Search found 85 matches

by MadeGray
Sat Mar 14, 2020 9:04 am
Forum: hardware
Topic: German Beeb upgraded to 1772 DFS
Replies: 1
Views: 176

German Beeb upgraded to 1772 DFS

This may interest a few people and I believe the same will be true for the American Beebs. My German beeb had a fault with the 8271 controller. I’d already removed and replaced the LS393 used to slice the clock and the 7438’s as well as trying another 8271 but *. Would give a corrupted title and any...
by MadeGray
Tue Dec 31, 2019 5:23 pm
Forum: hardware
Topic: 8271 controller read / write problems
Replies: 10
Views: 427

Re: 8271 controller read / write problems

Actually got some time earlier Linked up what was reading 2mhz on pin 5. But as I monitored it it went from 2mhz to 1mhz every so often so looks like counter is definitely back in preschool.... Monitored the 4Mhz in that was stable all the time, 0v on pin 2 is solid as well. Time to pull the chip an...
by MadeGray
Tue Dec 31, 2019 3:21 pm
Forum: hardware
Topic: 8271 controller read / write problems
Replies: 10
Views: 427

Re: 8271 controller read / write problems

Thanks Mark,

Didn’t get chance today to run the test on the 2mhz but as long as my head isn’t too sore tomorrow I’ll give it a try and see where we are!

Have a great New Year and I’ll update as soon as.

John
by MadeGray
Mon Dec 30, 2019 10:13 am
Forum: hardware
Topic: 8271 controller read / write problems
Replies: 10
Views: 427

Re: 8271 controller read / write problems

Hi Mark Thanks again I did check between 3 and 4 and no shorts or continuity. Checked each back to the 2/4 jumper all connected Checked 1 and 3 of the 2/4 jumper and no shorts either (just an extra check for my OCD) I’ve checked all outputs and are as follows Pin 1 - input at 8mhz Pin 3 - 4Mhz Pin 4...
by MadeGray
Sun Dec 29, 2019 3:19 pm
Forum: hardware
Topic: 8271 controller read / write problems
Replies: 10
Views: 427

Re: 8271 controller read / write problems

And a little more info. Found the clock divider 393 that drives the 8271 The 4/2 MHz link jumper is connected to pins 3 and 4 q0 and q1 as expected. The clock input in pin 1 of the 393 is at 8mhz which should be correct. Both pins 3 and 4 of the 393 produce 4Mhz. I would have expected 2 and 4 here a...
by MadeGray
Sun Dec 29, 2019 2:31 pm
Forum: hardware
Topic: 8271 controller read / write problems
Replies: 10
Views: 427

Re: 8271 controller read / write problems

After a little more checking - Pin 3 of the 8271 is running at 4Mhz - fault finding (service manual B+) says this should be running at 2Mhz - I’m guessing this could well be causing a problem.... I’m looking at the B+ service guide as has more info and closer to this German beeb. Suggested that a li...
by MadeGray
Sun Dec 29, 2019 1:33 pm
Forum: hardware
Topic: 8271 controller read / write problems
Replies: 10
Views: 427

Re: 8271 controller read / write problems

Hi Quick update. Take a working 40 track 5 1/4 disk. Verified on another machine. Try to read on German beeb - no cat just the standard text that’s displayed it drive Option etc. Corrupted name. Save file on German beeb then *cat and it shows however I believe this is just cached Try to load file on...
by MadeGray
Sat Dec 28, 2019 5:21 pm
Forum: hardware
Topic: 8271 controller read / write problems
Replies: 10
Views: 427

Re: 8271 controller read / write problems

Thanks Mark, I’ll do that test later this evening, good idea. I’d identified LS123 on the read lines from the diagram. Was going to bell from the read port on the interface connector to ensure I got the right one on the board and then firstly try jumpering a known working. Failing that I’ll start by...
by MadeGray
Sat Dec 28, 2019 5:02 pm
Forum: hardware
Topic: 8271 controller read / write problems
Replies: 10
Views: 427

8271 controller read / write problems

Good evening all, I wonder if anyone can cast a small light on a problem I have with a model B with an 8271 controller DNFS 1.2 installed. Using either a 5 1/4 drive or Gotek whenever I do the following the symptoms are as follows. Please note the 5 1/4 and Gotek I can plug into any of my 177x Beebs...
by MadeGray
Sat Dec 28, 2019 10:49 am
Forum: hardware
Topic: Pegasus 400 Disc Interface Electron
Replies: 16
Views: 602

