First post here...

[JohnnyGrey]

Hey everyone. I'm a 23 year old programmer, mostly into Linux, but I grew up with a lot of macs (and a 386).

My first Mac was my Dad's SE, 2 floppies AND an HD. I loved playing Vette, Oregon Trail, MacKarate etc. Still have that machine, but the SCSI controller is flaking out.

Second Mac was an SE/30 I bought from an electronics show for $40. Had 8MB RAM and a 150MB HD.

Third was an LCIII I bought in 8th grade, bone stock with an 80MB HD. On the way is a Sonnet upgrade with 32MB RAM, 33/66 68040 + FPU and 10base ethernet. Can't wait to install it. I know it was more expensive than just getting a quadra or whatever, but I really like the compactness of the pizzabox. I just found a huge archive of old Mac games and I figure after this upgrade, I'll be able to play 99% of them quite well. I plan to set up my Linux server to handle AppleTalk so I can use it for storage. Only problem with the LCIII is that it has a really annoying drifting squeal coming from the speaker. Bad caps maybe? Also if possible, I'd like to upgrade to a fast HD ~4GB. Any recommendations? Thanks.

This forum looks like a really great place.

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[Christopher]

My PowerMac 8500 does that sometimes too, and if I jiggle the cables inside it goes away.

 

[JohnnyGrey]

It doesn't seem to react to cable jiggling, but when I touch the caps, the squeal changes.

I'm confused about the whole 68040 clocking scheme. The upgrade card I purchased claims to have a 66/33mhz 68040 on it. A lot of the 040 Mac descriptions over at everymac.com say:

1. This model is sometimes designated as having a 66 MHz processor,

since the clock input runs at 66 MHz. However, the processor itself

is not "clock doubled", so technically it is only a 33 MHz processor.

How does the processor not run at 66mhz if it's clock signal is 66mhz? When the first 486DX2's came out, it was truly a clock doubled processor, so how does the 68040 compare? Is my upgrade board a true 66mhz chip, (2x as fast as the LC580) or not?

 

[TheNeil]

Sounds like you could have electrolite leakage. Long term solution is to change the caps. Short term fix is to clean up any gunk on the motherboard or try washing it (I'm not kidding - unplug every from the motherboard and wash it in warm soapy water, rinse in clean water and leave to dry for a couple of days).

 

[bigD]

1. This model is sometimes designated as having a 66 MHz processor,

since the clock input runs at 66 MHz. However, the processor itself

is not "clock doubled", so technically it is only a 33 MHz processor.

How does the processor not run at 66mhz if it's clock signal is 66mhz? When the first 486DX2's came out, it was truly a clock doubled processor, so how does the 68040 compare? Is my upgrade board a true 66mhz chip, (2x as fast as the LC580) or not?

That description is backwards. The chip is really being driven at 33MHz. The '040 has two clock inputs - PCLK and BCLK. In your case, BCLK is at 33MHz and is used for all the bus signal timing, while PCLK is at 66MHz and is used for internal logic timing.

Basically, it's a 33MHz chip. Your LC 580 is doing the exact same thing, just without an FPU.

 

[JohnnyGrey]

So how does that compare to say, a 486DX2/66 or pretty much all of the clock multiplied chips of today? Same deal, right? In other words, does the 68040 do much of anything between bus clocks? I'm just trying to figure out why 486+ are rated by the internal clock and 68040's by the bus clock.

 

[bigD]

I don't know how the DX2 works, so I'll leave that answer to someone more qualified. But when Apple released the Quadras, there was no talk of an internal frequency. A Quadra 700 was 25MHz, an 800 was 33MHz, and so on. Motorola also quoted the chips as 25MHz, 33MHz, etc...

But then the DX2 was released, and the Quadras benchmarked pretty well against the DX2 chips, and suddenly people were doing the 33/66 thing. I'm not sure if the marketing people at Apple ever jumped on the bandwagon. I am told that whatever Motorola does with the internal frequency is *not* the same as what Intel did with the DX2.

As far as how they stack up - I used to write scientific code in C on both platforms, and they're pretty much even in my experience. In other words my Quadra 700 (25MHz '040) used to about the same as a 50MHz DX2. Now that's just pure processor speed. My understanding is that the Quadras suffered from some bottlenecks in other areas that might not have made them as fast for general computing. And I do know that web browsing will be far inferior to a 486 based machine - for some reason web browsing has always been slower on a Mac than a PC for the same class of processor. You'll find that this isn't just true for the 680x0, but for the PowerPCs too.

 

[bigD]

At least as far as the Macintosh is concerned, the 68040 came in speeds of 20, 25, 33, and 40MHz. The 68LC040 was essentially the same processor, just minus the FPU. I mention this because there are accelerators out there listed with a 45/90MHz '040, but this is just an overclocked 40MHz chip.

