‘Tatung 81’ (ZX81 in a case)

Discussions about Sinclair ZX80 and ZX81 Hardware
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BarryN
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Re: ‘Tatung 81’ (ZX81 in a case)

Post by BarryN »

Lardo Boffin wrote: Fri May 28, 2021 1:58 pm Plugged in and switched on - no explosions! Also very little voltage at the 9V plug by the zeddy. About 0.08 so not much going to happen there!

Hey ho.
So then, with only 0.08V out from the 9V power supply, I'm guessing it doesn't work yet.
Lardo Boffin
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Re: ‘Tatung 81’ (ZX81 in a case)

Post by Lardo Boffin »

BarryN wrote: Fri May 28, 2021 4:15 pm
Lardo Boffin wrote: Fri May 28, 2021 1:58 pm Plugged in and switched on - no explosions! Also very little voltage at the 9V plug by the zeddy. About 0.08 so not much going to happen there!

Hey ho.
So then, with only 0.08V out from the 9V power supply, I'm guessing it doesn't work yet.
Sadly not. I will remove the zeddy from the case and try that. Hopefully that will be ok then it is just a matter of deciding what to do about the PSU.
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
Lardo Boffin
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Joined: Sat Nov 26, 2016 2:42 am

Re: ‘Tatung 81’ (ZX81 in a case)

Post by Lardo Boffin »

In amongst the box of stuff I also found this lot:
F552486F-8882-43EE-AA7E-5645E33A8F81.jpeg
B5B2BB33-3541-4DEA-972F-36665C9F9A27.jpeg
5ACD011E-BCC3-49D8-AEA5-C04ECC2D3785.jpeg
44B85CB4-A971-47EA-A2E9-67FB0251B735.jpeg
2C29F5E3-1DDA-49A6-8187-115FE17A5619.jpeg
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
Lardo Boffin
Posts: 2160
Joined: Sat Nov 26, 2016 2:42 am

Re: ‘Tatung 81’ (ZX81 in a case)

Post by Lardo Boffin »

And
369D943D-D041-4144-9D86-6F699E760F63.jpeg
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
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1024MAK
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Location: Looking forward to summer in Somerset, UK...

Re: ‘Tatung 81’ (ZX81 in a case)

Post by 1024MAK »

Lardo Boffin wrote: Fri May 28, 2021 1:58 pm Plugged in and switched on - no explosions! Also very little voltage at the 9V plug by the zeddy. About 0.08 so not much going to happen there!

Hey ho.
Aren’t you supposed to connect up to a nuclear power station first? :roll: :lol:

So have you checked those fuses? Obviously with the power off, use the continuity range or the resistance range.

Next up, just unplug the 9V power jack plug and use a normal Sinclair PSU...

OR, power up the existing power supply and test the voltage across the leads of both of the large electrolytic capacitors. But do be careful to keep clear of the mains wiring, fuses and connections.

Mark
ZX81 Variations
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:!: Standby alert :!:
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb :!:
Looking forward to summer later in the year.
Lardo Boffin
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Joined: Sat Nov 26, 2016 2:42 am

Re: ‘Tatung 81’ (ZX81 in a case)

Post by Lardo Boffin »

1024MAK wrote: Fri May 28, 2021 6:27 pm
Lardo Boffin wrote: Fri May 28, 2021 1:58 pm Plugged in and switched on - no explosions! Also very little voltage at the 9V plug by the zeddy. About 0.08 so not much going to happen there!

Hey ho.
Aren’t you supposed to connect up to a nuclear power station first? :roll: :lol:

So have you checked those fuses? Obviously with the power off, use the continuity range or the resistance range.

Next up, just unplug the 9V power jack plug and use a normal Sinclair PSU...

OR, power up the existing power supply and test the voltage across the leads of both of the large electrolytic capacitors. But do be careful to keep clear of the mains wiring, fuses and connections.

Mark
I’m legal not allowed to go near power stations… :?

I checked the fuses with the continuity setting and both are fine. I will check the zeddy at some point.

When I’m feeling brave I will check the caps voltage. I managed to a fit a BuzzOff to my Vectrex without killing myself so hopefully will be ok!
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
Lardo Boffin
Posts: 2160
Joined: Sat Nov 26, 2016 2:42 am

Re: ‘Tatung 81’ (ZX81 in a case)

Post by Lardo Boffin »

The zeddy and keyboard work fine! Picture is pretty good as well. 8-)

6DB840A7-60CE-408E-987B-FA495E158E9E.jpeg
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
Lardo Boffin
Posts: 2160
Joined: Sat Nov 26, 2016 2:42 am

Re: ‘Tatung 81’ (ZX81 in a case)

Post by Lardo Boffin »

Maybe this is the home my rebuilt zeddy has been looking for?….
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
Lardo Boffin
Posts: 2160
Joined: Sat Nov 26, 2016 2:42 am

Re: ‘Tatung 81’ (ZX81 in a case)

Post by Lardo Boffin »

Found a spare ZX81 (minus case) in the box with the Tatung 81 - in a bag cunningly labelled ‘Replacement mainboard’ (check out the bent heatsink!). No K initially but after some chip swapping it is up and running. The Z80 had died - I’m pretty sure I have had more dead Z80’s than ULAs now.

B317E4A7-D313-480A-87FA-AE8D8D554364.jpeg

The heatsink on the ULA is of course nothing to do with me! I guess in the context of the size of the case it made some sense.
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
Lardo Boffin
Posts: 2160
Joined: Sat Nov 26, 2016 2:42 am

Re: ‘Tatung 81’ (ZX81 in a case)

Post by Lardo Boffin »

It is rather large!

9B222F7E-C1CB-469D-AB01-7C85F2F58587.jpeg
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
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