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Book 8088 discovery and modification thread

sparkyjf said:
One thing I did learn - the Book 8088 (at least my unit) didn't like it when I powered the ISA expansion board only with the Book running off internal battery. The testing wasn't extensive, but I found:
  • Floppy drive powered by external PSU, Book 8088 and ISA expansion board both powered by the battery in the Book - OK
  • Floppy drive and ISA board powered by the same external PSU, Book running on battery - unstable, crashes, often will not POST.
  • Floppy drive, ISA board and Book all powered from the same external PSU - OK
I'm guessing this is a ground problem, as the Book running on battery will have a floating 0V rail, and cheap switch mode PSU's (like the one I bought) can be rather noisy, including the 0V rail unless it's actually tied to earth in the PSU. Connecting all 3 devices to the same PSU means they are all sharing the same 0V rail so I think that's why it works - but that's an educated guess and I could be wrong. Offering that in case it helps anyone else trying to power peripherals and use the Book 8088 at the same time.
Click to expand...

As for FDC support - all work is done by Sergey, my BIOS release is just a fork of his 10 years work with some added features :)
I actually removed real FDC support in first releases, but put back when i managed to implement BIOS settings support for Book.
Great it works, thanks for reporting!

PSU - i personally got into lot of issues, including incorrect video card behavior, when using supplied 0.7A 12V PSU (generic, got with Book V1) or 1A (with Book V2, Huawei mark). I switched to 3A i had from old router and it works perfect. When in doubt, i use 100W (8A) PSU from an old project, but that might be overkill, just to test when i got into something weird :)
 
I have a request for community.
Can someone with Book V2 and CGA card + some knowledge and oscilloscope try to find TTL R,G,B,I pins on B2 chip, if those are present (i'm not sure).
Yes, i've seen V1 (B1) and standalone CGA card (B3) schematics, but pins config looks different for B2.
The only thing i could get from DZT so far is this pinout (R,.G,B here are VGA-level outputs):
1711617873884.png
 
n0p said:
I have a request for community.
Can someone with Book V2 and CGA card + some knowledge and oscilloscope try to find TTL R,G,B,I pins on B2 chip, if those are present (i'm not sure).
Yes, i've seen V1 (B1) and standalone CGA card (B3) schematics, but pins config looks different for B2.
The only thing i could get from DZT so far is this pinout (R,.G,B here are VGA-level outputs):
Click to expand...
Well, you already know i have 2 v2s, and 2 vga and 2 cga.. (I presume you didn't mean the standalone cga card).. What do you want me looking for? (yes, i have a scope) I can see what i can do this weekend.
 
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sorphin said:
Well, you already know i have 2 v2s, and 2 vga and 2 cga.. (I presume you didn't mean the standalone cga card).. What do you want me looking for? (yes, i have a scope) I can see what i can do this weekend.
Click to expand...

I wish i fully understand that myself :)
The problem is that V2 doesn't have TTL CGA outputs on it's board and i want to have them.
But i'm unsure how they can be found and if they exist at all.

Here's Book V1 CGA "B" chip pinout:
CGA_B1.png
We see here needed pins, and they are already broken out on the board

CGA2VGA.png
On the top - some conversion to VGA RGB voltage standard(?)

Here's Shan's CGA card "B" chip pinout:
Pins changed, some stuff removed fully:
CGA_B3.png

So the idea is to get a graph of some predefined picture on real CGA output (it should show and using it, find similar pin on Book V2 CGA card "B" chip, and atm i'm thinking if that could be done with multimeter.

I understand that might be not enough info to do a normal research, but that's all i have now.

Only info on testing CGA with oscilloscope i found is https://www.andavno.com/?p=248
 
I have a new story to tell :)
I've got an ET826 multimeter, it has frequency measurement feature, that i used to test power line quality from main, genset, etc. Quite useful tbh.
Sure, i got thin probe set for it.
So i decided to put FAFO method to some use as i had some spare time.
Since i wasn't sure what values i should look for, except 15.6Khz for HSync and 60Hz for VSync, i created a small executable, that just draws white screen and was expecting to see something about 320x200x60 ~= 3,8Mhz on some pins. I found HSync and VSync quite soon and marked some points with strange 11.91Khz values (and something much less when screen is black) Made a "probe" - wire from ground and 100Ohm resistor and pinged that pins. What do you know, here they are :) Multimeter cannot Mhz it seems or i'm not getting something. One of "11.91KHz" pin didn't react to probe so i marked it as "I", other was quite clear R,G,B.
Next, i soldered some wires to socket (it's much easier than tucking, really) and to DE-9 connector.
It worked right away via RGB2HDMI and CGACOMP shows all palettes work :)

Here's the mod and nice pinout pic :) :
photo_2024-03-29_20-31-15.jpgV2CGA.png
 
386sx/40 is actually quite speedy for a number of tasks. Yes, it’s got a 286’s interfacing, but it’s entirely decent.

There’s a reason that there weren’t many 386dx laptops, too. Batteries were really no great, and the additional power savings from the 386sx, and later sl, were really useful.

- Alex
 
sorphin said:
I would... if it wasn't a 386SX... (unless it's desolderable and i can throw on a DX)
Click to expand...

