Book8088 V2 Internals

[n0p]

As my Book V2 arrived not working, i decided to do a quick photo session of it's internals.
If you're thinking about getting one that might help you a bit.

Main board, front:


You can see a good example of "Not my job" here (but that's not the actual problem with my V2):


Back of mainboard:

DMA and Interrupt controller PLCC chips are soldered to board, VGA card has BIOS chip soldered to board as well. Book V1 has DMA chip socketed.

Board part under video card:


VGA card closeup (there's nothing on it back), looks like 1MB RAM?:


Ports board, with (there's barely visible microcontroller under part that looks like oscilliator)

It's mounted to case with 5 screws, holds pretty good.


Battery has it's own compartment, which is good, but cannot be easily disconnected without disassembling the Book as i hoped.


CGA card, front and back:

Possibly newer RAM chip than in Book V1. ROM socketed - so you can write your codepage there. Most probably they still had a stock of those chips and sockets from discontinued Hand386.

 

[sergioag]

You can see a good example of "Not my job" here (but that's not the actual problem with my V2):
View attachment 1272544

That's horrible! Thankfully mine didn't arrive like that and is in a pristine condition. May I ask what is the problem with yours?

Back of mainboard:
View attachment 1272545
DMA and Interrupt controller PLCC chips are soldered to board, VGA card has BIOS chip soldered to board as well. Book V1 has DMA chip socketed.

This also makes more difficult to mod the board to make memory refresh work correctly, though not impossible.

Board part under video card:
View attachment 1272546

This has made some people (me included) hoping for a Trident card.

VGA card closeup (there's nothing on it back), looks like 1MB RAM?:
View attachment 1272552

I believe there is no clearance for using a socket in the video BIOS. Maybe with a low-profile socket, but it seems unlikely.

CGA card, front and back:
View attachment 1272550View attachment 1272551
Possibly newer RAM chip than in Book V1. ROM socketed - so you can write your codepage there. Most probably they still had a stock of those chips and sockets from discontinued Hand386.

It's not really a BIOS, but just the character ROM. CGA and MDA don't have a video BIOS, but the system BIOS itself will drive them.

 

[sorphin]

Ports board, with (there's barely visible microcontroller under part that looks like oscilliator)
View attachment 1272547
It's mounted to case with 5 screws, holds pretty good.
View attachment 1272548

Battery has it's own compartment, which is good, but cannot be easily disconnected without disassembling the Book as i hoped.

And here are my comments on this. The under the Crystal and it is a crystal is a 16550 for the uart. As for being able to disconnect the battery I was able to do it fairly easily pulled out of the connector with minimal effort when taking my V2 apart to hardwire turbo mode.

 

[n0p]

That's horrible! Thankfully mine didn't arrive like that and is in a pristine condition. May I ask what is the problem with yours?

Yes, it looks like a fix for a defects on board itself, technically that part works as it should
On first start it didn't detect COM port and CF card (LPT port was detected though). Didn't react to CTRL-ALT-DEL as well.
After quite long conversation with seller (DZT) they agreed to send replacement board, we'll see how it goes.
My V1 arrived broken too - keyboard had very strange behavior (wrong chars were entered). That time i found the problem - XT-IO CPLD chip pins were oxidized, i cleaned and "silvered" pins, it's working good since then.
Alas, this is not the case with my V2.
I cleaned all socketed chips - same problem - no COM, no CF. I inserted my BIOS fork to test USB and CF (it got my own detection code) - USB and CF still not detected.
Heated individual chips to check where it might break more - NEC D71059L (interrupt controller) prevented Book to turn on if heated a bit, so i desoldered it and ordered a replacement.
As for CGA, yes, that's why i called that ROM, not BIOS, no offence , though i'm unsure how it should be called. i made cyrillic (CP866) charset for V1 version long time ago, and version for V2 on request (simply doubled the V1 ROM). Interesting, it contains 8x16 character table as well, i never seen it used in CGA.

@sorphin - i was afraid to tear connector It appeared to stuck a bit on sticking-out capacitor pins.

