ZX Spectrum Harlequin rev. G problem with keyboard

A place to discuss the ZX80's and ZX81's younger brother - the Sinclair ZX Spectrum
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szymonu
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Joined: Tue Feb 14, 2017 7:03 pm

ZX Spectrum Harlequin rev. G problem with keyboard

Post by szymonu » Tue Feb 14, 2017 7:23 pm

Hello All,

I've bought recently in the Internet Harlequin rev. G board with all necessary parts.
After soldering - first test ... power on ... and success !!!
Screen ok. Sound ok.

But when I connected the keyboard it turned out that the keyboard didn't work :-(.

During soldering I had my doubts how to solder transistors 2SA1175.
On the board is mark ECB from bottom board to top.
B
C
E
In notes (datasheet) 2SA1175 transistor has: looking at flat side with text - from left to right - BCE.

It means that flat side with text should be on the left (on the board). I dit it in this way.
Unfortunately on many pictures with Harlequin rev. G is on the right :-(

Please help me!

Many thanks in advance.

RWAP
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Re: ZX Spectrum Harlequin rev. G problem with keyboard

Post by RWAP » Tue Feb 14, 2017 9:07 pm

You are best asking the seller of the board ....

It might also be asking shadow338 - see his post on viewtopic.php?t=1889

szymonu
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Joined: Tue Feb 14, 2017 7:03 pm

Re: ZX Spectrum Harlequin rev. G problem with keyboard

Post by szymonu » Tue Feb 14, 2017 9:20 pm

This is standard harlequin board rev. G.
See attached photo. My mainboard is the same.
Attachments
Harlequin_Rev_G_NTSC.jpg
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gozzo
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Re: ZX Spectrum Harlequin rev. G problem with keyboard

Post by gozzo » Tue Feb 14, 2017 11:19 pm

the E's of the transistors should definitely be towards the keyboard connector, other way round it certainly wont work, as for transistors pinout...according to the datasheet i've seen, the more sloped part of the case should be on the left, with the flatter side on the right..??

gozzo
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Re: ZX Spectrum Harlequin rev. G problem with keyboard

Post by gozzo » Tue Feb 14, 2017 11:20 pm

so..looks like you have them the wrong way round...

gozzo
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Re: ZX Spectrum Harlequin rev. G problem with keyboard

Post by gozzo » Tue Feb 14, 2017 11:24 pm

have just zoomed in on some pics of harlequin g boards, all have sloped part left, flatter part right....

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PokeMon
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Re: ZX Spectrum Harlequin rev. G problem with keyboard

Post by PokeMon » Wed Feb 15, 2017 11:09 am

On my Harlequin Rev. G both sides are flat - maybe it is a compatible transistor.

szymonu
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Joined: Tue Feb 14, 2017 7:03 pm

Re: ZX Spectrum Harlequin rev. G problem with keyboard

Post by szymonu » Wed Feb 15, 2017 9:24 pm

Issue is clear. Ben Versteeg helped me sending this pictures (attachments).

In the morning I desoldered transistors and put in correct position (side with text is on the right) and now keyboard is working properly.

I'm happy ;-) !
Attachments
Screen Shot 2017-02-15 at 09.19.46.png
Screen Shot 2017-02-15 at 09.19.46.png (161.58 KiB) Viewed 866 times

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