Search found 179 matches
- Sat May 04, 2019 6:36 pm
- Forum: 8-bit acorn hardware
- Topic: Non booting BBC/B Issue 7 - Continuous beep Mk 2
- Replies: 43
- Views: 2985
Re: Non booting BBC/B Issue 7 - Continuous beep Mk 2
Could you scope out the CPU's pins too Sure, pins 1 to 40 in order; 1 L 2 H 3 L 4 H 5 N 6 H 7 H 8 H 9 L 10 L 11 L 12 L 13 L 14 L 15 L 16 L 17 L 18 L 19 L 20 L 21 L 22 L 23 L 24 L 25 L 26 P 27 P 28 P 29 P 30 P 31 P 32 P 33 P 34 H 35 N 36 N 37 P 38 H 39 H 40 H Would you like images of the pulsing pins?
- Sat May 04, 2019 10:38 am
- Forum: 8-bit acorn hardware
- Topic: Non booting BBC/B Issue 7 - Continuous beep Mk 2
- Replies: 43
- Views: 2985
Re: Non booting BBC/B Issue 7 - Continuous beep Mk 2
Here's an image of pins 4 to 7 of IC6. No idea if it's what you wanted, as I freely admit, I'm not proficient with the scope.Could you confirm each of those measurements with your scope?
If you were expecting something else, measurement wise, just say and I'l try and do it.
- Sat May 04, 2019 9:50 am
- Forum: 8-bit acorn hardware
- Topic: Non booting BBC/B Issue 7 - Continuous beep Mk 2
- Replies: 43
- Views: 2985
Re: Non booting BBC/B Issue 7 - Continuous beep Mk 2
If that scope output is from measuring one of pins 3, 37 or 39 (the clock pins) on the CPU, then that's a good enough square wave to drive the CPU clock. CPU pin 37. Could you confirm each of those measurements with your scope? Will do. Can you confirm which ROM was/is in the OS socket for these te...
- Fri May 03, 2019 11:28 pm
- Forum: 8-bit acorn hardware
- Topic: Non booting BBC/B Issue 7 - Continuous beep Mk 2
- Replies: 43
- Views: 2985
Re: Non booting BBC/B Issue 7 - Continuous beep Mk 2
Uused 10X probe setting. Still learning with this (any) scope.
- Fri May 03, 2019 10:21 pm
- Forum: 8-bit acorn hardware
- Topic: Non booting BBC/B Issue 7 - Continuous beep Mk 2
- Replies: 43
- Views: 2985
Re: Non booting BBC/B Issue 7 - Continuous beep Mk 2
Got the scope out, not a square wave in sight, though admittedly, I could be doing something wrong 
Editted to add image (cpu clock);
Not sure if this means anything, will learn more in the morning.

Editted to add image (cpu clock);
Not sure if this means anything, will learn more in the morning.
- Fri May 03, 2019 9:57 pm
- Forum: 8-bit acorn hardware
- Topic: Non booting BBC/B Issue 7 - Continuous beep Mk 2
- Replies: 43
- Views: 2985
Re: Non booting BBC/B Issue 7 - Continuous beep Mk 2
I should have realised. Yes, pin 40 does change state on <BREAK>Sorry, typo, RES (Reset) is on pin 40...
- Fri May 03, 2019 9:29 pm
- Forum: 8-bit acorn hardware
- Topic: Non booting BBC/B Issue 7 - Continuous beep Mk 2
- Replies: 43
- Views: 2985
Re: Non booting BBC/B Issue 7 - Continuous beep Mk 2
It is only a cheapo Laser probe.Your probe(?) is detecting the 2 and 1MHz clocks on pins 5 and 4, but not the 4 and 8MHz clocks they're generated from. Perhaps your probe isn't able to detect frequencies that high?
- Fri May 03, 2019 9:28 pm
- Forum: 8-bit acorn hardware
- Topic: Non booting BBC/B Issue 7 - Continuous beep Mk 2
- Replies: 43
- Views: 2985
Re: Non booting BBC/B Issue 7 - Continuous beep Mk 2
Okay, assuming the remaining voltage tests are okay They did. can you test the various CPU pins using a logic probe or oscilloscope as follows: Can't access scope till morning, so, cpu pins; 1 low 2 high 3 low 4 high 5 nothing 6 high 7 high 8 high 9 low 10 high 11 low 12 high 13 nothing 14 high 15 ...
- Fri May 03, 2019 9:12 pm
- Forum: 8-bit acorn hardware
- Topic: Non booting BBC/B Issue 7 - Continuous beep Mk 2
- Replies: 43
- Views: 2985
Re: Non booting BBC/B Issue 7 - Continuous beep Mk 2
7, NothingCan you check what you find on pins 7-4 of IC6?
