I found a Macintosh SE/30

[6885P5H]

I found this computer at an antique store. I paid 60 dollars for it which is ~ what old Macs are worth. It came with a power cord (neat), a telephone cable (neat), an Apple Extended Keyboard II with two broken keys ( ) and two telephone talks ( ). These are little gray boxes that plug into the modem port and have two telephone jacks. They look awfully small to be modems, especially for the time period so I'm not sure what they are. There isn't anything written on them other than their name and you cannot open them up. And I guess it did not come with a mouse..? I hope I didn't lose it during travel. The Apple mouse I have is too old so I cannot use the computer.

An old Macintosh is a computer that I wanted to own for a very long time, although it was never a priority given how common and cheap they are. I saw a really old Mac in ~2005 in the office of a door and window shop. It was probably the one that people call the 128K. The computer was covered with piles of papers and hadn't been used for years. When I asked the boss of the company about it he said that he'd give it to me next time I visit, so that he could have the time to clean the area and get it out of there. My dad never went there again so I never got the computer. Weird story huh?

My SE/30 seems to work however the motherboard is covered in this strange greasy substance and many parts are corroded. I will try to clean it but I don't know from where the corrosion comes from, it doesn't seem to be the battery. It's almost like it came from the air...

I'd like to get the original mouse that came with this computer. It was built in 1990.

The keyboard is one of those kind that has individual switches for each key instead of a rubber mat. Can those switches be opened? Opening them would allow me to remove the keycap shafts of the two broken keys that are stuck in them. When I opened the keyboard I wasn't able to disassemble it, there's this black metal plate and I don't know what to do...

https://image.ibb.co/e6jMET/DSC06607_min.jpg

 

[zamp]

... two telephone talks ( ). These are little gray boxes that plug into the modem port and have two telephone jacks. They look awfully small to be modems, especially for the time period so I'm not sure what they are. There isn't anything written on them other than their name and you cannot open them up.

Those sound like Farallon PhoneNet connectors. PhoneNet is a way of doing local area networking on Macs (and PCs if you have LocalTalk cards for the PCs) over one pair of conductors in a telephone cable. You could plug one PhoneNet connector into each Mac, connect the PhoneNet connectors to each other using regular modular phone cables. For best reliability, you'd plug a resistor into the unused PhoneNet jack on the first and last in the string of PhoneNet connectors. This kind of networking was done up through (I think) Mac OS 9.

 

[GiGaBiTe]

Yeah those PhoneNet adapters worked up through OS 9.2.2.

I have a small pile of those things, but it's been ages since I've used them. If I remember correctly, you'll need to go into the chooser control panel and select either the printer or serial port (whichever port the PhoneNet adapter is plugged into) and then turn Appletalk on. I forget the rest of the procedure, but I don't remember it being difficult. I think there's an option in the file menu when you select an icon to choose which folders/drives you want to share and with what access privileges.

Just be aware that PhoneNet is VERY slow, expect to wait minutes or more for files in the megabyte range. It was however good for networked games, I remember playing Duke3D over Appletalk and it worked quite well.

As for the case corrosion, I would address it before using the machine. Any rust bits that flake off could cause a short. I'd recommend fully disassembling the machine and using krud kutter liquid or electrolysis if there's lots of corrosion.

 

[compaqportableplus]

The “greasy substance” that you find on the board is from leaky SMD electrolytic capacitors. They ALL need to be replaced (including the two axial caps). Just Google “Macintosh SE/30 caps” and you should be able to find a cap list for it.

 

[6885P5H]

Wow it seems that you are right. I thought a leaky capacitor was an electrical term, apparently it's also a literal term. I'm pretty sure it's the first time I see such a thing. The axial caps are bad too? Because of the corrosion or are they the same brand as the SMD ones?

How am I supposed to remove the capacitors?

 

[NeXT]

I think removing the axials is preventative maintenance but you can substitute them with radials if you insulate one of the leads.

Removing the caps is the most violating thing you can think of. Get a good pair of needle nosed pliers, put them 90 degrees to the cap, grab and rotate to rip the leads out of the cap so you can expose the fragile soldering pads underneath.
I still can't believe it's the best way out there to do this.

 

[3pcedev]

Buy yourself some good solder flux for soldering/desoldering. The capacitor goo tends to oxidise the solder which makes it hard to conduct heat from the iron to melt it.

Once the old caps are off give the board a thorough clean. I go for the all-out PCB wash and rinse with distilled water; however using isopropyl alcohol and a q-tip also works. Flux up the new caps/solder pads and reinstall.

Also the axial caps are still available from places like Mouser. They are a little more expensive but they fit in much nicer than a radial with the legs bent out at 90 degrees.

 

[6885P5H]

Does someone know why there are capacitors on the motherboard of the Macintosh SE/30 in the first place? Those gray surface-mounts and the two axial ones, are they all there to filter the lines/remove the noise?

 

[compaqportableplus]

Does someone know why there are capacitors on the motherboard of the Macintosh SE/30 in the first place? Those gray surface-mounts and the two axial ones, are they all there to filter the lines/remove the noise?

I’d imagine they are there for the same reason any computer has capacitors. I’ve never heard of a computer that didn’t have capacitors.

 

[3pcedev]

Does someone know why there are capacitors on the motherboard of the Macintosh SE/30 in the first place? Those gray surface-mounts and the two axial ones, are they all there to filter the lines/remove the noise?

The majority are there for that purpose.

The 1uF SMT capacitor is used in the audio circuit. I've never researched into it but my assumption is that it's used for a charge pump. Just about every mac from the 512k up to Quadra's has this capacitor.