Re: Pegasus 400 Disc Interface Electron

That’s interesting, I’ve one here that does exactly the same thing / however I’m convinced it’s the plus one. I tested ADFS in a separate plug in cartridge electron cartridge and found that had the exact same problems. Also depending on the version of ADFS sometimes parts would show at least. This d...
by MadeGray
Sun Oct 20, 2019 3:28 pm
Forum: hardware
Topic: Electron Plus 1 Rom upgrade
Replies: 5
Views: 431

Re: Electron Plus 1 Rom upgrade

Thanks Dave for all the help

New Rom all in and working.

Drop me a PM on the alternative disk interface if you can?

Thanks again for all the help,

John
image.jpg
by MadeGray
Sat Oct 19, 2019 8:50 am
Forum: hardware
Topic: Electron Plus 1 Rom upgrade
Replies: 5
Views: 431

Re: Electron Plus 1 Rom upgrade

Dave H, You are a superstar and the font of Elk knowledge! I’ve been dragged out by the wife shopping but I’ll look at the link later and give that a try. Whilst I have too many beebs the Elk was where I started way back and this one I want to keep. Miss my old Plus 3 but the chances of getting one ...
by MadeGray
Sat Oct 19, 2019 6:41 am
Forum: hardware
Topic: Electron Plus 1 Rom upgrade
Replies: 5
Views: 431

Electron Plus 1 Rom upgrade

Hi all, I’ve been looking at various posts and some conflicting information about upgrading the original Plus 1 Rom to the Slogger Rom. The original Rom is a 24 pin and the slogger 28pin which suggests some track changes may need to be made however the Slogger upgrade manual doesn’t say this, just s...
by MadeGray
Sat Oct 12, 2019 12:38 pm
Forum: hardware
Topic: Model B - Issue 7 - Beep of doom
Replies: 7
Views: 435

Re: Model B - Issue 7 - Beep of doom

Good afternoon all, A few more checks, unfortunately the same. Checked all address lines from all ROM sockets to 6502 all check ok Checked all data lines from all ROM sockets to 6502 all check OK. Noticed slight hot spot where the resistor next to ULA was laying on the board - checked and reflowed a...
by MadeGray
Thu Oct 10, 2019 4:39 pm
Forum: hardware
Topic: Model B - Issue 7 - Beep of doom
Replies: 7
Views: 435

Re: Model B - Issue 7 - Beep of doom

Hi all, I've checked all connections from OS chip side to underneath and reflowed them all to be sure. Checked between each rom socket and the expected connections are made. I need to test from the OS Chip back to processor etc but that will be one for tomorrow it seems as wife want's the kitchen ba...
by MadeGray
Thu Oct 10, 2019 3:51 pm
Forum: hardware
Topic: Model B - Issue 7 - Beep of doom
Replies: 7
Views: 435

Model B - Issue 7 - Beep of doom

Hi all, I wondered if one of our learned friends could offer a little advice on a poorly Issue 7. The machine exhibits the Caps Lock and Beep of doom with no screen display. I've done quite a bit of fault finding so far as follows: Checked all PSU voltages and at all locations. Tested a known workin...
by MadeGray
Fri Aug 09, 2019 7:09 pm
Forum: hardware
Topic: Will a BBC Master 128 PSU work in a BBC model B issue 7?
Replies: 13
Views: 613

Re: Will a BBC Master 128 PSU work in a BBC model B issue 7?

Thanks Mark, much appreciated. Having both masters and beebs appreciate the spade connectors but didn’t realise the older boards didn’t have the power rails connected. That’s quite interesting and a good thing to know for fault finding if I get a pre issue 4. Thanks for the information very useful s...
by MadeGray
Fri Aug 09, 2019 4:26 pm
Forum: hardware
Topic: Will a BBC Master 128 PSU work in a BBC model B issue 7?
Replies: 13
Views: 613

Re: Will a BBC Master 128 PSU work in a BBC model B issue 7?

