Display problem

[1024MAK]

resonators
MURATA CSTLS6M50G53-B0 (Farnell), (Mouser)

For example…

Mark

[sP1d3r]

resonators
MURATA CSTLS6M50G53-B0 (Farnell), (Mouser)

Thanks Mark, they look like a drop-in replacement.
The minimum order amount for Mouser and Farnell orders makes this more of a problem.

[1024MAK]

Cricklewood Electronics have one.

But do test the 3.25MHz clock from the ULA (pin 14) and pin 6 on the Z80 before going any further.

Mark

[sP1d3r]

Cricklewood Electronics have one.

But do test the 3.25MHz clock from the ULA (pin 14) and pin 6 on the Z80 before going any further.

Will do Mark, thanks again.

[sP1d3r]

I'm glad to say this problem has been solved, the problem wasn't the crystal it was some suspect soldering on the legs of C9 and pin 6 of the ROM chip socket.
Now the board boots up and works

Soldering to blame for the display fault

Board now works :-)

[1024MAK]

Excellent news

Mark

[Moggy]

Another Phoenix rises from the ashes, brilliant

[sP1d3r]

Thanks, all.
I look forward to using it

[sP1d3r]

Although this issue 1 ZX81 didn't have a faulty resonator, I bought one of the 6.5 Mhz resonators that Mark noticed from Cricklewood, before I found the soldering that I missed.
This ceramic resonator, which has the same form factor as the stock item, does work in this Zeddy but there's a slight difference on the monitor I was using, which is that there's a ghost line under the cursor;

6.5 Mhz ceramic resonator from Cricklewood

I entered an 8-line program which checks the available ram and although the ghost line was under the cursor and text on the cursor line, it wasn't anywhere else so far;

Ghost on the cursor line only, so far

It wasn't on the cursor line when the program completed;

Program complete, no ghost on the cursor line text

This may be artifacts produced by my little HDMI/VGA/Composite monitor, I haven't another monitor on hand to test.
After reading the ZXVid manual, I found that one pot controls the contrast and the other controls the output level, which can help with effects like ghosting.

In addition to this Cricklewood resonator, I also found a 6.5536 Mhz crystal on eBay, which I also tried and likewise, it worked and the display was better with no ghost under the cursor line;

6.5536 Mhz quartz crystal

But for some reason the cursor isn't quite right!

Strange cursor position

Interesting