6, High
5, Pulsing
4, Pulsing
Can't get the scope till the morning. Pin 40 of IC1 is high until break is pressed.
- Fri May 03, 2019 8:16 pm
- Forum: 8-bit acorn hardware
- Topic: Non booting BBC/B Issue 7 - Continuous beep Mk 2
- Replies: 43
- Views: 2985
Re: Non booting BBC/B Issue 7 - Continuous beep Mk 2
+5V supplyHave you tested both the +5V supply at each connection where the wiring connects to the main board
VCC1=5.03v
VCC2=5.023v
VCC3=4.995v
0V/Gnd (using +5 by S38)
VCC1=5.001v
VCC2=5.001v
VCC3=4.990v
I'll get onto the ICs ......
- Fri May 03, 2019 7:03 pm
- Forum: 8-bit acorn hardware
- Topic: Non booting BBC/B Issue 7 - Continuous beep Mk 2
- Replies: 43
- Views: 2985
Re: Non booting BBC/B Issue 7 - Continuous beep Mk 2
Yes, I have tried all of that, except IC4 is not socketed (though I did try a piggy back at some point).You may also want to try running in in a minimal configuration.
- Fri May 03, 2019 6:56 pm
- Forum: 8-bit acorn hardware
- Topic: Non booting BBC/B Issue 7 - Continuous beep Mk 2
- Replies: 43
- Views: 2985
Re: Non booting BBC/B Issue 7 - Continuous beep Mk 2
Yes.When you ran it with the test ROM in, was this EPROM in the OS socket? Were all the other ROM chips removed?
Thanks, I'll take a look at that now.You may also want to try running in in a minimal configuration.
- Fri May 03, 2019 6:44 pm
- Forum: 8-bit acorn hardware
- Topic: Non booting BBC/B Issue 7 - Continuous beep Mk 2
- Replies: 43
- Views: 2985
Re: Non booting BBC/B Issue 7 - Continuous beep Mk 2
Thread moved to the 8-bit hardware section. Thanks Mark. Has the machine had a disc interface or Econet fitted? I pulled the machine out of the loft to sell it so to be honest, I don't know much about it. It doesn't have econet and looks like it never has had. It doesn't have a disk interface thoug...
- Fri May 03, 2019 4:37 pm
- Forum: 8-bit acorn hardware
- Topic: Non booting BBC/B Issue 7 - Continuous beep Mk 2
- Replies: 43
- Views: 2985
Non booting BBC/B Issue 7 - Continuous beep Mk 2
Over in the BBC Hardware Department thread ( https://stardot.org.uk/forums/viewtopic.php?f=3&t=17016 ) I attached that board to a BBC B that now no longer boots. Initially, I thought the board was the cause but now I suspect the Beeb was suffering anyway. Too long in the loft. Anyway, I've worke...
- Thu May 02, 2019 9:05 pm
- Forum: wanted
- Topic: R6502AP / R65C02P
- Replies: 2
- Views: 529
Re: R6502AP / R65C02P
Thanks, I've sent him a pm.Contact Dave H.
- Thu May 02, 2019 8:43 pm
- Forum: wanted
- Topic: R6502AP / R65C02P
- Replies: 2
- Views: 529
R6502AP / R65C02P
As the subject says. Think one of mine in a BBC/B is fried.
- Thu May 02, 2019 8:31 am
- Forum: 8-bit acorn hardware
- Topic: BBC Equipment Department - UN27/25
- Replies: 18
- Views: 1600
Re: BBC Equipment Department - UN27/25
'A' needs to be connected to the South East corner of S21 For some reason I remembered a lone piece of wire soldered to a jumper that came out of the same box of bits, way back. So thinking it probably became detatched from this board in the box, I connected (using similar) East/West to the two low...
- Wed May 01, 2019 11:32 pm
- Forum: 8-bit acorn hardware
- Topic: BBC Equipment Department - UN27/25
- Replies: 18
- Views: 1600
Re: BBC Equipment Department - UN27/25
‘A’ probably needs to be connected to one of the link / jumper shunt pins on the Beeb main board. That makes sense. Here is the other thread with what looks like same board installed. Thank you. So, progress. Armed with the above two comments and some guess work, 'A' needs to be connected to the So...
- Wed May 01, 2019 9:39 pm
- Forum: 8-bit acorn hardware
- Topic: BBC Equipment Department - UN27/25
- Replies: 18
- Views: 1600
Re: BBC Equipment Department - UN27/25
If you can connect A to ground (it's effectively an active-low signal) then that might be enough to get the board working. With A connected to ground the beeb fails to boot. I don't get the seccond 'beeeep' and there is a slight ticking noise from the speaker. No display. Disconnect from ground and...
