The Sinclair QL Forum

Thanks for the extra info Pr0f, will help a lot

I assume I can just bridge pins 30 & 32 with a piece of resistor leg to get 5v to the correct place then please?

Have just dug out the resistors, switches and cables. Now I just have to wait for the eeprom’s

Many thanks
Tony

I've used that trick before too

I'm working on incorporate RTC to my 8-in-1 ROM, I have the idea, the PCB, but not finish, and I don't have estimated time to finish.

But whatever you do, you should do with smd, because I found there is no any way to made with through-hole and be able to close the cover of the QL.

aalea wrote: Sat Aug 09, 2025 11:42 pm I'm working on incorporate RTC to my 8-in-1 ROM, I have the idea, the PCB, but not finish, and I don't have estimated time to finish.

But whatever you do, you should do with smd, because I found there is no any way to made with through-hole and be able to close the cover of the QL.

As long as you put the 74ls on the underside of the pcb and don’t use any sockets the thru hole is a perfect fit under the keyboard (it’s no higher than one of Chr$ ROM boards)

I’m assuming the 1024k eeprom isn’t significantly taller than the 512k eeprom

I only need 2 ROMs, JS & Minerva 1.98, so don’t need to be able to re-program it.

It’s the I2c I’m more interested in, though the Rtc is nice to have (my QIMSI boot file sets the time via a WiFi modem normally and I’m currently using an SGC, so I can soft reset memory size, which has an Rtc)

Just realised that although there won’t be any issues with the initial test using the socketed version of mk2 when it comes to the final version the 128kb eeprom will foul the diodes and probably the battery leads

Will have to do what I did with the 74ls and solder the diodes to the underside of the PCB (possibly along with the battery leads) and then insulate the solder joints before soldering in the eeprom. Seems doable though… famous last words

Going to be tight with the trimmer too, but again just doable I think

128k EEPROMs arrived today

Have bodged the necessary connections on the eeprom with it fitted into the old socketed mk 2 board

Hopefully will get a chance to test in a QL tomorrow or Friday

Decided there’s no time like the present…

And it works!

Many thanks all

Next will come the fun of trying to build a version without the sockets

Built up a socketless version but it doesn’t work

Probably my lack of soldering skills so will have to see if I can spot any bad joints (highly likely) or shorts when I have time

Trouble is there’s joints under the eeprom I can’t access

Don’t think I can face building another!