• Please review our updated Terms and Rules here

Intertec SuperBrain ROM Dumps

EagleTG

Experienced Member
Joined
Sep 19, 2015
Messages
231
Location
Near Allentown, PA
I was working with dmemphis today in an attempt to build adapters (and power circuitry) to read the 2716 EPROM from a SuperBrain. Additionally, we re-burned some "backups" to 28C16 EEPROMs and built the associated adapter to use these in a SuperBrain.

The ROMs we read seem to be previously unarchived. I have uploaded them to my website, but we intend to get these up on BitSavers, too.

Here are the links:
http://retro.togeo.com/files/SuperBrain 4_003 VC8001.Bin
This was from a SuperBrain and was labeled as 4.003 (and displays that version upon boot)

http://retro.togeo.com/files/SuperBrain QD 3_05.Bin
This was from a SuperBrain QD and was most boringly just factory labeled with the "Intertec" logo and proved to be version 3.05

For comparison, the ROM image that is up on BitSavers at http://www.bitsavers.org/pdf/intertec/firmware/SuperBrain.bin is version 3.1 according to the boot prompt. We are not sure if this a QD ROM or not.

In another thread, user snuci posted a ROM that was very similar to our v4.003 above, differing by 3 bytes as-follows:
Code:
Comparing files SuperBrain 4_003 VC8001.Bin and SUPERBRAIN_TMS2716C.BIN
000003F7: 55 56
000003F8: 0C 0A
000003F9: 08 07

Thanks!
 
In short, yes we did have the SB functioning.

I have two, one regular and one QD.
The regular one, which I bought as a parts machine actually works, I found recently.
However, it is in rough shape and though the boot drive worked once I did not want to use the drives again
without refurbishing them.
My SB QD is currently disassembled so we could not use it but we could use its drives which I
refurbished last year.

We proceeded take the known ROM images (from bitsavers, from snuci, and those we read from
my two SBs) and successfully program them to 2816 EEPROMs.
Then we tried all the EEPROMs in the working SB using an adapter socket EagleTG fashioned to run 2816 EEPROMs in the problematic TMS2716 sockets of the SBs. Results:

Snuci's 4.003 VA7001 image: WORKED. Seemed to work just like the 4.003 VC8001 EPROM that came with the SB.
(As EagleTG noted, there are three bytes different between them)
Image from my SB QD, internally identified as 3.05: DID NOT WORK. Printed a prompt then hung.
BitSaver's image: internally identifed as 3.1: DID NOT WORK. Printed a prompt then hung.

Here is a successful bootup from floppy using the Snuci ROM:
Before the drive door was closed: SB_Successful_Boot_4.003.jpg
Drive door closed: Snuci_4_003_EPROM.jpg
These are the screens from the versions that did not work:
BitSaver Image: Bitsaver_3_1_EPROM.jpg
My QD EPROM: MySBQD_3_05_EPROM.jpg

Summary:
All the 2816 EEPROMS made from available images appear to be functional PROM media in the SB sockets.
Snuci's ROM appears to function the same as the EPROM that came with the SB.
My QD 3-.5 and the BitSaver's 3.1 EPROM image seem to function equivalently bad.
Perhaps the BitSaver is in fact a QD ROM image, and a bit later revision than mine.
Since my QD ROM did not function in the regular SB, ROMS between these two types are likely not interchangeable.

This was a significant push forward from where we were a few days ago. We did all this without destroying an
existing original TMS2716 ROM and now have images and 2817 replacements for everything. We know what
ROMs work in a standard SuperBrain. Soon I will be swapping some parts to my QD from the regular model, and then can try the 3.05 and 3.1 EEPROMs in the QD.

Next we have to try to locate some of the enhancement ROMs that were offered :O
 

Attachments

  • IMG_1953.jpg
    IMG_1953.jpg
    106.3 KB · Views: 1
Last edited:
Glad it helped, dmemphis!

I was able to get one of my two SuperBrains up but didn't have a good boot disk. Still working on that. I did have a successful boot and it turned out that both of my ROMs were good and identical (I had originally seen all 00s for one). My second SB powered up with flickering floppy drive lights for about 10 seconds, then the "magic smoke" started pouring out :( I need to find a schematic (haven't had a chance to look around yet) but I originally saw some blackness around three pins on one of the 4116 memory chips but when I went to take it out, it looks like a diode (?) blew as it crumbled when I got close to it.

