Search found 173 matches

by Sniffer
Fri Apr 05, 2019 8:03 am
Forum: 8-bit acorn hardware
Topic: Non booting BBC/B Issue 7 - Continuous beep
Replies: 60
Views: 2755

Re: Non bootong BBC/B Issue 7 - Continuous beep

That suggests a problem with either the RAM providing the screen memory or the data lines (or IC15, a 74LS273) between the screen memory and the teletext chip. Also possible is a fault with IC14, a 74LS245 transceiver. Also possible is an address line problem with the RAM or the feeds to it. Can yo...
by Sniffer
Thu Apr 04, 2019 11:23 pm
Forum: 8-bit acorn hardware
Topic: Non booting BBC/B Issue 7 - Continuous beep
Replies: 60
Views: 2755

Re: Non bootong BBC/B Issue 7 - Continuous beep

Posting from my phone as no internet due to Zen maint.

Thought I'd give the 74ls04 inverter a go whilst im waiting for some bits.

I get a sort of booted 32k beeb, but still the continuous beep but also a messed up screen. Attaching a foto.
by Sniffer
Thu Apr 04, 2019 9:15 pm
Forum: 8-bit acorn hardware
Topic: Non booting BBC/B Issue 7 - Continuous beep
Replies: 60
Views: 2755

Re: Non bootong BBC/B Issue 7 - Continuous beep

Fixed the housing and I've now tried 3 or 4 Vias in IC3, all with the same result. So I'll focus on IC31 & IC32.
by Sniffer
Thu Apr 04, 2019 8:34 pm
Forum: 8-bit acorn hardware
Topic: Non booting BBC/B Issue 7 - Continuous beep
Replies: 60
Views: 2755

Re: Non bootong BBC/B Issue 7 - Continuous beep

To check it and make sure, you could use a multimeter to do a continuity check between IC25 pin 1 and IC37 pin 10 (the generator of the 2MHZE signal) or any other pin that's labelled as being linked directly to 2MHZE, such as IC7 pin 10, IC59 pin 24, etc. Great, thanks. Track not broken. So I'll se...
by Sniffer
Thu Apr 04, 2019 8:11 pm
Forum: 8-bit acorn hardware
Topic: Non booting BBC/B Issue 7 - Continuous beep
Replies: 60
Views: 2755

Re: Non bootong BBC/B Issue 7 - Continuous beep

That’s too bad. Anyway, these things are sent to try us. Had a good look under where the plastic housing was, it seems somebody in the past has had a bit of a dig with a screwdriver (which is what I often use) or some such implement as there is some gouging and the track from pin 1, IC25 is damaged...
by Sniffer
Thu Apr 04, 2019 7:06 pm
Forum: 8-bit acorn hardware
Topic: Non booting BBC/B Issue 7 - Continuous beep
Replies: 60
Views: 2755

Re: Non bootong BBC/B Issue 7 - Continuous beep

Since switching S25 to get your machine booting, have you tried switching the two VIAs (IC3 and IC69) around? No, I haqdn't. I was pretty confident in both as they came from the good board. However, I thought I'd do it anyway and sadly, using the chip puller has pulled the pastic housing of IC3 off...
by Sniffer
Thu Apr 04, 2019 4:44 pm
Forum: 8-bit acorn hardware
Topic: Non booting BBC/B Issue 7 - Continuous beep
Replies: 60
Views: 2755

Re: Non bootong BBC/B Issue 7 - Continuous beep

Does the beeeeb stop after you press break? On switch on the monotonous tone continues. On pressing 'BREAK' I get a second tone which fades away quickly and is replaced by an undulating whistle, the first tone keeps going. At this point, when pressing keys, its like playing some kind of wierd elect...
by Sniffer
Thu Apr 04, 2019 4:35 pm
Forum: 8-bit acorn hardware
Topic: Non booting BBC/B Issue 7 - Continuous beep
Replies: 60
Views: 2755

Re: Non bootong BBC/B Issue 7 - Continuous beep

Does the beeeeb stop after you press break?
Only if I remove the speaker lead :D
by Sniffer
Thu Apr 04, 2019 2:20 pm
Forum: 8-bit acorn hardware
Topic: Non booting BBC/B Issue 7 - Continuous beep
Replies: 60
Views: 2755

Re: Non bootong BBC/B Issue 7 - Continuous beep

Some of the I/O lines used by the System VIA to communicate with the keyboard and sound chip are latched by IC32 (74ls259), which is in turn clocked by one half of IC31 (74ls74), so they're also worth checking. Ok, thanks. Before I go through the pain of desoldering and replacing those I think I mi...
by Sniffer
Thu Apr 04, 2019 1:11 pm
Forum: 8-bit acorn hardware
Topic: Non booting BBC/B Issue 7 - Continuous beep
Replies: 60
Views: 2755