 

[JohnnyGrey]

Hmm... thanks for the info. As far as web browsing goes, I think HD access has to do something with inferior performance. Did 68K Macs have DMA (or the equivalent)? PCs have had it since the 386 if not earlier.

 

[aphetica]

Short term fix is to clean up any gunk on the motherboard or try washing it (I'm not kidding - unplug every from the motherboard and wash it in warm soapy water, rinse in clean water and leave to dry for a couple of days).

I bet the first guy who did this had a really hard time convincing other people to try it... haha.

 

[LCGuy]

I know I have, lol.

 

[funkytoad]

Short term fix is to clean up any gunk on the motherboard or try washing it (I'm not kidding - unplug every from the motherboard and wash it in warm soapy water, rinse in clean water and leave to dry for a couple of days).

I bet the first guy who did this had a really hard time convincing other people to try it... haha.

Now I want to know what made him think to try that. Reminds me of the fact that cat pee glows under a black light. That just leaves us to wonder; who was the weirdo that figured that out?

 

[TheNeil]

Short term fix is to clean up any gunk on the motherboard or try washing it (I'm not kidding - unplug every from the motherboard and wash it in warm soapy water, rinse in clean water and leave to dry for a couple of days).

I bet the first guy who did this had a really hard time convincing other people to try it... haha.

It works though

 

[aphetica]

Now I want to know what made him think to try that. Reminds me of the fact that cat pee glows under a black light. That just leaves us to wonder; who was the weirdo that figured that out?

The black light thing seems like an accidental discovery though. I imagine it's pretty difficult to "accidentally discover" that you can fix some motherboards by dunking them in soapy water...

 

[TheNeil]

The black light thing seems like an accidental discovery though. I imagine it's pretty difficult to "accidentally discover" that you can fix some motherboards by dunking them in soapy water...

Err...I did. Got a dead Mac II which didn't want to do anything so, being a conscientious soul, decided to clean it inside and out (so that it was clean and pretty). Then plugged it all back together again and figured I'd try to get the PSU to fire up, spin its fan and dry the thing out (I know, I was young and foolish). Bingo, it chimes into life (and then I had the headache of finding a new hard drive, sorting out floppy drives etc.) 8-o

Only later did I find out that other people did the same thing

 

[JohnnyGrey]

I was able to replace 3 out of the 4 caps with electrolytics. The fourth one, I busted a trace off the motherboard so I couldn't install another. I suppose if I really wanted to, I could follow the trace, but I won't bother. All these caps failed open, so I don't think it minds too much that I can't install another. The audio oscillations seem to have gone away after I replaced the two closest to the sound chip.

 

[aphetica]

Err...I did. Got a dead Mac II which didn't want to do anything so, being a conscientious soul, decided to clean it inside and out (so that it was clean and pretty). Then plugged it all back together again and figured I'd try to get the PSU to fire up, spin its fan and dry the thing out (I know, I was young and foolish).

You're saying you plugged in... a wet motherboard??

Wow. I'm not saying you're dumb or anything, but it's unfortunate that you weren't taught as a child that such things were dangerous...

Something my father always used to tell us from a very young age about the nature of electricity was this; "It's faster than you are, it's invisible, and it'll kill you." ...sounds like some kind of terrifying monster.

 

[Temetka]

@ OP:

Welcome to the forums. Most of us are well versed in multi-platform systems. We all have a love for the older macs as we feel they had more personality than the machines now. So we toil on keeping the ones we have running and finding new (conquests, liberations) sources of parts and machines to fuel the madness.

RE: DX2

The DX was shipped at 33MHz. The DX2/66 is clock doubled to 66MHz. This occurs inside the chip, not the mobo. Yes I know most older 486 board had jumpers, but back in the day we also had to set the proc voltage and sometimes it varied. They (Intel) went to a clock tripled setup shortly with the DX4/75 and DX/100 machines. The DX4/100's were awesome.

When the Pentium came out, all we needed to set via jumpers was bus and multiplier ratios (voltage jumpers were still present if you had a Cyrix or AMD CPU though). This was years and years ago, I could be off on a detail or 2.

Enjoy your stay here.

 

[TheNeil]

Err...I did. Got a dead Mac II which didn't want to do anything so, being a conscientious soul, decided to clean it inside and out (so that it was clean and pretty). Then plugged it all back together again and figured I'd try to get the PSU to fire up, spin its fan and dry the thing out (I know, I was young and foolish).

You're saying you plugged in... a wet motherboard??

Wow. I'm not saying you're dumb or anything, but it's unfortunate that you weren't taught as a child that such things were dangerous...

Something my father always used to tell us from a very young age about the nature of electricity was this; "It's faster than you are, it's invisible, and it'll kill you." ...sounds like some kind of terrifying monster.

No, I plugged in a motherboard that had been hand dried and left on a radiator for half an hour. The layout in the Mac II means that no 'wet' components came in contact with the PSU save for the plug that supplies power to the board.

And I do not appreciate being called dumb