Can the power connector in an LC Mac be purchased new?

[MrFahrenheit]

I have found a compact 12v and 5v 2.0amp power supply with a molex connector that costs $10 with free shipping. I want to try one on an LC to see how well they work. 
 

The power supply is included in this kit:

 

https://www.ebay.com/itm/361594883718

 

Is there a Digikey part number or name for the power supply connector on the LC?  I don’t want to destroy a vintage power supply. Ideally I’d 3D print an enclosure or bracket for this power supply so it would fit inside the LC nicely. The specs indicate it should work, unless someone knows more about this than I do. 

 

I have the power supply already but I want to make a molex to LC adapter cable to plug it into a board and try it. Bad idea ?

[cheesestraws]

19 hours ago, MrFahrenheit said:

Is there a Digikey part number or name for the power supply connector on the LC?

 

You want a Molex KK396, 7-pin.  I got "compatible" ones from eBay and they've worked fine, or you can get 'official' ones if you're feeling fancy.  They don't have the blanked-off extra pin, but you can just ignore one of the pin positions.

 

Here's an old pic of my prototype LC PSU replacement using that connector.

 

[MrFahrenheit]

Great!  Thank you !!

 

If the specs are correct on the power supply, 12v and 5v 2.0 amps, do you foresee any issues?  The cost is certainly low. 

Edited April 6 by MrFahrenheit
Autocorrect

[cheesestraws]

The real ones are rated to 7A, 600V per circuit, per Molex's website—they are a connector actually designed for power applications.  I'd be surprised if even the dodgiest of clones would balk at 2A at 12V.  I've been using my cheap clone ones in the rackmount LC II router thing 24/7 for over a year now with no signs of trouble, certainly.

[MrFahrenheit]

20 hours ago, cheesestraws said:

The real ones are rated to 7A, 600V per circuit, per Molex's website—they are a connector actually designed for power applications.  I'd be surprised if even the dodgiest of clones would balk at 2A at 12V.  I've been using my cheap clone ones in the rackmount LC II router thing 24/7 for over a year now with no signs of trouble, certainly.

I meant whether I’d have issues with a power supply supposedly being 12v 2a and 5v 2a on an LC. 

[cheesestraws]

Oh, sorry, misunderstood.  I'd expect that to be fine; I think I'm running my LC II off a 2A 5V wall adapter.  That PSU you linked actually looks like a more sensible option than the way I went.  You've got more juice on the 12V line there than the stock PSU provides, and 2A should be fine on 5V, I'd expect, too.

 

The original LC PSU also provides a -5V line, but you only need that if you want to use differential serial (e.g. LocalTalk).  If you don't want that, you don't need it, and if you later decide you do want it, you can generate it from the 5V line without too much difficulty.

Edited April 6 by cheesestraws

[MrFahrenheit]

On 4/6/2021 at 1:55 PM, cheesestraws said:

Oh, sorry, misunderstood.  I'd expect that to be fine; I think I'm running my LC II off a 2A 5V wall adapter.  That PSU you linked actually looks like a more sensible option than the way I went.  You've got more juice on the 12V line there than the stock PSU provides, and 2A should be fine on 5V, I'd expect, too.

 

The original LC PSU also provides a -5V line, but you only need that if you want to use differential serial (e.g. LocalTalk).  If you don't want that, you don't need it, and if you later decide you do want it, you can generate it from the 5V line without too much difficulty.

I don’t know why but I had thought the original PSU was less than 2a on 12v but apparently it’s around 4-5a on 12v. This PSU I found is only 2a on 12v, so likely not good enough. I’ll have to keep looking. The cost and size was definitely attractive. Especially for retrofitting inside an LC. 

[cheesestraws]

22 hours ago, MrFahrenheit said:

I don’t know why but I had thought the original PSU was less than 2a on 12v but apparently it’s around 4-5a on 12v

 

The PSU on my LC II, which is stock from factory, is 0.75A on the 12V line, so if you've got a 4-5A one in yours it's either aftermarket or someone was having a massive overspec day.  Again, my rackmount LC II, which admittedly has a scsi2sd in instead of a spinning disc, can only pull about 0.3A on the 12V line and that is fine.

 

I think the one you linked looks like a sensible choice to try.

[cheesestraws]

OK, so in the factory ones, I just checked, the 5V line is 3.75A, but certainly neither the LC nor the II draw that much.  So, I suppose to a certain extent this depends on whether it's for you or for another person.  It will almost certainly work fine, but if you were doing this for someone else I appreciate you'd want to replace like for like.  But as I said, I've got one running absolutely fine on a significantly smaller PSU (including a network card) basically 24/7.

[MrFahrenheit]

On 4/7/2021 at 9:50 AM, cheesestraws said:

OK, so in the factory ones, I just checked, the 5V line is 3.75A, but certainly neither the LC nor the II draw that much.  So, I suppose to a certain extent this depends on whether it's for you or for another person.  It will almost certainly work fine, but if you were doing this for someone else I appreciate you'd want to replace like for like.  But as I said, I've got one running absolutely fine on a significantly smaller PSU (including a network card) basically 24/7.

 

You're right.  I was having an off day yesterday, and read the figures inverse.  I have over 50 LC/LC2/LC3/LC475 Macs (combined total) that I am in the process of restoring.  I need to also restore the PSU but I was thinking that maybe a brand new PSU inside an enclosure that's the same dimensions as the original LC would work better (considering PSU improvements over the past 30 years).

 

Maybe I should just recap the PSUs I have and call it a day.  I wonder if I could build a decent PSU that would still fit inside the metal enclosure, for at least my own overclocked LC 475 machines...  Hmmmm

[demik]

On 4/8/2021 at 7:36 AM, MrFahrenheit said:

Maybe I should just recap the PSUs I have and call it a day.  I wonder if I could build a decent PSU that would still fit inside the metal enclosure, for at least my own overclocked LC 475 machines...  Hmmmm

 

Just throwing thoughts here. LC PSUs are actually quite robust and only need a recap most of the time. I only recap those and never had a failure so far. I change the inside of the PSU on crappy ones though (IIcx Astec, 6200, 8100…).

 

One 68kmla member did a picoPSU integration here, if that's helpful: