[1/2] BETA-DISK-TURBO-HD

I am posting this here at the request of Aleksandr Kormishin aka AXLR.

(c)1998 AXLR
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I've been meaning to publish the results of my work for a long time, but
everyone got around to it... but the solutions presented here have
passed the test of time, and that's good.

So, what needs to be done to make a regular controller
work with high-density disks? If the computer already has a turbo mode installed, then all the modifications take literally an hour, and if not, well - here we offer an already
modified turbo scheme for the Pentagon - collect it. The turbine diagram for the Leningrad clones is not given here due to the high
complexity of setting it up.
So, even if you already have a turbine, you will have to
finish it a little. Actually, there are two improvements here: one for
turning on the turbo when DOS is running, the other generates /wait
when the processor accesses the ports.
Special mention should be made about the latter. It has been noticed that
some copies of KR1818VG93, namely 1993 and later
years of production, do not work well in the turbo. and this doesn’t seem to affect the quality of the exchange with the disk (they didn’t specifically test it), but who knows, VGshku. By the way, the glitches of the VG93 in the turbo are most clearly visible in my test ROM...
It would be best to give the fullturbo diagram for
Pentagon, but with modifications (the original is from Online#02,
it seems):
DD1 +5V
┌──┬──┐ │
clk (3.5 MHz) ────────────────────────────2│A0│ │ █K47
DD2.1 +5V ────5│A1│ │ │
┌──┐ ├──┤Y0│4──┴───>Z80:6
┌2│ 1°1───────────────┬────3│B0│ │ K10
7 MHz ────────┴3│ │ ┌──────6│B1│Y1│7─███──>Z80:24
└──┘ │ │ ├──┤ │
+5V DD3.1 ┌────────1│ S│ │
│ ┌──┬──┐ │ │ │ ┌15°OE│ │
DD4.1 ├─1° R│ │ │ │ │ ─┴─ └──┴──┘
┌──┐ ┌───2│ D│ │ │ │ │
D15:3 ────1│ 1│3──────3/ C│/Q°6┘ │ │
D15:6 ────2│ │ │ └─4° S│ │ │ │
└──┘ │ └──┴──┘ │ └──────────────┐
│ └──────────────┐ │
DD4.2 └───────────────────────────┐ │ │
┌──┐ │ │ │
/bit7#FF────4│ 1│6────┐ │ │ │
D76:9 ──────5│ │ │ │ │ │
└──┘ │ │ │ │
+5V DD5.1 │ DD4.3 "NORMAL" │ │ │
│ ┌──┬──┐ │ ┌──┐ S1 │ │ │
HLD ──┬──1° R│ │ └─13│ 1│11───── \ │ ││
│├─2│ D│ Q│6────┬─12│ │ ┌─ \──────┘ │ │
/IP ─────3/ C│ │ │ └──┘ │ │ │
│└─4° S│ │ │ DD6.1 │"TURBO" │ │
│ └──┴──┘ │ ┌──┐ │ │ │
│ └──1│ &│3────┘ │ │
└──────────────────2│ │ │ │
└──┘ │ │
│ │
/IORQ ─┬───────────────┐ │ │
│ DD7 │ │ │
│ ┌──┬──┐ │ DD4.4 DD6.2 │ │
└─14│ R│ 0│ │ ┌──┐ ┌──┐ │ │
+5В ──11°WR│ 1│ └─10│ 1│8 ───────4│ &│6──┘ │
┌─5/+1│ 2│6 ───── 9│ │ ┌─5│ │ │
│ ├──┤ 3│ └──┘ │ └──┘ │
│ │ │ │ │ │
│ └──┴──┘ │ │
├─────────────────────────────────────────┘
D15:2 ┬────────────────────┐ │
│ │ +5В DD3.2 │ DD2.2 │
│ │ │ ┌──┬──┐ │ ┌──┐ │
│ │ ├13° R│ │ └─5│ 1°4───┘
└─────12│ D│ Q│9───────6│ │
└───11/ C│ │ └──┘
└10° S│ │
└──┴──┘

Сигнал HLD берется с 28й ноги ВГ93, /IP - с ВГ93:35, /IORQ
- с Z80:20, а /bit7#FF- see below.

By the way, AY-3-8910 (not YAMAHA!) also works poorly in the
turbo, like the VG93, so this modification will also solve the problem
of the brake AYs.

I repeat: for normal operation of the turbo, change the diode
VD2 in the controller circuit. If it is not replaced, most
turboloaders in the turbo will fail, since they use jp #3d30 to access
DOS routines. In the turbo, this same VD2 greatly slows down switching ROM pages (DOS/BASIC). As a result
- the effects are familiar to everyone: the neglected one hangs and/or craps on the
disk...
Here is the diagram for replacing the VD2 diode (according to the Pentagon circuit
controller):
As it is:

DD77 (LL1) DD76 (TM2)
┌──┐ VD2 ┌──┬──┐
│ 1│11 ──│<──┬───┬─────13│ │ │
│ │ ─┴─ │ │ │ │
└──┘ C3 ─┬─ │ │ │ │
─┴─ █ R13 └──┴──┘
DD78(AG3) │
┌──┬──┐ │
│ │ │12──┘
│ │ │
└──┴──┘

And how it should be:

DD77 (LL1) LI1 DD76 (TM2)
┌──┐ ┌──┐ ┌──┬──┐
│ 1│11 ───┬─────────13│ &│11───13│ │ │
│ │ ─┴─ ┌──12│ │ │ │ │
└──┘ C3 ─┬─ │ └──┘ │ │ │
─┴─ │ └──┴──┘
DD78(AG3) │
┌──┬──┐ │ The free element LI1 is in the circuit
│ │ │12──┘ modifications to the turbo.
│ │ │
└──┴──┘

(To be continued.)

All the best.
Roman.