H19C Terminal Board!

[Norberto Collado]

All,

For this year I decided to try to develop the new H19C board to support the H89-SBC system, and to also support the original H19A enclosure. This new H19C board should replace the original H19A board with the added capabilities of supporting the VGA/Composite Video and PS2 keyboard along with the original H19A keyboard.

I decide to call it H19C as I'm leveraging the design from the original H19A board and also adding the capabilities provided by Lee on his H19B schematics (amazing work!). I'm adding jumpers to be able to configure the board as a H19A or H19B, which also allows me to be able able to debug both modes effectively.

The only new change from the H19B schematic is that I will be using a Micro-controller to emulate the logic that reads a character from the keyboard and provides such character to the Z80 data bus to decode it. The original design uses the keyboard controller and the output drives the keyboard ROM to provide the data to the Z80 bus. 

My question is as follows:

1. If the micro-controller detects that a key is being pressed for example "R", do I present to the Z80 data bus the following byte "01010010 = ASCII R" or it is something else? I took a look at the keyboard ROM binary file and was not able to figure it out; so many bytes and repeats of the same in some cases. I did a quick review of the H19 assembly code and not that much luck. Is there a keyboard map with corresponding binary code for all the keys? Or should I calculate this by sending a stream of bytes from 00Q to 377Q to the Z80 data bus to capture what character it represents?

I completed about 99% of the schematics and the board might be bigger than anticipated, but smaller than current board (see attached board file)... 

So I have a year to play with this baby and any feedback is much appreciated. 

Thanks,

Norberto

[Lee Hart]

Norberto Collado wrote:
> For this year I decided to try to develop the new H19C board to support
> the H89-SBC system, and to also support the original H19A enclosure.
> This new H19C board should replace the original H19A board with the
> added capabilities of supporting the VGA/Composite Video and PS2
> keyboard along with the original H19A keyboard.

Sounds like a great project, Norberto. And you're just the guy to pull
it off!

> I decide to call it H19C as I'm leveraging the design from the original
> H19A board and also adding the capabilities provided by Lee on his H19B
> schematics (amazing work!).

I'm delighted that it was of use, and that you can pick it up. :-) It
started as a real "retro" design that used only vintage parts and
construction from the 1980's. But it took 32 ICs. That's less than the
original (which used 54 ICs), but it still sounded like too many. I was
afraid no one today would be interested in building anything with that
many chips. I could "cheat" and use modern chips; but that wasn't
interesting to me. Besides, it's already been done to death by many
others (terminals made with Atmels, PICs, Propellers, etc.)

> I'm adding jumpers to be able to configure the board as a H19A or H19B,
> which also allows me to be able able to debug both modes effectively.

What do the jumpers do? I don't recall any differences between the Heath
H19 and H19A boards except the power connectors.

> The only new change from the H19B schematic is that I will be using a
> Micro-controller to emulate the logic that reads a character from the
> keyboard

I replaced the H19's hard-to-get keyboard encoder with a generic 8255
and Z80 software to read the H19 keyboard. That's pretty simple. What's
the reason for a second micro?

If you use a second micro, is it or the Z80 going to do the translations
from key to function to be performed? For instance, if you press a
keypad arrow key, there are at least 8 different functions that the Z80
might perform, depending on what mode you are in.

> My question is as follows:
> 1. If the micro-controller detects that a key is being pressed for
> example "R", do I present to the Z80 data bus the following byte
> "01010010 = ASCII R" or it is something else?

The H19 keyboard logic can generate a "scan code" like PC keyboards. You
can have unique codes for "r", "R", ctrl-R, ctrl-shift-R etc. The
terminal's Z80 can also see when a key is pressed, and when it is
released. For instance, a game can measure how long the SHIFT key is
held down, or if the CTRL key is down, the arrow keys can move the
cursor without sending any codes to the H89.

But it's up to the H19's firmware whether or not to use this capability.
Heath's stock firmware didn't do much with it, but add-on ROMs like the
HUG/Watzmann, Super-19 and my Superset did.

> I took a look at the keyboard ROM binary file and was not able to figure
> it out

I've got my old source and notes for the Superset. If I get a chance,
I'll look and see if I can re-remember how it all worked.

