I have a number of Quadra 630 computers. Recently, I picked up a spare board that motivated me to take a closer look at some of the differences.

Thus far, I have found three different boards in Quadra/LC 630 series of computers:
820-0548-B (the most common). One double-bank RAM slot. One unpopulated PCB footprint for a ROM. This is not a RAM slot!
820-0548-A. Same as the B board with some bodge resistors.



820-0624-A. Photograph below. This has one double-bank RAM slot (same as earlier boards) but the ROM slot is replaced with a single-bank RAM slot. The ROM version is slightly different as well.

Besides the left slot for RAM, compare the three circled areas in the photo above to the three circled areas in the photo below. (The copper heatsink was added by me and is not factory.) Most obviously, the reset button has moved, some chips came from the backside to the front side, and a small expansion slot was added.



You may get lucky and get the two-RAM-slot board in late manufactured 630s. It is the same board as used in the LC/Performa 580 series. Or, you can just buy the undesired 580 and use that board in a Quadra 630. It slides right in.

The added slot ("External Video Connector Slot") is intriguing at first, as it seems designed to allow the Performa 580 (with its built-in monitor) to produce an additional video output. However, in my testing, it only mirrors the video. I'm not sure why this would be valuable (other than 'presentation' mode). With two monitors connected, the Monitors control panel only shows one monitor. And, the display resolution is controlled by the monitor/adapter you connect to the primary video connector. That is, I chose 832x624 on the primary output but 640x480 on the added output. Yet, both displayed the identical image at 832x624.

When I booted with a monitor only connected to the added connector, nothing was displayed although the computer booted normally. If your LC 580's built-on monitor dies, you should be able to get video out on the added connector, as I assume the Mac will still see the internal monitor as connected.

The Macintosh LC 580 / Performa 580CD Service Source confirms the mirroring. Does anyone have the "Developer Note" for this model?



Video cable 922-1520 works in the slot.



Here is a close up of the video PCB. Maybe the Valkyrie video chip supports multiple monitors and just need to be triggered by a different circuit? The 1 MB of DRAM should be enough space for two 832x624 monitors at 256 colors.






Main Memory

Unlike what is listed in the Wikipedia article and Apple's official specification (and silkscreened on the newer board), you can put a 128MB 72-pin SIMM in the rightmost RAM slot to get 132 MB of RAM (4 MB onboard + 128 MB) for the earlier boards. You can also add a 64MB single-bank 72-pin SIMM to the left slot on the newer board to get up to 196 MB (4 + 128 + 64). This translates to 200,704K (196 * 1024 ).



This amount of memory takes about a minute and a half to check at cold boot.

Bodges

The 820-0548-A board has some very craftfully-placed SMD resistors bodged onto the video memory.



That's a 0-ohm (i.e. wire) resistor from Vcc leading to a pair of 100 ohm resistors leading to some input(?) pins. So, strong pullups on a couple of pins.



The next bodge is a little more frightening. I noticed that most of the earlier boards have a pair of 0-ohm SMD resistors on GC3.



One board did not.



What in the world? What kind of magically analog-ground-plain nonsense is this?

On the newer board, it seems like they cut off that end of the ground plain?



Ready for the alarming secret? They did NOT cut off the pad above. The metal prongs have shifted forward.

Looking at the bottom of the board, because the ground contact spring is not soldered in place, it can shift forward and back and make contact with a component, trace, or pad. In the case of the earlier (standard) Quadra 630 boards, R151 is apparently located in the no-go zone. Therefore, the two 0-ohm bodge resistors are installed to physically stop the ground contact from being able to shift far enough to cause a short. Ooops!



The newer board design moved components away from this location.

I know other people have had strange experiences with the ground-contact springs, such as lack of playing sound in the Color Classic. But, maybe there are other boards where Apple made layout mistakes in not respecting the shifting springs? It might be worth it for the community to look.

Non-Factory Bodge

The last interesting thing is a standalone board on bought on eBay. The 68040 had a heatsink. But, the chip socket does not have the notches for a heatsink to attach. It appears that a fellow enthusiast decided to upgrade from a 68LC040 to a full 68040. Yet, they only had a chip rated for 25 MHz. So, they 'secured' the heatsink with a lot of paste.