- Wed May 01, 2019 7:27 pm
- Forum: 8-bit acorn hardware
- Topic: Issue 4 Beeb - Modification
- Replies: 2
- Views: 446
Re: Issue 4 Beeb - Modification
Ok, thanks for that.
- Wed May 01, 2019 7:23 pm
- Forum: 8-bit acorn hardware
- Topic: BBC Equipment Department - UN27/25
- Replies: 18
- Views: 1600
Re: BBC Equipment Department - UN27/25
Having got up close with a magnifier, it still looks like TBP 24S10NThe TBP-24510N (5 rather than S) is a PROM (that's the non-erasable, pre-EPROM variety).

Editted to ask, probably a stupid question, would this be standard or programmed specifically for it's purpose?
- Wed May 01, 2019 7:10 pm
- Forum: 8-bit acorn hardware
- Topic: BBC Equipment Department - UN27/25
- Replies: 18
- Views: 1600
Re: BBC Equipment Department - UN27/25
Does your Beeb recognise ROMs on the mainboard with this expansion board fitted? Yes, ROMs on the mainboard are recognised. The "A" wire goes to a 'via' and then to the back of the board. A picture from the other side might show us where it goes, and what it might have done. Picture attac...
- Wed May 01, 2019 5:40 pm
- Forum: 8-bit acorn hardware
- Topic: Issue 4 Beeb - Modification
- Replies: 2
- Views: 446
Issue 4 Beeb - Modification
I have an Issue 4 Beeb which I intend to sell and it has had a mod done by a previous owner and I was wondering if anybody might know why. A schottky diode (lt1004) was soldered between D6 & D8, though the leg soldered to D6 was detached when I opened it up. Couple of not so good pics; mod1.jpg ...
- Wed May 01, 2019 5:04 pm
- Forum: 8-bit acorn hardware
- Topic: BBC Equipment Department - UN27/25
- Replies: 18
- Views: 1600
Re: BBC Equipment Department - UN27/25
Well, I didn't have any joy with this. Fitted it into IC76 & IC101 but it does not recognise any roms that are inserted into it. Not sure what ROM 0 is for or if it should be populated or what the solder point (marked 'A') below it is. 'A' appears to have had a wire soldered in it at some point....
- Wed May 01, 2019 1:54 pm
- Forum: wanted
- Topic: (Closed/sorted!) WTD: A3010 4MB upgrade
- Replies: 18
- Views: 1996
Re: WTD: A3010 4MB upgrade
Cool. I'm happy to do some soldering.And sniffer, I'll see what I have. Definitely got one.
- Wed May 01, 2019 9:13 am
- Forum: wanted
- Topic: (Closed/sorted!) WTD: A3010 4MB upgrade
- Replies: 18
- Views: 1996
Re: WTD: A3010 4MB upgrade
Are they still going?I got mine from IFEL. It works a treat.
- Wed May 01, 2019 8:07 am
- Forum: wanted
- Topic: (Closed/sorted!) WTD: A3010 4MB upgrade
- Replies: 18
- Views: 1996
Re: WTD: A3010 4MB upgrade
I don't have a complete upgrade, but I've got a blank circuit board which you could get the bits for? Slight pain to solder as you need to get SOJ memory ICs onto it, but they do work. Yours for a quid plus postage. If the OP doesn't take you up on the offer, or if you have more than one, I'll take...
- Sun Apr 28, 2019 10:14 am
- Forum: wanted
- Topic: BBC B Keyboard
- Replies: 3
- Views: 596
Re: BBC B Keyboard
Fantastic, thank you very much. I'll send you a PM.I have a spare one in need of a good home if you are interested.
- Sun Apr 28, 2019 9:02 am
- Forum: wanted
- Topic: BBC B Keyboard
- Replies: 3
- Views: 596
BBC B Keyboard
As the title says 

- Fri Apr 26, 2019 9:32 pm
- Forum: 8-bit acorn hardware
- Topic: BBC Equipment Department - UN27/25
- Replies: 18
- Views: 1600
Re: BBC Equipment Department - UN27/25
Ok, great. I'll have a play. Thanks all.UN27/25: BBC Micro ROM Extension Unit. Allows up to 16 paged ROM's to be fitted into the BBC Microcomputer. Single plug-in printed board fitted inside the BBC Micro case. Takes power from the BBC micro. Power requirements from BBC Micro. ED 1983.