Falcon maintenance

[exxos]

@stween Could you post a screenshot of your RAM card? I'm thinking it might have high latency chips.

Maybe so but the RAM access timings are lightly controlled by the Videl anyway... Might be interesting to see if it has a slightly different part number than later Falcons...

[stween]

@stween Could you post a screenshot of your RAM card? I'm thinking it might have high latency chips.

Sure; here's what I've got:

IMG_20210423_221215.jpg

[stween]

@stween Could you post a screenshot of your RAM card? I'm thinking it might have high latency chips.

Maybe so but the RAM access timings are lightly controlled by the Videl anyway... Might be interesting to see if it has a slightly different part number than later Falcons...

And here's the VIDEL chip:

IMG_20210423_230153.jpg

[exxos]

And here's the VIDEL chip:

Exactly the same one as in my Falcon...

Do you have the same oscillators ?

Capture.PNG

[stween]

Do you have the same oscillators ?

Here's what I have:

IMG_20210424_003430.jpg

[Steve]

@stween I think it's because your ram is 80ns, I've seen other boards with as low as 60ns before.

[exxos]

@stween I think it's because your ram is 80ns, I've seen other boards with as low as 60ns before.

How would the videl know what RAM speed was fitted ? Same as any other ST, you can fit any speed of RAM from 250ns to 50ns and it makes no odds as the MMU is hardwired to run at the same speed regardless.

[Steve]

Oh okay, sorry I had a misconception of how that worked :) I guess I was thinking of CAS latencies on PC's and how they influence speed.

[exxos]

@stween

On U63 - pin 19 has a 4.7K, solder another 4.7K across it.. And solder another 4.7K from VCC (pin 20) to pin 2.. It may or may not do anything but worth a try..

Capture.PNG

[Rustynutt]

NEVER seen an Atari 14mb Falcon ST RAM card.
Double wow. Not only the size, but cost at that time was huge.
One expensive Falcon there.