SuperMac PDQ, Spectrum 8, 24, Thunder ROMs

[David Cook]

I recently purchased a GQ-4x4 USB Universal Programmer for the purpose of reading video card ROMs and burning updating versions. The EPROM reader works well and is easy to use. https://www.amazon.com/dp/B011HVON3A

For the community, I am attaching six SuperMac Video Card EPROMs:
SuperMac Spectrum 8 24 PDQ v1.0
SuperMac Spectrum 8 Series III v1.2
SuperMac Spectrum 24 IV v1.6
SuperMac Spectrum 24 V v3.0.0
SuperMac Thunder 24 v1.7.0
SuperMac Thunder 24 v3.0.0

The last EPROM is included for completeness, as it had been previously uploaded to the forum by another user. I compared my copy to the earlier posted copy and they match. Based on this success, I assume my other ROMs are correct and usable since I used the same reader and process.

I would love to obtain a v3 ROM for the PDQ, Series III, or Series IV, because that version allows resolution changing via the Monitors control panel. If you have one of the ROMs, please upload it. If you don't have a reader, DM me and I would be happy to read and return your EPROM.



This Spectrum 8 Series III EPROM is a ST M27256.



This Spectrum 8*24 PDQ EPROM is a TMS 27C512. 200 ns? I obtained this card from Italy from @mgmac a couple of months ago. It works well! Thanks again.




This Spectrum IV uses a TMS-27C512 150 ns.

The video card seems identical to the Spectrum V. So, I copied the v3.0 ROM from the V board and installed it in the IV board. It works! I'd be interested if anyone knows the physical differences between the IV and the V.



The Spectrum V card was an eBay purchase. The board was heavy abused and looks like it was pulled from a discard pile. Components have corners broken and many pins were detached from their pins. Despite resoldering, cleaning, and careful inspection, the card does not work. Note the pullup resistor on U10 LS259. I'll cover that later.


This Spectrum V uses a NM27C512Q 200 ns EPROM.

Upon reading it, some of the text in the EPROM contents looked corrupted. Indeed, always click verify after a read! The EPROM was not reading consistently and verify at least will tell you if it read the same twice in a row. The pins had significant oxidation/tarnish. I used Deoxit, a pencil eraser, and final a scalpel to get a consistent read from the EPROM. As described earlier, I burned a copy and installed it in the Spectrum IV successfully. So, I believe this ROM image is valid.



This SuperMac Thunder 24 does not have a pullup on LS259.

This SuperMac Thunder 24 uses an AMD AM27C512 at 150 ns.

Wow! They sure used a wide variety of EPROMs. I guess this means you can substitute whatever compatible EPROMs you have laying around.



But this Thunder 24 card does have a pullup on U10.


Back to using a 200 ns EPROM. In this case, the NM27C512.


I have four SuperMac video cards with U10 using an LS259. I believe that is a 74LS259 8-bit addressable latch.





A 10 kilohm (brown, black, orange bands) resistor across pin 16 (Vcc) and pin 4 (Q0 output) would seem to provide a pullup to one of the outputs when the chip is not enabled. It will be overridden with the actual output signal (high or low) when the chip is enabled. I have no idea why this was needed, and why it was only needed on one output pin. Two of my cards have the resistor (V and Thunder with v3 ROMs), two do not (IV and Thunder without v3 ROMs). Was this a fix that SuperMac added to cards sent in the receive the upgrade?

Hope this information and the ROMs help you,

David

 

[mgmac]

beautiful work David, congratulations
I'm very pleased that my ex SuperMac has ended up in the right hands and is useful for all Mac users with your new EPROMs

 

[David Cook]

beautiful work David, congratulations
I'm very pleased that my ex SuperMac has ended up in the right hands and is useful for all Mac users with your new EPROMs

And thank you for selling your board to me!

 

[David Cook]

Attached is another SuperMac ROM. This is from a newly acquired SuperMac ThunderLight (or is it Thunder Light). I hadn't heard of this card before, although I now see it's existence is acknowledged on https://vintageapple.org/gamba2/vid-mon-matrix.html but without any details.