As I recall, the basic printable ASCII keys (a-z, 0-9, etc.) were
directly represented in the code sent to the Z80. But the various other
keys had special codes because the Z80 had to run a little subroutine to
decide what that key was currently supposed to do.

> I completed about 99% of the schematics and the board might be bigger
> than anticipated, but smaller than current board (see attached board
> file)...

Ye ghods! Is that your layout? Looks like a 100-layer PCB. :-)

--
Teaching children to program goes against the grain of modern education.
Just imagine the chaos if they learned to think logically, plan, create,
implement, test, and execute!
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com

[George Farris]

Hey all,

Does this mean I could put your board in and old H19 case and fit the H89-SBC in as well to turn it into an H89?

That would be very cool if that's the case.

George

--
You received this message because you are subscribed to the Google Groups "SEBHC" group.
To unsubscribe from this group and stop receiving emails from it, send an email to sebhc+un...@googlegroups.com.
To post to this group, send email to se...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/20170103170135.1321cca37f09b4ab87c5049afdc8ceaa.dfc6ebe7d0.wbe%40email09.godaddy.com.
For more options, visit https://groups.google.com/d/optout.

[Norberto]

That is the goal, and some might want to replace the glass tube with an LCD display. Also should replace the existing TLB if needed. The most important part for me is to have the H89-SBC being able not to depend on a Real H19 terminal to have a complete solution.

😃

Sent from my Verizon Wireless 4G LTE DROID

[Glenn Roberts]

That's my aspiration as well!  I've got a dead H19 just waiting for a new life!

Sent from my iPhone

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/1483503069.17145.3.camel%40gmail.com.

[Norberto Collado]

Thanks Lee and for you invaluable feedback is always appreciated. I learned a lot from your feedback and enjoy your simple solutions to problems coming ahead.

My approach on the H19C is to configured the board as the H19A, use the same Z80 ROM and same ROM for the video and it should work. So for this I added a few jumpers and for example some of the differences is as follows:

1. H19A Z80 CPU runs at 2.048 MHz. H19B Z80 CPU runs at 6.144 MHz. H19C Z80 runs at 2.048, 3.072 MHz, & 6.144 MHz.

2. H19A DotClock =  12.288 MHz. H19B runs at 24.576 MHz. H19C, runs at 12.228 MHz and 24.576 MHz.

3. etc...

On the 8255, I substitute it with a micro-controller to emulate the most critical signals to support the Z80. So the Z80 thinks that it is taking to the actual keyboard controller, so no need to update the existing Z80 ROM FW for now.

The board layout looks as a spider web in drugs but it will clean up as I position the parts in place. :)

If you can find on how the keyboard controller works along with the keyboard ROM that will be great as it will simplified the code. Data comes out of the keyboard controller and it drives the ROM address directly and data comes out (see attached picture of the first few bytes within the ROM). If the data out of the ROM (D7-D0) maps directly to the ASCII value of the key being pressed, then we should be fine. 

Thanks,

Norberto

 

-------- Original Message --------
Subject: Re: [sebhc] H19C Terminal Board!
From: Lee Hart <leea...@earthlink.net>
Date: Tue, January 03, 2017 5:08 pm
To: se...@googlegroups.com

Norberto Collado wrote:
> For this year I decided to try to develop the new H19C board to support
> the H89-SBC system, and to also support the original H19A enclosure.
> This new H19C board should replace the original H19A board with the
> added capabilities of supporting the VGA/Composite Video and PS2
> keyboard along with the original H19A keyboard.

Sounds like a great project, Norberto. And you're just the guy to pull
it off!

> I decide to call it H19C as I'm leveraging the design from the original
> H19A board and also adding the capabilities provided by Lee on his H19B
> schematics (amazing work!).

I'm delighted that it was of use, and that you can pick it up. :-) It
started as a real "retro" design that used only vintage parts and
construction from the 1980's. But it took 32 ICs. That's less than the
original (which used 54 ICs), but it still sounded like too many. I was
afraid no one today would be interested in building anything with that
many chips. I could "cheat" and use modern chips; but that wasn't
interesting to me. Besides, it's already been done to death by many
others (terminals made with Atmels, PICs, Propellers, etc.)

> I'm adding jumpers to be able to configure the board as a H19A or H19B,
> which also allows me to be able able to debug both modes effectively.

