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VEB Robotron - Any opinions?

MCollins

MCollins

Experienced Member
Joined
Mar 27, 2025
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64
Location
Ohio
Hello everyone! Does anyone have any experience with VEB Robotron computers? As an American, I'm most knowledgeable about IBMs, Commodores, Radio-Shacks, Dells, Gateways, and others, however, I'd love to know more about ones from Eastern Europe, particularly Robotrons. If anyone has one, please tell me about it! Specs, programs, capabilities, general use, fun aspects; anything would be appreciated! Thank you!
 
Not sure what you are after. There are two main lines of PC Compatibles. A7150 - 8086 somehow compatible on DOS level and the EC1834, that is almost an XT Clone. The fun part with EC1834 is that they use an NEC7220 graphics controller to emulate a CGA compatible Graphics Card. So you have a 640x480x16 Resolution plus CGA compatibility modes.
What I find most intriguing in Eastern Europe the 8088 was never seen a real option for a CPU. Only 8086 type has been used for speedup that comes with 16-bit databus.

Here is the complete overview.
 
OLI-FIX said:
Not sure what you are after. There are two main lines of PC Compatibles. A7150 - 8086 somehow compatible on DOS level and the EC1834, that is almost an XT Clone. The fun part with EC1834 is that they use an NEC7220 graphics controller to emulate a CGA compatible Graphics Card. So you have a 640x480x16 Resolution plus CGA compatibility modes.
What I find most intriguing in Eastern Europe the 8088 was never seen a real option for a CPU. Only 8086 type has been used for speedup that comes with 16-bit databus.

Here is the complete overview.
Click to expand...
That's exactly what I'm after! It's really interesting they chose for it to be CGA compatible. It would be telly interesting how many other models Robotron made had the same controller. It's also wild they chose against using the 8088 chips. Thank you!
 
The choice of 8086 over 8088 seem straight forward. Since the maximum frequency of any CPU were limited to somewhere around 5 MHz and cycle time of a DRAM between 250ns and 450ns. The only way to get much improvement is to increase the bus size from 8 bit to 16 bit. In that sense a "16-bit" CPU would allow 2x the calculating speedup.
Our taiwanese or japanese colleagues instead choose to increase clock frequency. By 1990 8 MHz CPUs 8088 were available at low cost.
The CGA compatibility was about some registers, palette or memory layout, probably VSYNC, base on the fact that many programs access the HW directly. If you want to have some fun you may check the schematics for details:
 
OLI-FIX said:
The choice of 8086 over 8088 seem straight forward. Since the maximum frequency of any CPU were limited to somewhere around 5 MHz and cycle time of a DRAM between 250ns and 450ns. The only way to get much improvement is to increase the bus size from 8 bit to 16 bit. In that sense a "16-bit" CPU would allow 2x the calculating speedup.
Our taiwanese or japanese colleagues instead choose to increase clock frequency. By 1990 8 MHz CPUs 8088 were available at low cost.
The CGA compatibility was about some registers, palette or memory layout, probably VSYNC, base on the fact that many programs access the HW directly. If you want to have some fun you may check the schematics for details:
Click to expand...
That is true. I suppose it just seemed strange that Robotron wouldn't have chosen the 8088 since it was less expensive, even if it meant sacrificing speed since most processors cost about ten times or more than they could be produced in West Germany. I suppose the move to 16-bit with using the 8086 was probably a way to try to catch up with western comptuer development since they tried being XT compatible in the late 80s. Also thank you for the schematics! they're really interesting!
 
