The Sinclair QL Forum

I've made some modifications to respin the 4MB SuperRAM board. I've re-positioned the GALs and CPU so they can all be socketed. I've moved some passives to better supply the ICs. Nasta has redesigned the logic to make it more flexible, which also required a track change. Finally, we inserted a miss...

Dave,

I'm going to poke it a few times first. Check for shorts etc.

Where the heck is the RTC battery?

Whopper

Dave,

Yeap. First thing I tried. Checked both computers working without SGC, both same noise & no output with the SGC.

Whopper

Vanpeebles,

Tried pressing RESET, no effect.

Whopper

Dave wrote:If there is a wire link, even with an external 5V supply, it still could be shorting 9V QL power to the 5V line.

can you check across the outside two pins

Opps. Didn't see this until I'd done the previous table

Dave, Naming the three pins from left to right, as shown in your photo, A, B and C Results - Resistance (Ohms) +ve to -ve A to B 35M B to C 1.3K A to C 34M -ve to +ve A to B 243K B to C 3.2K A to C 252K Diode test (Volts) +ve to -ve A to B 0.0 B to C 0.23 A to C 0.0 -ve to +ve A to B 0.56 B to C 0.6...

Dave,

I thought about the external power supply. I tried a 2.5A 5V wall wart I have, centre negative as per the manual. Just the same though.

Whopper

Vitaliy,

It's just the same with or without the original CPU fitted.


Whopper

Vitaliy,

On power up it makes a horrible sound (from around MDV_1.) The QL doesn't POST or anything else.



Dave,

If you PM me your address I'd be glad for you to have a look at it. Obviously I'd pay for postage both ways, and I think you're in Texas aren't you?

Whopper.

Vitaliy,

Do you have any circuit information for the SGC.

I know you were recently asking to borrow an SGC, I can't remember if you got one or not.

Whopper