By the way, the Quadra 630 / Performa 580 boards support overclocking to 40 MHz. See:

I tried using the software overclock control panel / extension that have been floating around. But it only targets the 475-type boards.

- David

>> David Cook said:

I have a number of Quadra 630 computers. Click to expand...

They're great little computers :) I really like them. They were super cheap when all other 040s had gone expensive, but will punch blow for blow with a Quadra 800 in most benchmarks, and have some cool upgrades available. Overclocked to 40MHz they out benchmark an 840av.

>> David Cook said:

820-0548-B (the most common). One double-bank RAM slot. One unpopulated PCB footprint for a ROM. This is not a RAM slot! 820-0548-A. Same as the B board with some bodge resistors. Click to expand...

These ones are easy to overclock with just a resistor swap. They'll take a 128MB RAM SIMM for 132MB total.

>> David Cook said:

820-0624-A. Photograph below. This has one double-bank RAM slot (same as earlier boards) but the ROM slot is replaced with a single-bank RAM slot. The ROM version is slightly different as well. Click to expand...

Initially this board was used in DOS compatible machines, although Apple clearly just started using it sometimes, and then progressively more of the time, as time went on. For the DOS compatibility board, you need the GIMO port and the locations to mount four standoffs around the CPU. You can see the four holes.

The second RAM slot only takes single bank SIMMs because the other bank is used for onboard RAM, so it will generally take... 4, 16 or 64MB SIMMs, giving you a total of 196MB of RAM. Edit - sorry, as you said.

>> David Cook said:

the reset button has moved Click to expand...

I... I think this is a CUDA reset button, rather than a logic board reset button... I'd need to double check.

>> David Cook said:

The added slot ("External Video Connector Slot") is intriguing at first, as it seems designed to allow the Performa 580 (with its built-in monitor) to produce an additional video output. However, in my testing, it only mirrors the video. I'm not sure why this would be valuable (other than 'presentation' mode). With two monitors connected, the Monitors control panel only shows one monitor. And, the display resolution is controlled by the monitor/adapter you connect to the primary video connector. That is, I chose 832x624 on the primary output but 640x480 on the added output. Yet, both displayed the identical image at 832x624. Click to expand...

While labelled "External Video Connector Slot" in that document, as mentioned above, this was officially called a "GIMO" slot... I forget what it stands for. Video mirroring was useful in a school setting - teacher could see their screen and project, that is the main reason it exists, but... what you've overlooked is the GIMO port is both input and output - the reason this board was needed for the DOS Compatible 630 is that this is where the DOS card's video is injected into the host motherboard! This means you don't need the weird Y cable that you need with the 6100.

>> David Cook said:

The Macintosh LC 580 / Performa 580CD Service Source confirms the mirroring. Does anyone have the "Developer Note" for this model? Click to expand...

I swear... I've seen it somewhere. Can't see it after a quick search, perhaps it was on one of the CD images?

>> David Cook said:

Video cable 922-1520 works in the slot. Click to expand...

@daanvdl has kindly reverse engineered this with modern components and shared the design. https://github.com/daanvdl/M4099LL-B

The same cable works in everything from the 630 (with the 580 style logic board only) through to the TAM, via the 6200, 6300, 6400 and 6500, plus weird things like the 4400 and even the 7200 and 8200. Plus all the 5**/* equivalents where applicable.

>> David Cook said:

Here is a close up of the video PCB. Maybe the Valkyrie video chip supports multiple monitors and just need to be triggered by a different circuit? The 1 MB of DRAM should be enough space for two 832x624 monitors at 256 colors. Click to expand...

I believe it is mirroring only on all computers that use this cable. It really does seem to be for connecting projectors or a bigger external monitor.

>> David Cook said:

Unlike what is listed in the Wikipedia article and Apple's official specification (and silkscreened on the newer board), you can put a 128MB 72-pin SIMM in the rightmost RAM slot to get 132 MB of RAM (4 MB onboard + 128 MB) for the earlier boards. You can also add a 64MB single-bank 72-pin SIMM to the left slot on the newer board to get up to 196 MB (4 + 128 + 64). This translates to 200,704K (196 * 1024 ). Click to expand...

