SOLVED:Issues with my bbc b

[marcelaj1]

Hi, got my old bbc b out of storage, it had been there over 30 years! Plugged it in and switched it on and it booted up. I could even read some of the old floppys. While playing Castle Quest there was a loud crack and smoke - switch off and brought a capacitor referb kit. 11 capacitors later and the beeb was back.
Brought a MMC kit and got it up and running, so thought I can image all the floppys and put the drive away. This is where I hit a wall, the documentation was a bit rubbish and there was no "howto". After a lot of frustration due to most of the programs crashing I realised that I needed a sideways rom/ram card. Found one on ebay that was cheap due to broken pins, always up for a challenge, soldered some silver coated wire to replace the pins and the board was up and running. Loaded the utilities into sideways ram and they came up when I typed *HELP. Tried again with the image programs and they still crashed with syntax errors.
The penny finally dropped when I issued a REPORT command, even though I purchased my beeb in 1983 it has the old BASIC.
I downloaded the romtool and loaded the BASIC 2 image into my sideways RAM typed *BASIC2 and ran one of the utility programs and no syntax errors, the issue now is that the OSCLI commands fail, but at least I know whats was wrong.
Anyone know how I can get my basic upgraded, is there a rom blowing service or a replacement rom?
Another issue I am having is a "twitching" picture, I have read that this can be symptomatic of one of the video chip failing/overheating and a replacement chip or fan is required.

[flaxcottage]

Welcome, marcelaj1.

That is quite an introduction and an absolute litany of problems!

BASIC 1 is not very common. I found one in a beeb recently but that had been put in there specially, so that the company who originally used it could test their software for BASIC 1 compatibility.

Getting a BASIC 2 ROM will not be difficult. People here will have a spare. I can blow one for you if not. You will need to contact the Admin people to get your personal messaging set up though first.

[tricky]

Welcome,
we might need a little more description on the twitching, but have you tried any other TVs, maybe on composite or RF?
I got an issue 7 with basic 1 about a year ago and it took me a while to work out what was wrong with some games

[marcelaj1]

I am using a beeb to scart converter on a old lcd tv, which gives a good picture except that every now and then the screen seems to move a pixel to the right and back again, this takes less than a second, a twitch is the best way I can describe it. I used a scart to hdmi converter to my p.c. monitor and that gave the same result, although looking at the beeb on a 32" high def monitor was pretty amazing. I did try the rf interface but that was really hard to tune in and the picture quality was rubish, so no way to tell if its the scart lead.
When I was using the machine back inthe 80s I used a Sony trinitron monitor which gave a rock solid picture, for some reason it refuses to wake up, the power led comes on but thats it, looking in the back I don'tsee the crt element heat up, as its full of high voltages I thought it best to leave alone.
Who would I contact to get the basic issue sorted, I am stuck as all the utilities here and elsewhere seem to need basic 2.

[Kazzie]

I am using a beeb to scart converter on a old lcd tv, which gives a good picture except that every now and then the screen seems to move a pixel to the right and back again, this takes less than a second, a twitch is the best way I can describe it. I used a scart to hdmi converter to my p.c. monitor and that gave the same result, although looking at the beeb on a 32" high def monitor was pretty amazing. I did try the rf interface but that was really hard to tune in and the picture quality was rubish, so no way to tell if its the scart lead.
When I was using the machine back inthe 80s I used a Sony trinitron monitor which gave a rock solid picture, for some reason it refuses to wake up, the power led comes on but thats it, looking in the back I don'tsee the crt element heat up, as its full of high voltages I thought it best to leave alone.

If you can get some photos or video footage of the jumpy behaviour, that might help us diagnose what's going on.

Old CRT displays are wonderfully simple and straightforward, in that they steer the electron gun wherever the computer's video signal tells it to go. As a result, they're much more forgiving of slightly odd screen resolutions and timings.

