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#1 2014-07-26 02:11:30

ScutBoy
Member
Registered: 2014-05-25
Posts: 159

MacGusto Upgrade Board

I picked up an "original" Macintosh last fall from a CL post. The seller stated it had been upgraded - I figured that meant it got a 512K upgrade like most all original 128K machines.

When I picked it up it seemed extra heavy, but I didn't think much about it.

When I got it home, it would chime and come up to the flashing disk, but the drive was gunked up and wouldn't accept disks. I didn't have my FloppyEmu at that point, so I cracked it open to check things out.

To my surprise, there was a hard drive stuffed in there! Digging further, I found that there was an upgrade daughterboard in there, which also had SCSI out. Best part, the SCSI port was connected to a SCSI-MFM converter board, and the drive was an MFM drive...

The board is called MacGusto, and besides bringing out SCSI, it upgrades the RAM of the machine to 1 meg. Power for the drive (and converter board) comes from molex connectors soldered right on to the backside of the analog board - I can't imagine that did much for the health of the board.

I fired it back up tonight with my FloppyEmu, and it will boot up fine through systems before System 6.x The hard drive is dead. I suppose I could hook up a 50 pin SCSI drive directly and see what happens, but that's for another night.

Flickr Link:

https://flic.kr/s/aHsk13wK15

Anyone heard of this board? The only Google reference I can find is that there was a 1 meg and 2.5 meg version. As far as I can tell, it's stuck on a 128K motherboard, though it looks like it could go on either a 128k or 512k board.

Comments or more info welcome.

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#2 2014-07-26 03:54:55

bbraun
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Registered: 2014-05-29
Posts: 1,064
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Re: MacGusto Upgrade Board

Nice!  I hadn't heard of this particular board before, but I've got a hand full of others that are similar.  It looks like this plugs into the ROM sockets (and possibly also connects to the CPU underneath?).  The ROMs have been upgraded to Plus ROMs to make the HDD work.  Cover up those windows on the EPROMs!  UV exposure will erase them.
The SCSI to MFM adapter seems particularly neat.  I haven't seen one of those before.

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#3 2014-07-26 04:26:48

mcdermd
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From: Corvallis, OR
Registered: 2014-05-12
Posts: 1,022
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Re: MacGusto Upgrade Board

A nice, original AB on there too although i'ts missing the "fence" up top. Most of them were removed if any mods were made as it improved air flow.


Daily Drivers: 27" iMac 2.8 GHz Quad-Core i7 (Late 2009), 21.5" iMac 2.7GHz Quad-Core i5 (Late 2013), 11" Macbook Air 1.6 GHz i5 (Mid-2011)
See the restored heroes here.

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#4 2014-07-26 16:53:34

jt
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From: Bermuda Triangle, NC USA
Registered: 2014-05-21
Posts: 1,470

Re: MacGusto Upgrade Board

Fence?

That looks like an odd (small) number of overlarge (high pincount) DRAM ICs at first look. Does the expansion board plug into the empty DRAM sockets on the MoBo for the data, addressing and control lines not available on the ROM Socket? As opposed to going the usual Killy Klip route for I/O?

I'm in a rush, sans caffeine ATM, so I'm likely way off base, but very curious.

Last edited by jt (2014-07-26 17:39:02)

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#5 2014-07-26 18:10:12

mcdermd
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From: Corvallis, OR
Registered: 2014-05-12
Posts: 1,022
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Re: MacGusto Upgrade Board

The "fence" was a flat piece of metal that attached in those four holes on the very top edge of the AB. Only the 128k had it.


Daily Drivers: 27" iMac 2.8 GHz Quad-Core i7 (Late 2009), 21.5" iMac 2.7GHz Quad-Core i5 (Late 2013), 11" Macbook Air 1.6 GHz i5 (Mid-2011)
See the restored heroes here.

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#6 2014-07-27 04:58:33

jt
Member
From: Bermuda Triangle, NC USA
Registered: 2014-05-21
Posts: 1,470

Re: MacGusto Upgrade Board

Sort of like that ground bar fence in the back for RFI shielding a/o stiffness or some such? haven't seen it in pics yet.

On the Subject of Classic Cooling:
The only passive cooling mod for inside the case of the compacts that looked workable at all to me was a paper or plastic gasket mounted to the chassis underneath the drive cage that came with some of the Killy-Klip Radius upgrade cards. It appears to have partially mimicked (footprint only) the Twiggy drive's metal enclosure. That sheet metal box appears to me to have been a key component in the Power/Cooling budget of the seminal Mac with its ludicrous spec for passive cooling. IIRC the designer of the Twiggy/512k original Mac made the move to Radius with the other founding members.

When Apple dumbed it down to 128k and switched to the Sony drive with its smaller footprint and sheet metal cage, the cooling budget went right out the window. The revised design (miserable cost savings inspired kluge) failed to channel the side vent airflow across the bottom of the chassis and straight up the side of the built in MacChimney created by the side of the TwiggyBox and right across the hottest components of the A/B.

original post with dead pic attachment links

One day I'll have the thermal sensors or IR imaging to prove that point!

jt

Last edited by jt (2014-07-27 14:36:57)

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#7 2014-07-27 07:42:19

mcdermd
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From: Corvallis, OR
Registered: 2014-05-12
Posts: 1,022
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Re: MacGusto Upgrade Board

That all makes a lot of sense, actually.


