Source for Mac Plus power switch?

[larwe]

Remember how I said I almost never have problems with a Plus... I pulled this one at random because it was the closest thing in my garage I could use to check what's on a 400K floppy someone sent me. Right off I noticed it had an unusual amount of battery corrosion. I rarely see much damage beyond the battery holder itself. So I opened it and it's a mess. Blech. In particular I heard a buzzing noise when I tested it, and there was a lot of arcing going on inside the power switch.

Vapors coming off the corrosion even seem to have stained the CRT pins blue, it was intermittent until I removed the connector, buffed the pins, and added deoxit.

The machine works with the switch bypassed but needs some heavy maint, including replacement of that power switch. Is there an orderable part? Every search result I get leads me back to picoPSU, which is not what I want/need.

 

[daanvdl]

I designed a drop-in replacement PCB for the Mac Plus power switch (SW1), intended specifically as a serviceable replacement when the original switch is arcing, intermittent, or physically beyond saving.

https://github.com/daanvdl/mac_plus_sw1

 

[larwe]

O.M.absoluteF.G. That is perfection and you have won three internets today. And I even have a resin printer (it's currently printing me a couple of transparent Apple II mice but it'll free up ).

Now for your next trick you'll tell me where to source a VIC-20 (2-prong) power switch - it looks like such a normal SPDT right-angle switch but nobody makes one like it any more.

Thanks so much!

 

[dankcomputing]

With the VIC-20 you can get new PCBs for a VIC-20CR motherboard, move all the chips over, and then 3d print a new side plate, upgrading around the power switch problem (VIC-20CR uses the same power switch and power supply as the C64).

 

[larwe]

With the VIC-20 you can get new PCBs for a VIC-20CR motherboard, move all the chips over, and then 3d print a new side plate, upgrading around the power switch problem (VIC-20CR uses the same power switch and power supply as the C64).

Haha. my problem is not "I need a working VIC-20". I have close to a hundred VICs and most of them work. My specific problem is, the 2-prong units used a power switch that freezes in place after long disuse, and they are really hard to unstick. I have quite a few of them that have been broken in an attempt to unstick them. It seems like a very vanilla sort of switch - a very long time ago (2000-ish) I found some on one of the surplus sites - but I have spent ages poring catalogs recently and not found a viable replacement.

The switch used on the VIC-20CR, C64 and C128 seems to be a lot more reliable but it is completely different and not a drop-in.

(Also you can't _just_ transplant chips from a 2-prong to a CR motherboard, e.g the RAM is different - but no big deal, the CR used 8-bit SRAM which is easy to obtain).

 

[dankcomputing]

People have been looking high and low for the original VIC-20 switch for decades and it seems fruitless now. I've never even seen it crop up in other equipment. I always liked the CR better, that use of a 120V shaver cord for a 9V connection has always irked me. Did that surplus site indicate a part number of any kind?

Back to the original question, does the Mac 128-Plus power switch have a part number? I know I've seen it on other things, it's not an Apple proprietary design. When I was working on a Plus I lucked out and had access to a bunch of scrap analog boards to pull switches and battery compartments from.

 

[larwe]

Like I say, it was a long time ago, no later than 9/11 - so no I don't remember a part number - I just remember looking at the dims, thinking "hmm yes" and ordering some, and they fit fine. Which is why it irks me that I can't find a direct replacement these days - it seems like it should be a very simple thing. I believe the site was goldmine-elec.com which is defunct.

The non-CR version is more "important" to me since my first family computer was a PET keyboard 2-prong Australian VIC-20. And the most important VIC I have in my collection right now is a PET keyboard 2-prong NTSC VIC-20 signed by Michael Tomczyk. But my collection includes many (but not all) variants - I have a German VC-20, a couple of UK VIC-20s, a few PET NTSC VIC-20s, a few Eurostile NTSC VIC-20s, and lots of C64 keyboard VIC-20CRs.

In some markets the 9VAC input on the 2-prong VIC was a weird connector specifically to avoid the shaver designation