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View Full Version : Superbrain vs. Model xx



falter
October 13th, 2017, 06:52 AM
Googled around for a bit but couldn't find answers. The Intertec Model xx machines (30, etc)... are these successors to the Superbrain? Are they massively different in any way?

krebizfan
October 13th, 2017, 07:33 AM
http://www.classiccmp.org/dunfield/supbrain/index.htm indicates that the Model 30 is identical to the Superbrain II.

Intertec also had a proposed HeadStart which was a portable 8088 and Z80 system using 3.5" disks and nothing like the Superbrain line. There were a number of other systems designed by Intertec before reinventing themselves as an IBM PC clone maker under the name Wells American. I don't have information about them.

falter
October 13th, 2017, 08:00 AM
Thanks! Is there anything more desirable about the original Superbrain vs. the II?

krebizfan
October 13th, 2017, 08:18 AM
Original Superbrain was first so it has that. Otherwise, II is just a modest improvement on the design which started with 64k of RAM and better shielding. Either one would be fine for most purposes and a challenge to differentiate without opening the case.

There was also the related Intertube II (same basic design with no drives as a terminal) and Amoeba (16k version with built-in cassette as word processor) which can be potential sources of spare parts. The Amoeba seems to be very scarce.

JonB
October 15th, 2017, 12:14 PM
Superbrain II has lower case descenders. I think also definable character sets (don't quote me on that!)

I actually thought the 30 was equivalent to a QD. I have a Compustar 30 boot disk and it runs on my QD spec SB I perfectly. Gives auto repeat on the keys, too.

Why do you ask? About to acquire one?

falter
October 16th, 2017, 12:09 PM
Was thinking about it. Haven't been huge on CP/M machines in the past but the Superbrain is just a neat looking machine and the later models look about the same.

JonB
October 16th, 2017, 10:23 PM
Well do it, then! :)

They're nice machines, albeit with non standard CP/M implementation, caused by the way the hardware is set up. There is no MOVCPM.COM because it has fixed areas in upper RAM for the floppy drive buffer. It's got a sort of shared memory thing going on so that sectors read by CPU2 (which controls the floppy drives) can be passed to CPU1 (does this using bank switching). The net effect is that it is not easy to extend the BIOS when you want to add new hardware (as I do). Also of note are the undocumented routines in the BIOS. One does initialisation, the other manages disk access. Other than those, we have all the source of the various BIOSes.

On the plus side, though:


They are quite pretty, especially if you get one in decent condition. Impressively huge, though!
The case doesn't suffer from yellowing as it is a painted surface, although the keys do.
Keyboard is really nice to use (especially after a good clean).
There is a lot of stuff out there for it, including BIOS and boot ROM disassemly and different versions of CP/M.
There are a large number of useful hacks (for example, to make the floppies only start up when accessed) which are easy to do.
The white phosphor screen is very clear and easy on the eyes.



I think the main thing when you get one is to recap the PSU immediately. There are a lot of capacitors on that board, all of which can fail. The CPU board is sensitive to noise and electrostatic damage. If the machine hasn't been turned on for a while, check the power lines for short circuits before plugging in. There are tantalum capacitors which can fail and short circuit. They are near the RAM banks and look like diodes. Also, the boot ROM is a TMS2716, non standard thing that modern programmers can't handle. Occasionally you get corruption in the ROM which prevents boot up. If this happens, you can get an adapter board (from me) that allows you to fit a modern EEPROM to restore the boot.

Schematics are available.

Minimum spec to look for should be a Superbrain I QD. A II would be nice, but check the disk capacity. 340k per disk should be the minimum.

dmemphis
November 11th, 2017, 04:47 PM
Jon speaks the truth!
We have suffered through Superbrain woes here but several of us are big fans.
There is (or was? where did all the old posts go? ah- I see- in the archive) a lot of good reading on it all in
this forum.

JonB's post reminds me that though mine works its time to pay attention to the old caps to keep it working!

JonB
November 12th, 2017, 12:25 AM
Question is, did he get one?

falter
November 12th, 2017, 08:04 AM
I put in an offer on the Model 30 that is on ebay. I didn't like the photos.. it looked rusty.. like it has been under water. The seller insists it's just grime and took some photos with it cleaned up a bit. They autorejected my offer but suggested for a bit more I could have it. I don't know what it's worth rrally and it isn't *the* Superbrain so I'm kind of waiting them out a bit... see if they get more flexible on price. I have seen actual Superbrains go for $500-800 recently.