What do the jumpers do? I don't recall any differences between the Heath
H19 and H19A boards except the power connectors.

> The only new change from the H19B schematic is that I will be using a
> Micro-controller to emulate the logic that reads a character from the
> keyboard

I replaced the H19's hard-to-get keyboard encoder with a generic 8255
and Z80 software to read the H19 keyboard. That's pretty simple. What's
the reason for a second micro?

If you use a second micro, is it or the Z80 going to do the translations
from key to function to be performed? For instance, if you press a
keypad arrow key, there are at least 8 different functions that the Z80
might perform, depending on what mode you are in.

> My question is as follows:
> 1. If the micro-controller detects that a key is being pressed for
> example "R", do I present to the Z80 data bus the following byte
> "01010010 = ASCII R" or it is something else?

The H19 keyboard logic can generate a "scan code" like PC keyboards. You
can have unique codes for "r", "R", ctrl-R, ctrl-shift-R etc. The
terminal's Z80 can also see when a key is pressed, and when it is
released. For instance, a game can measure how long the SHIFT key is
held down, or if the CTRL key is down, the arrow keys can move the
cursor without sending any codes to the H89.

But it's up to the H19's firmware whether or not to use this capability.
Heath's stock firmware didn't do much with it, but add-on ROMs like the
HUG/Watzmann, Super-19 and my Superset did.

> I took a look at the keyboard ROM binary file and was not able to figure
> it out

I've got my old source and notes for the Superset. If I get a chance,
I'll look and see if I can re-remember how it all worked.

As I recall, the basic printable ASCII keys (a-z, 0-9, etc.) were
directly represented in the code sent to the Z80. But the various other
keys had special codes because the Z80 had to run a little subroutine to
decide what that key was currently supposed to do.

> I completed about 99% of the schematics and the board might be bigger
> than anticipated, but smaller than current board (see attached board
> file)...

[Norberto Collado]

Hello Lee,

I took a look at the "Superkey.asm" file that you created and the keyboard map is fully defined and very well documented. I will review in detail and will ask questions as needed, but I think I'm fine for now. Based on the Superkey.asm code, the micro will need to monitor both Shift keys, CNTL, and CNTL-Shift to calculate the proper byte sequence. 

;  ___ASCII code to send; if msb=1, gets special treatment

; |  ___"X" row number in matrix

; | |  ___"Y" column number in matrix

; | | |   ___U=unshifted, S=shifted, C=control

; | | |  |    ___notes

[Norberto Collado]

I was wondering if someone has an spare H19A terminal board that I could borrow to support this design and it doesn't need to be operational. My experience with the H89-SBC design was that the Heath schematics had so many mistakes and Jack provided an H89 Heath board which I used to trace the signals to ensure proper connection and that was invaluable when I power-on the new H89-SBC system for the first time.

Thanks,

Norberto

 

[Dan Emrick]

Hi, Norberto,

I have an 85-2376-2 (1979) and an 85-2650-1 (1981).  The first is probably not what you need.  The second has a full sized shield on the back, a flat rectangular heat-sync on the component side plus the keyboard connector pins point down rather than perpendicular to the board.  Might this be what you need?

Dan

[Douglas Miller]

I was not following the thread closely, so maybe this has already been
resolved or forgotten. But the question on the H19 keyboard encodings
got me thinking about the H19 code I was recently looking at. I was able
to get a complete datasheet/appnote for the MM5740 and write a small
program to decode the H19 KEYB ROM. I've attached the output (plain
text), with some annotations about what I saw in the H19 code, here.

I think all the codes now make sense, although it took a few passes
before I got it right.

I also noticed that the KEYB ROM image from Les Bird had some strange
data in it. The last 3/4 of KEYB is identical to the same part of FONT
(character generator), but it appears that only the first 512 bytes of
KEYB are used (at least with default PCB jumpers on U.S. models), and
the data looks complete (in the first 512 bytes).

Anyway, there is a lot of translation done in software (H19 CODE ROM),
and I'm not sure I got all that documented, but it is a start.

I used hexadecimal in the document, flame me if you want but I won't
turn crispy.

[Norberto Collado]

Hello Dan,

Yes on the second board and thanks for all your support! Do you have my address?