Converting that to a series of frames for an LCD display is a little bit fiddly, and most converters (inside a TV or as a separate box) assume that it's converting a perfectly standard TV signal to make life easier. As a result, a retro machine with "slightly-off" timing can result in an occasional "jump" of the display like you mention; I have a Mega Drive that does the same thing.

One fix that some people have reported success with, especially when using HDMI upscalers, is to replace the master 16MHz clock crystal with a new, modern crystal, which is manufactured to a much more accurate frequency. This clears up some noisy pixels that are caused by mis-sampling by the upscaler, and may also help with your jumpy picture.

Repairing CRT displays can be safe to do, as long you are careful, cautious, and competent. If you don't feel you've got the skill to do it, you may be able to pass the display on to someone who can. A good CRT would be worth repairing if possible, as they're not making them any more!

[marcelaj1]

I will try and get some footage, it is intermitent and may well not happend with the cover off. I have noticed that with the sidewise board fitted the psu is running hot. I am contemplating getting one of these
http://www.cjemicros.co.uk/micros/indiv ... CPSU-NEW-E
as it should run cooler. There are a lot of variables, I noticed the ic front middle with the heatsink gets quite warm/hot to touch.
The monitor in question is a Sony KTX-1400UB an RGB teletext monitor and is very heavy. I had a quick look for a service manual and they are about but pricey, also spotted that there was a product recall on them due to component overheating. The inside is really cramped which is what put me off withou a manual.

[flaxcottage]

The CJE PSU looks to be one of the Meanwell +/-5v +12v switchmode PSUs fitted into an old BBC PSU case. If you can't make one yourself it could be a way to go as it will come with a cast-iron guarantee.

If you are competent though the Meanwell can be bought for about £15 and there is info on the forum about how to fit it into the case.

[1024MAK]

RetroClinic often has various spare parts for Beebs.

Try Mark at RetroClinic

He is also a member here (link). But as a new member, you will not yet be able to send private messages (PM).

The BASIC II ROM you are after is often marked HN613128PB05 if it is an Acorn mask ROM.

The PSU fitted in the vast majority of Beebs is a switch mode type and apart from C1, C2 suffering due to age (and sometimes C9) are mostly reliable. They are not as efficient as more modern SMPSUs, but are reasonable units.

The chip that is fitted with a heatsink will run hot (this is normal). It’s a ULA and runs at 16MHz. It’s called the Video ULA / Video Processor.

Mark

[retroclinic]

Thanks, replied to this by eMail.

[marcelaj1]

Thank you for the parts. Just fitted the new crystal and rom, beeb up and running again.
The new crystal has improved the sharpness of the picture (I think) but has not sorted the twitch, if anything it happens more often.
I have a video of it, how do I upload it.

[marcelaj1]

I have uploaded the file to google drive
https://drive.google.com/file/d/1UHTgmP ... p=drivesdk

The "twitch" happens at about 11 and 14 seconds in the clip.

[Kazzie]

Having looked at the video, I can't think of anything inside the Beeb that could be causing that vertical twitch of the screen (now that the crystal's been replaced), and would wonder about the cable and television upscaler instead.

I wonder if other members with more experience with HDMI outputs could offer some insight here?

[marcelaj1]

I am using a pre-made beeb to scart lead,
https://www.ebay.co.uk/itm/BBC-MICRO-MO ... 2749.l2649
and plugging into the scart socket in the tv.

The twitch is different to what it was before I changed the crystal.

[retroclinic]

What brand of TV are you using?

Also, I've not seen how the ones from that seller are wired, and they're not all wired the same, and with the same value components to give the correct voltage reduction. Can you remove the SCART plug plastic end and do a close up photo of it, to see if the components are visible? Not saying it's the cable, but it's one possible area of trouble.

Thanks, Mark.

[CMcDougall]

/\ yip, had threads about rubbish cool novelties before

Retro Computer Shack ones sorted it.

