Broken 6128?

[Blurredman]

It was the unsuccessful removal of the HAL/PAL chip that made it become a flickering mess instead of being what it was (a box like the 464). I did notice though on the 6128 that the CPU was indeed at an angle in the holder. But straightening it made it no better

Yes bryce the monitor works, but with the already broken CPC's. I don't want to plug a working CPC into the monitor incase the monitor makes the CPC do as the broken ones do.

[Bryce]

Why did you remove the PAL, that would just disable the RAM.

If the monitor is producing that picture on a broken CPC, I very very much doubt, that it would damage a working CPC. But I'm not going to guarrantee it 100%. I'd go with 99.999% though.

Is that the monitor, that you think broke the others?

Bryce.

[Blurredman]

yes

[Bryce]

Very strange indeed.

Bryce.

[arnoldemu]

btw, when I removed the pal on my machine (which i did with it off and I did it very carefully, it gave the same result as on the 464).
same happens with a bad pal I think.

I then put some wires in to patch it to 64k and the machine booted.

I bought a new pal and put it in and the cpc worked.

so I was just wondering if this was the cause.

the crazy lines indicates the crtc has not been setup. all this is done in rom, so it seems either the z80 or the rom is stuffed or both.

[Blurredman]

Okay, so it's possibly the HAL chip or ROM. Obviously, the Hal is the cheapest and easiest to replace so i'll look into that first.
On the 464, what chip number is it?

It's very annoying this 

[Blurredman]

Okay everyone. I took a risk! And here we have it:



The monitor WORKS! I know many one or two of you were thinking "how could he risk ANOTHER CPC" but, if I told you my heart was not beating as I was hovering over the power button I would be lying, and that shows that I do care!

[Bryce]

Well congratulations! My 99.999% was only 0.001% wrong

I love the multimeter. You use retro test gear to repair retro computers, now that's what I call dedication.

Bryce.

P.s. Careful! There's some dodgy looking bloke hanging around in your garden!

Edit: This also means that it wasn't the monitor that broke the CPCs, it must have been something else....?

[arnoldemu]

Okay, so it's possibly the HAL chip or ROM. Obviously, the Hal is the cheapest and easiest to replace so i'll look into that first.
On the 464, what chip number is it?

It's very annoying this 

hal is on 6128 only.

for the 464, I would suggest the ram.

if you have a multimeter and you're not scared to use it, you could try using the "clock" function to see if some of the chips are alive by checking their clocks are ticking over.

EDIT: Looking at the picture I don't think that multimeter will be sufficient. sorry. I was thinking a slightly more modern one, one which can check frequencies.

[Bryce]

@Arnoldemu: How did you program the PAL/HAL? Do you have the configuration file?

Bryce.

[arnoldemu]

@Arnoldemu: How did you program the PAL/HAL? Do you have the configuration file?

Bryce.

I didn't. I bought one from ebay, and it's a miracle it worked!

I wish I had a configuration file to make another, but I don't think one exists, and I don't think the PAL is readable (I think it's been protected from reading)?

[Bryce]

Well it's not that they are read-protected, more the fact that they just don't have a read function. Once the fuses have been set, the only way of finding out the configuration is by testing every possible input combination, creating a truth-table from the output results and then re-writing the fuse configuration file. A lot more work than it's worth.

Bryce.

[Gryzor]

Well congratulations! My 99.999% was only 0.001% wrong

Actually, your 99.999% was 100.00% wrong, but anyhow... :p

Oh, you got a kitty!

[Bryce]

? Why was it 100% wrong? The monitor obviously didn't damage the CPCs.

Or am I missing the pun?

Bryce.

[Gryzor]

Nah was just kidding; it's philosophical: when you're wrong, you're wrong. Can't be half-pregnant, for instance...