Thanks,

Norberto

-------- Original Message --------
Subject: Re: [sebhc] H19C Terminal Board!

--

You received this message because you are subscribed to the Google Groups "SEBHC" group.
To unsubscribe from this group and stop receiving emails from it, send an email to sebhc+un...@googlegroups.com.
To post to this group, send email to se...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/67d412e0-6f77-45fb-8a74-147790d06736%40googlegroups.com.

[Glenn Roberts]

Wow. I’ve got an 85-2237-2 (yet another number!) in my H19 with the dead CRT.  Didn’t realize there were so many variants.

 

From: se...@googlegroups.com [mailto:se...@googlegroups.com] On Behalf Of Norberto Collado
Sent: Thursday, January 05, 2017 8:36 PM
To: se...@googlegroups.com
Subject: RE: [sebhc] H19C Terminal Board!

 

Hello Dan,

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/20170105183618.1321cca37f09b4ab87c5049afdc8ceaa.ef7fbede08.wbe%40email09.godaddy.com.

[Norberto Collado]

Thanks for the file Douglas. Hex is fine with me and every information that I can get on my hands it will allow me to design the board in a way that I can support easily!

Norberto

--
You received this message because you are subscribed to the Google Groups "SEBHC" group.
To unsubscribe from this group and stop receiving emails from it, send an email to sebhc+un...@googlegroups.com.
To post to this group, send email to se...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/586EE044.4050202%40durgadas.com.

[Dan Emrick]

Norberto,

Yes, and the package will be on its way tomorrow. 

Don't let the inner packing box confuse you.  I re-used a box from a PC MoBo I recently purchased.

I believe the board to be operational, but did not test before packaging.

Keep as long as you need it, but I would like to put it back into and H89 at some point.  Again, no rush.

Dan

[Norberto Collado]

Thanks!

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/0a49041d-86c6-4a3c-8bb9-0efeb36f536d%40googlegroups.com.

[Mark Garlanger]

BTW, there were at least 4 different Terminal boards.

85-2237-2	042479	Terminal Logic	H19/H89 Terminal Circuit board
85-2376-2	101579	Terminal Logic	H19/H89 Terminal Circuit board

85-2634-1

042381

Terminal Logic

H19/H89 Terminal Circuit board

and the 85-2650-1 that Dan is sending. I'm guess the 2650 is the last one Heath made.

Mark

Thanks!

To unsubscribe from this group and stop receiving emails from it, send an email to sebhc+unsubscribe@googlegroups.com.

To post to this group, send email to se...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/0a49041d-86c6-4a3c-8bb9-0efeb36f536d%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

--

You received this message because you are subscribed to the Google Groups "SEBHC" group.

To unsubscribe from this group and stop receiving emails from it, send an email to sebhc+unsubscribe@googlegroups.com.

To post to this group, send email to se...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/20170106102457.1321cca37f09b4ab87c5049afdc8ceaa.88b3814347.wbe%40email09.godaddy.com.

[Glenn Roberts]

the small 6 digit number is the date I presume?  (042479, etc.)

 

Thanks!

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/0a49041d-86c6-4a3c-8bb9-0efeb36f536d%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

--
You received this message because you are subscribed to the Google Groups "SEBHC" group.

To unsubscribe from this group and stop receiving emails from it, send an email to sebhc+un...@googlegroups.com.
To post to this group, send email to se...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/20170106102457.1321cca37f09b4ab87c5049afdc8ceaa.88b3814347.wbe%40email09.godaddy.com.

For more options, visit https://groups.google.com/d/optout.

 

--

You received this message because you are subscribed to the Google Groups "SEBHC" group.
To unsubscribe from this group and stop receiving emails from it, send an email to sebhc+un...@googlegroups.com.
To post to this group, send email to se...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/CAAjkm7_u9JAkOZGdxp_cmHNV-QnHJnZtjV67mRXMLUZJTTfJhA%40mail.gmail.com.

[Mark Garlanger]

Yes, all Heath's boards had a date code on them.

Thanks!

To unsubscribe from this group and stop receiving emails from it, send an email to sebhc+unsubscribe@googlegroups.com.

To post to this group, send email to se...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/0a49041d-86c6-4a3c-8bb9-0efeb36f536d%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

--
You received this message because you are subscribed to the Google Groups "SEBHC" group.

