so I'm stuck with 832x624 resolution, but once again, with period appropriate software has not proven to be an issue.

The CD drive is original and has not had any work done on it, and still works well - though with the BlueSCSI device, I have not ended up needing to use it much. It was great for installing Mac OS on various SD cards though!

 

[joshc]

Is FTP the best way to transfer files?

I much prefer this: https://www.macip.net/
Get a Pi, download and write the image from there to it, hook it up to your network and you've instantly got a file share that will work from your Windows box, and from the Centris 650. Works like a dream for me, and makes it so easy to download stuff from Mac Garden and then instantly get it to show on your Centris.

You will need an AAUI->Ethernet adapter for your 650 if you plan to use the onboard Ethernet. Or you can install a NuBus RJ45 Ethernet card.

RAM - I would like to super-charge the system with as much RAM and VRAM as possible because ... why not? The memory is not terribly expensive. That may be something for next month after I figure out the system better. One step at a time.

Yup, just bear in mind these old machines are slow at checking the memory at boot, so a full 128MB RAM does make it boot a bit slower. I got used to it.

Can I just mount ISO images and run applications from inside there, like Windows?

Depending on how much you want to spend, look into MacSD or ZuluSCSI as SD drive options which include CD-ROM emulation, including the ability to cycle through and mount saved disc images.

I see some people use adapters and converters to connect to VGA monitors.

Yes, a DB15->VGA adapter is what you want. Someone on the forum probably has a spare for you if you can't find one, otherwise check eBay and the like.

 

[Melkhior]

Yes, a DB15->VGA adapter is what you want. Someone on the forum probably has a spare for you if you can't find one, otherwise check eBay and the like.

Or if you're even a little bit electronic-minded, build your own, it's not complicated and might be cheaper in particular if you end up needing more than one (mine's here, using info from here).

 

[MrFahrenheit]

For VRAM you’ll need 2x256KB 80ns (there’s VRAM soldered to the board and the 650 can only be bumped by 512KB using the two sockets).

For RAM, I see that the prior owner used RamDoubler. The 32768kb seems strange considering it says built-in memory at … 13MB? You’ll have to get it and see what’s actually inside because that’s a very weird number.

There will be 4 or 8MB soldered to the board and then 4x72 pin sockets. 32MB will bring it up to 132/136MB which is plenty, but will take a minute to boot each time. A good medium would be to use 16MB SIMMs and get 68/72MB which is still plenty.

 

[cheesestraws]

I can only really echo what other people have said: the 650 is probably one of the best and most practical 68k Macs from a hobby perspective. It's upgradable, reasonably nippy, overclockable if that's your thing, reliable, the case doesn't disintegrate very much, the video system works pretty nicely with modern screens, and it can run A/UX if you want to go exotic.

You will need an AAUI->Ethernet adapter for your 650 if you plan to use the onboard Ethernet. Or you can install a NuBus RJ45 Ethernet card.

According to the auction photos, it already comes with one. So, OP, you're all set to plug it in over Ethernet. You can use FTP or something if you're not going to use it that often, but it's not ideal. As @joshc suggested, something like MacIPPi would be better if it's an option, it just gives you a file share that works between both the old and modern machines. The OS comes with built in file sharing support, unless the original owner explicitly chose not to install it...

 

[1200XL M.U.L.E.]

Thank you for all your replies, everyone! I did not expect so many replies with so much good information! It is greatly appreciated. All these replies make me more and more excited about this computer. There is so much to learn, experiment with, and play with!

SCSI/SD adapters - This reminds me of the UltraSatan for the Atari ST and the XT-IDE for the PC. Those devices make moving files back and forth a breeze. I'll have to research the BlueSCSI and ZuluSCSI devices. Are the SD cards formatted such that they are readable by both modern Windows and the Mac? That would make think the card would be in some sort of FAT format and the hardware acts like a translator for the SCSI protocol. I Google searching what the largest allowable hard drive partition size is and it sounds like it's 4GB. There is seemingly no limit to the number of partitions a Mac can handle though. Is that true?