 

[n0p]

Today i received the replacement board!
DZT sent it together with ports, bottom case part, V20 CPU, ROM and CF card (!)
Put everything together, my V2 now works
--
Noticed a new design change - XT-IO CPLD chip socket is now through-hole.

 

[sorphin]

Today i received the replacement board!
DZT sent it together with ports, bottom case part, V20 CPU, ROM and CF card (!)
Put everything together, my V2 now works
--
Noticed a new design change - XT-IO CPLD chip socket is now through-hole.

pic.

 

[n0p]

here

 

[3lectr1c]

Question for those who have them: what's the appeal?
Seems they're not really useful for more than as a hobbyist project, which I believe is what they were created as in the first place? It has a tiny, cramped keyboard, a terrible screen that's not the correct aspect ratio for DOS games, and they seem to be pretty unreliable.
I think it's really neat that someone's manged to build a brand new DOS compatible system - I just really wish they would have made it into a more usable form factor, like a properly sized laptop with a larger better screen and a good keyboard. Then use the Hand386's internals to give it more performance, add in a built in input device of some sort (maybe a trackball, 386 laptop-style?) and then I think you'd have a good product.
This thing just has so much potential, I wish it was exercised.

 

[n0p]

Question for those who have them: what's the appeal?
Seems they're not really useful for more than as a hobbyist project, which I believe is what they were created as in the first place? It has a tiny, cramped keyboard, a terrible screen that's not the correct aspect ratio for DOS games, and they seem to be pretty unreliable.
I think it's really neat that someone's manged to build a brand new DOS compatible system - I just really wish they would have made it into a more usable form factor, like a properly sized laptop with a larger better screen and a good keyboard. Then use the Hand386's internals to give it more performance, add in a built in input device of some sort (maybe a trackball, 386 laptop-style?) and then I think you'd have a good product.
This thing just has so much potential, I wish it was exercised.

Got V1 out of pure curiosity and nostalgia, and V2 - why woudn't i buy it for $150 at that moment?
Though it's made of recycled parts (and that's not exactly bad) - it's a working XT, which has CGA/Screen/CF card/Adlib/Speakers right away and in compact form.
I do agree on keyboard and screen, that's what i personally complained about from the start, not to mention overall quality issues - but i successfully addressed that issues in V1 by connecting external display and keyboard (V2 is not good target for that),
And i seriously doubt we'll have anything alike in the future

 

[3lectr1c]

I guess it just isn't the product for me. I'd just rather spend that money on an actual vintage laptop - they do have more upkeep, but you can pick up a really nice one for $150-200. The upkeep required is why I wish that a modern one was made - the Book8088 is close, but not quite there to me.

 

[sorphin]

I bought my 2, because it's neat and it's a counter to the actual vintage gear I have without being "too new"... 386 and greater started getting old for me and by the pentium era, meh. and this is from someone who aside from my first "pc" (Tandy 1000), every machine (of x86 variety anyway) has been self built. To me it's just neat. Yes I could get an actual vintage laptop but then I have to worry about when is the screen going to die or do I have to recap it and so on. I have 2 286 laptops that I got from CR and neither one of those work and probably never will. I guess part of it is what you're expecting from it. I wasn't expecting it to do XYZ so if it didn't deliver that's fine. I have plenty of other machines that can play whatever games. Whenever this gets brought up it reminds me of a thread I read about the 2600 plus that Atari released. There's some people like me that got it now because it's neat and I know it will work. Yes it's an emulator in an Atari shell but I still am fine with that. But yet you have the people who say well you could just run an emulator on your modern computer it's not worth $130. I guess basically it comes down to this, like I said multiple times now I thought it was neat, I still think it's neat which is why I bought a second one. They're small which is a benefit and a detriment. People have said well why not use a NuXT? I do in fact I have two of them one is a spare board and the other one is in a tower case and is my conversion machine it's also not small. One of the major things with the book is its tiny size and integration.