To unsubscribe from this group and stop receiving emails from it, send an email to sebhc+unsubscribe@googlegroups.com.

To post to this group, send email to se...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/20170106102457.1321cca37f09b4ab87c5049afdc8ceaa.88b3814347.wbe%40email09.godaddy.com.

For more options, visit https://groups.google.com/d/optout.

--
You received this message because you are subscribed to the Google Groups "SEBHC" group.

To unsubscribe from this group and stop receiving emails from it, send an email to sebhc+unsubscribe@googlegroups.com.

To post to this group, send email to se...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/CAAjkm7_u9JAkOZGdxp_cmHNV-QnHJnZtjV67mRXMLUZJTTfJhA%40mail.gmail.com.
For more options, visit https://groups.google.com/d/optout.

--

You received this message because you are subscribed to the Google Groups "SEBHC" group.

To unsubscribe from this group and stop receiving emails from it, send an email to sebhc+unsubscribe@googlegroups.com.

To post to this group, send email to se...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/002901d2686b%24b7148390%24253d8ab0%24%40gmail.com.

[Norberto Collado]

I scanned the H19A schematics for the TLB and the Video board as well. Links here:

 

http://koyado.com/Heathkit/H19C_Terminal_files/H19A_Schematics.pdf.zip

 

http://koyado.com/Heathkit/H19C_Terminal_files/H19A_Video_Schematics.pdf.zip

 

Thanks,

Norberto

[Kenneth L. Owen]

Hi Norberto,

 

Attached are the H89 TLB and Video Boards redrawn for the TMSI Flicker-Free modification.

 

-- ken

 

From: Norberto Collado

Sent: Saturday, January 07, 2017 7:33 PM

To: se...@googlegroups.com

Subject: Re: [sebhc] H19C Terminal Board!

 

I scanned the H19A schematics for the TLB and the Video board as well. Links here:

--

You received this message because you are subscribed to the Google Groups "SEBHC" group.
To unsubscribe from this group and stop receiving emails from it, send an email to sebhc+un...@googlegroups.com.
To post to this group, send email to se...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/FECB32F8-7569-4D27-B489-669B2A21621B%40koyado.com.

[Terry Gulczynski]

Ken,

On the TLB diagram, you have Address Bus A11 and A12 shorted together between JP4 and JP5.  That can't be right - there has to be a cut trace in there somewhere.

Regards,

Terry

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/3B29B33198834D69A43E49C858D174D6%40KenPSPC.

[Lee Hart]

Terry Gulczynski wrote:
> Ken,
>
> On the TLB diagram, you have Address Bus A11 and A12 shorted together
> between JP4 and JP5. That can't be right - there has to be a cut trace
> in there somewhere.

The Heath 444-46 ROM had A11 on pin 18. The 27C32 replacement supplied
with the Low-Power kit had /CE on pin 18. The jumper change shown on
Ken's schematic is only correct if you are replacing the 444-46 with a
27C32.

Background: The Flicker-Free kit came first. Then it was expanded to the
Low-Power kit (which included the Flicker-Free mod and new EPROMs). Then
the Superset (which had both, plus new firmware in the ROMs).

The key points for the Flicker-Free mod were as follows (parts
designators are for the H19A TLB; the older H19 TLB designators were
different):

- Increase Z80 clock speed from the stock 2 MHz to 3 MHz.
- Replace U412 (74LS00) with a faster 74F00.
- Replace U435 (74LS138) with a faster 74F138.
- Replace U408-U411 (2114) with faster 1K RAMs with at least a
200 nsec access time (2114-2, 5514-2, 2148, etc.)
- Bend out pin 1 of U424 (74LS273) and tie it to +5v. This removes
the "black flecks" that used to appear when the Z80 wrote
to screen RAM.

The 74F138 is then patched so it multiplexes the RAM between Z80 and
6845 at a 1.5 MHz rate. The phase of the 1.5 MHz clock is chosen so it
just happens to enable RAM for the 6845 when it needs a character for
video, and just happens to enable RAM for the Z80 when it does its reads
or writes.

As I got more familiar with the various chips and revisions of the TLB,
I found additional changes that might be needed.

