Return-Path: Delivered-To: craig@sbc-85.com Received: from gator4254.hostgator.com by gator4254.hostgator.com with LMTP id uiMoDhRWCWXYuQ0AcizydQ (envelope-from ) for ; Tue, 19 Sep 2023 03:04:36 -0500 Return-path: Envelope-to: craig@sbc-85.com Delivery-date: Tue, 19 Sep 2023 03:04:36 -0500 Received: from smtp31.cix.co.uk ([77.92.64.18]:38477 helo=smtp1.cix.co.uk) by gator4254.hostgator.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1qiVil-003lth-0K for craig@sbc-85.com; Tue, 19 Sep 2023 03:04:36 -0500 Received: (qmail 23582 invoked from network); 19 Sep 2023 09:04:23 +0100 DKIM-Signature: v=1; a=rsa-sha1; c=relaxed/relaxed; d=logicmagic.co.uk; s=cix; x=1695715463; h=Message-ID:From:To: References:In-Reply-To:Subject:Date:Organization:MIME-Version: Content-Type:Importance:X-Mailer; bh=YC7oe6nx1xy4iqcyRghoQhmffRw =; b=O9aYZ3zFAziLhmUU8N1c5wyxXAn19p6Un78SNNuvOQ4lJREBz21h0+Cw57y Wgbxup/mQ36AeOmWFC6htu/gCZtFWZXrc8FtF9NKWCZLEU0pAjqoLFmmIZuet4nv +8JDxkyqKs/2LE0gOj3wmdBoo/ySrS0Kbq/l8ZvUcdB5w8ZM= Received: from unknown (HELO LM010) (86.129.211.241) by smtp1.cix.co.uk with SMTP; 19 Sep 2023 09:04:23 +0100 Message-ID: From: "Sid Jones" To: References: <002301d96665$7d4627a0$77d276e0$@sbc-85.com> <5BF15F2CAC7942E8AA92A5CF7141C4CF@LM010> <098201d9ea99$e990b110$bcb21330$@sbc-85.com> In-Reply-To: <098201d9ea99$e990b110$bcb21330$@sbc-85.com> Subject: Re: imm6-28 board layout... Date: Tue, 19 Sep 2023 09:04:20 +0100 Organization: Logic/Magic MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0042_01D9EAD8.46944D20" X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 16.4.3528.331 X-MimeOLE: Produced By Microsoft MimeOLE V16.4.3528.331 X-Spam-Status: No, score=-0.7 X-Spam-Score: -6 X-Spam-Bar: / X-Spam-Flag: NO This is a multi-part message in MIME format. ------=_NextPart_000_0042_01D9EAD8.46944D20 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Thanks for the update! I=E2=80=99m digging through the logic of the memory board to see how it = does the in/out and nibble business. If I find anything of interest, = I=E2=80=99ll report! I=E2=80=99ve started powering up the boards and the total =E2=80=9310 = volts current so far looks a bit much for a PC PSU. (Well, my PSU is = rated at 0.5 A. Time to scrounge a beefier version?) And time for a bit = more testing. This is a bit of nostalgia, in that I started with this intellec 4 mod = 40 at Uni and then jumped to a MDS-888 (which is under my desk!) at my = one and only place of employment. Being spoiled by floppy discs (all of 500K) and missing out on the = cassette tape stage of microcomputer evolution, I later bought a = Series-III for my business. That=E2=80=99s in the garage... With its = =E2=80=98white=E2=80=99 cousin for spares... Given that PCs and Windows have gone in a direction that I do not wish = to follow, perhaps all these venerable beasts will take pride of place = on my desk again... Regards Sid From: craig@sbc-85.com=20 Sent: Tuesday, September 19, 2023 2:37 AM To: 'Sid Jones'=20 Subject: RE: imm6-28 board layout... Hi Sid, =20 For power, I just use a PC-AT power supply for these sorts of things = since it has all the +5V I ever need (30+ amps) and the -5V when I need = it. I do have to drop the -12 to -9V but I put a LM7909 on the = backplane