SOLVED ntsc sinclar ql schematics ??

[techy]

Is there any information available about the usa / ntsc version of the ql ??

does a service manual excist ?

[Dave]

The only changes to the US QL from the German QL are:

• US modulator/filters/xtal and modest component value changes around MC1377.

• A bodge board glued on the RAM from the clock crystal that passes the clock through two inverting gates to buffer and clean it up a bit. This gets the clock much closer to a 50/50 duty cycle.

• The OS sets a bit in the 8301 to NTSC. This is the only difference in JSU from JS. Only one ROM IC is affected so the other ROM will likely just say JS. The character set, default Mode 2 resolutions and window positions are different.

• The incoming 9VAC nominal line is wrapped through a large circular ferrite ring to reduce noise.

• On some units, extra tantalum bead capacitors are laid diagonally from Vdd to Vss to decrease ground bounce.

• The interior of the enclosure is metalized and contains grounding strips to force good electrical contact between the shell halves.

[Peter]

A little off topic, but what was the US QL keyboard layout? Was it close to UK?

[Dave]

Exact UK layout no changes.

[martyn_hill]

Hi Peter

To be fair, the UK keyboard was already pretty much based on the US layout - something I was surprised to discover when developing the extra language maps for the Qbase

[Derek_Stewart]

Hi,

I was updating the QL Service Manual, which details only Issue 5, 6 UK boards.

Is the USA and German QL circuit board require to be detailed.

The problem, I do not have either these QL boards, so it would be guesswork.

[techy]

Thanks for this info ( kept me searching for some time )


regarding the rgb output , will that still be the same as our uk versions ?

[Derek_Stewart]

The only changes to the US QL from the German QL are:

• US modulator/filters/xtal and modest component value changes around MC1377.

• A bodge board glued on the RAM from the clock crystal that passes the clock through two inverting gates to buffer and clean it up a bit. This gets the clock much closer to a 50/50 duty cycle.

• The OS sets a bit in the 8301 to NTSC. This is the only difference in JSU from JS. Only one ROM IC is affected so the other ROM will likely just say JS. The character set, default Mode 2 resolutions and window positions are different.

• The incoming 9VAC nominal line is wrapped through a large circular ferrite ring to reduce noise.

• On some units, extra tantalum bead capacitors are laid diagonally from Vdd to Vss to decrease ground bounce.

• The interior of the enclosure is metalized and contains grounding strips to force good electrical contact between the shell halves.

Hi,

I have added this detail to the QL Service Manual update.

[bwinkel67]

regarding the rgb output , will that still be the same as our uk versions ?

The RGB is, yes. The one small difference is that the US QL's (as well as some other regions) don't seem to give a color composite signal on pin 1. Instead, it just outputs 5 volts. You can grab the composite off of the MC1377. The monochrome composite is, however available on pin 3.

[techy]

Thanks to all ,

this has given me a clear insight in the differences between the versions .

And would also benefit others to know them .