The Sinclair QL Forum

getting some flux on the suspected joint, and then 'sweating' the joing using hot air gun or soldering iron applied somewhere the heat can transfer can sometimes fix these hidden joints.

They can be a pig to find though...

t0nyt wrote: Thu Aug 14, 2025 3:10 pm 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!

Do you have a scematic or drawing, I could have go at makining one.

Pr0f wrote: Thu Aug 14, 2025 6:07 pm getting some flux on the suspected joint, and then 'sweating' the joing using hot air gun or soldering iron applied somewhere the heat can transfer can sometimes fix these hidden joints.

They can be a pig to find though...

Hi Pr0f,

I don't have any flux, just what's in the solder. I've tried re-flowing the joints I can reach without any luck

Have decided to build one more board tomorrow or the weekend, since my first 2 Mk 2's worked ok

Many thanks
Tony

Derek_Stewart wrote: Thu Aug 14, 2025 6:51 pm

t0nyt wrote: Thu Aug 14, 2025 3:10 pm 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!

Do you have a scematic or drawing, I could have go at makining one.

Hi Derek,

This is the Mk2 I built https://github.com/alvaroalea/QL_Minerva_MK2

The first 2 I built (1 socketed, 1 unsocketed to fit inside QL) both worked perfectly

The one I've built today is the same but with a 128k EEPROM and switch as per this thread

I also converted the socketed version to 128k without a problem, so am sure it's just my soldering or a faulty chip

Have decided to make 1 more attempt Friday or the weekend with the parts I have left

Thanks
Tony

Well that's frustrating as hell

Built up a new one and JS works BUT when I turn off and switch to Minerva I get the Minerva logo and then thin green lines down the screen

This was the already tested EEPROM from the socketed test version, so I assume it's probably ok. But I can't reprogram it now anyway

Not sure what other possible causes could be

t0nyt wrote: Fri Aug 15, 2025 2:33 pm Well that's frustrating as hell

Built up a new one and JS works BUT when I turn off and switch to Minerva I get the Minerva logo and then thin green lines down the screen

This was the already tested EEPROM from the socketed test version, so I assume it's probably ok. But I can't reprogram it now anyway

Not sure what other possible causes could be

This is the screen and MDV1 spins constantly too

t0nyt wrote: Fri Aug 15, 2025 3:16 pm

t0nyt wrote: Fri Aug 15, 2025 2:33 pm Well that's frustrating as hell

Built up a new one and JS works BUT when I turn off and switch to Minerva I get the Minerva logo and then thin green lines down the screen

This was the already tested EEPROM from the socketed test version, so I assume it's probably ok. But I can't reprogram it now anyway

Not sure what other possible causes could be

This is the screen and MDV1 spins constantly too


IMG_4955.jpeg

A short on one of the data lines?

XorA wrote: Fri Aug 15, 2025 3:19 pm

t0nyt wrote: Fri Aug 15, 2025 3:16 pm

t0nyt wrote: Fri Aug 15, 2025 2:33 pm Well that's frustrating as hell

Built up a new one and JS works BUT when I turn off and switch to Minerva I get the Minerva logo and then thin green lines down the screen

This was the already tested EEPROM from the socketed test version, so I assume it's probably ok. But I can't reprogram it now anyway

Not sure what other possible causes could be

This is the screen and MDV1 spins constantly too


IMG_4955.jpeg

A short on one of the data lines?

Just taking a look, thanks. Wouldn’t that affect JS as well though please?

Many thanks
Tony

Just taking a look, thanks. Wouldn’t that affect JS as well though please?

Hmmm it would, unless its your switch shorting to the data line!

XorA wrote: Fri Aug 15, 2025 3:47 pm

Just taking a look, thanks. Wouldn’t that affect JS as well though please?

Hmmm it would, unless its your switch shorting to the data line!

Thanks. Have re-done the switch connections and made sure there’s no shorts but still the same sadly