Date   : Sun, 20 May 2001 13:05:12 +1000
From   : "Adam" <alomac@...>
Subject: Re: Have I killed my Beeb?

> > Unfortunately, rather than plugging
> >the RCA plug of the cable into 'UHF out' and the Co-ax and into the TV, I
> >plugged the Co-ax end into the BBC's "video-out" port and the RCA jack
into
> >my VCR's input (from where it would filter down into my TV).
>
> That should be OK.  Can you not see anything on the screen at all?  Does
> the screen flash/flicker when you switch the machine on?

Not for the moment, however I think this has more to do with my TV-VCR setup
than anything. Does anyone know what type the co-ax connector on the BBC's
video cable is? I'll be needing an adaptor to use it properly, I think.
Also, is there supposed to be a pin in it's (the connector's) centre? There
seems to be a short one right at the very bottom of the connector, if it's
supposed to extend any distance into the connector's "cavity" then I suspect
my cable is broken.

> The fact that your machine almost gets there means it's probably only a
> minor fault.

I hope so :)

> > Once it stops the computer did nothing,
> >only a faint buzz comes from the speaker. If I press BREAK I hear a
feeble
> >beep when I release it.
>
> that doesn't sound right.  you should only get a beep when you press
> control and break together, not just break on its own.

It's a very feeble beep. If I press Control-Break I get the 5-second
BEEEEEEP! again.

> The grey ribbon cable between the keyboard and the main board does
> develop dirty contacts over time.  Switch off, unplug it and plug it
> back in and try again.  When it develops dirty contacts, the machine
> won't boot properly (it'll give a blank screen with a small flashing
> cursor in the top left hand corner.)

I tried re-plugging it and cleaning the contacts with alcohol (isopropynol)
still nothing. There is however, some kind of modification to the keyboard.
Looking at the exposed keyboard from the top, there is a set of "jumpers"
(actually holes in the PCB bridged by bits of stiff wire) This is where the
modifications are.
To get the right perspective on this, flip the keyboard over so you're
looking at it's underside with the space-bar closest to you and the cursor
keys now on the left. The mods are:

Almost all of the bottom row of contacts have been shorted together A wire
has been run across and soldered to each contact except for two (the third
and fourth from the right) The fourth-from-the-right contact might be making
accidental contact with this 'bridging' wire. I'll check again later.

Three of the top row of contacts are connected to their respective number on
the bottom row. These are the first, fourth and fifth from the right. The
trace has been pulled away from the fourth-from-the-right contact, so really
only two are truly connected - the first and fourth-from-the-right. If this
doesn't make sense (and I'm sure it doesn't) let me know and I'll draw a
diagram of the mods and put them on a web-page somewhere.


> > A "32K Sideways RAM Module" has been fitted and
> >wires run from it to just infront of the keyboard connector and to a chip
> >near the power supply.
>
> Does this RAM module have a battery you can see?

No. This module is just a chip which has been inserted in a ROM socket,
along with the DFS chip and two Acorn-branded chips. The Sideways chip looks
to be in it's own socket which has then been inserted into the motherboard's
socket. Two of the pins (the rearmost) aren't inserted. Rather they're
connected to wires which are in turn connected to other parts of the board
as mentioned.


> >My questions are:
> >
> >1. Is the BBC dead?
>
> No.
>
> >2. Is it my fault?
>
> No.
>
> >3. Is there anything I can do about it?
>
> See above.
>
> >4. What are my chances?
>
> pretty good, as long as you don't start fiddling.  If reseating the
> keyboard connector doesn't work, the next step is to remove the RAM
> board and reinstate the default jumpers.  If it is battery backed, it
> may have a corrupt ROM image in it which is preventing the BBC from
> booting.
> But post here first.

I will.

If none of this makes sense, let me know. It's getting late here so I
probably sound weird...

Thanks,
Adam.