The card does not look like a SuperMac Thunder. Instead, it is identical to the Spectrum 24 Series IV and V boards.

The Spectrum 24 IV uses a 30.240 MHz crystal. The V and Thunder Light use a 40.000 MHz crystal.



However, unlike my Spectrum 24 boards, the Thunder Light has C5 (1 µF), R33 (100 Ω) and R33 (100 kΩ) populated.



Maybe if you have a Spectrum 24 Series IV card, you could swap out the crystal, add the three passive components, and swap in the Thunder Light ROM to get a Thunder Light card?

- David

 

[Compgeke]

Here's a link with Spectrum/8 Series III v1.30 and Spectrum/24 PDQ, both my own dumps: https://fsck.technology/software/ROM Dumps/NUBUS Expansion Cards/

 

[jeremywork]

Nice work, these lineage and ROM gathering threads are really useful!

I don't have any Spectrum cards at the moment, but in case it's handy here's ROM v3.0.0 for the Thunder II•1360.

I do have these two blurry auction photos for a "Thunder II Light" with ROM v3.1, but I didn't win that one.


Another tangent:
I spotted this on eBay recently. Seems like a Thunder/24 repurposed as a Spectrum/24 PDQ+ by Radius, also with v3.1, but not sure whether the ROM more closely matches the Thunder or Spectrum. Didn't pick this one up either, though.

 

[David Cook]

Back in 2009, Steve Blank posted a number of inside stories about SuperMac.

Steve Blank SuperMac

Posts about SuperMac written by steve blank

steveblank.com

One of those stories, "Rabbits out of a hat", discusses how they rebranded one board as nine. I think there is a little hyperbole there, but the point is that they were very good about reusing hardware. So, it doesn't surprise me that the Thunder Light and other such ROMs exist.

I didn't see either of those auctions on eBay. They must have been grabbed immediately.

 

[David Cook]

I just obtained a SuperMac Spectrum 24 PDQ Plus. It is physically different from the shorter Spectrum 8 24 PDQ pictured beneath it.



The board is revision B1, which must stand for "Bodge" as it has a pair of wires near the NuBus connector.



The PDQ+ has ROM revision 1.292


On a TMS 27C512-20JL EPROM.


The ROM file is attached.

- David

 

[David Cook]

There is a v3.1 ROM file floating around in a folder labeled Spectrum 24 PDQ (no plus). Inside the folder, the read me and the file contents indicate it is actually a Spectrum 24 PDQ+ (yes plus) v3.1 ROM. This is from Daniele Gratteri. I have attached a copy to this thread.

Burning a EPROM and putting it into my PDQ+ confirms that it works.

 

[David Cook]

Sometimes eBay taketh away, sometimes eBay giveth. A battery-bombed Quadra 650 held a fully working unicorn -- a Radius Thunder IV GX 1600 with DSP card.



The EEPROM (not EPROM) is labeled v1.2 but was already upgraded to v1.2.3 by the RadiusWare Mr. Flash updater.



I am including obnoxiously large images of the fronts and backs of both boards, as the DSP board is Rev B and I've only seen Rev A images online.

 

[olePigeon]

Does anyone know if the Thunder II GX 1600 has a ROM version that allows 16 colors?

 

[jeremywork]

Sometimes eBay taketh away, sometimes eBay giveth. A battery-bombed Quadra 650 held a fully working unicorn -- a Radius Thunder IV GX 1600 with DSP card.

View attachment 49950

The EEPROM (not EPROM) is labeled v1.2 but was already upgraded to v1.2.3 by the RadiusWare Mr. Flash updater.

View attachment 49953

I am including obnoxiously large images of the fronts and backs of both boards, as the DSP board is Rev B and I've only seen Rev A images online.

View attachment 49951View attachment 49952

eBay presented this listing to me but it was sold out by the time I had loaded it. Glad you snagged it!

I've been looking at the two revisions of DSP card and haven't yet spotted a difference...

Does anyone know if the Thunder II GX 1600 has a ROM version that allows 16 colors?

I can't confirm on this exact card, but SuperMac cards usually support 16 color modes (not to be confused with 16-bit color modes, which SuperMac cards generally do not support; opposite story for most Radius cards.)