Re: Non bootong BBC/B Issue 7 - Continuous beep

By the way, thank you both for your inputs thus far, it's very miuch appreciated.
by Sniffer
Thu Apr 04, 2019 12:53 pm
Forum: 8-bit acorn hardware
Topic: Non booting BBC/B Issue 7 - Continuous beep
Replies: 60
Views: 2755

Re: Non bootong BBC/B Issue 7 - Continuous beep

The sound chip (IC18) is controlled by the System VIA (IC3), so if the VIA's not there, the OS can't tell the sound chip to shut up (as it normally does at boot).
The implication being that the System Via is missing or faulty? It's not though so maybe a board/track problem. I'll take a closer look.
by Sniffer
Thu Apr 04, 2019 12:51 pm
Forum: 8-bit acorn hardware
Topic: Non booting BBC/B Issue 7 - Continuous beep
Replies: 60
Views: 2755

Re: Non bootong BBC/B Issue 7 - Continuous beep

No, it’s not. Does the keyboard work? Did you (correctly) replace the system VIA (6522, IC3)? Yep, both VIAs in situ. Keyboard Caps Lock & Shift Lock leds lit, keyboard does NOT respond until break is pressed. At this point I can use the keyboard but apart from the default MODE, no others seem to b...
by Sniffer
Thu Apr 04, 2019 11:20 am
Forum: 8-bit acorn hardware
Topic: Non booting BBC/B Issue 7 - Continuous beep
Replies: 60
Views: 2755

Re: Non bootong BBC/B Issue 7 - Continuous beep

Well, I can't explain this but, I put all the ICs back (actually the ICs from the good board because I left this faulty boards original ICs in the good board, as it was working) and tried booting with S25 completely off but again no change. So, I tried with S25 south, which I had already tried, and ...
by Sniffer
Thu Apr 04, 2019 10:58 am
Forum: 8-bit acorn hardware
Topic: Non booting BBC/B Issue 7 - Continuous beep
Replies: 60
Views: 2755

Re: Non bootong BBC/B Issue 7 - Continuous beep

I don’t see you mention trying S25 south? See this (very recent) post: viewtopic.php?f=3&t=16852&view=unread#p232947
Sorry, yes, I tried that, no change. I didn't try with S25 off completely though. Thanks for the link, I'll check it out.
by Sniffer
Thu Apr 04, 2019 10:09 am
Forum: 8-bit acorn hardware
Topic: Non booting BBC/B Issue 7 - Continuous beep
Replies: 60
Views: 2755

Non booting BBC/B Issue 7 - Continuous beep

I've googled myself to death almost and read through tons of articles, including one here but still no joy. So if anybody can help .... I have an issue 7 BBC/B that when powered on gives a continuous beep (or beeps). I say 'or beeps' because it sounds like I get the first beep and the second but all...
by Sniffer
Sun Mar 31, 2019 7:29 pm
Forum: 8-bit acorn hardware
Topic: WE SOLDERLESS 12 ROM Board
Replies: 3
Views: 458

Re: WE SOLDERLESS 12 ROM Board

It's a 74LS04N
Thanks for that.

Replaced the two caps, a little clean up and all looks good. Taken the battery 'off' the board to avoid any future spills.
by Sniffer
Sun Mar 31, 2019 12:30 pm
Forum: 8-bit acorn hardware
Topic: WE SOLDERLESS 12 ROM Board
Replies: 3
Views: 458

WE SOLDERLESS 12 ROM Board

I'm looking to get this working but before I start I thought I'd make a note of all the ICs in case any need replacing. There was a battery attahced which must have leaked at some point. No major visual damage. Any body any idea what the IC is, third row up second from left (ringed in red on attachm...
by Sniffer
Fri Mar 29, 2019 12:08 pm
Forum: 8-bit acorn hardware
Topic: BBC B Issue 1 board documentation/service manual
Replies: 1
Views: 273

Re: BBC B Issue 1 board documentation/service manual

Ok, ignore my ramblings, I've obviously gone senile.

It's a B+, hence the Issue 1 board. :oops:
by Sniffer
Fri Mar 29, 2019 11:36 am
Forum: 8-bit acorn hardware
Topic: BBC B Issue 1 board documentation/service manual
Replies: 1
Views: 273

BBC B Issue 1 board documentation/service manual

Anybody know if any exists? Anybody got a service manual that caters for the Issue 1 motherboard? I'm under orders to sell some of my hoarded BBC kit (as we are downsizing) and one of the Beebs I have is an Issue 1, but for some reason and I can't remember why, there was no PSU in the case (I do hav...
by Sniffer
Tue Mar 26, 2019 1:53 pm
Forum: wanted
Topic: Wanted Intel 8271
Replies: 2
Views: 458

Re: Wanted Intel 8271

Hi,

Beebmaster (Ian Wolstenholme) used to sell a 8271 Disc Upgrade kit, have you tried him?