JonB
November 12th, 2017, 12:33 PM
They don't rust as the case is made of plastic (of sorts). However, the paint finish can get damaged. I have one here that looks like it's rusty, but it is just the textured plastic showing through the paint (the plastic is light brown, paint is off white). No idea how it got like that...

If it is the one being sold by wehaveelectronics, the main problem is acquiring the missing keys. The keyswitches themselves are pretty common, so broken stems are no bother. It looks OK, a bit grimy but no rust as such. The keyboard surrounds do go like that, they're a funny textured matte paint, brown on the earlier models, grey on the later ones.

The other one being sold by heatheteniso_0 looks bad but it is a Superbrain II in effect (2 ROMs) and has some sort of extension card. Definitely a good one. Sure, the front is filthy and you might need to strip and respray, or it may come up with a good scrub. However, it is obviously broken. I'd be surprised if it fetched $450. If you're confident fixing it I'd say go ahead.

On the other hand, the one I bought earlier on this year cost 160 in a UK auction (not "Buy it Now"). It needed many repairs, but now is doing well. Expect both of these to be relisted many times over; maybe the owners will see sense in due time.

Chuck(G)
November 12th, 2017, 12:41 PM
High-density PU foam, perhaps? About the color of the foam on a root beer ice cream float. Great stuff; doesn't need expensive mold tooling; usually painted (the baby-dumpling brown color is unappealing), strong, resists cracking and yet you can drive an ordinary staple into it.

snuci
November 12th, 2017, 12:47 PM
One of my Superbrains has paint flaking off of the base. It was a very smooth plastic surface so they either used bad paint or the paint just didn't have much to stick to.

JonB
November 12th, 2017, 12:48 PM
It's a sort of recycled plastic. I read that Intertech made a big thing of its green creds. May be foam, but it is hard as nails. Not sure a staple would go into it!

snuci
November 12th, 2017, 12:53 PM
It's almost like a fibreglass but it's heavier.

falter
November 12th, 2017, 03:24 PM
They don't rust as the case is made of plastic (of sorts). However, the paint finish can get damaged. I have one here that looks like it's rusty, but it is just the textured plastic showing through the paint (the plastic is light brown, paint is off white). No idea how it got like that...



Yeah I wasn't so much worried about the case as I was about the ports on the back (DB25, etc). To my eyes, they looked rusty. And usually when there's rust there, it means there's the potential for rust inside the machine, ie traces, etc. and may speak to it being stored in bad conditions. At least that's been my experience. In the event, I asked the seller about it and they said it wasn't rust, but then pulled the pic down. They did, however, do some cleanup on the case and took some pics of that and the inside, which was appreciated.



The other one being sold by heatheteniso_0 looks bad but it is a Superbrain II in effect (2 ROMs) and has some sort of extension card. Definitely a good one. Sure, the front is filthy and you might need to strip and respray, or it may come up with a good scrub. However, it is obviously broken. I'd be surprised if it fetched $450. If you're confident fixing it I'd say go ahead.


Yes it's the heatheteniso one. I think I could fix it.. I've (with considerable help from others here, or occasionally on my own) managed to get other machines going in similar or worse shape. I think the sticking point for me, especially after buying this hantavirus nest of a terminal from another seller, is that pictures may be deceiving. And the other thing is, yeah, it's more or less a Superbrain II, but it doesn't say 'Superbrain'.. to me, that gives it less cachet than one with that one word on the badge. And since I have limited space, if I'm going to have a Superbrain in the collection I'd kind of like it to be an actual Superbrain, unless the price differnce is enormous. I realize it's all in my head.. but to me I see this Model 30 and just think.. ah.. that's just another generic CP/M machine in Superbrain form factor.

Chuck(G)
November 12th, 2017, 03:47 PM
Well, I never fooled with a Superbrain, but I did use an Interterm III for awhile. It definitely did have a high-density foam case.

http://terminals-wiki.org/wiki/images/f/f8/Intertec_Intertube_III_CL_4775431940-1.jpg

JonB
November 12th, 2017, 10:39 PM
I realize it's all in my head.. but to me I see this Model 30 and just think.. ah.. that's just another generic CP/M machine in Superbrain form factor.

You're the buyer - and the buyer is always right... :)