16k internal RAM and graphics issue (I think).

[1024MAK]

Don’t bother with the 10kΩ resistor, as this is only required if you are fitting a battery back-up system [see http://www.zx81.de/english/32k-rame.htm ].
Without a battery, it serves no purpose.

With modern faster SRAM chips, sometimes a control line to the SRAM chip may need a low value capacitor (47pF to 100pF) to delay the timing. Connect between pin 20 and 0V/GND.

However, if BASIC runs okay, the first thing when having display problems is always to try different TVs/monitors. The normal SLOW mode from BASIC is not a standard broadcast video signal, and the various hi-res schemes will also not be generating a standard broadcast video signal. Hence some TVs/monitors may not like it.

Mark

[Papalapa]

Don’t bother with the 10kΩ resistor, as this is only required if you are fitting a battery back-up system [see http://www.zx81.de/english/32k-rame.htm ].
Without a battery, it serves no purpose.

With modern faster SRAM chips, sometimes a control line to the SRAM chip may need a low value capacitor (47pF to 100pF) to delay the timing. Connect between pin 20 and 0V/GND.

However, if BASIC runs okay, the first thing when having display problems is always to try different TVs/monitors. The normal SLOW mode from BASIC is not a standard broadcast video signal, and the various hi-res schemes will also not be generating a standard broadcast video signal. Hence some TVs/monitors may not like it.

Mark

Many thanks for the information Mark