Yes I know this is long, but people have asked this multiple times in all the various threads. The appeal is going to be different for everyone and it may not appeal to everyone. If you want a micro-size 386 maybe you could design one and put it out there? I have an industrial 486 board that would fit in this case but to me that doesn't have any novelty. More than anything else I think it's the novelty.

 

[n0p]

Looking at the LCD board that originally came with the Book V2, i've noticed a quite efficient way implemented to reduce resistance
Take a look at R3

 

[boggit]

For those of you who own (any incarnation of) a Book8088: What is your verdict on the CGA card?

I've seen lots and lots of new CGA cards on eBay from what i assume is the same manufacturer (as it sports chips labeled CycleLogic) for like $30.

 

[n0p]

For those of you who own (any incarnation of) a Book8088: What is your verdict on the CGA card?

I've seen lots and lots of new CGA cards on eBay from what i assume is the same manufacturer (as it sports chips labeled CycleLogic) for like $30.

It passes all CGACOMP tests.
The standalone card will require real CGA display to work with iirc.

 

[eiffelben]

For those of you who own (any incarnation of) a Book8088: What is your verdict on the CGA card?

I've seen lots and lots of new CGA cards on eBay from what i assume is the same manufacturer (as it sports chips labeled CycleLogic) for like $30.

I have the stand alone card and yes, you need either an RGBI screen or a converter like MCE2HDMI (which I use). It is to a certain degree identical to the original IBM CGA but with all the chips logic crammed into the two CPLDs plus external charrom (EPROM), SRAM and CRTC (MC6845). It even has the CGA "snow"!

 

[Zare]

There is a micro design 386 but it's in a "PDA" form, looks like oversized HP Windows smartphone.

I've thought a lot about making an entire custom built box, out of standard. In pizzabox form ala Mac Performa. I'm not sure what would be the procedure and cost to order a fabrication of all the sheet and plastics.

But in such a design you make so many compromises compared to standard IBM ISA spec'ed case, you need to make sure you don't narrow down target audience too much.
Book8088 had many compromises to take but they did catch the market.

This is an interesting topic for me, I'll post it as a thread so this one doesn't get polluted by offtopic.

 

[n0p]

There is a micro design 386 but it's in a "PDA" form, looks like oversized HP Windows smartphone.

I've thought a lot about making an entire custom built box, out of standard. In pizzabox form ala Mac Performa. I'm not sure what would be the procedure and cost to order a fabrication of all the sheet and plastics.

But in such a design you make so many compromises compared to standard IBM ISA spec'ed case, you need to make sure you don't narrow down target audience too much.
Book8088 had many compromises to take but they did catch the market.

This is an interesting topic for me, I'll post it as a thread so this one doesn't get polluted by offtopic.

I have the Hand386 as well. Got it together with Book V1. I actually like it - it has VGA and PS/2 connector, the only thing i miss there - any kind of DSP (it has only YM FM chip), but PicoGUS solves that and ports (but not much). Almost perfect machine for old Lucas Arts games. Main problem - it consumes more than charger supplies.

 

[n0p]

Back to topic. Today i received three CMOS 8284 chips (i burnt one, incorrectly inserted), and i received earlier two 8259 chips.
Repair started.
As i said before, i thought interrupt controller was the problem - heating it a bit caused Book to stop working completely.
So i desoldered it with air and flux (some time ago), and soldered new (better idea is to order SMD PLCC sockets, and i will do that).
But that didn't work, Book didn't boot and actually stopped working right after playing start sound.
As the only chip near is DMA controller, I desoldered it and Book started working right away (XT can work w/o DMA controller). I used a CGA card with it.
This time i'm surely gonna order sockets first. And i already have a spare DMA chip from my experiments with DMA fix (i ordered two, so i could replace it when something goes wrong).
Speaking of which, here's photo that shows DMA hack/fix is impossible on V2 w/o desoldering DMA chip:

--
So i soon will possible be the only person (instead Ali sellers) with three Books :D
Anyway, here's the plan, if putting new DMA chip will fix it completely:
* Remove keyboard chip, put Waveshare Zero there, and use external keyboard. As i finally learned to control it's led, it may be used for power on / kbd conn / turbo indication, not only control.
* I don't plan getting Adlib card for it, but making mute option for speaker and replacing it with a bigger one should be good
* Making hw switches for turbo and mute..
* Would be great to put both RGBI and VGA connectors there. But "CGA" sockets are SMD, so it won't be nice.
* Maybe as a part of learning process, hook CH375 interrupt line to Pico, it's not connected anyway, connect there a small audio board to Pico and do random floppy noises when USB is active :D
* DMA hack/fix
* Thing i did on TV with my XT clone 35+ years ago - some way to swap RGB signals. I absolutely don't understand how i would do that here, some kind of 9 position dial i guess.
* As for display - understanding how to make RTD firmware recognize 15Khz is the key. Some 7-8" 4:3 screen should do. I asked several sellers of RTD boards on Ali and didn't get a one actual answer. and it looks like DZT put me into ignore list :D I just asked - if Shan cannot share VGA firmware as it's outsourced, why he cannot share his CGA 15Khz hack? Nothing criminal :D. I see some iPad displays together with boards for sale on Ali, but cannot be sure they really support 15Khz.

 

[n0p]

New story and question for experts
First thing i decided to test on my PlayBook board - Turbo of course
I removed STM keyboard controller and connected it's Turbo pin to ground.
I noticed something strange right at the memory test - it was slow, not fast as in Turbo mode.
Quick notice - i never booted this board, it was faulty right from start, so i cannot say if that part was working before.
But i did use it for voltage measurements and tracing lines exactly for Turbo mod
Landmark test showed speed equivalent of 2Mhz AT, so it's about 1.5 times slower than in normal mode.
Next, traced line from small 24Mhz crystal to CPLD - it's pin 81 now.
Out of curiosity, and it's play board anyway - i desoldered 24Mhz crystal - and Book didn't work, no signs of life at all (turbo line connected to ground). Soldered it back - Book works.
The question is - can crystal be that faulty? I mean work, but oscillate at 2 or 3 times less frequency? It's minor nuisance, but i'm really curious, as i though that parts work or not at all.
From Book V1 schematics it looks like CPLD chip takes OSC from 14Mhz and 24Mhz and i may suggest it switches to 24Mhz, and there's no additional lines for that, so there's might be some problem with CPLD itself.
Main problem is that SMD crystals are unavailable here and i'll have to order them from China, so it's gonna be a long wait, and i would love to be sure that replacing crystal at least might help (and i will order higher values as well for sure )

 

[n0p]

Some progress on my not so broken board now.
I installed PLCC sockets for interrupt controller and DMA, new DMA chip. Installing those was ok, but they are very close to each other, so i has to move that a bit to be able to solder them to point. Before installing DMA socket i cut pin 22 point from ground, so it would be possible to do dma fix.
Next, i inserted the chips and everything worked. Including Turbo (and i retested again removing and reinserting DMA chip) - so DMA chip presence affects turbo.
But anyway i ordered 32Mhz crystals just to check if that'll work
Done dma fix as well.
You might notice that there's no CH375 chip - and that's another story
I was using some generic 256MB CF card that even identified itself as "256MB CF Card" with this board for tests.
At some point i turned Book on and it shut off, like it shorted or something. I removed and reinserted power - power led started blinking in very short pulses.
Next, i removed keyboard, unsoldered power from Waveshare Zero and removed CF card.
It powered on, but gave "low memory error" sound pattern.
Ouch.
Reinserted CF card - same short led pulses.
Remembering an advice from a friend to check shorts to ground on chip data lines i started testing and found out that memory line D1 has somewhat 50Ohm to ground.
Long story short - it was the CH375B chip. good thing almost all chips are socketed, modern fluxes are great, and i anyway planned to remove interrupt controller to install socket.
I don't know who killed who, but again, ordered five CH375B
CF card is dead, so i just disassembled it to have a look and it's board has Apacer mark.
Otherwise, all good!