I have just had a look at my block of removed chips and I do have a couple if you are struggling. Not sure why I have them, maybe I fitted 1770's in their place in the dim and distant past.

Mike.
by Sniffer
Tue Mar 19, 2019 3:01 pm
Forum: 32-bit acorn hardware
Topic: Poorly A440/1
Replies: 4
Views: 420

Re: Poorly A440/1

All back together and booted up fine. Great stuff. The initial issue of running any software immediately locking up the machine was still there though. That turned out to be the SharedCLibrary (v5.59) that is in the Etherlan 500 podule. It had become replugged. Unplugging it again solves that problem.
by Sniffer
Tue Mar 19, 2019 12:48 pm
Forum: 32-bit acorn hardware
Topic: Poorly A440/1
Replies: 4
Views: 420

Re: Poorly A440/1

Some of the later machines didn't have tantalum decoupling caps but it's worth checking and removing the 16v/25v tantalum caps if they're fitted, especially the ones on the 12v rail. Not sure which tantalum caps you are refering to to be honest, however, on removing the motherboard for close inspec...
by Sniffer
Tue Mar 19, 2019 11:26 am
Forum: 32-bit acorn hardware
Topic: Poorly A440/1
Replies: 4
Views: 420

Poorly A440/1

The A440/1 that I recently aquired has become very poorly. Not a good sign. I fitted a scsi podule and the machine booted but at some point, running any software, for example the scsi setup program or sparkplug just hung the machine. The podule is known good, or was. I removed the scsi podule and th...
by Sniffer
Fri Mar 15, 2019 2:40 pm
Forum: wanted
Topic: A440/1 3.5" Floppy Drive
Replies: 4
Views: 501

Re: A440/1 3.5" Floppy Drive

Thanks for the link, I'll take a look. Having done some rudimentary checks I suspect the step motor is dead.
by Sniffer
Fri Mar 15, 2019 1:52 pm
Forum: wanted
Topic: A440/1 3.5" Floppy Drive
Replies: 4
Views: 501

Re: A440/1 3.5" Floppy Drive

Yeah, had the drive out, cleaned the heads, no go. Lights up but gives disk error 4 blah blah. Same error if accessing or formatting.

Tried a known good drive and that works so it's not the machine.
by Sniffer
Thu Mar 14, 2019 5:19 pm
Forum: wanted
Topic: A440/1 3.5" Floppy Drive
Replies: 4
Views: 501

A440/1 3.5" Floppy Drive

Mine seems caput so need a replacement. They seem to be not as sturdy as the rest of the machine these floppy drives, I think the one on my A3000 is on it's way out too.

Anybody got one or know of a suitable substitute? Modify PC floppy maybe?
by Sniffer
Sat Mar 09, 2019 1:01 pm
Forum: 32-bit acorn hardware
Topic: RISC OS ROM format
Replies: 1
Views: 414

RISC OS ROM format

Sorry if this all sounds a bit basic but would just like to better understand. I assume it's possible to use EPROMs to hold the opeating system (talking about 3.1x here) but how would you get the OS into the EPROM? I know, using an EPROM programmer but I mean how are the ROMs formatted? The OS can b...
by Sniffer
Fri Mar 08, 2019 4:20 pm
Forum: wanted
Topic: A5000 8MB upgrade
Replies: 0
Views: 387

A5000 8MB upgrade

Anybody got one or know where one might be reasonably obtained? I'd like to upgrade my 4MB A5000.

Cheers,
Mike.
by Sniffer
Thu Mar 07, 2019 9:51 pm
Forum: 32-bit acorn hardware
Topic: Extension ROMs - A5000
Replies: 5
Views: 547

Re: Extension ROMs - A5000

Success! So, I built the extension rom flashed it, installed it, all good.

The problem with the BASIC program was simply a couple of variables (filestoadd & nooffiles) not initialised in the right place. It would have worked as is for a podule rom I guess.
by Sniffer
Thu Mar 07, 2019 3:42 pm
Forum: 32-bit acorn hardware
Topic: Extension ROMs - A5000
Replies: 5
Views: 547

Re: Extension ROMs - A5000

Should have checked the BASIC content first. :oops:

There is an error in the code, it's a while since I've done BBC BASIC but I should be able to work it out. Sorry for the noise.

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