Falcon CA401332-003 Rev D/C Service blog

[derkom]

Aha! Guess that got mangled when the old port was removed for whatever reason. Very nice work overall!

[dhedberg]

Great work fixing the Falcon!

Looks like that track could very well become broken again by the wear from the connector. The repair is in a bit of a bad position (it'll be partly or completely covered by the connector). Perhaps adding a bodge wire would be a better solution?

[Steve]

Great work fixing the Falcon!

Looks like that track could very well become broken again by the wear from the connector. The repair is in a bit of a bad position (it'll be partly or completely covered by the connector. Perhaps adding a bodge wire would be a better solution?

Hmm I was going to coat it with PCB overcoat epoxy, but perhaps you're right. I'll add a bodge wire on the underside of the board just in case

Oh and we're not finished yet with this Falcon. That was just the first 'issue'. Second is that it is reported to be unstable with its ct60 accelerator. So I will be testing that and attempting to solve it.

[Steve]

Just checking with others familiar with the Falcon, isn't R221 usually 33ohm? This board just has a zero ohm... Odd.

PXL_20210527_083930380.jpg (490.83 KiB) Viewed 3652 times

[mikro]

R221 has been changed to 0 Ω in PCB rev.H.

[Steve]

Thanks @mikro

[Steve]

@mikro

With this particular revision:
CA401332-003 Rev D/C
Y43502003362

Are you aware of any factory fixes it may be missing, or is it a final revision? Thank you

[mikro]

It's hard to say, generally speaking, all boils down to having a good clock patch and maybe update the audio circuirty but I have personally never done that. So as long the bus is fine and there are no DMA issues, you're good to go.

[Steve]

UPDATE:

So, we fixed the monitor port - second job was to fix stability with ct60. This board had the 47ohm resistor termination 'clock patch' if you can call it that. Initially I removed this and replaced it with Exxos's clock patch, but upon doing this the system display would go crazy and garbled. LUCKILY Exxos was working on a similar Falcon and fixed the issue by using a 100k resistor on the sdma line. Thankfully this fix also worked on this Falcon! What a happy coincidence!

Photos of work in the last few days:

NVRAM replacement:

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Clock patch install & 100k install:

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ct60 ram shielding & replaced 220uf caps on ct60

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Cleaning
Customer has some nice old stickers he always kept on the machine, as they are sentimental for him I carefully removed, cleaned & put back:

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Working, testing some games!

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Conclusion of story:
GATES HAS NO CHANCE!

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[exxos]

Very nice work @Steve Good to know the 100K Also fixed the problem with your machine and also good to know the exxos clock patch works with the CT60