STE: Thanks for the memory?

[LeakyBatz]

Hi all,

I'm guessing this is a noob question. I have a poorly 520STE & am trying to narrow down the issues.

Without any ram sticks installed I get this screen. The lines at the top of the black bars change & shift.

520STE no memory

520STE_NoRam.JPG (52.34 KiB) Viewed 264 times

Does anyone know if this normal behaviour in a machine with no ram installed, or is this an issue?

Cheers

[Steve]

Pretty sure you need RAM installed. Perhaps you could describe the problems your STe has.

[exxos]

Normally you would get a blank screen without memory installed.. The image looks like memory is installed but not working for some reason..

But if you are getting that screen without memory installed, then it seems like you have a deeper issue somewhere...

[LeakyBatz]

Pretty sure you need RAM installed. Perhaps you could describe the problems your STe has.

Cheers for the replies,

When memory is installed I get a thump from the TV speakers, & then just a white screen, it doesn't drop into GEM

White screen

520STE_2MBRam_WhiteScreen.JPG (14.73 KiB) Viewed 252 times

The keyboard power & drive leds are on & stay on

KBd

520STE_KB_Floppy_lights.JPG (97.13 KiB) Viewed 252 times

The floppy sounds like it's spinning & makes a "Tick" noise.

Floppy

520STE_Floppy_LED.JPG (57.17 KiB) Viewed 252 times

It also seeks when you insert a disc, but stops after the attempt & the white screen & lights remain.

Steps done so far:
I've removed the chips, used contact cleaner & reseated them.
I tested the outputs from the PSU checking for 5v & 12v. Both "near as" there.
Tried a number of 30 pin memory sticks.

The MB

MB & floppy

520STE_ViewMBFloppy.JPG (219.98 KiB) Viewed 252 times

Another question, does the TOS look like it's correctly installed here?

TOS

TOS_Installed.JPG (74.43 KiB) Viewed 252 times

Any observations or advice would be most welcome!

Cheers

[exxos]

I suggest reseat and clean the shifter (under the PSU) and blitter IC (front side of MB) . If the system is trying to access the floppy.. then sounds like its graphics related as your getting nothing on screen.

Really you need a diagnostic cart with serial link to a PC to test that RAM is stable.. as of course, video is held in RAM.

[LeakyBatz]

I suggest reseat and clean the shifter (under the PSU) and blitter IC (front side of MB) . If the system is trying to access the floppy.. then sounds like its graphics related as your getting nothing on screen.

Really you need a diagnostic cart with serial link to a PC to test that RAM is stable.. as of course, video is held in RAM.

I'll try that again & make sure I check all the legs. Can it run without the blitter if I pull it? Would that test anything or would that make things worse?

I also forgot to say that none of the chips warm up except the CPU which gets quite warm (I've tried a few 68Ks.) Don't know if that helps to narrow things.

[exxos]

Can it run without the blitter if I pull it? Would that test anything or would that make things worse?

It may get to desktop without it, but likely floppy wont work and maybe cause other issues. not something I extensively tested.

[LeakyBatz]

Can it run without the blitter if I pull it? Would that test anything or would that make things worse?

It may get to desktop without it, but likely floppy wont work and maybe cause other issues. not something I extensively tested.

Ok ta. Will have a look later. Thanks for the advice.

[rubber_jonnie]

So with regards to the Blitter, I think TOS 1.62 has the Blitter disabled by default, so it may work, but 2.06 has it enabled by default so it may not.

Whilst a shifter reseat is definitely worth doing, but I would add that a full white screen usually means a ROM issue and a white border with black screen usually means a RAM issue.

As for the TOS being correctly installed, if you pop one IC out and look at the silkscreen on the board, it should show positions for 28 and 32 pin mask ROMs which will confirm if in the correct location. I'd suggest they likely are, based on what you're seeing on screen.

What you could do is try a Diagnostic ROM, hooked up to serial and a terminal on your PC, that might give some clues if it works, but would will need to have some RAM installed.

Also, I note your RAM sticks are parity ram, in other words they have 9 IC's. There is some disagreement around parity RAM and STE's but I would suggest you use non-parity RAM to avoid any potential issues. I use non-parity RAM in mine and don't have any issues.

[LeakyBatz]

So with regards to the Blitter, I think TOS 1.62 has the Blitter disabled by default, so it may work, but 2.06 has it enabled by default so it may not.

Whilst a shifter reseat is definitely worth doing, but I would add that a full white screen usually means a ROM issue and a white border with black screen usually means a RAM issue.

As for the TOS being correctly installed, if you pop one IC out and look at the silkscreen on the board, it should show positions for 28 and 32 pin mask ROMs which will confirm if in the correct location. I'd suggest they likely are, based on what you're seeing on screen.

What you could do is try a Diagnostic ROM, hooked up to serial and a terminal on your PC, that might give some clues if it works, but would will need to have some RAM installed.

Also, I note your RAM sticks are parity ram, in other words they have 9 IC's. There is some disagreement around parity RAM and STE's but I would suggest you use non-parity RAM to avoid any potential issues. I use non-parity RAM in mine and don't have any issues.

Ah! I did wonder if there would be a specific type of RAM that it would use. I'll see what else I have.
If it's a ROM issue do I just need to order some TOS replacements?