BBC Master 128 Circuit Schematics (Remastered PDF)

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Ukwebb
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BBC Master 128 Circuit Schematics (Remastered PDF)

Post by Ukwebb »

As an admirer of the work of dv8 with the remastered pdf manuals, the only thing missing was the circuit diagrams.

As a result I decided to do my bit towards this preservation task and started to redraw the Circuit/Schematic Diagrams.

So as a first presentation, I give you the BBC Master 128 Diagram, completely re-drawn, Hi-res, full size (A0) PDF.

I've already started work on the BBC Micro version and I'll add that to this post as soon as I have it completed.

Printed out onto A3 or better still A2, these plans look super clean compare to any scans out there.

Although I've checked the drawings many times, if anyone notices any errors please let me know and I'll correct them.

Enjoy !


BBC Master 128 Circuit Schematic (latest update 07/07/2021)
bbc master circuit diagram.pdf
(255.47 KiB) Downloaded 24 times
Log of corrections completed:
26/05/2021 22:20 : corrected CO to CQ and Added A5/A6 ( missing from original ) on ICs 17/18/23/26
26/05/2021 22:36 : corrected L1 value to 33μH
27/05/2021 12:50 : correct C40 and C43 to 4n7
07/07/2021 : changed crystal near C86 on page 1 to X2
Last edited by Ukwebb on Wed Jul 07, 2021 12:45 pm, edited 7 times in total.
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IanS
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Re: BBC Master 128 Circuit Schematics (Remastered PDF)

Post by IanS »

Looks incredible, well done.

I haven't checked the original, but was curious why the A5/A6 pins are not labelled on the RAM (IC17/18/23/26). Aren't the data pins D0-D3, rather than all D0?
Ukwebb
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Re: BBC Master 128 Circuit Schematics (Remastered PDF)

Post by Ukwebb »

IanS wrote:
Wed May 26, 2021 9:58 pm
Looks incredible, well done.

I haven't checked the original, but was curious why the A5/A6 pins are not labelled on the RAM (IC17/18/23/26). Aren't the data pins D0-D3, rather than all D0?
Thats a very good question - I dont know.
2021-05-26 22_08_20-master1.gif (4096×2842).png
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IanS
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Re: BBC Master 128 Circuit Schematics (Remastered PDF)

Post by IanS »

Ah, the data pins should be labelled DQ, not D0.
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Ukwebb
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Re: BBC Master 128 Circuit Schematics (Remastered PDF)

Post by Ukwebb »

IanS wrote:
Wed May 26, 2021 10:21 pm
Ah, the data pins should be labelled DQ, not D0.
on which chip ? --

edit : forget that - I see now ! I'll edit that now !
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KarateEd
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Re: BBC Master 128 Circuit Schematics (Remastered PDF)

Post by KarateEd »

Just wondering if you're following the Copywrite and asked Acorn first.......

:roll: 8) :lol:
Ed...... :-)

3 working Beebs, 1 RetroClinic Master, 1 normal Master, 1 A3010, 1 Pi2 RISC OS, 2 broken Beeb Motherboards, 1 Omnibus A7000+ server, 1 A7000+ Desktop, 1 PET, 1 C64, 1 C128, 1 Amiga 500 and 1 Roamer.
Ukwebb
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Re: BBC Master 128 Circuit Schematics (Remastered PDF)

Post by Ukwebb »

thankyou :)
dp11
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Re: BBC Master 128 Circuit Schematics (Remastered PDF)

Post by dp11 »

C40 and C43 should be 4.7nf caps.
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DaveLecky
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Re: BBC Master 128 Circuit Schematics (Remastered PDF)

Post by DaveLecky »

Great work, a fantastic resource... =D>
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TobyLobster
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Re: BBC Master 128 Circuit Schematics (Remastered PDF)

Post by TobyLobster »

Nice. See also my circuit diagram for the BBC B https://tobylobster.github.io/mos/mos/S-s25.html
Ukwebb
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Re: BBC Master 128 Circuit Schematics (Remastered PDF)

Post by Ukwebb »

dp11 wrote:
Thu May 27, 2021 8:29 am
C40 and C43 should be 4.7nf caps.
thanks :) - fixed
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Re: BBC Master 128 Circuit Schematics (Remastered PDF)

Post by Ukwebb »

TobyLobster wrote:
Thu May 27, 2021 11:13 am
Nice. See also my circuit diagram for the BBC B https://tobylobster.github.io/mos/mos/S-s25.html
Nice work :) -
nice site too :)
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retroclinic
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Re: BBC Master 128 Circuit Schematics (Remastered PDF)

Post by retroclinic »

Both brilliant, well done.

Can either of you do a recreation now of the B+ and Compact schematics? The only ones available (that I know of) are really bad quality, these are the ones we could really do with having a good version of!

Thanks, Mark.
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arg
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Re: BBC Master 128 Circuit Schematics (Remastered PDF)

Post by arg »

TobyLobster wrote:
Thu May 27, 2021 11:13 am
Nice. See also my circuit diagram for the BBC B https://tobylobster.github.io/mos/mos/S-s25.html
Do you have the resources to produce variants for the different PCB issues (I'm not quite sure which issue yours is).

I have a dyeline print of Issue 3 BBC, though it's faded to almost unreadable having been stuck on the wall for some years. Notable differences are the Econet clock/terminator deleted from your version (empty space top right-hand corner), R172 (suppressing the audio buzz from the 1MHz bus connector), and minor changes around the printer port (the latter crudely drawn on this print - but obviously on the master from which the print was taken rather than my annotation; I think these were changes done as rework on earlier PCBs, maybe reworked on iss2 and rolled in to iss3, or maybe this print was meant to show how iss3 came out of the factory with rework done).
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TobyLobster
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Re: BBC Master 128 Circuit Schematics (Remastered PDF)

Post by TobyLobster »

arg wrote:
Fri May 28, 2021 9:21 am
Do you have the resources to produce variants for the different PCB issues (I'm not quite sure which issue yours is).
I don't, I only have the one diagram, which has no issue marked, but I would assume is Issue 7.
marcelaj1
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Re: BBC Master 128 Circuit Schematics (Remastered PDF)

Post by marcelaj1 »

Very useful and as it's a PDF you can text search it.
Spotted page 1 top right hand corner, 16MHz crystal should be X2.

Ashley.
Ukwebb
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Re: BBC Master 128 Circuit Schematics (Remastered PDF)

Post by Ukwebb »

marcelaj1 wrote:
Wed Jul 07, 2021 11:40 am
Very useful and as it's a PDF you can text search it.
Spotted page 1 top right hand corner, 16MHz crystal should be X2.

Ashley.
Thanks and amended :)
nicolagiacobbe
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Re: BBC Master 128 Circuit Schematics (Remastered PDF)

Post by nicolagiacobbe »

Wonderful. Thanks for the effort, it is gorgeous.
Ukwebb
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Re: BBC Master 128 Circuit Schematics (Remastered PDF)

Post by Ukwebb »

nicolagiacobbe wrote:
Thu Jul 15, 2021 8:22 pm
Wonderful. Thanks for the effort, it is gorgeous.
thankyou :)
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