for that purpose. =20 I have attached the build files for the imm6-28 reproduction board v1.0 I need to refresh my memory as to where I left off on this project. I = am pretty sure that I had fully tested this board, I do not see any = patches on the ones I built. The only thing on my change list is that = the ejector hole needs to be enlarged to 0.109=E2=80=9D =20 For the MOD 40, don=E2=80=99t you need to retain the byte1 byte2 = functionality for nibble transfers? If so, using a pair of 6168s may be = better. One for the low nibble, another for the high. The addresses up = through /MAD_11 could be wired right through to the chips. All of the = /CEn signals can be ignored. Changing from individual DataIN and DataOUT to a common Data I/O pin = presents the biggest issue. WDENBL is asserted when this board is = addressed and a /WRITE strobe goes low. The board then passes through = the write data and latches the data when /WR goes high. Then the actual = /WR to the RAM comes along, delayed by the two 9602 monostables. The = 3404 output presents that data byte RAM until the next data byte is = latched. That presents a problem with a common I/O pin since it will = cause contention when the RAM goes into a read mode and turns on = it=E2=80=99s output transceivers. =20 I was thinking that using a larger RAM was going to be trivial until I = started thinking about going from dedicated data in/out lines to a = common data I/O. I think that presents enough of a problem that it = isn=E2=80=99t worth considering larger RAM with common I/O. maybe I am = not seeing this correctly, it has been a long time since I looked at = this schematic or thought about this board. Maybe I did a video on the = details of this board so that future-me could catch up with what past-me = already figured out. Let me know if I am wrong. =20 Regards craig =20 =20 From: Sid Jones =20 Sent: Saturday, September 16, 2023 6:49 AM To: craig@sbc-85.com Subject: imm6-28 board layout... =20 I=E2=80=99m busy refurbishing an intellec 4 mod 40 and trying to get the = electronics work outside the box. =20 (I had this particular box =E2=80=93 SN/027 - back in 1975-1977 for my = post-grad studies.) =20 The CPU card works (with re-programmed 1702A EPROMs) on the backplane = out of the case. See pic! =20 However, I=E2=80=99m having to lash up several bench power supplies to = provide the amount of amps needed at 5 volts. =20 The original Power-1 PSUs work, but are awaiting a bit of soaking on = load in a safe environment, to check that they won=E2=80=99t go pop any = time soon. =20 Which brings me to the imm6-28 board, which cooks along at 1.25-2.5 = amps. A toasty 6.25W-12.5W. For meagre 4 K of RAM. =20 You have a reproduced board design and I wonder if either a copy of the = PCB or the design files are available? =20 My thoughts are to jury rig said board to take something a bit less = power hungry, such as a pair of 6116 RAMs, to reduce stress and improve = reliability. =20 Comments gratefully received! =20 Regards =20 Sid Jones Logic/Magic 12 Meadowcroft Cross Lanes Wrexham GB LL13 0UJ =20 (44) 7836 592040 =20 =20 ------=_NextPart_000_0042_01D9EAD8.46944D20 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable
Thanks for the update!
 