Daily Drivers: 27" iMac 2.8 GHz Quad-Core i7 (Late 2009), 21.5" iMac 2.7GHz Quad-Core i5 (Late 2013), 11" Macbook Air 1.6 GHz i5 (Mid-2011)
See the restored heroes here.

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#8 2014-07-27 14:50:05

jt
Member
From: Bermuda Triangle, NC USA
Registered: 2014-05-21
Posts: 1,470

Re: MacGusto Upgrade Board

THX, If I can find the password for my iFrog account I'll try to find the pic of the Radius baffle and my sheet metal reconstruction of the TwiggyBox. I'm glad somebody finally read and understood what I was trying to say on the subject and commented on it. wink

p.s. Sorry for the tangent/threadjack, I hope it's related enough to your OP to be useful in preserving your very cool setup.

p.p.s. Admin's, it was refreshing to have been able to add one word and fix one typo to clear up that post this morning. Unlimited editing to fix typos, grammatical gaffes, dead links and  upload ephemeral iFrog pics to non-volatile iStorage would be about the only things I miss about about being promoted to lowly 68040 status elsewhere. smile

Last edited by jt (2014-07-27 15:26:28)

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#9 2014-07-27 15:44:48

jt
Member
From: Bermuda Triangle, NC USA
Registered: 2014-05-21
Posts: 1,470

Re: MacGusto Upgrade Board

Thanks, mcd! I was just musing about documenting the TwiggyBox Gambit while washing the short stack of dishes in the sink. Images of comparative videos of "smoke testing" the Visible Plus hack resolved themselves in in the ole' noggin!

I then visualized using the same stick of incense for the "smoke testing" emissions control!  big_smile

< /tangential threadjack mode: to be continued in Hacks  .  .  .  eventually hmm  >

Last edited by jt (2014-07-27 15:46:07)

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#10 2014-11-15 04:06:43

ddenowh
Member
Registered: 2014-11-15
Posts: 8

Re: MacGusto Upgrade Board

A friend and I are the developers of the MacGusto and MacGusto II RAM/SCSI/FPU upgrade cards for the Mac 128! It has been a long time since I thought about that but I am more than happy to answer any questions.
David Denowh

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#11 2014-11-15 05:05:59

jt
Member
From: Bermuda Triangle, NC USA
Registered: 2014-05-21
Posts: 1,470

Re: MacGusto Upgrade Board

Welcome aboard! smile

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#12 2014-11-15 14:17:42

LCGuy
Administrator
From: Sydney, Australia
Registered: 2014-05-13
Posts: 855

Re: MacGusto Upgrade Board

Welcome! smile We're honoured to have someone such as yourself, an engineer from back in the day on board smile

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#13 2014-11-15 21:00:00

ddenowh
Member
Registered: 2014-11-15
Posts: 8

Re: MacGusto Upgrade Board

Thanks guys! My friend Tim Vold and I worked on this back before the Mac Plus came out. We were upgrading 128K Mac's with 256K chips to begin with. Then we came up with the idea to expand more. We had the circuit boards built locally here in Rockford Illinois. We sold them as "kits" with the circuit board and all the parts needed to assemble into a working expansion board. It was for the true geek thats for sure! smile When we first made it I remember the RAM chips, 256K variety were very expensive but I can't put my finger on a number at the moment. I will ask Tim to see if he remembers what they were. There were 2 models as mentioned above, a 1Meg and a 2.5Meg version. That included the RAM already on the motherboard. If you had a 128K motherboard you needed to remove the existing 64K RAM chips and replace them with 256K RAM chips before attaching the MacGusto expansion. Both models had a SCSI interface and the MacGusto II used 1Meg RAM chips and also had a socket for a 68882 Floating Point Co-Processor. At that time in the Mac's existence the only software that used the Co-Processor was Microsoft Excel! We just put the chip on the bus and Excel saw and use it! It was amazingly fast.

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#14 2014-11-15 23:36:34

jt
Member
From: Bermuda Triangle, NC USA
Registered: 2014-05-21
Posts: 1,470

Re: MacGusto Upgrade Board

Oh so very cool. I don't see the equivalent of a Killy Klip, did you interface entirely through the ROM Sockets? Is the opening above the 68000 for cooling?

Did you make that SCSI<->MFM adapter card as well?


.

