FPU and SCSI2SD for LC550

[68krazy]

Hello everybody!  This is my first post, but I have been lurking for a few months now.  It's good to finally join!  I have been wanting to get back into the world of Vintage Macintosh for a while now and finally scored a sweet LC550 from a recycler.  She is running System 7.1P5 and works pretty well!  I plan to eventually recap and upgrade this machine, money permitting.

I was wondering if anyone had any experience with FPU upgrades.  Can the ones on eBay that ship from China be trusted?  Do they do anything besides look cool in the expansion socket on the LC motherboard?  Would they help SimCity 2000 run any better?  (it runs very slowly at the moment)  Does anybody know if I need a 68881 or a 68882, and which speed?

The Quantum HDD in the machine is also half-dead.  It often refuses to spin up unless I pull it out of the machine and let it sit in the sun for a while.  Once warm, it spins up and works until I shut it off again.  Does anyone have any experience with the SCSI2SD adapters?  How are they speed-wise?  I'd love to hear any input/stories/experience you guys have with them.

Thanks everyone  :b&w:

 

[johnklos]

FPUs will be fine from China. The problem with some Chinese sellers is that some will take older versions of a chip, or different versions of a chip, and relabel them as something newer / with more features. For instance, I ordered a late mask Freescale m68040, only to find it was an older and relabeled EC040 when I got it.

Regarding m68881 and m68882 chips, there are no older ones to worry about.

Any socket which can take one can take the other, but the m68882 will be a little faster than the m68881 at the same clock speed, so that's usually preferable. No clue whether it'd speed up SimCity, but it's worth a try.

 

[uniserver]

not sure how you would install the SCSI2SD into a LC520/550/575 - mac tv.  with that funny adaptor they use ... i dunno.

i think artmix's doesn't mechanically fit either.

 

[68krazy]

johnklos - Thank you for the info.  I will just go with the m68882 then, it costs the same.

uni - On the SCSI2SD, the spacing between the 50-pin SCSI connector and the 4-pin Molex looks about the same as it does on an actual hard drive.  Wouldn't that mean the LC5xx adapter should fit the SCSI2SD?

 

[uniserver]

i tried the artmix version and it didn't work… not sure scsi2sd… i hope it works.   would be glad of something said that it did!  

 

[dougg3]

From what I can tell, the molex connector on the SCSI2SD is upside-down from how it would be oriented on a hard drive.

 

[68krazy]

dougg3 - good catch, I did not notice that.  Looks like I will have to get creative with interfacing the SCSI2SD.

Updates on the machine:  The Quantum drive is definitely struggling.  It now refuses to spin up every single time, unless I heat it up either in the sun or in the oven at 170F for a few minutes.

I added 32MB of RAM ($5 shipped on eBay.... can't believe how cheap that was) and holy crap, what a difference that made.  SimCity runs much, much better now.  I will still get the FPU in there at some point, but it is not a priority anymore.

I have been experimenting with the original install of 7.1, 7.5.3, and now I am installing 7.6 as I type this.  I have been using burned disk images from Macintosh Garden.  So far I like the original install of 7.1 the best.

I installed a Farallon Ethernet Card (also from eBay), but I can't figure out how to get a browser on this machine.  I installed Internet Explorer off a MacOS 8 CD, but it refuses to start and says I need the "CFM 68k Runtime Enabler".  I can't find this elusive piece of software anywhere.

Any input/suggestions?

Thanks guys.  Having lots of fun with this machine.  I am especially digging the built-in Trinitron, as picture tubes are an eccentric interest of mine.  I could take the cover off a CRT and stare at the innards for hours, I think the way they work is fascinating.

 

[68krazy]

Some pics of the machine for you guys.

Here she is the day I brought her home.  I got her for $22 including the StyleWriter II.



The day after I brought her home, she refused to boot.  I'm not sure why she worked perfectly the day I brought her home and then refused to start the next day but hey, what do you expect from a 23-year-old machine?  I washed the motherboard with Simple Green and rinsed with distilled water:



I haven't had any boot failures since, and now the motherboard is minty fresh.  I plan to replace those capacitors soon.