I'll have to find out what the value of that is as it is unreadable.

SB bad component.jpg
 
snuci,
From the photo you attached it appears that device is connected to Pin 1 of the 4116 Ram IC.
4116
Pin 1 Vbb -5 VDC
Pin 8 Vdd +12 VDC
Pin 9 Vcc +5 VDC
Pin 16 Vss GND

My guess is that it is a Capacitor as the Intertec Schematic shows 6 Bypass Caps on the first row of RAM IC's,
5 bypass caps on the next three rows of RAM IC's, and there are also 5 larger caps at RAM IC's
Z7, Z15, Z23, and Z31 (Z31 has one below it also). The unmarked decoupling caps are noted to be 0.1uF caps.
There are no diodes shown on the layout drawing around the area of the RAM IC's.
The print is unclear as to the value of the larger caps over the RAM chips. The best thing would be to unsolder
another one close to the blown one and measure it's value.

Larry
 
Your right. I was looking over the schematic on Bitsavers and it looks like it might be 10uF but it is blurry. At least I know the blurry markings are the same for each cap on that vertical row so I'll what you suggest.

By the way, I am not complaining. Blurry is better than nothing. I'm happy that the schematic is even there.

Thanks for the advise. I appreciate it.
 
SB QD Lives.

SB QD Lives.

Finally after two years of it sitting around, and a year ago since I gave up on fixing the power supply,
I have the Superbrain QD back together with pieces from the doner Superbrain.
So I was able to test the 3.1 ROM image. As fate would have it, when I did the first power on
with the original 3.05 ROM, I got NOTHIN. Oh No. It behaved like the ROM was dead.
But fate was also kind: I put in the 3.1 Atmel 2817 EEPROM in the adapter, and it sprang to LIFE.
Wouldn't you know my ROM would fail now? Bad handling? On the edge? We'll never know, but
at least we have the image file and we can make copies if we think we need it.
I neglected to make a 2816 EEPROM of the 3.05 image and EageTB has the burner.
So figuring out if that image is good (it probably is, it looked good but all bets are off) will have to wait.
But the 3.1 Image from bitsavers seems to be fine.
Here's the machine finally back in its glory:
IMG_1969.jpg
 
Last edited:
Socket Adapter to run a 2816 EEPROM in TMS2716 socket

Socket Adapter to run a 2816 EEPROM in TMS2716 socket

2816_to_tms2716_Adapter.jpg
 
TMS2716 Read Adapter

TMS2716 Read Adapter

Our adapter for reading a TMS2716 ROM in a more modern ROM programmer.
5V is coverted to + & - 12v, then -12v is converted to -5v.
TMS2716_Read_Adapter.jpg
(Ground of regulator wasn't solder well... that's fixed now :)
 
Last night I overlooked a 2816 containing the image from my original QD rom, 3.05 VC8001.
Good news, it works. So though my original QD ROM is non functional now, I know the ROM image is good.
It appears to operate the same as the bitsaver 3.1 version in the QD.
 
Hi,

I fixed a SB a couple of years ago, gave it back. But I did make a copy of the ROM if you're interested?

Cheers,
Josh Bensadon
 
So I take it that the TMS part needs -5v to read in a modern programmer, but most don't provide this voltage.

What ROM do you select in the programmer's software to read a TMS2716C? I presume 2816.

I drew up a schematic for the programmer adapter. The 5 pin header connects to the +5v to +-12v board.

TMS2716C Programmer read adapter.jpg

I also drew up a schematic for the Superbrain 2816 adapter that you fit to the motherboard so that the SB can read a 2816.

Superbrain 2816 EEPROM adapter.jpg

Could you check them to see if they are correct, please?

Thanks
JonB
 
This ROM adapter might be made to fit under the top cover of the Superbrain:

Superbrain ROM adapter.jpg

It all depends on the pins used to solder in the "legs" of the thing. The board needs to be as close to the Superbrain's motherboard as possible. I suppose it would be possible to remove the ROM socket from the SB motherboard and solder this directly to it - that should give clearance, at the cost of not being able to use a TMS ROM again. Not an issue in my opinion, because you can always dump the TMS ROM and program a nice shiny new 2816 EEPROM with the contents.

