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Re: BBC Model B No2. Will it live again!

Posted: 21 May 2021 16:06
by rubber_jonnie
stephen_usher wrote: 21 May 2021 15:50 Where are you getting the parts from? They're taking an awfully long time.
I only ordered them yesterday. I use various small suppliers and it usually takes 1 or 2 days. I have got the ars*hole with the larger suppliers right now as the likes of Farnell, RS, DigiKey, Mouser etc charge ridiculous amounts for shipping small orders. Paying more in shipping than the order cost really gets my goat!

One order I placed with a supplier with a UK website actually took weeks, cost quite a lot in shipping and was actually sent from the States.

I've found some good small ones like Cricklewood Electronics who can do it quicker and cheaper for the small quantities I need.

My post is also complicated at the moment by redirection services due to the house move. That seems to add a day :(

Not only that, but because we are renting a granny flat in a larger house, there is only one letter box, and sometimes my stuff gets mixed up with the house next door. He's pretty good at dropping it off daily, but it can add a delay too.

Frustratingly I cannot get a straight answer about when our house will be ready. That'll sort out a LOT of my problems when my workshop is re-assembled. Oh to have a 2CH decent scope again!!

Re: BBC Model B No2. Will it live again!

Posted: 22 May 2021 13:07
by stephen_usher
Any signs of those components?

Re: BBC Model B No2. Will it live again!

Posted: 22 May 2021 13:35
by rubber_jonnie
stephen_usher wrote: 22 May 2021 13:07 Any signs of those components?
The capacitors have arrived, as have the crystals, but no 74S04's, which is annoying.

Trouble is, we have to go and meet with the site manager regarding progress on our house and see if it's actually going to be finished by the end of June as promised now, and then tomorrow I have my 2nd jab, so not sure if I'll be able to do anything this weekend :(

Re: BBC Model B No2. Will it live again!

Posted: 22 May 2021 13:45
by rubber_jonnie
@stephen_usher A very quick question before I head out, are you aware of anyone using a signal generator one of the small IC2 driven clock boards like this:

https://www.ebay.co.uk/itm/192784891475 ... %3A2334524

To drive the clock on something like a BBC or other retro machine. I think Adrians digital basement did something like that on a C16, but just wondering if it's possible?

Re: BBC Model B No2. Will it live again!

Posted: 22 May 2021 14:04
by exxos
rubber_jonnie wrote: 22 May 2021 13:35 The capacitors have arrived, as have the crystals, but no 74S04's, which is annoying.
Assuming they are hard to find ..I also assume a LS04 would work fine ?

Re: BBC Model B No2. Will it live again!

Posted: 22 May 2021 14:11
by BennehBoy
rubber_jonnie wrote: 22 May 2021 13:45 @stephen_usher A very quick question before I head out, are you aware of anyone using a signal generator one of the small IC2 driven clock boards like this:

https://www.ebay.co.uk/itm/192784891475 ... %3A2334524

To drive the clock on something like a BBC or other retro machine. I think Adrians digital basement did something like that on a C16, but just wondering if it's possible?
Not used one but it's an interesting idea, I can't see why it wouldn't work as long as the clocks are ttl levels - it looks to be 3.3v though.

I assume you need a microcontroller in circuit continuously too in order to drive the power on configuration - a pro mini arduino or similar is a v cheap option (or a bluepill etc).

Re: BBC Model B No2. Will it live again!

Posted: 22 May 2021 14:50
by stephen_usher
rubber_jonnie wrote: 22 May 2021 13:45 @stephen_usher A very quick question before I head out, are you aware of anyone using a signal generator one of the small IC2 driven clock boards like this:

https://www.ebay.co.uk/itm/192784891475 ... %3A2334524

To drive the clock on something like a BBC or other retro machine. I think Adrians digital basement did something like that on a C16, but just wondering if it's possible?
I've not seen this done as I think that the simple clock circuit and very common crystal speed means that no-one's bothers. Plus using the video chip to supply the clocks means that the video chip is always in sync as it has control.

Re: BBC Model B No2. Will it live again!

Posted: 22 May 2021 14:51
by stephen_usher
exxos wrote: 22 May 2021 14:04
rubber_jonnie wrote: 22 May 2021 13:35 The capacitors have arrived, as have the crystals, but no 74S04's, which is annoying.
Assuming they are hard to find ..I also assume a LS04 would work fine ?
On the Beeb the LS variant can be too slow to switch. In this case it's in a clock circuit so timing's critical.

Re: BBC Model B No2. Will it live again!

Posted: 22 May 2021 15:08
by rubber_jonnie
exxos wrote: 22 May 2021 14:04
rubber_jonnie wrote: 22 May 2021 13:35 The capacitors have arrived, as have the crystals, but no 74S04's, which is annoying.
Assuming they are hard to find ..I also assume a LS04 would work fine ?
Back from the house, could only look through the windows as they were putting up the plasterboard, so hopefully end ofJune might be a possibility. Fingers crossed.

I have some S04's on the way, it's just they haven't arrived yet. As Stephen said, they are part of a clock circuit so I need the right ones.

Re: BBC Model B No2. Will it live again!

Posted: 22 May 2021 15:09
by rubber_jonnie
BennehBoy wrote: 22 May 2021 14:11
rubber_jonnie wrote: 22 May 2021 13:45 @stephen_usher A very quick question before I head out, are you aware of anyone using a signal generator one of the small IC2 driven clock boards like this:

https://www.ebay.co.uk/itm/192784891475 ... %3A2334524

To drive the clock on something like a BBC or other retro machine. I think Adrians digital basement did something like that on a C16, but just wondering if it's possible?
Not used one but it's an interesting idea, I can't see why it wouldn't work as long as the clocks are ttl levels - it looks to be 3.3v though.

I assume you need a microcontroller in circuit continuously too in order to drive the power on configuration - a pro mini arduino or similar is a v cheap option (or a bluepill etc).
I can get a level converter pretty cheaply too, so going from 3.3v to 5v should be possible. Still thinking about it and it depends how the clock circuit repairs go.