ZX Spectrum +2: Difference between revisions
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{{Infobox computer | {{Infobox computer | ||
| cpu = [[Z80|Z80A]] @ 3.5469MHz | | cpu = [[Z80|Z80A]] @ 3.5469MHz | ||
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*''Comments:'' Presumably the earliest versions of this board were created prior to the Sinclair takeover | *''Comments:'' Presumably the earliest versions of this board were created prior to the Sinclair takeover | ||
*''Place of manufacture: ''These boards appear to have been manufactured in Taiwan, this is embossed on the underside of the case. | *''Place of manufacture: ''These boards appear to have been manufactured in Taiwan, this is embossed on the underside of the case. | ||
*''Date of manufacture (batch):'' The date code for the PCB batch is recorded on the top right corner on the rear of the PCB in the traces | *''Date of manufacture (batch):'' The date code for the PCB batch is recorded on the top right corner on the rear of the PCB in the traces. | ||
*''Distinguishing features: ''Fitted with radial capacitors, 2 bodge resistors and a capacitor on the rear of the PCB. | *''Distinguishing features: ''Fitted with radial capacitors, 2 bodge resistors and a capacitor on the rear of the PCB. | ||
*''Problems:'' | *''Problems:'' | ||
**[https://www. | **[https://www.bytedelight.com/wp-content/uploads/2021/05/ZX-Spectrum-128K-video-fixes-and-video-cables.pdf Requires TR4 mod for misplaced transistor.] | ||
** Not only should TR4 be rotated but also TR7. If TR7 is mounted in the false direction then the transistor, which normally acts as an emitter follower, only acts as a diode. The base-collector-diode together with R65 realizes the OR function. But in this case A0 is loaded by 470 Ohm which would be avoided if TR7 would be mounted correct. ([https://www.worldofspectrum.org/forums/discussion/comment/834739/#Comment_834739 Ingo]) | ** Not only should TR4 be rotated but also TR7. If TR7 is mounted in the false direction then the transistor, which normally acts as an emitter follower, only acts as a diode. The base-collector-diode together with R65 realizes the OR function. But in this case A0 is loaded by 470 Ohm which would be avoided if TR7 would be mounted correct. ([https://www.worldofspectrum.org/forums/discussion/comment/834739/#Comment_834739 Ingo]) | ||
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*U-091998: 8639 [https://www.worldofspectrum.org/forums/discussion/comment/833728/#Comment_833728] | *U-091998: 8639 [https://www.worldofspectrum.org/forums/discussion/comment/833728/#Comment_833728] | ||
*U205749: 8641A [https://www.nightfallcrew.com/22/08/2009/sinclair-amstrad-zx-spectrum-2-in-the-grey-case-issue-3sinclair-amstrad-zx-spectrum-2-grigio-issue-3/] | *U205749: 8641A [https://www.nightfallcrew.com/22/08/2009/sinclair-amstrad-zx-spectrum-2-in-the-grey-case-issue-3sinclair-amstrad-zx-spectrum-2-grigio-issue-3/] | ||
''Photos'' | ''Photos'' | ||
*[https://www.nightfallcrew.com/22/08/2009/sinclair-amstrad-zx-spectrum-2-in-the-grey-case-issue-3sinclair-amstrad-zx-spectrum-2-grigio-issue-3/ Nightfall crew] | *[https://www.nightfallcrew.com/22/08/2009/sinclair-amstrad-zx-spectrum-2-in-the-grey-case-issue-3sinclair-amstrad-zx-spectrum-2-grigio-issue-3/ Nightfall crew] | ||
*[https://www.worldofspectrum.org/forums/discussion/comment/833728/#Comment_833728 MatGubbins] | *[https://www.worldofspectrum.org/forums/discussion/comment/833728/#Comment_833728 MatGubbins] | ||
[[Category:Spectrum]] | |||
[[Category:Hardware]] |
Latest revision as of 19:15, 26 May 2021
Infobox: ZX Spectrum +2
Manufacturer | Amstrad |
Mfg. volume | |
CPU | Z80A @ 3.5469MHz |
ROM | 64KB |
RAM | 128KB |
as pages | 8×16KB |
Gfx Res | 256×192 |
Gfx Colours | 15 (2 per 8×8 cell) |
- This article is about the early "Grey +2". For the later "Black +2" (+2A and +2B) see ZX Spectrum +3/2A/2B
Hardware Revisions
This is an attempt to pin down the various hardware revisions of the +2 Grey. There seem to be three main revisions of the PCB, within these there appear to be separate date coded batches
Z70500
- Comments: Presumably the earliest versions of this board were created prior to the Sinclair takeover
- Place of manufacture: These boards appear to have been manufactured in Taiwan, this is embossed on the underside of the case.
- Date of manufacture (batch): The date code for the PCB batch is recorded on the top right corner on the rear of the PCB in the traces.
- Distinguishing features: Fitted with radial capacitors, 2 bodge resistors and a capacitor on the rear of the PCB.
- Problems:
- Requires TR4 mod for misplaced transistor.
- Not only should TR4 be rotated but also TR7. If TR7 is mounted in the false direction then the transistor, which normally acts as an emitter follower, only acts as a diode. The base-collector-diode together with R65 realizes the OR function. But in this case A0 is loaded by 470 Ohm which would be avoided if TR7 would be mounted correct. (Ingo)
- Variants:
Standard 8632 (1986 Week 32)/ 8642 (1986 week 42): Schematic [1] Mid (1987? Week 21): ROM has text rotated on it, date code 8721 [2](image nvg)
Serial numbers:
- A six digit number proceeded by a U
- U-102726: 8632
Photos
Z70700
- Comments: Manufactured in the UK once stocks of the toast rack PCB were used up?
- Place of manufacture: These boards appear to have been manufactured in UK, this is embossed on the underside of the case.
- Date of manufacture (batch): The date code for the PCB batch is recorded on the bottom left corner on the PCB in the silkscreen
- Distinguishing features: Fitted with axial capacitors (excess stock left over from the toast rack?). Lots of small coloured stickers on the modulator and elsewhere in the case.
Variants:
- 3886 (1986 Week 38): Bodge resistor on bottom left hand corner of the board (R86?)
- 8640 (1986 Week 40): Colour of capacitors change [4] (Ben Verstee)
- 8645 (1986 Week 45): Colour of capacitors change, different diodes, changes to resistors in bottom left corner of the board [5] (Tom Dalby)
Serial numbers:
- A six digit number followed by a T, e.g.:
[6]:
Photos
0500 (Z70500 is on the rear side)
- Comments: A later variant of the Z70500 (see also) possibly originally for the French market, but UK versions also exist.
- Place of manufacture: Taiwan (embossed on bottom of case and PSU sticker).
- Date of manufacture (batch): ? 8641A listed on the front bottom silkscreen of later revisions
- Distinguishing features: Encased inductor, capacitor colour change, rear-side bodges of Z70500 corrected and paced on the front. Fixed HAL chip.
Variants:
- UK (1986 Week 37): [11] (Tom Dalby)
- UK 8641A (1986 week 41): Amstrad 4056 instead of PCF1306P [12] (nightfall crew)
- France (1986): The modulator and associated components are not fitted, French ROM (40068)[13] (moo5)
Serial numbers: A six digit number proceeded by a U
Photos