The Sinclair QL Forum

t0nyt wrote: Tue Mar 04, 2025 10:28 am Well the only line on the edge connector that has any power, according to my multi-meter, is the 9v line, and that is only 0.5v

Not sure what's going on though because when I check voltage at the FDD cable (where it meets the motherboard) I get no volts on my meter but the FDD powers up seemingly ok (both lights & mechanically)

It seems like the multi-meter is the problem, but it works when tested with batteries or walwarts

tofro wrote: Tue Mar 04, 2025 10:32 am

t0nyt wrote: Tue Mar 04, 2025 10:28 am Well the only line on the edge connector that has any power, according to my multi-meter, is the 9v line, and that is only 0.5v

Not sure what's going on though because when I check voltage at the FDD cable (where it meets the motherboard) I get no volts on my meter but the FDD powers up seemingly ok (both lights & mechanically)

It seems like the multi-meter is the problem, but it works when tested with batteries or walwarts

You'll likely have not found a proper GND or have set the MM to AC voltage.

t0nyt wrote: Tue Mar 04, 2025 11:08 am Well this is insane

I poked around a bit to try and find some voltage (using 6116 ground) and suddenly it all popped into life

The Speccy now works with the Opus attached and I get the start screen with the opus arrow thingy

My only concern at the moment, other than it stopping working again for no reason, is the the 9v line shows as 14v on my multi-meter (the 9v walwart I use normally for it shows as 12v on my meter though)

Any thoughts please?

Many thanks

tofro wrote: Tue Mar 04, 2025 11:14 am

t0nyt wrote: Tue Mar 04, 2025 11:08 am Well this is insane

I poked around a bit to try and find some voltage (using 6116 ground) and suddenly it all popped into life

The Speccy now works with the Opus attached and I get the start screen with the opus arrow thingy

My only concern at the moment, other than it stopping working again for no reason, is the the 9v line shows as 14v on my multi-meter (the 9v walwart I use normally for it shows as 12v on my meter though)

Any thoughts please?

Many thanks

Are the 14V under load (i.e. with the Spectrum connected and running) or open circuit? For the latter, it would be OK, for the former, it would create unnecessary heat in the Spectrum. (While most 7805 that are fed with this voltage are specified for 25V Vin max., closer to 9V is a lot better for the thermal sanity of your Spectrum)

t0nyt wrote: Tue Mar 04, 2025 11:23 am

tofro wrote: Tue Mar 04, 2025 11:14 am

t0nyt wrote: Tue Mar 04, 2025 11:08 am Well this is insane

I poked around a bit to try and find some voltage (using 6116 ground) and suddenly it all popped into life

The Speccy now works with the Opus attached and I get the start screen with the opus arrow thingy

My only concern at the moment, other than it stopping working again for no reason, is the the 9v line shows as 14v on my multi-meter (the 9v walwart I use normally for it shows as 12v on my meter though)

Any thoughts please?

Many thanks

Are the 14V under load (i.e. with the Spectrum connected and running) or open circuit? For the latter, it would be OK, for the former, it would create unnecessary heat in the Spectrum. (While most 7805 that are fed with this voltage are specified for 25V Vin max., closer to 9V is a lot better for the thermal sanity of your Spectrum)

Thanks tofro

Open circuit, so sounds ok please?

As it has a 6116 fitted already and I’ve burned & fitted the latest ROM, I guess my next job is to fit the gotek and make the original drive secondary and then see if they work

Many thanks

t0nyt wrote: Tue Mar 04, 2025 11:23 am

tofro wrote: Tue Mar 04, 2025 11:14 am
Are the 14V under load (i.e. with the Spectrum connected and running) or open circuit? For the latter, it would be OK, for the former, it would create unnecessary heat in the Spectrum. (While most 7805 that are fed with this voltage are specified for 25V Vin max., closer to 9V is a lot better for the thermal sanity of your Spectrum)

Thanks tofro

Open circuit, so sounds ok please?

XorA wrote: Tue Mar 04, 2025 11:41 am If I remember correctly you will need a tape/tape image to make the boot floppy unless you already have one or an image thereof!