Ah sorry - forgot that you mentioned this when I commented above! :)

The issue is that Apple Supported and "Works" aren't the same thing. People get muddled and quote what Apple tested prior to release and confirmed working, as the definitive values. One of the worst instances is the LC 475 - officially it supports 36MB... but will take a 128MB SIMM for 132. That's like, a 300% increase :ROFLMAO: (or 400% if you look at it like that).

I tried to document some of the real values here : https://elephantandchicken.co.uk/stuffandnonsense/?p=2439

>> David Cook said:

I know other people have had strange experiences with the ground-contact springs, such as lack of playing sound in the Color Classic. But, maybe there are other boards where Apple made layout mistakes in not respecting the shifting springs? It might be worth it for the community to look. Click to expand...

That is extremely interesting.

>> David Cook said:

The last interesting thing is a standalone board on bought on eBay. The 68040 had a heatsink. But, the chip socket does not have the notches for a heatsink to attach. It appears that a fellow enthusiast decided to upgrade from a 68LC040 to a full 68040. Yet, they only had a chip rated for 25 MHz. So, they 'secured' the heatsink with a lot of paste. Click to expand...

The Quadra version did ship from factory with a full 040 (unlike the Quadra 605), but as you realise, given the 25MHz chip, this is obviously someone's home upgrade.

>> David Cook said:

By the way, the Quadra 630 / Performa 580 boards support overclocking to 40 MHz. See: Click to expand...

Hum... are you sure the 580 does? I thought the mods weren't documented for the 580 and Apple had removed the resistors used for that part of the circuit. It should be still technically possible, but you'd have to do a bit more detailed work, likely cut traces and some investigation to work out exactly what. I was going to do mine, but didn't want to overclock my DOS card. Effectively, my belief was that the 580 board is hard wired for 33MHz, while you can switch the speed on the 630 board (i.e. the single slot one).

Its perfectly do-able - you'd just want to cross reference the Quadra 605 schematic and the arrangement on a standard 630.

Yes, you can bump the 580 type to 40MHz, I was wrong.

>> David Cook said:

I tried using the software overclock control panel / extension that have been floating around. But it only targets the 475-type boards. Click to expand...

The soft overclock method is theoretically possible on the 630, but sadly we don't have documentation on the F108 chip used in the 630 if they moved the registers. Have you actually tried it in the 630? I actually have the 630 undocumented in the Extension's whitelist to allow testing "just in case". I can't remember if I removed it later though. You'd need to do it on a stock 33MHz machine as I don't think I added the machine ID for a 40MHz machine.

I've tried it on a 6200 and it didn't work, so I never actually got around to it and tested on a stock 630 (mine are all overclocked and I couldn't remember the overclocked gestalt when I was writing the list).

Sorry for the rambling reply :)

Hum, and just to collect info in one place. Here is a few more ramblings about upgradability :

The Performa 630 family have quite a lot of expansion slots. As well as an IDE (great for Compact Flash disks) hard disk and SCSI CD ROM bay (not always fitted from factory) they also have...

