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Re: It's 600XL time!
Posted: 02 Feb 2022 16:29
by rubber_jonnie
BennehBoy wrote: 02 Feb 2022 16:16
Which IC type failed the tests? I've a bunch of 74 logic at home and 2 different ways to test them so I could see if it's a generic issue with the profiles that the TL866 includes - are you using the latest xgpro release?
Yeah, the version I have is the latest, downloaded in the last week or two. Unless of course there is a newer version!
The IC that failed was a 74LS51, all of the rest of the LS ICs passed in the TL866. The new LS51s failed identically.
I suppose as it's only a 2 output device, and the datasheet has the truth table, I could easily hook one up on a breadboard and see what the results are.
Re: It's 600XL time!
Posted: 02 Feb 2022 16:33
by BennehBoy
I don't have any 51's anyway :lol:
Re: It's 600XL time!
Posted: 02 Feb 2022 16:41
by stephen_usher
What does the delay line do? Is it just a series of inverters?
Re: It's 600XL time!
Posted: 02 Feb 2022 16:52
by rubber_jonnie
stephen_usher wrote: 02 Feb 2022 16:41
What does the delay line do? Is it just a series of inverters?
Pretty much yes, but is vitally important to the way CAS/RAS works on these machines. The XEs used the Freddie chip instead.
There is a GitHub project:
https://github.com/redhawk668/Atari-CO6 ... eplacement and a replacement has been made, which I am getting.
It uses resistors and a 74LS14, so in theory I could build one, just don't have the time right now as heading up to the Wirral tomorrow.
Re: It's 600XL time!
Posted: 02 Feb 2022 16:58
by stephen_usher
That's a very strange schematic. There's no input.
Re: It's 600XL time!
Posted: 03 Feb 2022 00:03
by rubber_jonnie
BennehBoy wrote: 02 Feb 2022 16:33
I don't have any 51's anyway :lol:
Never mind, worth a try :)
Re: It's 600XL time!
Posted: 03 Feb 2022 00:09
by rubber_jonnie
stephen_usher wrote: 02 Feb 2022 16:58
That's a very strange schematic. There's no input.
Yeah, it is weird. Also weird that on the original delay line IC, Atari cut a bunch of pins off that they didn't need, so theres only about half the legs on it.
Re: It's 600XL time!
Posted: 11 Feb 2022 12:14
by rubber_jonnie
Well, my replacement delay line just arrived, let's see if that helps
Re: It's 600XL time!
Posted: 11 Feb 2022 12:53
by stephen_usher
:crossed fingers: ;-)
Re: It's 600XL time!
Posted: 11 Feb 2022 13:26
by rubber_jonnie
Sadly not :( Bit of a head scratcher as to what's next, so I think back to the schematics, service manual and Google for more research.
Whilst I'm doing some figuring out, I will replace all of the boards single wipe sockets, I don't trust them to make contact properly as most feel a bit loose, and have the spares to hand anyway.
I have already changed the one for Sally and also the delay line, and since I have my desolder gun, it won't take very long at all.
Hopefully by the time I've done that I will have a plan, unless of course it fixes it!