It uses base of Hand386, M6117 SoC, but unknown submodel so far. There's a breakout named "Parallel port" (but not "COM"?) which might be interesting, as M6117 variant used in Hand386 has no integrated COM/LPT ports.
Main problem with Hand386 - power supply not enough, it was discharging fast even when used with external power.
Secondary: dim display (external is dim when connected too), no DAC-capable sound card, no network interface, no ports.
But it runs Second Reality with PicoGUS connected :) so i guess Pocket 386 could do some tasks.
Not the Windows 95 for sure, it's not very usable, 1st person experience, DOS/Win3.1 are good there.
Anyway, i won't fall for it :)
For example https://www.aliexpress.com/item/1005005230887110.html has similar price, and i think DOSBox with dynamic core on that machine will emulate 386 quite good with all the interfaces you might want, if we talk about some very portable format.
 
n0p said:
ere.
Anyway, i won't fall for it :)
For example https://www.aliexpress.com/item/1005005230887110.html has similar price, and i think DOSBox with dynamic core on that machine will emulate 386 quite good with all the interfaces you might want, if we talk about some very portable format.
Click to expand...
The other seller Shan uses has it up now too. Your link shows unavailable in my country.
 
ajacocks said:
386sx/40 is actually quite speedy for a number of tasks. Yes, it’s got a 286’s interfacing, but it’s entirely decent.

There’s a reason that there weren’t many 386dx laptops, too. Batteries were really no great, and the additional power savings from the 386sx, and later sl, were really useful.

- Alex
Click to expand...
only 386 I had back when they were cool was a self built dx40 running linux. Laptops wouldn't have even been in my price range. lol
 
sorphin said:
only 386 I had back when they were cool was a self built dx40 running linux. Laptops wouldn't have even been in my price range. lol
Click to expand...

I somehow almost skipped 386/486 era, after conscription service i got me a Pentium 90, so it was rather big jump :)

Here's the screen with device specs (something about $240)
Not an ad, and i'm personally not getting one, just to show what you can get for similar money in portable form:
1711868285226.png
 
n0p said:
I somehow almost skipped 386/486 era, after conscription service i got me a Pentium 90, so it was rather big jump :)

Here's the screen with device specs (something about $240)
Not an ad, and i'm personally not getting one, just to show what you can get for similar money in portable form:
Click to expand...
I get ya.. Well, most of us (with exceptions), don't buy these things for "practical" reasons. :)
 
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I received the Monotech MicroRAM yesterday and started playing with that. Using USE!UMBS + DOSMAX now I boot to DOS 6.22 using only 10KB, which is amazing! I found the Windows startup .bat files in DOSMAX and have 430KB free in Win 3.0, which was a pleasant surprise. 10/10 - I do recommend UMBs.

With regard to the ISA8-EXP-01 expander board, a couple of things. Using the MicroRAM, external power for the board is not strictly required. However, using 12V external/second power adapter works just fine. I'm stating this because I found a YouTube video where they had major issues and let out the magic smoke and stated it was due to using 12V external power. I had zero issues, and I think the expander is actually NOT 'hot garbage'. I would note that I replaced the original 12V adapter with a known-good high-quality one rated for 1.5A. I used the original adapter to power the ISA slot when experimenting with that.

What would actually be very cool is to create a MicroRAM clone that uses a slim PCB and plugs directly into the Book8088 ISA connector getting rid of the need to use the bulky ISA expander adapter. Something that matches the dimensions of the rear of the system and just hangs out, maybe with a 3D printed cover.

At the same time, I also received an Intel 8087 FPU and installed it. It was detected without issue. Indeed, it gets really hot. I think something is actually wrong with the setup because after being powered up for 20-30min the FPU goes to out to lunch. After this occurs, the system fails to reboot. The system fails to detect the IDE-XT / CF card, and hangs at the point where the BIOS attempts to hand off control to a boot loader (No system disk error, or similar). After the chip cools down, the system is fine again. I have other plans for that chip anyway (and some AMD 10MHz rated 8088 CPUs i'm acquiring), so nothing lost here I think.

10 year old me would have been very impressed with 630KB of free conventional RAM on an XT! Maybe I can look into creating the MicroRAM Slim so I can easily take my UMBs with me.
 
More notes - The VGA card in my first Book8088 V2 was/went bad. It was fine the first couple of hours that the system was on, but then started to develop screen corruption that got worse. After that happened, the system would boot up clean usually, but then the screen corruption would pop up again after 30-60 seconds. I'm interested in either fixing the card, or shipping it to someone that wants to tinker with it. I already reflowed some pins that looked suspect, but it had no effect. Here is what it looks like ->
&

If anyone has any idea if it's the RAM chips, or the GPU itself, or any other suggestions please let me know. Not sure if they had different variants, but this VGA card is using a Cirrus Logic CL-GD5429-86qc-c ( C Logic Rev M3-1.0 ).

The seller sent me a new VGA card, which solved the issue. This particular system is an earlier V2, so it still has issues with the LCD controller. The seller sent me the newer FW, so I'll try to flash it, but I think he's sending a new controller to make sure everything is sorted. I bought a second/later V2 and haven't had any issues at all (LCD behavior is perfect).

The differences between my two Book8088 systems, besides a bad VGA card and the LCD controller situation, is that the earlier system has a matte finish screen, while the other is glossy. The newer unit has a brighter screen as well.
 
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