• Built in IR that works with a remote - this even allows you to power on and off the computer! As well as control CD and video playback.
• As mentioned, a full FPU 68040 can be fitted to machines which didn't ship with one (everything other than Quadra branded machines).
• Optionally, a UHF (TV) input module, or the fancy option, a UHF and FM Radio module. This goes in a weird place in the case that needs you to take a lot of the machine apart.
• An AV card (needed if you have the above I think) that lets you do video and audio capture. This has a dedicated slot on the far right, near-side (looking from the edge connector side)
• An MPEG hardware acceleration card that goes in the LCPDS slot and has a bridge cable to connect to the AV card - take care, there are two types of AV card and only the older one has the correct connector. While the newer ones work otherwise, they are designed for newer machines such as the 6400 and 6500 and their internal connection is actually a DAV connector designed to work with (usually) the PCI Avid card these machines could be bought with.
• A Commslot 1, for modem, or more usefully, an ethernet card. On the far left (looking from the edge connector side)
• As well as the GIMO video out (mirroring) cable, a thirdparty actually made some kind of GIMO video input module that uses the same rarely used breakout opening on the back. I've only heard of them online and have never seen one.
• The DOS compatibility card. This only works with the 580 style boards as it needs the GIMO port and the mounting positions. It uses the LCPDS slot for some functions, but actually the card itself plugs directly into the CPU socket and the 040 is moved to a socket on the DOS card. Video goes from the DOS card into the GIMO port and no external Y cable is needed. There is a joystick port on the back of the LCPDS card, which sadly doesn't support MIDI. The card is functionally equivalent to the card for the 6100 with a 66MHz 486 and a SoundBlaster 16 module. Be warned that the opamps on the SoundBlaster sometimes fail, so if sound out is distorted, that might be the cause. There is a single 72pin RAM slot on the DOS card which can optionally be used to fit dedicated RAM. Don't bother fitting a Intel Overdrive 100MHz chip because the DOS card is a huge bottleneck (no cache, slow graphics) and you barely see any improvement, considering you just dropped a fortune on a hard to get chip (ask me how I know). Note that due to the socket that Apple fitted, you can use the slightly cheaper DX4ODP100 chips, as well as the DX4ODPR100 chips.
• Other LCPDS cards - it has the extended later LCPDS type connector as you'd expect. Because the LCPDS slot is on a bridged 030 style bus, this slot isn't compatible with CPU upgrades (not sure why you'd want to use one - they'll do 40MHz and have an 040 anyway), but video, sound, ethernet... etc cards work fine.
• PowerPC Upgrade. The same PPC upgrade card that fits the LC 475 / Quadra 605 also works in the Performa 630 family. It was available in 66 and 100MHz, from Apple (only the 66MHz I think), Daystar and later, Sonnet.
• Logic boards from the 6200 and 6300 are a direct swap (and the 5200 / 5300). Logic boards from the 6400 and 6500 (etc.) can be made to work, but you need to account for the fact that the 6400 and later need 3.3v for PCI, and this goes through the edge connector. You would probably want to modify the loom, or inject 3.3v into the logic board using a 3.3v regulator on the 5 or 12v rails from the PSU.

>> phipli said:

Hum... are you sure the 580 does? I thought the mods weren't documented for the 580 and Apple had removed the resistors used for that part of the circuit. It should be still technically possible, but you'd have to do a bit more detailed work, likely cut traces and some investigation to work out exactly what. I was going to do mine, but didn't want to overclock my DOS card. Effectively, my belief was that the 580 board is hard wired for 33MHz, while you can switch the speed on the 630 board (i.e. the single slot one). Click to expand...

I used to have a Performa 580CD with two RAM slots which I was running at 40MHz. I forget what guide was used but I don't recall having any issues following whatever instructions and bumping the speed up. The pictures in the Schrier speedup instructions look mighty familiar. My understanding was that it is basically the same as the dual slot 63x boards.
I don't have that 580 to reference anymore, but I do have a 630(one RAM slot) and 631 (two RAM slots).

>> Oelmuvun said:

I used to have a Performa 580CD with two RAM slots which I was running at 40MHz. I forget what guide was used but I don't recall having any issues following whatever instructions and bumping the speed up. The pictures in the Schrier speedup instructions look mighty familiar. My understanding was that it is basically the same as the dual slot 63x boards. I don't have that 580 to reference anymore, but I do have a 630(one RAM slot) and 631 (two RAM slots). Click to expand...

You're entirely correct, I've just got muddled at some point in the past. Thank you for making me look. It is a pain to look because I have the DOS card installed and the resistors are under there.

A DOS Compatibility setup for anyone interested :




This poor machine has had a rough life. It was struck by lightning, and then left outside in the rain... all before I got my hands on it. The negative voltage rail was dead. It had shorted and killed the regulator after the lightning vaporised half the modem serial port and tried to take some of the DOS sound card with it.