Last edited by jt (2014-11-15 23:39:45)

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#15 2014-11-16 15:24:03

ddenowh
Member
Registered: 2014-11-15
Posts: 8

Re: MacGusto Upgrade Board

When we first designed this board the Killy Klip either did not exist or was way too expensive for our project, I don't remember for sure. We used the ROM sockets for the bulk of the connections but we did need a few other signals which we picked up using some individual pin/socket connectors which were soldered to selected "thru-holes" on the motherboard. It was quite a project to install one of these but it was very secure yet still removable. And yes the hole in the board was for cooling. We did not do any "air flow" analysis or anything like that, just thought it looked like it would work!
As for the Hard drive, that was not one of ours. There was a product called HyperDrive for the Mac Plus so that may be one of those or it may have been home made by someone. I did install a couple of those for people so who knows maybe I did that one! There were a couple of popular MFM to SCSI boards back in the day. There was one by Adaptec and one by OMTI that worked well with the Mac. I believe the OMTI was an RLL controller which added 50% to the storage of the drive compared to the MFM if the drive was capable. I probably have one in my basement somewhere smile

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#16 2014-11-16 15:37:17

jt
Member
From: Bermuda Triangle, NC USA
Registered: 2014-05-21
Posts: 1,470

Re: MacGusto Upgrade Board

Damn straight it worked! The proc would have drawn air in from the sides of your board and boosted it up through your planar MacChimney. I'll bet it ran cooler than when it was before you did that conversion.

Were most of your sales to DTP houses?

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#17 2014-11-16 16:09:47

ddenowh
Member
Registered: 2014-11-15
Posts: 8

Re: MacGusto Upgrade Board

I agree it probably did run cooler. We never had one fail once installed and working. It was just such a simple design.
Since it was a "kit" I think we sold mostly to geeks and engineering types. We advertised in Dr Dobbs Journal. Remember there wasn't an Internet back then! At least not like we know it today. I just had a thought, I wonder if I can find our install guide. I will look for it and post it up here. I do still have a box of parts for these. Probably have a few dozen blank boards in the closet yet.

Last edited by ddenowh (2014-11-16 16:25:24)

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#18 2014-11-16 17:29:15

ddenowh
Member
Registered: 2014-11-15
Posts: 8

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#19 2014-11-16 21:54:48

ClassicHasClass
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From: Electron Alley
Registered: 2014-05-26
Posts: 1,118
Website

Re: MacGusto Upgrade Board

Excellent!!


Machine room (updated for 2019!): http://www.floodgap.com/etc/machines.html

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#20 2014-11-17 02:09:14

bbraun
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Registered: 2014-05-29
Posts: 1,064
Website

Re: MacGusto Upgrade Board

Awesome, thanks for sharing the manuals.  I'm increasingly finding that documentation and software is more difficult to come by than hardware!

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#21 2014-11-17 02:34:29

ScutBoy
Member
Registered: 2014-05-25
Posts: 159

Re: MacGusto Upgrade Board

ddenowh,

I think I found a whole 2 references to the MacGusto while combing Google, so have one of the creators pop up here is very cool!

The HD that was installed in my machine used the OMTI interface card, with a Seagate drive. A question of mine is how "standard" is the SCSI interface compared, say, to a regular Mac Plus? My thought for putting this thing back together is to use a regular 50 pin SCSI drive instead of going through the conversion from SCSI out of the MacGusto back to RLL/MFM (if I could even find a working drive). I only ask since I know the Mac Plus SCSI implementation was a bit finicky, and it seems plausible (and understandable) that this might be also.

I have to say that for a "kit" the board and the install are very well done. Seems much more robust than the killy clip solutions that were out there.

I look forward to going through the doc you posted. If you need a trip down memory lane, I can take more/better pics of the board I have.

Glad you're here!

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#22 2014-11-17 02:59:45

ddenowh
Member
Registered: 2014-11-15
Posts: 8

Re: MacGusto Upgrade Board

Very cool! The SCSI interface on our card is exactly the same as what was on the Mac Plus so any "Mac" SCSI cable that you have with the DB25 connector on one end will work on any 50 pin standard SCSI drive including CD's and tape drives if you have the software for it. There are resistors on the board and the SCSI system requires one set of resistors on each end of the SCSI bus. There can be 6 devices daisy chained to this machine.

I am wondering if the drive that you have is an MFM drive and the OMTI is an RLL controller. We used to get away with that from time to time but the MFM drives just could not be reliable running in RLL mode a lot of the time. It just depended on the overall quality of the platters I suspect. If you do not have or cannot find any cables I may have one in my stash I could send you if you like.

I have not thought about these boards in a long time and I appreciate the chance to think back on them! Very enjoyable smile Thank you.

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#23 2014-11-17 03:21:31

jt
Member
From: Bermuda Triangle, NC USA
Registered: 2014-05-21
Posts: 1,470

Re: MacGusto Upgrade Board

I double checked, Seagate ST-125 is MFM, I didn't trust my memory. roll

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#24 2014-11-17 03:38:26

ddenowh
Member
Registered: 2014-11-15
Posts: 8

Re: MacGusto Upgrade Board

You might try to let it warm up for a few hours and the drive may come around and work for a bit for you. Just leave it on for a while and then do a restart and see if it loads up. I am struggling to remember the model number of the OMTI board that I used to use but 3127 comes to mind.

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#25 2014-11-17 22:09:56

max1zzz
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Registered: 2014-05-18
Posts: 207
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Re: MacGusto Upgrade Board

ddenowh wrote:

I do still have a box of parts for these. Probably have a few dozen blank boards in the closet yet.

I have to ask, would you ever consider selling one of those boards? I think it would be a fun project to build one these and install it onto my one of my 512k boards smile

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