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Various Mac Plus things

ßœœ

Active member
So I got a Macintosh Plus and it immediately blew its RIFA when plugged in. Great start! I removed C33, C37 and C38 and attempted to boot it. I got a sound, and a drive, and the more peripherals I plugged in the more sounds I got, but no screen. I plugged in the mouse, switched it on, clicked for the hell of it and something exploded. A large spark flew out of the bottom front. I was alarmed and unplugged it to handle later. I figured I should take out the motherboard to inspect it, and found a fan had been installed, which I before didn't realize wasn't stock. This and two wires off the connector cable from the analog board made the motherboard quite difficult to remove, I had to lever the chassis open. It seems this board had been installed on top of the motherboard! Thankfully it's a solderless design so I removed it and now if I am correct the mac should function normally, as I've heard these rom accelerators can be troublesome. Does anyone know what these boards are worth? I assume old mods like this are of interest to some. Also pictured is the ram which seems to be aftermarket, is this an expansion?

Side note: in the lower right on the accelerator board you can see the capacitor that exploded. Fun stuff!
 

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Johnnya101

Well-known member
Wow, that's a lucky find! Looks like a Radius Accelerator upgrade, I see a 68020 on there. From what I see online, it should be 16mhz.

Definitely worth something. What, I don't know. At least $100 I'd think. Maybe more.

Not sure on the ram, someone else will probably know.
 

Byrd

Well-known member
What a nice unexpected find! Yes, any accelerator like this can cause additional issues if not pulled and checked over; that and the RAM slots look broken so the tape repair there might not be holding up. Having said that, if you're considering selling it when removed, please PM me - I'd love to charge up my Mac Plus.

With no video on a Plus, the first port of call would by dry solder joints on the analog board - usually fairly obvious, and sometimes you can elicit video with a bump or two on the board to see if the display flickers on.
 

ßœœ

Active member
What a nice unexpected find! Yes, any accelerator like this can cause additional issues if not pulled and checked over; that and the RAM slots look broken so the tape repair there might not be holding up. Having said that, if you're considering selling it when removed, please PM me - I'd love to charge up my Mac Plus.

With no video on a Plus, the first port of call would by dry solder joints on the analog board - usually fairly obvious, and sometimes you can elicit video with a bump or two on the board to see if the display flickers on.
I'll definitely keep that in mind! I don't plan on doing video stuff with this so I'd totally be willing to sell the board. I found the broken pieces of the capacitor that exploded, it seems to be 150ųf 10v or at least i think that's what it says
 

Byrd

Well-known member
Thanks for keeping in mind - I've a Mac Plus Novy 68020 accelerator which clips onto the CPU, but it's missing some chips and I'm not too confident it'll ever work - the Plus was my first Mac.
 
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