MCollins said:
That is true. I suppose it just seemed strange that Robotron wouldn't have chosen the 8088 since it was less expensive, even if it meant sacrificing speed since most processors cost about ten times or more than they could be produced in West Germany. I suppose the move to 16-bit with using the 8086 was probably a way to try to catch up with western comptuer development since they tried being XT compatible in the late 80s. Also thank you for the schematics! they're really interesting!
Click to expand...
Note how stuffed with RAM many of the East German 8-bit machines were. It didn't make much sense to design an 8088 machine that supported less RAM. Single RAM bank, pointless. The cost to build an 8086 was the same as the cost to build the 8088. By the time East Germany bothered with 8086 designs, the 16-bit accessory chips had fallen in price eliminating the cost savings of using 8-bit support chips. East Germany made so few computers that only a tiny bit of the world market needed to be imported to supplement whatever was manufactured internally.
 
krebizfan said:
Note how stuffed with RAM many of the East German 8-bit machines were. It didn't make much sense to design an 8088 machine that supported less RAM. Single RAM bank, pointless. The cost to build an 8086 was the same as the cost to build the 8088. By the time East Germany bothered with 8086 designs, the 16-bit accessory chips had fallen in price eliminating the cost savings of using 8-bit support chips. East Germany made so few computers that only a tiny bit of the world market needed to be imported to supplement whatever was manufactured internally.
Click to expand...
Looks like I need to hit the books more and read up more on these chips and their clones, especially Soviet and East German ones. I suppose was still thinking about the late 70s and very early I'm terms of cost when such a dramatic difference in expense still existed. Thank you for your insight! I admitted don't know as much about 80s computers as I do ones from the mid to late 90s, so this is very helpful!
 
Hi, I just joined to put some light on the East German computers. ;) I also go by the handle "Dresdenboy" in the demoscene, not living in Dresden, but near Berlin.

I own some Robotron computers, especially several A5105, which were developed on behalf of the Ministry of Education to be used in universities and schools. These machines also use the NEC uPD7220A for graphics. This chip (or its cloned variant U82720) has been used in many computers and add on graphics cards.
 
I'd say that you kind of need to learn to read German, or at least be good at telling when auto translation are doing a good or bad job.

I recently learned that the "C" in EC1834 is really a Cyrillic letter, and it should had been an S in the Latin alphabet, as it's part of the ESER thing:
https://en.wikipedia.org/wiki/ESER

East Germany didn't make the 8086 processor itself, it was manufactured in the Soviet Union (I think Belarus).
East Germany made their own Z80 clone, U800, and they also made memory chips and a bunch of clones of various 74xx chips (usually called Dxx instead of 74LSxx). This is the reason for most of their smaller non-PC-like computers being Z80 compatible. I can't remember the details but I think that they kind of just stole CP/M and patched it for their U880/Z80 computers.

They made the LC80 "lern-computer" = learning computer) single board trainer like computer, where they used the keyboard of a calculator as input, bur regular 7-segment LED displays for output. (7-segment displays was also used in their production of TVs with remote control).
They also made a range of computers similar to the western home computers. KC= KleinComputer = Small Computer. A bit weird is that KC87 and KC85/1 are two different names for the same computer, and then there were the KC85/2, KC85/3 (and maybe /4? that were part of a different range.

They also made large IBM style mainframe computers starting in the 60's. For these they made terminals that seems to be somewhat similar in concept to the IBM synchronous terminals (I.E. send a form to the terminal, have the user fill in various fields, press send and the user response is sent in one go to the mainframe). There is a Youtube video demonstrating this, in German (IIRC) filmed at some vintage computing meetup or whatnot.

Fun fact: I've read somewhere a long time ago about some country in Africa (maybe Angola?) wanting to computerize their calculations of the state budget or whatnot. They looked at what for example Robotron had to offer, and eventually settled for the UK produced Grundy Newbrain which was a small home computer, but it had ports for two cassette recorders. By using that feature it could do batch processing of more or less unlimited amounts of data, or rather how much you could fit on a tape.
 
To make things more complicated, the idea of joining/combining various industries to large conglomerates hit the GDR, and thus a bunch of companies were combined into "kombinat". Robotron was one of those "kombinat"s, with the result of some non-computer stuff also carrying the Robotron name. For example I have a table radio with the Robotron name, although you'd expect it to be called RFT (which was the GDR "kombinat" for electronics in general).
It's interesting to note how some things are so similar to things made in the west, while others are so different. For example this radio has a red LED rather than a light bulb on the pointer on the tuning scale, and it uses IC's, but at the same time it uses a rather large variable capacitor that you'd only find in valve/tube western made radios.
In the mid/late 80's TVs made in the GDR didn't use a simple plastic cover to protect from scratches during shipping. Instead they used a textile cover, probably made of whichever textile color they had a surplus of at the time, with an elastic band at the bottom opening. These were great for consumer electronics shops generally transporting customer TVs (delivery of new TVs or picking up TVs for repair / delivering repaired TVs).
Also at least the GDR made TVs had a slightly different smell than western TVs.

