BBC Model B No2. Will it live again!

[rubber_jonnie]

So, when it starts working, "Bob's your uncle"?

(Or, if you're a Blackadder fan, "Bob's your aunty".)

Yup, sounds about right :)

[JezC]

I'm kind of sad they didn't use Fred, Jim or Sheila...just to be consistent with the s/w! :D

[rubber_jonnie]

I'm kind of sad they didn't use Fred, Jim or Sheila...just to be consistent with the s/w! :D

:dizzy:

[JezC]

@rubber_jonnie Sorry, possibly a bit too niche for non-BBC nerds ... :ugeek:

Those names relate to specific address ranges in the memory map...worth a search on the net if you want to learn some totally useless info ...

Sadly, I seem unable to forget these pointless bits of trivia & forget much more useful & important stuff instead!
:lol: :roll:

[rubber_jonnie]

@rubber_jonnie Sorry, possibly a bit too niche for non-BBC nerds ... :ugeek:

Those names relate to specific address ranges in the memory map...worth a search on the net if you want to learn some totally useless info ...

Sadly, I seem unable to forget these pointless bits of trivia & forget much more useful & important stuff instead!
:lol: :roll:

Lol, all good to me, I like nerdy stuff :)

[rubber_jonnie]

Ok, so I'm about halfway through the socket replacement program with major chips now in new sockets. The fault remains though, so no further down the path.

I think I'll take up an offer on stardot of Tricky's diagnostic ROM (Can't burn one myself ATM) as that may give me the answers I need.

In the meantime I will continue replacing the awful sockets as I simply don't like them and don't think they can be helpful if I want to make this machine last another 40 years :)

[rubber_jonnie]

Ok, so all the RAM sockets have now been replaced too, as has the socket for the reset chip, which, surprise surprise, is a 555.

No change to the symptoms though, which is pointing me at a couple of things:

1. RAM - Removing the RAM makes no difference, so perhaps a look at the cas/ras select logic.
2. ROM - If the OS ROM is nadgered (Yes, it's a technical term) then nothing will happen.

I must go and double check what happens if I try to boot with no CPU, see if the problem remains. I think I did, but don't recall the outcome.

[BennehBoy]

What sockets are you using for the replacements? There seems to be a lot of differing viewpoints between turned pin and double wipe with folk being equally vocal about the benefits of both kinds. (I've got plenty of both here, mainly in 24 & 28 pin for making ROM adapters).

I've been thinking of upgrading my breadbin C64 to be fully socketed so I can use it as a test platform, and I spied these beautiful low profile zif sockets that someone else has used: https://www.arieselec.com/product/10018 ... st-socket/

I was all set on them until I saw the prices ~10 quid each!

[stephen_usher]

It's probably the bus buffer chips, they're always a bit flakey on all machines. Without a decent oscilloscope though it's rather a case of flying blind.

[rubber_jonnie]

What sockets are you using for the replacements? There seems to be a lot of differing viewpoints between turned pin and double wipe with folk being equally vocal about the benefits of both kinds. (I've got plenty of both here, mainly in 24 & 28 pin for making ROM adapters).

I've been thinking of upgrading my breadbin C64 to be fully socketed so I can use it as a test platform, and I spied these beautiful low profile zif sockets that someone else has used: https://www.arieselec.com/product/10018 ... st-socket/

I was all set on them until I saw the prices ~10 quid each!

Personally I'm not a fan of turned pin sockets for chips and much prefer double wipe where the surface area in contact is much larger. Turned pin is fine if you're plugging in turned pin adapters, I just don't see any benefit for chips.

Adrian of Adrians Digital Basement has a C64 with ZIF sockets, though I don't think they are low profile.