stween's build

[Icky]

Finally got some time to get back to this. I may have been a bit quiet from project work at the moment as life is getting in the way. The New Year definitely has been a distraction this January.

Anyway, I have put the CPU and GLUE sockets back in place added all the chips in and the RESET line is working as expected. However nothing on the screen and I could not see a 16MHz CLOCK. Thought I would go round poking chips and lo and behold touching the SHIFTER and the machine came up with a white screen. Looking around the socket the XTAL pin is a bit iffy i.e wider but it is something round the socket that is not connecting. I tried with another SHIFTER chip and resoldering the socket but that did not do anything so am going to replace it.

[Icky]

A bit more of an update and log of what has been replaced so far. Pictures are better than words so the following pic shows the components replaced so far.

IMG_2132.jpeg (232.48 KiB) Viewed 3194 times

On boot I am getting a white blank screen and the diagnostics cart is spitting out these errors:

Code: Select all

I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0000000010111110 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0010010110100010 000008
I1 RAM/data line error 0000000000000000 0111110110111110 000008
I1 RAM/data line error 0000000000000000 0111000010111110 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0000000010101110 000008
I1 RAM/data line error 0000000000000000 0000101010010000 000008
I1 RAM/data line error 0000000000000000 0010000010111110 000008
I1 RAM/data line error 0000000000000000 0000000011000111 000008
I1 RAM/data line error 0000000000000000 0011000011000111 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0000000010000101 000008
I1 RAM/data line error 0000000000000000 0000111010010101 000008
I1 RAM/data line error 0000000000000000 0000000010111110 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0000000010100010 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0011000011000111 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0101010110101110 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0011000011000111 000008
I1 RAM/data line error 0000000000000000 0000000010000101 000008
I1 RAM/data line error 0000000000000000 0010111010010101 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0101010110101110 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008

Am just investigating those the reasoning for those.

[Icky]

OK, have got the error codes now down to this stable issue as opposed to random data by doing a bit of solder clean up.

Now I need to go hunting round the D7 line to see what is wrong.

Code: Select all

I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008
I1 RAM/data line error 0000000000000000 0000000010000000 000008

[PhilC]

That’s some good progress @Icky , I think it’ll be booting very very soon.

[stween]

Amazing work. Going to these lengths would have been beyond me! Honestly interested in how far off-piste some parts are on mine.

Re the intermittent clock signal, this one was waaaay on my backburner. Once in a very rare while I seemed to not get a good 16MHz out, but I couldn't reliably reproduce. I usually wedged a resistor across a couple of shifter pins like in this post just to help things out. But it sounds like the resistor on the board was actually at fault?

[Icky]

Have still been chasing this down and I have not found any continuity issues with the D7 RAM line. After diagnosing that the D7 line pulses on start up there is something good going on here to which I have looked at replacing the LS244 and LS373 chips on the D7 line. This too hasn't yielded any improvement the D7 line is still reporting error in the diag serial output screen. The SIMM works fine in another H5 and I have tried more than one. This issue is very perplexing. Will try using a Falcon RAM board in place of the SIMM socket as another avenue to methodical tracing.

[PhilC]

@Icky is it worth cutting the D7 track and wiring it with a bodge wire etc?

Also lately I’ve noticed a few SMT components which appear to be soldered correctly but one side is simply touching and not soldered properly (not by me).

[Icky]

A little progress, just need to sort out the video.

IMG_2217.jpeg (59.86 KiB) Viewed 2958 times

[JezC]

Now, if that was shades of pink rather than purple, you might have @exxos claiming that for his own!

[exxos]

Now, if that was shades of pink rather than purple, you might have @exxos claiming that for his own!

Oh I don't know, that is a very nice shade of purple...

Looks like ROM is running at least now @Icky