LC and LC II Power Supply Question

[peafour]

Hi all,

I've been googling and searching the forum, but I don't know if I've found a clear answer to this question: can I use a LC power supply in an LC II, and vice versa?  

The LC uses model number 699-1053: http://imgur.com/gIQGXRm

The LC II uses model number 614-0003: http://imgur.com/KHi4V28

The output on the LC II is a tad higher, but I've seen people say that it can be done for testing purposes, but maybe not great as a long term solution.  The LC power supply that I have is faulty, but ideally I'd like to pop in the LC II's to see if it works otherwise.  It seems like I can, but I figured I'd run it by the commentariat first.

Thanks in advance!

 

[360alaska]

They are completely interchangeable. An LC power supply is an LC power supply.

 

[peafour]

They are completely interchangeable. An LC power supply is an LC power supply.

That's a tremendously clear answer, thanks so much!

 

[Elfen]

They are all interchangeable except for the LC 475 (Q 475, Performa 475/476). The LC - LC III PSU is not strong enough to run a LC 475 because of its 680LC40. People have done it and supposively it has worked but later on had issues with the machine.

Every time I used a LCIII PSU on my LC 475, I get no video (100% of the time) and and mac tones (about 30% of the time).

 

[novusgordo]

Does that mean conversely that an older machine will be more reliable with an LC475/Q605 power supply?

 

[360alaska]

That's extremely incorrect, they are all the freaking same! And I should should know:



On a side note a 475 with a bad prom battery will not give video.

 

[EvieSigma]

What about a 605?

 

[360alaska]

475 = 605

 

[EvieSigma]

Huh, I guess I'll have to hit the battery store if I ever find a 605. Been looking for one but no luck yet.

 

[novusgordo]

The battery store here sells the Xeno ones for $6 CDN and the Saft for $10 CDN. What sort of prices do others pay?

 

[360alaska]

Huh, I guess I'll have to hit the battery store if I ever find a 605. Been looking for one but no luck yet.

I have a 475 for sale, pm me if interested.

 

[Elfen]

Does that mean conversely that an older machine will be more reliable with an LC475/Q605 power supply?

That's extremely incorrect, they are all the freaking same! And I should should know:

image.jpg

On a side note a 475 with a bad prom battery will not give video.

I have just as many LCs in my collection. The PSUs on the LC - LC III is usually a Sony or TDK which pushes out 5V @ 3.25A. The LC 475 (and others in that 68lc040 LCs) use a Dyna Corp Inc. PSU which pushes 5V @ 4.75A. One should read the labels on the PSU to see which PSU is in what machine.

The 68040 needs more power to run than the 68030 (LC II/III) or 68020 (LC). Putting in a weaker PSU meant for the LC - LC III into a LC475 will give you a flaky operating machine if it turns on at all. As a bare board LC 475 with no added RAM, VRAM or expansion card, it may work though I personally doubt it. Add RAM, VRAM and/or an expansion card (like Ethernet card), and it will not turn on. (I'm forgetting the hard drive, which the LC 475 will turn on with a weak PSU if there is no hard drive or had a SSD like CF2SCSI or SD2SCSI; but add a mechanical hard drive, it will give issues.)

Using a more powerful PSU into a weaker machine will turn it on but it does not mean that it will be more reliable. It will mask problems if any exists, like a flakey hard drive. If anything, you should put in lower powered options like a SSD into the LC to give the PSU less of a strain.

 

[360alaska]

Elfen,

Your completely incorrect, I'll prove it:

Look in the apple service manual:
http://tim.id.au/laptops/apple/legacy/quadra_605.lc_series.pdf

For LC I - 475 notice there is only one part number for the power supply:




2nd, look what is provided in the LCD 475 upgrade kit:


No power supply is included in the official upgrade kit. Also, that dynacorp ps is an aftermarket unit and If you find you need it to power your 475 board then you likely have a bad component on the board pulling higher then normal current.

 

[Scott Baret]

I once owned a 475 with a TDK power supply inside. It seems some of them came with these on board. It worked fine for the 8 years I owned it. (Someone on here actually bought it).

To answer the OP's question, I have swapped PSUs between LCs and LCIIs before without any problem. In general, the TDK ones get flaky after a while due to capacitors. They can be rebuilt pretty easily though. It's like caps in any of these machines though--do it now or it will just cease to function. I have a pile of TDKs that do nothing but click.

There's another brand I've seen in these computers called Delta. It seems to be better than the TDK. I've never seen a Sony inside an LC (but have seen plenty of them in SEs). 

Isn't the Dyna the one with the black switch? I put one in an LC with a dead PSU (pulled the black switch one from a 605) and it works fine.