 

[Bolle]

I've got both revisions and I'd say they are identical.
The Rev A came with a 1600, the Rev B is on a 1360.

 

[olePigeon]

@jeremywork I can confirm that my Supermac Thunder II GX 1600 does not support 4-bit color mode. I don't use it precisely because of that. Several of my games require 16 colors. It goes from 2-bit to 8-bit, with no option to select 4-bit 16 colors.

 

[slomacuser]

@jeremywork I can confirm that my Supermac Thunder II GX 1600 does not support 4-bit color mode. I don't use it precisely because of that. Several of my games require 16 colors. It goes from 2-bit to 8-bit, with no option to select 4-bit 16 colors.

Strange. Mine Thunder II GX 1360 with ROM 3.0 supports all color modes.

 

[olePigeon]

@slomacuser Ooooo. I'll pop my card in and check the ROM version. Maybe I just need a ROM update. I assume the 1360 and 1600 use the same ROM?

 

[jeremywork]

@slomacuser Ooooo. I'll pop my card in and check the ROM version. Maybe I just need a ROM update. I assume the 1360 and 1600 use the same ROM?

Strangely, only some of the Thunder cards had upgradeable ROMs.

In SuperMac's Thunder Q&A, under the 'My display reverts to black & white mode...' question:

SuperMac Thunder/24 & Thunder II Cards Q&A

Upgradeable cards are the Thunder II GX•1360, Thunder II and Thunder II•1360, Thunder II Light, Thunder/24, and ThunderLight. This ROM upgrade will also ensure Power Macintosh compatibility. ROM upgrades are available by dialing 800-977-7060. For the Thunder II GX•1360, order upgrade part # SK0006. For Thunder II and Thunder II •1360, order SK0007. For Thunder II Light, order SK0005. For Thunder/24, order SK0004. For ThunderLight, order SK0010.

Otherwise the document doesn't seem to indicate anything about upgrading the ROM on the 1600 cards. Other than I guess this catch-all in the final section:

2) Make certain that you have the latest ROM and software for your Radius product. Some ROM upgrades are FlashROMs which can be downloaded with the software for the card from online services.

Also, this got a bit tangled in my mind:

I can't confirm on this exact card, but SuperMac cards usually support 16 color modes (not to be confused with 16-bit color modes, which SuperMac cards generally do not support; opposite story for most Radius cards.)

The Radius cards usually lack 2-bit (4-color) mode;
The SuperMac cards usually lack 16-bit (Thousands) mode.
Other than some of the cards which don't support 16-bit or 24-bit, those two are the only common bit depths I've found skipped, so it's odd that @olePigeon's 1600 is missing more. Curious to see what ROM revision is currently running...

 

[olePigeon]

Well, the ROM isn't socketed on the GX 1600. But I wonder if that still means it's not upgradeable. It'd have to desolder it.

I'd provide a picture but my phone's rear camera & flash doesn't work. Hasn't worked properly since I bought it new, but I had assumed it was a software issue because I could get it work again by restarting. Now it just doesn't work no matter what. :/

 

[David Cook]

Well, the ROM isn't socketed on the GX 1600. But I wonder if that still means it's not upgradeable. It'd have to desolder it.

I'd provide a picture but my phone's rear camera & flash doesn't work. Hasn't worked properly since I bought it new, but I had assumed it was a software issue because I could get it work again by restarting. Now it just doesn't work no matter what. :/

On the Thunder IV GX 1600, the ROM is electrically programmable using the Mr. Flash software that came with the Radius software. Perhaps there is something similar for the SuperMac Thunder II GX 1600?

 

[David Cook]

Attaching three additional ROMs:
SuperMac Spectrum 8 24 v1.60
SuperMac Spectrum 8 SI v1.0
SuperMac Spectrum 24 PDQ+ v1.60 (For archive purposes. A better version, 3.1, is available.)

All three were on the same type of TMS 27C512-2 EPROM.



The PDQ+ was a newer revision (D1, as opposed to my earlier posting for B1). Yet, it has the same bodge wires to U43 as did the earlier revision.



- David