exxos's Atari, Amiga & retro forum

My original Beeb is an issue 3...so it had to undergo a bit of surgery when the Acorn DFS was added (with the "good old" intel 8271). I think I then upgraded it again to allow me to use the 1770 or 8271 (can't for the life of me remember why I wanted to do that...but, hey ho).

I'd better look at the recommended refurb steps for it before I try powering up as it's probably not been powered up much at all in the last 20 years...

JezC wrote: 27 May 2021 14:16 My original Beeb is an issue 3...so it had to undergo a bit of surgery when the Acorn DFS was added (with the "good old" intel 8271). I think I then upgraded it again to allow me to use the 1770 or 8271 (can't for the life of me remember why I wanted to do that...but, hey ho).

I'd better look at the recommended refurb steps for it before I try powering up as it's probably not been powered up much at all in the last 20 years...

I'd say 1st step is a replacement of the 2 Rifas and the PSU startup cap. In my dead one I did a full recap, but unless you have other problems then just those 3 are a good place to start. Nobody wants a house that smells like failed Rifa!

Usually just the smoke generators are enough I find. The start-up one doesn't fail that often. The other caps to fail are the ones which are on the -5V, I think they're C8 and C9. If one or both of those go you can get noisy sound or no sound at all and the cassette interface can't read cassettes. With one of the caps gone you get a -5V which oscillates at about 15KHz between -5V and 0V. This doesn't help the opamp. :-)

rubber_jonnie wrote: 27 May 2021 13:59 Forgot to mention, the new working one is an issue 4, just like the dead one.

My first Beeb was an issue 7, only problem I ever had with it was when the op amp for the tape went pop and wouldjust save buzzing to the tape instead.

PhilC wrote: 27 May 2021 15:51

rubber_jonnie wrote: 27 May 2021 13:59 Forgot to mention, the new working one is an issue 4, just like the dead one.

My first Beeb was an issue 7, only problem I ever had with it was when the op amp for the tape went pop and wouldjust save buzzing to the tape instead.

Can't recall which issue my 'in storage' Beeb is, but glad to have another iss 4 to compare to my broken one. I 'may ' go down the Gotek route, we'll see, but will try the MMC adapter first.

@rubber_jonnie from my limited use of the MNC, it works very well once you get the hang of all the extra star commands.

PhilC wrote: 27 May 2021 16:08 @rubber_jonnie from my limited use of the MNC, it works very well once you get the hang of all the extra star commands.

Just been reading the docs on CD, looks promising :) I will report back :)

Well, that was an interesting evening.

I plugged in the new Beeb (No3) and was about to take some measurements to compare to the dead beeb (No2). @JezC take note!!

There was a fizz and a pop and both Rifa smoke generators in Beeb No3 let go!!! I was secretly pleased as this is my first live Rifa event!!

Luckily I had spares, so I swapped them out, but the fact that I had to remove the keyboard made me think that I should try the known good keyboard in Beeb No2, since the keyboard for that had some nasty bodge wires on it.

So, keyboard 3 is connected to Beeb 2 and I flick the power switch, and what do you know, Beeb 2 only does a BooBip and I see a 15Khz signal on the monitor port.

I blind type *CAT and hit return. Click goes the relay and the cassette motor light comes on. I hit ctrl+break and I get a reset beep. I blind type *MOTOR 1 and the relay clicks and the cassette motor light comes on. I blind type *MOTOR 0 and off goes the cassette motor light with a click of the relay. Woo hoo!!!!

OMG it's only bloody working!! It was only the bloody keyboard!! This goes to prove that having at least one working machine, and I got No3 late this morning, can be instrumental in getting you what you need to fix a dead machine.

I'll test video on both machines over the weekend, as at present we only have one suitable TV and the wife was busy with it tonight.

As it happens, I already procured a replacement keyboard PCB last week, as I didn't like the look of old one anyway, so next up I'll be rebuilding the KBD on a new PCB.

I'm quite ecstatic at this point!!

I had read that the Beeb needs a working KBD to boot, unlike a lot of older machines like the ST, ZX series etc, so it was really really nice to have this result.

I'll share some photos tomorrow, but this is a good way to wrap up the day.

Well done! Fire and success in one evening ! Bonkers the keyboard sent you down the rabbit hole !
:girldance:

rubber_jonnie wrote: 28 May 2021 00:06 live Rifa event!!

:lol:

These days I guess that's the best live event we can expect. :D

Congrats on the the simple keyboard fix!