General Stuff(tm)

[PhilC]

@stephen_usher still looks a bit 3d printed as you said but at a glance it looks pretty good.

[Icky]

@stephen_usher may be that’s the next project to have a black anodised aluminium plate made. Although the 3D print is not bad you know deep down it’s has to be aluminium for the MTX. I know my OCD would be kicking me about it.

[stephen_usher]

The problem would be the supports for the ethernet and SD card PCBs.

[stephen_usher]

The mini-HDMI to HDMI converter cable from Amazon arrived today so I was finally able to test the RGB2HDMI I bought from SellMyRetro last week.

I'm pretty impressed with the video quality. It's not very useful for machines which need sound on the HDMI or those with lots of colours (3 bits luminance per colour per pixel) but it's really very good given those limitations and a great deal cheaper than an OSSC.

Here's the output from the QL. (Note that the RGB2HDMI is being powered by the TV's USB port.)

IMG_2789.jpg

P.S. There are still 4 available (and they include the Raspberry Pi Zero): SellMyRetro - RGB2HDMI

[stephen_usher]

This afternoon I had to take off work as a prospective builder for my outbuilding wanted to make a site visit before he submitted his tender. So, after he came and went I not have the whole afternoon to myself.

The first job has been modifying one of my external Gotek drives to allow it to be switched from drive 0 to drive 1 without dismantling the case. Luckily the 3D printed case, modelled upon the Atari 8 bit floppy drive but at a 3.5" drive scale, has a hole in the front for a switch (which on the original Atari drive would be the power switch). I bought some tiny single pole, double throw switches from RS to fit this so this afternoon I wired them up.

I carefully measured the length of the wires, seemingly giving ample extra length (sure, right), put DuPont connectors on one end and soldered the others to the switch and then hot glued the switch in place.

After leaving the glue to cool enough I attempted to plug the wires into the S0 and S1 headers on the Gotek and reassemble the unit. You know I said that I'd given ample extra length on those wires? Well, I hadn't! Thankfully, with a very slight stretch and some lateral thinking I got it all back together. It seems to work fine, testing it with the Apricot F1. I'll have to switch it to drive 1 and test it with the Apricot FP next as that won't work if it's drive 0.

[alexh]

I was finally able to test the RGB2HDMI I bought. It's not very useful for machines which need sound on the HDMI or those with lots of colours (3 bits luminance per colour per pixel)

I thought RGB2HDMI was 4-bits per colour component (RGB), 12-bits total (4096 colours)?

[stephen_usher]

Sorry, yes, I can't count. It's 12 bits, which is three times four. D'oh! :-)

[stephen_usher]

I think that the Apricot F1 has another memory fault.

During the testing of the external Gotek yesterday I tried the memory tester on the diag floppy image. Every time it got up to about 200K the machine would crash or reboot. I think one of the chips probably has an addressing error. I've not really got time before Cyber Legends to investigate. Maybe afterwards. I'll have to see how many 41256 chips I have. I may just desolder them all, put sockets on the board and put them all through the tester. Given that I've already had to replace one chip which had a fault I'm wondering if they're all iffy, after all 41256 chips were very cutting edge when this machine was built.

[stephen_usher]

I've got enough 41256 chips, I don't know about the sockets.

I may just go ahead anyway. It shouldn't take too long to de-solder the old chips. (Famous last words?) I can then test them all out of circuit. I could just replace them anyway as they seem to be going flaky.

During some testing tonight the machine did once start up showing 232K of RAM.

Of course, if after replacing them the problem still persists then I also know the problem is elsewhere. I'm not sure what could cause RAM to fail at such an odd location though if it's external to a chip.

[rubber_jonnie]

I've got enough 41256 chips, I don't know about the sockets.

I may just go ahead anyway. It shouldn't take too long to de-solder the old chips. (Famous last words?) I can then test them all out of circuit. I could just replace them anyway as they seem to be going flaky.

During some testing tonight the machine did once start up showing 232K of RAM.

Of course, if after replacing them the problem still persists then I also know the problem is elsewhere. I'm not sure what could cause RAM to fail at such an odd location though if it's external to a chip.

I have a bit of a hoard of 41256s if you find yourself short.