Search found 179 matches

by Sniffer
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?
by Sniffer
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

Could you confirm each of those measurements with your scope?
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.

IC6_P4-P7.png

If you were expecting something else, measurement wise, just say and I'l try and do it.
by Sniffer
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...
by Sniffer
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.
by Sniffer
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);
SDS00001.png

Not sure if this means anything, will learn more in the morning.
by Sniffer
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

Sorry, typo, RES (Reset) is on pin 40...
I should have realised. Yes, pin 40 does change state on <BREAK>
by Sniffer
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

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?
It is only a cheapo Laser probe.
by Sniffer
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 ...
by Sniffer
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

Can you check what you find on pins 7-4 of IC6?
7, Nothing
6, High
5, Pulsing
4, Pulsing

Can't get the scope till the morning. Pin 40 of IC1 is high until break is pressed.
by Sniffer
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

Have you tested both the +5V supply at each connection where the wiring connects to the main board
+5V supply
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 ......
by Sniffer
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

You may also want to try running in in a minimal configuration.
Yes, I have tried all of that, except IC4 is not socketed (though I did try a piggy back at some point).
by Sniffer
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

When you ran it with the test ROM in, was this EPROM in the OS socket? Were all the other ROM chips removed?
Yes.
You may also want to try running in in a minimal configuration.
Thanks, I'll take a look at that now.
by Sniffer
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...
by Sniffer
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...
by Sniffer
Thu May 02, 2019 9:05 pm
Forum: wanted
Topic: R6502AP / R65C02P
Replies: 2
Views: 529

Re: R6502AP / R65C02P

Contact Dave H.
Thanks, I've sent him a pm.
by Sniffer
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.
by Sniffer
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...
by Sniffer
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...
by Sniffer
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...
by Sniffer
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.
by Sniffer
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

The TBP-24510N (5 rather than S) is a PROM (that's the non-erasable, pre-EPROM variety).
Having got up close with a magnifier, it still looks like TBP 24S10N :)
24S10N.jpg
Editted to ask, probably a stupid question, would this be standard or programmed specifically for it's purpose?
by Sniffer
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...
by Sniffer
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 ...
by Sniffer
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....
by Sniffer
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

And sniffer, I'll see what I have. Definitely got one.
Cool. I'm happy to do some soldering.
by Sniffer
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

I got mine from IFEL. It works a treat.
Are they still going?
by Sniffer
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...
by Sniffer
Sun Apr 28, 2019 10:14 am
Forum: wanted
Topic: BBC B Keyboard
Replies: 3
Views: 596

Re: BBC B Keyboard

I have a spare one in need of a good home if you are interested.
Fantastic, thank you very much. I'll send you a PM.
by Sniffer
Sun Apr 28, 2019 9:02 am
Forum: wanted
Topic: BBC B Keyboard
Replies: 3
Views: 596

BBC B Keyboard

As the title says :)
by Sniffer
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

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.
Ok, great. I'll have a play. Thanks all.

Go to advanced search