>> Oelmuvun said:

I used to have a Performa 580CD with two RAM slots which I was running at 40MHz. I forget what guide was used but I don't recall having any issues following whatever instructions and bumping the speed up. The pictures in the Schrier speedup instructions look mighty familiar. My understanding was that it is basically the same as the dual slot 63x boards. I don't have that 580 to reference anymore, but I do have a 630(one RAM slot) and 631 (two RAM slots). Click to expand...

I worked out what the confusion was and the reason I had thought it wasn't possible....

The resistors are on the bottom of the 630 style board, and on the top of the 580 style board. Basically I'd gone looking in the same place and found only one of the four resistor footprints.

Don't know the switchover date, but by introduction of the 6360/6400/5400 Alchemy generation the backplane opening had been switched over to PCI card support as in the DOS version pic @phipli posted above. That makes it easy to spot late production boards, even in external only pics on eBay.

I've got a soft spot for the Q630, got it brand new at first release along with cards meant for dealer installation at Tekserve. It was the rug rat's bedroom AV Unit/HomeWorkStation and my late night graphics machine while he was asleep.

Apple dropped long running Portrait support in the Q630, probably due to potential blockage of the cooling fan.

>> phipli said:

I tried to document some of the real values here : https://elephantandchicken.co.uk/stuffandnonsense/?p=2439 Click to expand...

I can confirm the Power Macintosh 4400 can indeed reach 160 MB of RAM.

[Image: Power Macintosh 4400 RAM.GIF]

Here's a treat for @daanvdl if he hasn't already seen it. The Interware GrandVimage 17DU LC slot video card has a connector that installs in the video slot.



This enables a variety of choices for monitor output. Going left-to-right and then the second row:
1. Disable the internal monitor and just output to an external monitor using the Vimage card.
2. Dual monitor.
3. Display both internal and Vimage video on the internal monitor.
4. Disable the Vimage card and just use the internal monitor.



Here is a close up of the video slot connector. Note the cut traces and bodge resistor.



Back side with bodge capacitor and flux that has not been cleaned.

Photos of the GrandVimage 17DU card. Bodge crystal and bodge diode.



Nice choice of resolutions.



80 MHz clock and 1.5 MB of VRAM.

>> David Cook said:

3. Display both internal and Vimage video on the internal monitor. Click to expand...

A short update: I tried this video mode. I thought it was going to be some weird split screen or require a toggle key.

The Vimage card is set to the same resolution as the internal video. When you scroll the mouse cursor to the side of the internal video screen, the image switches to where the Vimage monitor would have been located. For example, imagine that you had the second monitor (Vimage) to the right of the primary monitor. When the mouse moves just off the right side of the primary monitor, the video image switches to the Vimage card and cursor jumps to the far left, as though you had just turned your head to follow it to the second monitor. It is a cool effect that works pretty seamlessly.

Very interesting, reminiscent of Virtual Desktop features of early VidCards supporting far higher resolutions than their RAMDAC and contemporary displays could support. What's the highest resolution that card can support on its external connector?

>> Trash80toG4 said:

Very interesting, reminiscent of Virtual Desktop features of early VidCards supporting far higher resolutions than their RAMDAC and contemporary displays could support. What's the highest resolution that card can support on its external connector? Click to expand...

1152x870 is the best I ran across. However, with 1.5 MB of VRAM, I would think it could do more at 8-bit color.

A Contemporary 21" CRT sitting center stage beside a 5x00 would make a very nice setup. ;)

>> David Cook said:

1152x870 is the best I ran across. However, with 1.5 MB of VRAM, I would think it could do more at 8-bit color. Click to expand...

Looks like it has pads to take up to a total of 3MB.

>> croissantking said:

looks like it has pads to take up to a total of 3MB. Click to expand...

I saw that. :p

Ebay only has the 'J' package. It looks like this needs the 'TR' package. "TC528257TR" I guess I could get a quote through Octopart

>> David Cook said:

I can confirm the Power Macintosh 4400 can indeed reach 160 MB of RAM. View attachment 20720 Click to expand...

Excellent, thank you! I'll update the page.

I'd like to get a 4400 some time, just because of their weird-ness. I keep being tempted by bare boards on eBay. :)