I have one, but it does not jump to correct scart channel when beeb turned on, only down side with it. A home made one does

[1024MAK]

The BBC-SCART cable that I have from cool-novelties works fine with my BBC B, Master 128 and Electron machines. I don’t have the details to hand on the wiring, but IIRC, it is wired conventionally using 220Ω resistors for the three colour channels, plus one 270Ω resistor for the sync and one 220Ω resistor for the pin 16 SCART blanking/RGB selection input. +5V is fed to pin 8 SCART status/aspect ratio input.

I do know that the biggest variation is the TV set that is used. Some work fine, others, not so much.

So my advice would be to try your machine on another TV set, just to see if the problem remains the same.

Mark

[marcelaj1]

A couple of pics of the scart plug....
https://drive.google.com/file/d/1Uctdg4 ... p=drivesdk
https://drive.google.com/file/d/1Ue25wT ... p=drivesdk

Unfortunately some of the heat shrink is shrunk too tight to see the value of all the resistors, the exposed ones appear to be 220 and I suspect the end one with the yellow wire to be the sync wire which should 270, I could be more aggresive and split the heat shrink.

I tried it on an LG tv and it works ok, so it may well be the Daewoo tv that is showing the new twitch is less forgiving.

My intention is to use a scart to hdmi converter. I did try one before and the picture was great but the setup menu kept overlaying on the screen, I returned the unit thinking it was faulty but maybe it was the crystal or the cable causing it, as I said the twitch is different to what it was before I changed the crystal.

[marcelaj1]

Had a brainwave, I think there were 2 issues. The first was the crystal in the beeb which, when replaced, produced a different issue that showed a fault in the Daewoo tv. I carried out a factory reset on the tv and the twitching stopped. There is an issue with the colour of the characters displayed where the right hand edge is slighter than the rest of the character, this could be due to the cable, but the picture is stable. Thank you for the help.

Have other issues which are for another board but on the subject of hardware has anyone used one of these

https://www.amazon.co.uk/gp/slredirect/ ... ame=sp_atf

Seems to tick the right boxes

[marcelaj1]

The device on Amazon although claims to support rgb, it does not.

Tried a new cable from Retro Computer Shack, and it did not clear the problem, the factory reset on the tv did not fix it, the issue is intermittent. The problem seems to happen at random times with varying intensity, next time it happens I with put my osciliscope on the bnc socket and see if there is any twitch on that signal. The problem with intermittent is that it may have gone away when I moved the beeb to a different tv.

I gave up trying to get the MMC disc imager working as I had the "mmc not active" issue when I loaded the COP113 utils into the ram on my Sidewise board, after a lot of going in circles I went through the IDTOM code and added a memory switcher to it. Although this worked it used up a lot more ram which meant I had to reduce the track buffer to 2 tracks which made it a bit slow but got there in the end.

The other issue is the psu is getting very hot any one know what sort of temerature these things can tolerate?

[1024MAK]

The Beeb PSU or do you mean another PSU?

The Beeb PSU will run rather warm inside the case.

Mark

[marcelaj1]

The device on Amazon although claims to support rgb, it does not.

Tried a new cable from Retro Computer Shack, and it did not clear the problem, the factory reset on the tv did not fix it, the issue is intermittent. The problem seems to happen at random times with varying intensity, next time it happens I with put my osciliscope on the bnc socket and see if there is any twitch on that signal. The problem with intermittent is that it may have gone away when I moved the beeb to a different tv.

I gave up trying to get the MMC disc imager working as I had the "mmc not active" issue when I loaded the COP113 utils into the ram on my Sidewise board, after a lot of going in circles I went through the IDTOM code and added a memory switcher to it. Although this worked it used up a lot more ram which meant I had to reduce the track buffer to 2 tracks which made it a bit slow but got there in the end.

The other issue is the psu is getting very hot any one know what sort of temerature these things can tolerate?


The beeb psu, it feels hot through the case.

[Wheel_nut]

I gave up trying to get the MMC disc imager working as I had the "mmc not active" issue when I loaded the COP113 utils into the ram on my Sidewise board, after a lot of going in circles I went through the IDTOM code and added a memory switcher to it. Although this worked it used up a lot more ram which meant I had to reduce the track buffer to 2 tracks which made it a bit slow but got there in the end.