Hi Mark,

Just out of interest (I’ve only issue 4 and 7 boards) what were the changes that stop the newer power supplies working with issue 3 etc? Interested to understand in case I come up with an issue 3.

Many thank John
by MadeGray
Tue Jul 30, 2019 7:03 am
Forum: hardware
Topic: High res picture of area around composite video out
Replies: 19
Views: 775

Re: High res picture of area around composite video out

As per the pics mine isn’t modified, I always use RGB I’m afraid.

As per the others I’m really surprised this wasn’t a standard link option. Maybe most had moved towards RgB screens then perhaps?

I can look more closely this evening if that helps and see if can get better shots of numbers.
by MadeGray
Mon Jul 29, 2019 7:55 pm
Forum: hardware
Topic: High res picture of area around composite video out
Replies: 19
Views: 775

Re: High res picture of area around composite video out

thanks Andy - I was a little confused myself thought there was just one. Service guide says the caps don’t need fitting on an issue 2. Surprised that the master didn’t come with a link like the later BBC B’s
by MadeGray
Mon Jul 29, 2019 6:18 pm
Forum: hardware
Topic: High res picture of area around composite video out
Replies: 19
Views: 775

Re: High res picture of area around composite video out

Although rumour is there was only one issue Master board? I’m sure others will be able to provide more info.
by MadeGray
Mon Jul 29, 2019 3:55 pm
Forum: hardware
Topic: High res picture of area around composite video out
Replies: 19
Views: 775

Re: High res picture of area around composite video out

However check revision of 128 board

If an issue 2 then you only need to add link to LK11 mod only needs doing to an issue 1 master 128
by MadeGray
Mon Jul 29, 2019 3:53 pm
Forum: hardware
Topic: High res picture of area around composite video out
Replies: 19
Views: 775

Re: High res picture of area around composite video out

Here you go.

Can’t really see the numbering though.

Let me know if need any more.

John
by MadeGray
Mon Jul 29, 2019 3:47 pm
Forum: hardware
Topic: High res picture of area around composite video out
Replies: 19
Views: 775

Re: High res picture of area around composite video out

Give me a few minutes I’ll take a few
by MadeGray
Sun Jul 21, 2019 3:57 pm
Forum: hardware
Topic: Beeb black plastic surround
Replies: 43
Views: 2498

Re: Beeb black plastic surround

Perfect! Thank you
by MadeGray
Sun Jul 21, 2019 3:35 pm
Forum: hardware
Topic: Beeb black plastic surround
Replies: 43
Views: 2498

Re: Beeb black plastic surround

Great Pics Marcus thank you! Can you let me know where the area of the underside cream shows around the caps lock and which bit on an issue 3 has the 45 degree angle? Looks pretty good even if I do say so myself! I’ll do the mods you mentioned for issue 3 and send you up some templates. Appreciate y...
by MadeGray
Sun Jul 21, 2019 11:55 am
Forum: hardware
Topic: Beeb black plastic surround
Replies: 43
Views: 2498

Re: Beeb black plastic surround

Marcus has kindly sent me a few changes to an issue 3 case and I’ll cut a few paper templates for testing this week and get them over to him so we should have issue 3,4 and 7 cases covered. I’ve a relatively quiet week next week so hopefully get this all sorted and work out costings etc. Could also ...
by MadeGray
Sun Jul 21, 2019 11:23 am
Forum: hardware
Topic: Beeb black plastic surround
Replies: 43
Views: 2498

Re: Beeb black plastic surround

Just for info these were the two surrounds I sent to Marcus. As I’ve mentioned before I haven’t had chance to look into screen printing the caps lock etc but to me they look really close to the originals and doesn’t distract much at all. I fear screen printing would take the cost up too much? Once t...
by MadeGray
Fri Jul 19, 2019 1:34 pm
Forum: hardware
Topic: Beeb black plastic surround
Replies: 43
Views: 2498

Re: Beeb black plastic surround

If there is any real difference then yes, if it’s a minor change I can cut some paper templates instead as a test.
by MadeGray
Fri Jul 19, 2019 1:02 pm
Forum: hardware
Topic: Beeb black plastic surround
Replies: 43
Views: 2498

Re: Beeb black plastic surround

I’ve tried on an issue 4 and 7 so be good to see what difference etc. Marcus if there is much can you save the old issue 3 surround even if in bits?