FTP - Now that I think about it, FTP transfers sound a little slow. What I mean is that I have to download whatever I want or need from the web first onto my Windows machine and then transfer via FTP to the Mac. That's two transfers. On the plus side, I imagine the SD card adapters are not hot-swappable (or are they?). That would mean I would have to power down the Mac, mount the SD card on my Windows machine, and then remount the card on the Mac. If I don't wear out my feet walking back and forth between the machines, then I will probably wear out the power supply in the Mac! Maybe FTP/online sharing is the way to go.

MacPi - My mind is a little tired from a long workday. Now after reading a bit about the MacPi, my mushy mind is blown! I think I will have to reread that website a bit later.

Ethernet - Oh, I think I see what may be an Ethernet adapter! Is it the "ASANTE FriendlyNet 10T Adapter"? The microphone must be the round doohickey. What are the other boxes? One has two telephone jacks, so I assume it's a modem. What's the box with the coaxial connector and Ethernet (or phone?) jack?

Thanks!

 

[rjkucia]

Are the SD cards formatted such that they are readable by both modern Windows and the Mac?

The SD cards themselves are formatted in exFAT. However, you don't put files directly on there - you put disk images (.hda etc) on there, the device mounts those, and that's what the Mac sees over SCSI. They'll generally be formatted as HFS. It's not *super* easy to talk to HFS (we can expand on that if you'd like), but you can use HFS+ if you're using only Mac OS 8.1. HFS+ still works on modern Macs, so that's just a matter of mounting images like you would normally.

BlueSCSI does offer a new tool to make this much easier though - you can put files directly on the SD card and use the software to import them. I haven't tried this yet, and it only works one way (I think), but it sounds very useful.

I Google searching what the largest allowable hard drive partition size is and it sounds like it's 4GB.

HFS limit is 4GB on 7.5+. I think there's third party software that lets you use up to 2TB volumes? HFS+ goes up to 2TB, but the bootable volume must be less than 200GB (limit for all Classic Mac OS).

There is seemingly no limit to the number of partitions a Mac can handle though.

I'm not aware of a limit myself, although there's probably a practical limit somewhere in terms of just organizing all your files across dozens of partitions.

On the plus side, I imagine the SD card adapters are not hot-swappable (or are they?).

To my knowledge only BlueSCSI V2 is hot-swappable. I'm not sure how that works technically, or if this actually works in Mac OS. It sounds like that's targeted more towards samplers. I wouldn't expect it to behave like "hot-swapping" in a modern, USB-like sense.

You're right that it can be a pain to shut down, pop out the SD card, put the files on it, pop it back in, and boot back up. Networking makes this a lot easier. You can use FTP or AFP. I recommend AFP because it's a lot faster and integrates nicely in the Mac OS interface. For AFP sharing you can use macOS (but only up to Big Sur or Catalina or so, not sure which) or a *nix system with Netatalk. RaSCSI/PiSCSI has this built in and makes it super easy to set up. I run Netatalk on my Linux server, which gives me a share that works with both modern macOS and with my SE/30.

Ethernet - Oh, I think I see what may be an Ethernet adapter! Is it the "ASANTE FriendlyNet 10T Adapter"? The microphone must be the round doohickey. What are the other boxes? One has two telephone jacks, so I assume it's a modem. What's the box with the coaxial connector and Ethernet (or phone?) jack?

The box with coax and RJ-45 looks like the basically the same thing as the Asante - coax is just a different, older medium for Ethernet (instead of twisted pair). I agree about the modem and microphone.

 

[avadondragon]

The two telephone jack dongle I saw in the ebay listing is a PhoneNet LocalTalk adapter for old school networking with other old Macs.

 

[rjkucia]

The two telephone jack dongle I saw in the ebay listing is a PhoneNet LocalTalk adapter for old school networking with other old Macs.

Oh that's right - it's far too small to be a modem