COP113 (and COP114) will only work with the IFEL TurboMMC Hardware and either the TurboSPI ROM or Steve Picton's C.MMFS variants. This is documented on the CD that comes with the IFEL TurboMMC adapter and ROM.

[marcelaj1]

The mmc I got was supplied with a cd with COP113 on it, so I made an incorrect assumption, the upside is that I had to re-learn beeb basic and assembly as I have spent the last 25 years using C, C++ and loads of Java and MS variants, pen and paper instead of an IDE, took me back a bit.

[Wheel_nut]

The mmc I got was supplied with a cd with COP113 on it, so I made an incorrect assumption, the upside is that I had to re-learn beeb basic and assembly as I have spent the last 25 years using C, C++ and loads of Java and MS variants, pen and paper instead of an IDE, took me back a bit.

I think I have seen the device you have being sold on eBay (not by IFEL) and it appears to be an older version of the IFEL Product. Certainly, the CD is down level because the current CD has COP114 on it.

If you use the ROM that came with it and install it ABOVE the DFS in your Beeb, I believe that COP113 should work. If you are using MMFS, you MUST use the C.MMFS variants which are modified to allow the *DISK commands to switch to the DFS and Floppy Drive. Read the documentation on the CD titled MMFS+SWMMFS+MAMMFS.pdf

[marcelaj1]

I have the mmc installed at 13 and the dfs at 12, so the default is mmc. The mmc functions fine if I don't need to switch between mmc and dfs as the dfs over writes the mmc workspace.
It would be good to get the utils to work properly as a matter of personal principle, it will eat away at my OCD until I can make it work, even though I wrote a work around.
What I tried was to load the COP113 into sidewise ram, socket 15 only place I can install it with this board, pressed cntl break and the utils listed up after a *HELP, any attempt to run an mmc command resulted in "MMC not active" response.

[Wheel_nut]

Could you post the ROM names and levels listed by either *ROMS or *HELP and I will try to assist you in getting this working. I need to know the details of the DFS and the SD Card Filing system that you are using.

I haven't used TurboSPI for some time as I much prefer MMFS ... especially MMFS V1.44 which has some usability features that Hoglet implemented for me. In particular, it has a *OPT 5,1 command which stops MMFS from responding to *DISK and *DISC; allowing these to pass to the DFS. It also responds to *CARD as a synonym for *MMFS to select the SD Card filing system.

I would also suggest that you use COP114 which is Steve Picton's latest version of the Copy Utility.

[marcelaj1]

I figured some pics would be helpful, not heared back from admins about uploading pics so I put them on google drive...

This pic is straight from power on and I tried *ROMS and got an error, then did *HELP
https://drive.google.com/file/d/1XmqoXB ... p=drivesdk

This pic *HELP DUTILS
https://drive.google.com/file/d/1Xumcks ... p=drivesdk

This pic *HELP UTILS
https://drive.google.com/file/d/1XvuQET ... p=drivesdk

This is a pic of my ATPL Sidewise board with the ROMS installed
https://drive.google.com/file/d/1YR7FBu ... p=drivesdk
The ROM marked DFS is in slot 12, the MMC (orange dot) is in 13

[KenLowe]

Google is saying I need permission to view the pictures. Can you not just add the pictures as an attachment to this thread?

[marcelaj1]

Sorry I forgot to turn on link sharing.

I did try once before but the pictures would not appear.

Did this from my pc rather than my tablet which seems to have done the trick.

[Wheel_nut]

OK, You have a Sidewise ROM expansion Board in there and seem to have 5 ROMS installed

Enigma Disc Imager
Wordwise
DFS 0.9
Super MMC (based on DFS 0.9)
BASIC

Now, the MMC Hardware you have is almost certainly the standard User Port Adapter and NOT the IFEL Turbo MMC hardware so COP113 will never work with it. You should persevere with IDTOM and IMTOD which do not allow you to transfer individual files but instead will image Disc to SSD and SSD to Disk sector by sector.