A poorly Zeddy

General Chit Chat about Sinclair Computers and their Clones
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Andy Rea
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A poorly Zeddy

Post by Andy Rea » Fri Sep 01, 2017 4:35 pm

Question what do you with with a zeddy that looks like this ?
Image

some may say scrap it.... but me...
Image

i see it as more of a re birth.... for a little project i have in mind :lol:

Andy
6 x ZX81, 1 x TS1500 , 1 x +3e, 1 x timex 2040 printer, 1 x timex 2020 cassette deck, siclair printer and some spectrum

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sirmorris
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Re: A poorly Zeddy

Post by sirmorris » Fri Sep 01, 2017 6:00 pm

Keep those pictures coming!
--=== ZXpand+ ... A more moderner all-in-one upgrade solution for ZX81 ===--
* SD/MMC storage * 32K Hires-capable RAM * AY sound chip * Joystick port * Serial *
* BASIC enhancements - plug & play * Reset button * Auto-boot facility *

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Andy Rea
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Location: notts UK

Re: A poorly Zeddy

Post by Andy Rea » Thu Sep 07, 2017 9:35 pm

a little more progress on the re-build
ula, cpu and rom socket in place... and a few other bits that are too big...
Image

I'm tying to squeeze most of the passives on the back side using SMD ( if i have the correct values )
Image

regards Andy
6 x ZX81, 1 x TS1500 , 1 x +3e, 1 x timex 2040 printer, 1 x timex 2020 cassette deck, siclair printer and some spectrum

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sirmorris
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Re: A poorly Zeddy

Post by sirmorris » Thu Sep 07, 2017 10:10 pm

DO IT! Only the best people have smd passives on the back side ;) ;)

With the right size you can place them between the pins. I think these are 0805s.
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IMG_4037.jpg
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But why would you want to remove obstructions from the top side? Careful. You know where this kind of tomfoolery ends up...

IMG_4048.jpg
IMG_4048.jpg (4.92 MiB) Viewed 419 times


WHAT ARE YOU DOING MAN! STOP IT! THINK OF THE CHILDREN!
--=== ZXpand+ ... A more moderner all-in-one upgrade solution for ZX81 ===--
* SD/MMC storage * 32K Hires-capable RAM * AY sound chip * Joystick port * Serial *
* BASIC enhancements - plug & play * Reset button * Auto-boot facility *

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Andy Rea
Posts: 1268
Joined: Fri May 09, 2008 1:48 pm
Location: notts UK

Re: A poorly Zeddy

Post by Andy Rea » Sun Sep 10, 2017 8:25 pm

more work on the board today, most of the top side done.
Image
The Bottom side, mix of through hole and smd.
Image
bit of a hodge podge of diodes :D
Image
bodge on a nearly empty RF can, you might notice no ear / mic circuit yet !
or memory :mrgreen:
Image
and after a little debugging and poking around with a scope i found 2 shorts,
one that i should have definitely spotted had i have looked properly, the other
a tiny solder splash across 2 adjacent tracks.
Image
i just need to add some ram... now then how do you fit an SMD ram chip into
an 81... oh yeah i remember now....
Image

Regards Andy
6 x ZX81, 1 x TS1500 , 1 x +3e, 1 x timex 2040 printer, 1 x timex 2020 cassette deck, siclair printer and some spectrum

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sirmorris
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Re: A poorly Zeddy

Post by sirmorris » Sun Sep 10, 2017 10:48 pm

YES! That's what I'm talkin' about ;)
--=== ZXpand+ ... A more moderner all-in-one upgrade solution for ZX81 ===--
* SD/MMC storage * 32K Hires-capable RAM * AY sound chip * Joystick port * Serial *
* BASIC enhancements - plug & play * Reset button * Auto-boot facility *

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1024MAK
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Location: Looking forward to summer in Somerset, UK...

Re: A poorly Zeddy

Post by 1024MAK » Mon Sep 11, 2017 8:09 am

sirmorris wrote:
Sun Sep 10, 2017 10:48 pm
YES! That's what I'm talkin' about ;)
Calm down lad, you're blow the top off your chip! :lol:

Mark

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Paul
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Re: A poorly Zeddy

Post by Paul » Mon Sep 11, 2017 8:16 am

You could solder the SMD RAM directly to the underside of the zeddy
In theory, there is no difference between theory and practice. But, in practice, there is.

nollkolltroll
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Re: A poorly Zeddy

Post by nollkolltroll » Mon Sep 11, 2017 1:50 pm

This is starting to look really interesting. Give us MORE!
/Adam

Zxkim81
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Joined: Sat Mar 18, 2017 6:44 pm

Re: A poorly Zeddy

Post by Zxkim81 » Tue Sep 12, 2017 7:58 pm

I take my hat off to you Andy and your vision for that poorly zeddy brought back to life is memorising.
Is that a re-designed ula on that atmega chip I see.😋
Well done Andy well done🤔

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