My mother recently got someone’s old IBM 330-75 computer. It’ll suit her needs just fine, because she only wants to send the occasional e-mail and play Solitaire. The only thing is that the computer doesn’t have a modem. Only after I bought an internal hardware modem and went to install it I found out that these old IBM boxes need some sort of key to open. There a small slot in the front on top, with a ‘lock’ sign next to it. There wasn’t any key with the computer, so my question is if any of you have any experience with opening one of these things without the key? I figured I would just force in a screw driver and turn it, but before I do that I thought it wise to consult the Teeming Millions first. Any suggestions?
Forget trying to get a key. Get a big screwdriver and a hammer and have at it.
Are you sure that’s not just a kehole for the keyboard lock?
Try opening the case the normal way first. It may be just what Mangetout said: a slot for a security cable for the keyboard, to keep people from wandering off with it. I’ve seen those on a few old professional workstations. I’ve been looking online for instructions to open the case of that machine, with no luck so far. Whatever you do, don’t bang hard on it. Those old machines are terribly shock-sensitive.
The unit’s monetary value is on the “How much will you charge me to get rid of it?” category so being rough with it is not that much of a big deal.
You could take it to a computer store & ask them to open it with a key. Seems all the keys look the same to me.
IBM is one of the few exceptions handy. Their cylinder keys were real keys.
Ah, IBM: Real keys for Real Programmers. 
Seriously, why do you want an internal modem anyway? External modems are better for a few good reasons:
[ul]
[li]Easier to debug: External modems have little green lights on their front panel. Those lights are keyed to things the modem is doing (waiting for input, holding the line, sending data, etc.) and being able to see that information even if the computer itself is being less than helpful can be a big boost. (For example, if the modem is dialing the phone number but not getting any further, you have a lot less to do than if the modem isn’t even responding to the commands in the first place.)[/li][li]OS-independent: Every external modem I’ve ever seen is Hayes-compatible. That means it implements in hardware a certain standard protocol that nearly every home computer can use. My dual-boot desktop runs Windows ME and RedHat Linux, and both OSes can get a good connection through the selfsame external modem because of that compatability. Internal modems tend to be Winmodems, little computer cards that are crippled versions of real modems in that they rely on OS-dependent drivers to implement the Hayes protocol. It’s damned-near impossible to get Winmodems working on anything but MS-Windows.[/li][li]Easy to swap around: Say the IBM dies (the way of all hardware is but to the junkheap, after all). If you go with an internal modem, you’ll have to crack the case again to salvage it. If you get an external modem, all you have to do is remove a single cable.[/li][/ul]
Plus, you don’t have to crack the case to install an internal modem. 
AARGH! Kill me now. Wrap a modem cable around my neck and cause a ground-fault interrupt.
You don’t need to crack the case to install an external modem.
Well, I tried to buy an external modem but I couldn’t find a simple (cheap) one. They were for ISDN or ADSL. So now I’m stuck with this internal one. I indeed found out that IBM used real keys, no generic ones.
Does anyone have any hands on experience with the official IBM tool (the screwdriver)? I don’t want to break the lock and then find the case still closed…
Actually, what I was thinking of was a keyswitch that when turned, renders the keyboard inactive; nearly every AT based computer I have seen has one of these and many of the earlier ATX machines had them too - they don’t mechanically lock anything at all - it’s just a keyswitch attached to a connector on the motherboard.
This may not be what kip70 describes though…
How old is the machine?
It might just be old enough to be one of the last surviving machines with a MCA bus. In the Bad Old Days[sup]TM[/sup] IBM decided (quite correctly) that the old ISA bus was old fashioned, and instead designed the MCA (aka Micro Channel) bus. Fortunatelly it didn’t catch on, and everyone else went with Intels new PCI bus. But IBM didn’t give up that easily, and kept cranking out machines with their very own bus for quite some time.
The moral of the story:
If you have one of those machines, a standard internal PCI modem won’t work. (And if you want to find an MCA modem you’d have to look in museums.)
I second Derleths suggestion of going fot an external modem.
I worked for a company that had hundreds of similar machines (IBM PC 350s, to be specific). We had to open them all with a screwdriver. It worked pretty well. Just shove a big, flat screwdriver into the keyhole and turn. What was more difficult was getting the case back on. Not because of any damage done to it. Just because it was a crappy case design. You have to line everything up perfectly, sacrifice a rubber chicken, and pray to the god of heckfire, but eventually you’ll get the case back on. And make sure you get it on far enough for the little latch in the back to latch, or the whole cover will slide right off the first time you pick it up.
For those who haven’t seen this case style, this is an actual lock to prevent the cover from being removed, as opposed to the keyboard lock a couple people have mentioned.
As I remember it, with enough pushing and leverage you could get the side of the case to bulge out enough so that the latch cleared the lock and the case could be removed. With the case off, there were a couple screws holding the lock in place that could now be unscrewed, and the lockassembly reattached in the unlocked position.
“IBM is one of the few exceptions handy.”
Those keys that I have all look the same to me.
Maybe you could just get a drill use that? Want a cheap external modem? try ebay.com
Pick it.
It’s probably a wafer-tumbler lock, the same kind that are used on most desk drawers and such, and they’re amazingly easy to pick. If you can’t, take it to a locksmith and ask him to do it; shouldn’t take more than a few seconds.
Kip, get thee to IBM.com and see if they have instructions
for opening that case. Their online support documentation
is outstanding. If you can find the actual model number,
you may be able to download the hardware reference and
that would tell you which way to turn a screwdriver.
- jam
Well, all of the above answers might work. _Not all the IBM’s have unique keys. _In the office where I used to work it was one key fits all.
A screwdriver in the slot might be able to force it, but as I recall most had the round keys so that won’t work.
The locks are generally made of pretty hard material, so drilling would be really difficult. _Consider using a “Dremel tool,” which is a high-speed motor with a chuck to hold cutting blades and other tools. _With enough time and patience they’ll cut through anything, even glass. _Try cutting a slot in the lock, then force it with a screwdriver. _If that doesn’t work, try a number of cuts around the edge to cut the lock out.
BTW, one other good thing about external modems: _You can turn them off when you’re not using them, so you don’t have to worry that your computer is making calls in the middle of the night. _(It happens!) A lot of “mon & pop” computers sell used modems, and they’re usually dirt cheap.
I can’t seem to edit my own post, so I’ll post a follow up for a paragraph I left out.
No lock is more secure than the material it’s mounted in. You can always cut a hole in the case around the lock (again, a Dremel tool is a good choice) and let it fall out, then glue a piece of metal over the hole as a patch. I take it this is not a machine you’re terribly proud of.