Delta s

It was produced by different plants in the early 1990s. Delta-SA was produced by the Kursk Production Association Pribor, other versions were produced by Delta-S and the Elara plant in Cheboksary. Perhaps also produced in Zelenograd.

Models "C" and "CA" differed in the execution of the case, but they used the same power supplies and operating instructions. Several slightly different versions of these computers were produced.

Separate memory, RAM 16K on KR565RU6, 32K on KR565RU5, halves KR565RU5D2 are often used. There is a system connector. Part of the circuit is made on PLM KR556RT1. Processing of additional keys is done on KR1656RP2-04.

Also known are the Delta-Sekam-Disk models (with a drive controller and SECAM encoder) and Delta-Micro models.

• Processor: КР1858ВМ1 (or another clone Z80A ) at a clock frequency of 3.5 MHz
• Memory: RAM - 48 (128 for Delta-C 128) KB, ROM - 16 KB; Separate RAM: the first 16 KB of memory was performed on the KR565RU6, the remaining 32K on the KR565RU5
• Sound: AY8910 , Cheboksary PCs did not have a sound chip.
• Graphics: 256 × 192 - standard ZX Spectrum video mode
• Built-in speaker
• System connector

Depending on the version, I used regular or non-standard (Russified) firmware. To switch the layout, commands No. 209 and No. 210 ( CAT , FORMAT ) were used, perhaps the developer assumed that the drive would not be connected to this model. There were several hardware revisions, some of which were incompatible with many games - for example, games hacked by a Polish hacker with the nickname “Bill Gilbert” hung at the boot stage, after the inscription “CRACKED BY BILL GILBERT” appeared ^[1] . About 30% of the programs did not work, as indicated in the manual.

• Delta-C - two options, with a separate memory field (75 microcircuits), and with a solid memory field (52 microcircuits). There was an option on BMK 1515XM1 ( T34VG1 ). There were also options that differed in the keyboard used.
• Delta-SA , Delta-SB
• Delta-Sekam-Disk - with drive controller and SECAM encoder
• Delta Micro
• Delta-C 128 - an analogue of the ZX Spectrum 128K, manufactured by Delta-S, Cheboksary. Built on BMK KB01VG1-2 produced by the Mikron plant.

Only one version of this model is known. The keyboard is made in the form of a printed circuit board with separate keys of the same type (for wide buttons - two keys side by side) with removable transparent plastic covers, under which there were paper tabs with inscriptions. The computer is Russified - the firmware has been changed, and a language switch key has been added (in the lower right corner of the keyboard). When the computer was turned on, the line was replaced by (C) 1990 Delta (in the Cheboksary version the standard line was saved - Sinclair research LTD 1982). Russification affected compatibility with programs, about 30% of programs do not work on it (indicated in the manual).

There were versions with and without Russification. Versions without Russification, when turned on, display the (C) 1989 Delta message, in some versions the original firmware was used. There were also versions with different keyboards - with a similar Delta-SA, and with a membrane keyboard with opaque plastic keys (used in several other domestic ZX Spectrum clones). Cases of this version of the computer were produced in several colors - orange, white and black. There were two versions of the computer - with separate memory fields (assembled on 75 microcircuits) and with one field (on 52 microcircuits). The scheme of the second version is similar to the Pentagon 48, this version is less common. The well-known copy, released in June 1990, has the number 0102947 (the keyboard is similar to Delta-SA).

An analogue of the ZX Spectrum 128K, manufactured by Delta-S, Cheboksary. Built on BMK KB01VG1-2 produced by the Mikron plant.

The analogue of the ZX Spectrum 48K is made using ULA T34VG1 . There are not soldered places on the board for the drive controller.

• Spectrum-compatible Delta-C48 computer (52 IPs)
• Delta C on SpeccyWiki
• Demo inclusion of the Delta-S computer on the YouTube channel (Blogs and reviews of Soviet radio)