If you want to have a go, you can order them from OSH Park in sets of three. I've got one set of 3 on order (minimum quantity) so if any UK Superbrain owners fancy a card, let me know.

** DISCLAIMER **
Untested as of this post, so order at your own risk!
 
Last edited:
Here's my implementation of the TMS2716C reader for modern programmers.

IMG_0848.jpg

That's the Superbrain ACT HDD ROM sitting in the socket. Guess what I found when I attempted to read it in my TOP853 programmer?

View attachment SuperBrain V3.1 ACT HDD ROM.zip

Yep, looks like bit rot hasn't got it yet. And in this ROM we can see the following strings:

  • "3.1 INSERT DISKETTE INTO DRIVE Á", and (this is the money shot...)
  • "PRESS 'F' TO BOOT FROM FLOPPY, ANY OTHER KEY TO BOOT FROM HARD DISK"

The content might not be complete, but there it is.
 
Last edited:
That's nice to see! There's hope yet! Have you ever been in touch with that guy in the Netherlands who worked during the 1980's customising Superbrains with non OEM HDs and controllers, forget his name - seemed very knowledgeable if slightly reticent.
 
I'm guessing the answer will be yes as a google search led me back here to a long post and a guy named Roland Huissman. Seemed quite the expert, wonder what he'd have to say about your non standard HD setup?
 
Very nice JonB!

What is that adapter board (the PCB itself?)... Looks like something cool to know about.

Sorry for my delay in reply, but it looks like you have everything sorted out very nicely. Your schematics are very small thumbnails. Any chance to get a slightly higher resolution copy? Might not matter as it seems like you've confirmed they work.

Are you planning on any runs of the 2816 adapters? If so I might be interested.

Also, I have to apologize but I really don't remember what EPROM we used in the reader config to read the 2716. I would guess it was either 2516 or 2816. I remember we looked up pinouts of similar size and vintage EPROMs. I guess that you don't need that info, as it appears you read yours already. :)
 
Hi Todd

The board is a Z80 shim I designed for the uIDE general purpose Z-80 IDE adapter card, hacked about a bit. Read all about it here:

http://www.cpcwiki.eu/index.php/UIDE_Universal_IDE_adapter_cards_for_Z-80_computers

..and I will offer these cards to Superbrain owners with suitable drivers, once I have got mine running. Yes, you too can have a whopping 128MB of HDD space available to your Superbrain, maybe, for peanuts. Better days are at hand for Superbrain owners...

To the TMS27C16 adapters, then. I designed a proper PCB for both host and programmer adapters and sent them to OSH Park for fabrication. There's only three of each at this stage and they are (mostly) spoken for, but it's easy enough to get more. I would need to make sure they work properly first.. and fit; the host adapter doesn't really have enough space inside the Superbrain, unless the original socket is fully removed and the adapter is soldered into its position, but even then..

You're correct in that I have read my EPROM and it is OK (this is the special ACT HDD ROM). I posted a copy of the dump earlier on. To do this I set the programmer to a 2816 EEPROM and read. Worked first time, with the "red board" adapter (prototype). Since then I hacked up a host adapter out of pin header strips and jump wire, programmed a 2816, shoved it in the Brain's EPROM socket and attempted boot. Naturally, it didn't work! Not becasue the ROM is bad, or the adapter, but because the Brain is sick.

I have a Z80-ICE here and I can see that memory access is not working properly. I suspect it is something to do with the ROM paging logic. Do you know anything about it? I've been working with ldkraemer on this, he has been looking out for useful info and came up with this stuff from comp.os.com:

View attachment Superbrain Lobotomies.zip

In it a chap called Warren W. Gay muses about the EPROM of the Superbrain and how it works with the first and second CPU. I've not read it all, but I am very keen to work out how the memory paging is triggered (probably via I/O ports), then I can check mine is OK. It's frustrating, because all this has been done before, but the information seems to have been lost.

If you have any information on this, please let me know as I am at a bit of a standstill. The schematic confuses me!

Cheers
JonB
 
Last edited:
Back
Top