- You may need to replace the Z80 with a faster Z80A.
- You may have to replace the firmware ROMs with faster ones
(which I did when it became the Low-Power kit). The new
EPROMs I supplied were single-supply CMOS parts, and needed
some jumper changes compared to Heath's 3-supply parts.
- The noise filter inductors and capacitors Heath added in the -A
versions introduced rather variable timing delays. I had to
either remove some of them, or add other capacitors to restore
timing accuracy to neatly interleave Z80/video accesses.

Hope this helps!

[Kenneth L. Owen]

Hi Terry,

 

I looked at the print wiring for JP5 and it did not make sense to me either!  So, I pulled the board from my H89 and found that what was shown on the drawing was indeed wrong.  Attached is a revised drawing for what I found on the working TLB.

 

-- ken

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/55d4f9c3-7f96-e84e-572a-18d8932bb1c1%40cfl.rr.com.

[Terry Gulczynski]

Ken,

That looks better to me.  I'll stick with 'do not short the CPU's A11 and A12 bus lines together' as a good rule of thumb.


Terry

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/E6B50CA992A448DC81BF963CF3490755%40KenPSPC.

[Norberto Collado]

Great and thank you for the information and will add to the website.

 

Norberto

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/3B29B33198834D69A43E49C858D174D6%40KenPSPC.

[Norberto Collado]

Hello Dan,

I did receive the board and it just looks brand new. What I noticed already is that on P401 connector, pin 1 is on the right side. I wonder if the attached connector is the same for P401 before ordering some.

Also the board gives me the holes to attached it to the TLB bracket, so that it will be easy to replace.

Thanks for all your help,

Norberto

-------- Original Message --------
Subject: Re: [sebhc] H19C Terminal Board!

From: Dan Emrick <dsem...@verizon.net>
Date: Fri, January 06, 2017 8:52 am
To: SEBHC <se...@googlegroups.com>

Norberto,

Yes, and the package will be on its way tomorrow. 

Don't let the inner packing box confuse you.  I re-used a box from a PC MoBo I recently purchased.

I believe the board to be operational, but did not test before packaging.

Keep as long as you need it, but I would like to put it back into and H89 at some point.  Again, no rush.

Dan



On Thursday, January 5, 2017 at 8:36:20 PM UTC-5, Norby wrote:

Hello Dan,

Yes on the second board and thanks for all your support! Do you have my address?

Thanks,

Norberto

-------- Original Message --------
Subject: Re: [sebhc] H19C Terminal Board!

From: Dan Emrick <dsem...@verizon.net>
Date: Thu, January 05, 2017 2:07 pm
To: SEBHC <se...@googlegroups.com>

Hi, Norberto,

I have an 85-2376-2 (1979) and an 85-2650-1 (1981).  The first is probably not what you need.  The second has a full sized shield on the back, a flat rectangular heat-sync on the component side plus the keyboard connector pins point down rather than perpendicular to the board.  Might this be what you need?

Dan

On Thursday, January 5, 2017 at 12:57:59 PM UTC-5, Norby wrote:

I was wondering if someone has an spare H19A terminal board that I could borrow to support this design and it doesn't need to be operational. My experience with the H89-SBC design was that the Heath schematics had so many mistakes and Jack provided an H89 Heath board which I used to trace the signals to ensure proper connection and that was invaluable when I power-on the new H89-SBC system for the first time.

Thanks,

Norberto

 

--
You received this message because you are subscribed to the Google Groups "SEBHC" group.
To unsubscribe from this group and stop receiving emails from it, send an email to sebhc+un...@googlegroups.com.
To post to this group, send email to se...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/67d412e0-6f77-45fb-8a74-147790d06736%40googlegroups.com.

For more options, visit https://groups.google.com/d/optout.

--
You received this message because you are subscribed to the Google Groups "SEBHC" group.
To unsubscribe from this group and stop receiving emails from it, send an email to sebhc+un...@googlegroups.com.
To post to this group, send email to se...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/0a49041d-86c6-4a3c-8bb9-0efeb36f536d%40googlegroups.com.

[Dan Emrick]

Hi, Norberto,

I believe the original connector has round posts instead of square, but that may not matter; may even be better.  Also, the original is not a locking style - again, may not matter.  Careful measurement of the connector on the board is all I can recommend.

