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tezza
October 3rd, 2008, 04:24 PM
Hi Guys,

One of the classic computers I've been looking for was a Sinclair QL. Well, I've now got one (see below) but, like many old Sinclairs, it suffers from a few (actually a lot) of non-working keys.

From reading on the web, this is likely to be the membrane. I've know where I can get a replacement, BUT before I order I want to be sure it IS a keyboard membrane and not an IC that drives the keyboard. The keys affected are all down one end. They are clustered at the top, right hand side of the keyboard. About 16 keys are affected.

I know in Commodore machines the chip driving the keyboard can fail, and affect certain keys. You can relate the affected keys to a published matrix (either one row fails or one column) which is a strong hint it is actually the chip rather than, say, a dirty keyboard. Anyone know of such a matrix chart published for the QL I could check? Or is it almost 100% certain it's the keyboard. All other keys apart from the ones that don't work at all seem fine.

My gut feeling says it's the membrane. Any comments?

http://www.classic-computers.org.nz/blog/images/08-10-04-sinclair-ql-web.jpg

(still a bit dusty..I need to give it a clean)

Tez

tezza
October 4th, 2008, 12:11 AM
Ok, I've done a bit more exploring and I'm sure it's the keyboard membrane.

I took the unit apart. I found that some of the keys that weren't working actually worked when I used them on the keyboard when it was folded back (and upside down). Simulating a keypress by squeezing the extacted membrane also worked with many non-working keys. However, when bent back over the motherboard (as it would be normally) these stopped working.

So, looks like it's time to order one.

http://www.classic-computers.org.nz/blog/images/08-10-04-sinclair-ql-open.jpg

Tez

Sharkonwheels
October 5th, 2008, 02:44 AM
Always wanted a QL....
System was WAY ahead of it's time, save for the silly WaferTapes...


T

channelmaniac
October 9th, 2008, 09:24 PM
The TS-1000 had problems with that silly plastic ribbon cracking just above the connection point on the motherboard. Take a close look at yours to see if it's cracked. If it is, and there's enough slack, you might be able to trim it back past the crack and plug it back into the board.

Use a bright light to shine through the silver traces. If there's a scratch or an area where it's worn through and breaking the trace you can get a silver pen and repair it.

RJ