ZXmore - questions and answers (FAQ)

[rune]

Hi Karl,

I may have found the problem. Resistor Array 1 is a 10K array instead 4.7K Do you think this would cause the problems? I cant do anything tonight but I'll try to get it swapped out tomorrow.

Dave

[PokeMon]

Hi David,

difficult to say for me - never tested.
I guess this is maybe not the problem with the resistor arrays.
You could do one other test, add a wire from pin 2 (A16) of IC4 (flash rom) which should immediately start a ZX81 session and let the led light up in blue colour. Just to see if this works as this is not complicate to start up ZXmaster software which requires more hardware components to be used.

About the flash rom contents - it is right about 00 or FF in unused data areas. Just belongs to alignments which are filled with NOPs while the ZXmaster instance is filled with FF in empty area. By the way - the rom is addressed inverted, $70000 is ZXmaster (instance 0), $60000 is instance 1 and so on.

Karl

[rune]

Hello Karl

I've desoldered the R1 array. Checked what was sent to me as a 4.7K array only to find its a 10K. Got some ordered but it will probably be Monday before it arrives.

I've replaced that big inductor with the same one that's in the build document.

You said to connect pin 2, but to where? I guess it needs to go high or low so 5v or ground?

I'll keep checking, and making off, connections between components until my resistors arrive.

If I press the reset button, sometimes (30%) the LED lights. Colours are random and the pattern on screen changes slightly.

Thanks for your help.

Dave

[PokeMon]

Yes - pin 2 directly to GND of flash rom. This is what the rotary switch does (if assembled which is optional).
If there is something wrong with the hardware, anything can happen with reset.
This doesn't really help. As long as there is no instance started, led colour would not light up at all.
So if ZX81 instance is started directly it is less complex and 50% of hardware is not used from ZX81 instance.

Anyway I offered you my help while sending me high resolution photos with email to info@ginger-electronic.com. If an array is wrong I would see as the 4k7 array has a yellow colour while the 10k arrays are black colour.

[rune]

Hi,

I've found a 4.7K resistor array at work and will put it in the board tonight and try the trick with ROM P2.

If nothing happens, I'll get some photos taken of each side and send of the PCB them to you. Your offer to look at them is really appreciated, I just wanted to try and fix it myself first. But its looking beyond my ability now.

Hopefully I will have learned a little more than I knew before.

Dave

[PokeMon]

Try that ZX81 hack with pin 2 tied to GND.

[Dim_75]

Hi all
As many here, i got the zxmore board (i received the already manufactured one from Karl two days ago). The board is quite impressive.
I couldn't wait for the weekend to test it so i give it a try yesterday night.

But it seems i may have some issues with mine, can you tell me if i did something wrong ?

I connected the ZXmore to my monitor and used a tested 9v power supply plugged in, taking care to avoid ESD
- i didn't use the Power supply of my ZX81 because i tested it before and my multimetre indicate 14,6v insted of 9v.
The voltage may decrease when connected but i was caution about using it so i took a 'modern' 9v power supply -

PluggedFirst.JPG

(75 KiB) Downloaded 396 times

Welcome screen where ok but some times with indication "no drive present" (i plugged an usb key with some P files).

I went on the instance #1 and typed in a very short programme to test it, run OK.
going back on instance #0, trying to go to menu Tools : no reaction i was not able to go to Tools' menu

open instance #2 (different color of the led ok), i had the cursor but when typing a line it loose the display and the led went off.

Freezed.JPG (46.56 KiB) Viewed 5157 times

No key responding, i had to press the reset button.

back to welcome screen, press a key and the next screen was displaying a very strange configuration screen with lines like :
* 1 ???? 6.5MHZ 64-64k CtrlOff (same thing for the 7 instances)

ZXMoreConfigKO.JPG (22.93 KiB) Viewed 5157 times

made reset again, seem to be normal but after typing a few lines of code , i went to instance 0, pressed T and the Zxmore hang again.
Reset again but all entered lines where gone.

Tryed also to load a programm from the usb key (fat 32).
First try i was not able to load a programme.

USB not reconized.JPG

(44.04 KiB) Downloaded 396 times

Second try, i loaded a P files and played a little : OK

Third try, i was on a new instance, i went to the load screen but it freezed indicating Version 00/00.0000 instead of 19/01.2017 !?

Version000000.JPG (33.04 KiB) Viewed 5157 times

After a fiew keys pressed trying to go back on the main screen, it loose display and i switch off the Zxmore.

Well, it seems a bit confusing
Does the 9v power supply is not enought ? Should i use the original ZX81 power supply giving near to 14,5 V ?
(it is working with my original ZX81)

Should i have to look at some part of the board to verify something ?

Last question, i wish to use also original tapes but this version of ZXmore do not have EAR and MIC connectosr anymore.
Is this option totaly diseabled or can we solder two 3.5mm audio jack at their initial place on the board ?

Thank for your help and advices
Demetris

[PokeMon]

Hi Demetris,

just the upper USB port is supported for loading and saving files.
Not sure if there is some bad contact or try to press all ICs in their seat carefully - maybe some loose contact ?

If the loader hangs for some reason, you can reset it with just an empty filename (NEWLINE only) and access loader again - it should show version message again. This works without power-off. A reset does not reset the USB chip and if there is unread data waiting it get confused. The empty filename tries to empty any queue while reading just 64k data.

And yes - EAR and MIC work in principle but requires the connectors. The rest is on board. I left them unsoldered at the second version of ZXmore (V2) because normally nobody uses the audio LOAD/SAVE option. You are one of the exceptions ...

Good luck,

Karl

PS: Pressing ENTER tries to load a system capture from USB disk - try to use another key as any key as long as you don't want a system restore (need system backup first).
PPS: Reset can be done best with pressing SHIFT during reset (with key or power-on) - this initiates a cold boot.
PPPS: And there may be some issue with the TOOLS menu, have to look here in the software.

[1024MAK]

14.6V from a Sinclair ZX81 PSU when not connected to a load (computer) is in the normal range (12V to 16V approx). The Sinclair PSU is only a smoothed DC type, there is no regulation system. When it is connected to a load (a ZX81 say), the voltage will drop to between 9V and 12V approx.

What is the current rating (in Amps) or the power rating (in Watts or in VA) of the PSU that you are using?

Mark

[PokeMon]

PS: Here you get the desired connectors for EAR and MIC:
https://www.sellmyretro.com/offer/details/3473