I have been unable to find a part number or even a Heathkit reference number for the connector.  The TLB came pre-assembled even in the kits so I guess Heathkit didn't feel it necessary to describe the components - although they did for the CPU board.  The kit did require assembly of the connecting cable between the CPU board and P401.  I found a Heathkit number but nothing cross-referencing it to a "real world" part number.

FWIW, I've attached a scan of the pictorial for the TLB for model 85-2166 - which is NOT the board I sent to you but may be helpful in some way.  I note that some boards do not have pin numbers but rather wire colors - maybe just the kit versions.

Dan

[Lee Hart]

Dan Emrick wrote:
> I believe the original connector has round posts instead of square, but

> that may not matter; may even be better. I have been unable to find a

> part number or even a Heathkit reference number for the connector.

The H19/89 power connectors are a common standard product, still
available today. It's the Molex KK series, with pins on 0.156" centers.
Digikey.com WM4628-ND for example.

As I recall, the early round pins had a current rating of 3 amps; the
square ones 5 amps. Heath discovered the difference in the power supply,
where the round pins of the +8vac supply would burn up. For the TLB,
either round or square are fine.

There are dozens of variations in this connector family. On the H-1000,
I used ones with double-length pins. Since Heath used both 10-pin and
11-pin connectors for H89 and H19A respectively, this way I had both
versions on one board. The long pins allowed you to stack *two*
connectors on one set of pins.

The long pins can also be used to stack two boards. For example, Heath
could have eliminated the jumper cable between the CPU and TLB, and just
have one board plug directly into the other.

From: Dan Emrick
> I have an 85-2376-2 (1979) and an 85-2650-1 (1981). The
> first is probably not what you need. The second has a
> full sized shield on the back, a flat rectangular
> heat-sync on the component side

The metal square on the front is just an RF shield over the crystal
oscillator.

[Norberto Collado]

Thanks for the pictorial scan as it helps me with the part placements and board layout!

Norberto

-------- Original Message --------
Subject: Re: [sebhc] H19C Terminal Board!
From: Dan Emrick <dsem...@verizon.net>
Date: Tue, January 17, 2017 6:18 am
To: SEBHC <se...@googlegroups.com>

Hi, Norberto,

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/2adb29ba-dc64-4b52-b943-db2a9188529f%40googlegroups.com.

[Norberto Collado]

Thanks Lee for the Molex KK information, very helpful.

Norberto

-------- Original Message --------
Subject: Re: [sebhc] H19C Terminal Board!

From: Lee Hart <leea...@earthlink.net>
Date: Tue, January 17, 2017 12:44 pm
To: se...@googlegroups.com

Dan Emrick wrote:
> I believe the original connector has round posts instead of square, but

> that may not matter; may even be better. I have been unable to find a

> part number or even a Heathkit reference number for the connector.

The H19/89 power connectors are a common standard product, still
available today. It's the Molex KK series, with pins on 0.156" centers.
Digikey.com WM4628-ND for example.

As I recall, the early round pins had a current rating of 3 amps; the
square ones 5 amps. Heath discovered the difference in the power supply,
where the round pins of the +8vac supply would burn up. For the TLB,
either round or square are fine.

There are dozens of variations in this connector family. On the H-1000,
I used ones with double-length pins. Since Heath used both 10-pin and
11-pin connectors for H89 and H19A respectively, this way I had both
versions on one board. The long pins allowed you to stack *two*
connectors on one set of pins.

The long pins can also be used to stack two boards. For example, Heath
could have eliminated the jumper cable between the CPU and TLB, and just
have one board plug directly into the other.

From: Dan Emrick

> I have an 85-2376-2 (1979) and an 85-2650-1 (1981). The
> first is probably not what you need. The second has a
> full sized shield on the back, a flat rectangular
> heat-sync on the component side

The metal square on the front is just an RF shield over the crystal
oscillator.

--
Teaching children to program goes against the grain of modern education.
Just imagine the chaos if they learned to think logically, plan, create,
implement, test, and execute!
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com

--
You received this message because you are subscribed to the Google Groups "SEBHC" group.
To unsubscribe from this group and stop receiving emails from it, send an email to sebhc+un...@googlegroups.com.
To post to this group, send email to se...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/587E822C.6070601%40earthlink.net.