Sorry for going on a slight tangent, my tiny actual experience from back in the days was working (extra) in a consumer electronics shop (in a western country) that sold some GDR consumer electronic products. In particular their TVs were quite decent, with the picture quality kind of like the previous phased out Philips TV chipsets. I don't know if the GDR made chips were just copies or licenses, but they were equivalent to TDA 3510 (color to component decoder) and TDA 3520 (component to RGB) chips. This was handy as for the few times a chip went bad, it was easy and cheap to take a compatible chip from an old worn western made TV.

Fun fact: At the time I think the GDR made TVs were the only TVs on the market where you could use buttons on the front panel to put the TV in standby mode, so you later could turn it on using the remote control. IIRC you held in channel down and up at the same time to do this. Also just turning on the main power switch put the TV in standby mode rather than turning it on. These are features that every modern TV has but at the time it was a tiny unique selling argument.

Another fun fact: Most of the GDR and a lot of BRD (West Germany) could receive "the other Germany's" TV broadcast. Thus the GDR TVs could be fitted with a PAL decoder, and almost all TV's made in West Germany had decoders both for PAL and SECAM. East Germany used SECAM like the rest of the east block, but all the other broadcast standards for TV and FM radio were the same as the west, in contrast to the rest of the east bloc, so all radios could recieve the neighbors broadcasts, and all TVs could at least recieve a black/white picture and correct sound from the neighbors transmission even if it lacked the matching color decoder. When someone talks about this topic it's common for east germans watching west german TV mentioned, but for some reason west germans watching east german TV is never ever mentioned, even though it's blantantly obvious why West German TVs had decoders both for PAL and SECAM. (And it wasn't to recieve french transmisisons, for doing that you'd need a different IF stage too as France used inverted video polarity and AM modulated sound. Sure, you could use a West German TV to receive french TV via satellite, but that can't had been the reason for almost all TVs having a SECAM decoder...).
 
East Germany did put a lot of effort into jamming outside signals. It was also illegal to receive (some) foreign broadcasts. That gets a bit of attention since it was a bit riskier than over in the West receiving the broadcasts of the East. The East German introduction of Basicode accompanied with official instructions on the frequencies and times of Dutch broadcasts was rather strange. Getting free computer software trumped the need for ideological security.
 
As I understand it it seems like things varied during the years, where receiving western broadcasts was risky at some times, and less so at other times. In the later years there were even "TV reception associations", kind of like cable TV networks, but for receiving western TV in areas where that was possible but required large antennas. Like you'd put perhaps four antennas directed towards a western sender, combining the signal from all four, and then amplify and send it to all recipients (mixed with the regular GDR transmissions and whatnot).

I don't know if there ever were any similar reception associations for other countries TV transmissions. Language would had been a barrier, but also the 5.5MHz sound-picture carrier distance of the mostly West European B/G transmission standard used in the GDR v.s. the 6.5MHz sound-picture carrier distance, D/K standard, used everywhere else in the east bloc, would had been a technical problem. For a reception association someone with the right skills could build a receiver for the sound, fixed at the frequency of one Czechoslovak or Polish transmitter, and combine that with retransmitting it 1MHz shifted in frequency to fit regular GDR TVs. The other solution would be to just add an extra IF filter and whatnot in the sound demodulator circuit of the TV. (This was also a compatibility problem between the UK and Belgium + the Netherlands, and I've seen a DIY description of just adding an extra filter in parallel to get both the Western European 5.5Mhz and the UK (+ IIRC Ireland) 6MHz), and the receiver would just lock in to whichever signal were present).
 
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