One of my favorite things about this machine is the caddy-load CD drive.  My first computer was a Performa 6116CD when I was a kid, so I missed the era of caddy-loading drives by several years.  The drive is currently working great, but I peeked inside the slot with a flashlight and saw a lot of surface-mount capacitors.  Those will need to be replaced ASAP before they leak and ruin the drive.  Here, I am loading a classic 90s album into my 90s computer:



And here she is, just chillin'.  When I was a kid, I remember seeing a few LC5xx machines in the back of the computer lab at school.  I thought they looked very cool, especially the QuickTime sticker under the CD drive.  There was something very striking about the design of these to me even as a kid.  I think these machines are a thing of beauty - I love the 90s curves and that vertically-flat Trinitron.

 

[68krazy]

Almost forgot one last pic.  Guess what I removed from the machine in the car right after I paid for her?



You might have thought you were going to ruin another vintage mac, but not today Maxell.  Not today....

 

[uniserver]

Love for the LC5XX!  

 

[CC_333]

A 578 was one of my first 68k Macs. I remember having to replace the analog/power board on it, because the controls went weird (this was 2005, so such things could still be found for a reasonable price). It probably needs to be recapped by now....

I think I got the logic board taken care of, though.

c

 

[aplmak]

So happy you caught that Maxell battery in time!!! That logic board should be recapped even though you cleaned it!!

 

[68krazy]

Hey guys, there is a fairly loud ringing sound coming from around the flyback area.  I did not notice it until I started running the machine without a (noisy) HDD.  The ringing sound is directly related to HV, and it gets louder when bright white objects are shown on the screen.  I also noticed that the CRT picture shifts down a little bit whenever the CD drive spins up.

Do you think a recap of the analog board will make that go away?  Has anybody ever recapped one of these analog boards?

 

[uniserver]

yup those tin can leakers are toast… i re-cap these all the time.

 

[mwdmeyer]

I'm not sure specifically about the LC550, but the SCSI2SD works great in my LC475. I love it.

Here is a video: 

How much ram in that machine did you have before adding the extra 32mb?

I __think__ an FPU will help Sim City 2000, I had the standard 68LC040 25MHz in my LC475 and after upgrading to a full 68040 I *feel* sim city runs better, but not a massive amount. I thought it used the FPU, but I'm now not 100% sure, maybe only the DOS version does? I would be very interested to know if you do a an FPU.

 

[68krazy]

Before the upgrade, the machine had 5mb of RAM in it.  Once I get her up and running again I will order the FPU and let you know if it makes any difference! For now, the Quantum HDD is completely dead and so she is sitting in the closet waiting on a SCSI2SD, minty fresh caps, a new PRAM battery, and a hot air rework station.  

Unfortunately, Life™ keeps getting in the way.  The restaurant has been quite slow lately so I'm low on cash, and the car needs new tires so the LC is on the back burner at the moment  :-/

 

[68krazy]

Finally got down to business and removed the old capacitors with a hot air station. Do you guys think I did OK? Do any traces look damaged?

There is corrosion under several caps, but this board was booting before I removed them so I hope nothing is too far gone.

 

[uniserver]

as long as when you removed the caps they came off with out force,  looks good to me but then you have not cleaned up the pads and leaked goo with solder wick and then q-tips + acetone

 

[68krazy]

I hit the board with some desoldering braid and the q-tips.  Didn't have acetone so I used 91% IPA.

I am happy to report that none of the pads lifted, and after the cleaning the cap goo is completely gone and there is no sign of damage to the board.

I went ahead and ordered tantalum caps for the motherboard, a brand new purple Tadiran battery, and a SCSI2SD.  I am feeling quite stoked at all the progress I made today and will keep you guys updated.

Thank you for the input uniserver and mwdmeyer, I enjoyed your video about the SCSI2SD.  I really like the way you have your 475 set up.