I=E2=80=99m digging through the logic of the memory board to see = how it does the=20 in/out and nibble business. If I find anything of interest, I=E2=80=99ll = report!
 
 
I=E2=80=99ve started powering up the boards and the total = =E2=80=9310 volts current so far=20 looks a bit much for a PC PSU. (Well, my PSU is rated at 0.5 A. Time to = scrounge=20 a beefier version?) And time for a bit more testing.
 
 
This is a bit of nostalgia, in that I started with this intellec 4 = mod 40=20 at Uni and then jumped to a MDS-888 (which is under my desk!) at my one = and only=20 place of employment.
 
Being spoiled by floppy discs (all of 500K) and missing out on the = cassette=20 tape stage of microcomputer evolution, I later bought a Series-III for = my=20 business. That=E2=80=99s in the garage... With its = =E2=80=98white=E2=80=99 cousin for spares...
 
Given that PCs and Windows have gone in a direction that I do not = wish to=20 follow, perhaps all these venerable beasts will take pride of place on = my desk=20 again...
 
Regards
 
Sid
 
Sent: Tuesday, September 19, 2023 2:37 AM
Subject: RE: imm6-28 board layout...
 

Hi Sid,

 

For power, I just use a PC-AT power supply for = these sorts of=20 things since it has all the +5V I ever need (30+ amps) and the -5V when = I need=20 it.  I do have to drop the -12 to -9V but I put a LM7909 on the = backplane=20 for that purpose.

 

I have attached the build files for the imm6-28 = reproduction=20 board v1.0

I need to refresh my memory as to where I left off = on this=20 project.  I am pretty sure that I had fully tested this board, I do = not see=20 any patches on the ones I built.  The only thing on my change list = is that=20 the ejector hole needs to be enlarged to 0.109=E2=80=9D

 

For the MOD 40, don=E2=80=99t you need to retain = the byte1 byte2=20 functionality for nibble transfers?  If so, using a pair of 6168s = may be=20 better.  One for the low nibble, another for the high.  The = addresses=20 up through /MAD_11 could be wired right through to the chips.  All = of the=20 /CEn signals can be ignored.

Changing from individual DataIN and DataOUT to a = common Data=20 I/O pin presents the biggest issue.  WDENBL is asserted when this = board is=20 addressed and a /WRITE strobe goes low.  The board then passes = through the=20 write data and latches the data when /WR goes high.  Then the = actual /WR to=20 the RAM comes along, delayed by the two 9602 monostables.  The 3404 = output=20 presents that data byte RAM until the next data byte is latched.  = That=20 presents a problem with a common I/O pin since it will cause contention = when the=20 RAM goes into a read mode and turns on it=E2=80=99s output = transceivers.

 

I was thinking that using a larger RAM was going to = be=20 trivial until I started thinking about going from dedicated data in/out = lines to=20 a common data I/O.  I think that presents enough of a problem that = it isn=E2=80=99t=20 worth considering larger RAM with common I/O.  maybe I am not = seeing this=20 correctly, it has been a long time since I looked at this schematic or = thought=20 about this board.  Maybe I did a video on the details of this board = so that=20 future-me could catch up with what past-me already figured out.  = Let me=20 know if I am wrong.

 

Regards

craig

 

 

From: Sid Jones = <jonesthechip@logicmagic.co.uk>=20
Sent: Saturday, September 16, 2023 6:49 AM
To:=20 craig@sbc-85.com
Subject: imm6-28 board=20 layout...

 

I=E2=80=99m busy=20 refurbishing an intellec 4 mod 40 and trying to get the electronics work = outside=20 the box.

 

(I = had this=20 particular box =E2=80=93 SN/027 - back in 1975-1977 for my post-grad=20 studies.)

 

The = CPU card=20 works (with re-programmed 1702A EPROMs) on the backplane out of the = case. See=20 pic!

 

However, I=E2=80=99m=20 having to lash up several bench power supplies to provide the amount of = amps=20 needed at 5 volts.

 

The = original=20 Power-1 PSUs work, but are awaiting a bit of soaking on load in a safe=20 environment, to check that they won=E2=80=99t go pop any time=20 soon.

 

Which = brings me=20 to the imm6-28 board, which cooks along at 1.25-2.5 amps. A toasty = 6.25W-12.5W.=20 For meagre 4 K of RAM.

 

You = have a=20 reproduced board design and I wonder if either a copy of the PCB or the = design=20 files are available?

 

My = thoughts are=20 to jury rig said board to take something a bit less power hungry, such = as a pair=20 of 6116 RAMs, to reduce stress and improve=20 reliability.

 

Comments=20 gratefully received!

 

Regards

 

Sid=20 Jones

Logic/Magic

12=20 Meadowcroft

Cross = Lanes

Wrexham

GB = LL13=20 0UJ

 

(44) = 7836=20 592040

 

 

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