This is not a language

for bbc micro/electron hardware, peripherals & programming issues (NOT emulators!)
User avatar
1024MAK
Posts: 8097
Joined: Mon Apr 18, 2011 4:46 pm
Location: Looking forward to summer in Somerset, UK...
Contact:

Re: This is not a language

Post by 1024MAK » Sat Nov 03, 2018 10:44 am

roganjosh wrote:
Sat Nov 03, 2018 10:10 am
1024MAK wrote:
Sat Nov 03, 2018 8:03 am
The WDC W65C22S6TPG-14 is a CMOS chip for new designs, as the interrupt pin (IRQB) output is a totem pole type which should not be directly connected to existing circuit designs if more than one device is connected to the CPU's interrupt input.

The WDC W65C22N6TPG-14 is also a CMOS chip, but designed to be compatible with previous CMOS 65C22 and NMOS 6522 designs. This is the correct type for use in a Beeb.
Very good to know they're still made and thanks for the type warning. I suppose if anyone has bought the S type in error then they might get it working by lifting IRQB and sticking a diode in line?

Alan
Yes, a suitable signal diode could be used so that the S type can’t pull up the interrupt line.

Mark

User avatar
1024MAK
Posts: 8097
Joined: Mon Apr 18, 2011 4:46 pm
Location: Looking forward to summer in Somerset, UK...
Contact:

Re: This is not a language

Post by 1024MAK » Sat Nov 03, 2018 10:57 am

Elminster wrote:
Sat Nov 03, 2018 10:43 am
1024MAK wrote:
Sat Nov 03, 2018 8:03 am
The WDC W65C22S6TPG-14 is a CMOS chip for new designs, as the interrupt pin (IRQB) output is a totem pole type which should not be directly connected to existing circuit designs if more than one device is connected to the CPU's interrupt input.

The WDC W65C22N6TPG-14 is also a CMOS chip, but designed to be compatible with previous CMOS 65C22 and NMOS 6522 designs. This is the correct type for use in a Beeb.

Note, there is only one seller on eBay that is known to supply genuine WDC chips. Other sellers that appear to sell WDC chips, are likely to be selling remarked chips.

Mark
Thought you meant you were running the S version. Have amended my post to be less ambiguous.

I have bought wdc from eBay before without issue, will have to check which buyer.
Seller toucano76 sells genuine WDC chips. Is this who you have bought from before?

Mark

Jungsi
Posts: 26
Joined: Mon Oct 01, 2018 1:50 pm
Contact:

Re: This is not a language

Post by Jungsi » Sat Nov 03, 2018 1:34 pm

Now I've checked the keyboard an I think I know why the Power LED is not working.....
Have a look at the picture - can this be a ptoblem for other things also?
Attachments
BBC Master Keyboard.jpg

User avatar
danielj
Posts: 6685
Joined: Thu Oct 02, 2008 4:51 pm
Location: Manchester
Contact:

Re: This is not a language

Post by danielj » Sat Nov 03, 2018 2:09 pm

Ouch. Feasible I guess? Get that repaired and see if it improves anything. If it doesn't then I'm still thinking it's IC8.

d.

User avatar
1024MAK
Posts: 8097
Joined: Mon Apr 18, 2011 4:46 pm
Location: Looking forward to summer in Somerset, UK...
Contact:

Re: This is not a language

Post by 1024MAK » Sat Nov 03, 2018 2:30 pm

Jungsi wrote:
Sat Nov 03, 2018 1:34 pm
Now I've checked the keyboard an I think I know why the Power LED is not working.....
Have a look at the picture - can this be a ptoblem for other things also?
Any and all broken / cracked / fractured PCB tracks can and do cause all kinds of keyboard problems.
Is the actual board cracked / broken?
If yes, repair this first. Use epoxy resin glue for the larger breaks. For the thin cracks, a liquid glue, such as super glue (be very careful with this) or a hard plastic glue for modellers can be sparingly applied so that it drains into the crack.

If there is an area on the top (component) side which is clear of components, create a key by using sandpaper or emery cloth. Then use a thin layer of epoxy resin glue to stick down a piece of 80g or 100g paper. Coat with epoxy resin glue again, then put a second piece of paper with the ‘grain’ at right angles. Finally carefully coat with another thin smear of epoxy resin glue. When fully set this will add enough mechanical strength for most boards to live on.

Then you can solder on thin solid core wires to bypass the broken / cracked copper tracks. If you are not using an existing solder pad, use a small flat bladed screwdriver to carefully scrap off the green solder resist layer. Once the bare copper is exposed, use new solder to tin it. It’s then ready to solder a wire to it.

Mark

Jungsi
Posts: 26
Joined: Mon Oct 01, 2018 1:50 pm
Contact:

Re: This is not a language

Post by Jungsi » Sat Nov 03, 2018 2:42 pm

Thanks for the tips!
Because of my bad eys (glaucoma) I can't do this myself. Now it's really time to send it to retroclinic.
I've already contacted Marc and will send the board and keyboard next week on it's journey to him :-)

Jungsi
Posts: 26
Joined: Mon Oct 01, 2018 1:50 pm
Contact:

Re: This is not a language

Post by Jungsi » Sat Dec 08, 2018 1:10 pm

Just want to let you know that my master is working again. Mark at Retroclinic get it going.
On the first trip I sent the board and the keyboard to Mark. He found nothing wrong with it.
He changed the VTI ULA because they are known for all sort of problems and also the LS259.
The keyboard wasn't woth repairing so we changed the complete keyboard.

As the board and keyboard was back to me I put all together and the problem wasn't gone!!!
The board was working for Mark but in my case not.
So we found out that the power supply which I had for my local engineer for changing capacitors only was delivering 4.38 volt when
the Master was turned on. Thats not enough!

So the complete computer did a second journey to Mark. He recalibrated the power supply to run on 5V and the mainboard worked
again without problem. Some more was done:
- new mains switch and cable
- MultiOS
- Raspberry PI Second Processor
- GOTEK Drive
This is now the ultimate Master for me! :-) Thanks again to Mark for helping with the problem and answering a lot of questions :-)

User avatar
1024MAK
Posts: 8097
Joined: Mon Apr 18, 2011 4:46 pm
Location: Looking forward to summer in Somerset, UK...
Contact:

Re: This is not a language

Post by 1024MAK » Sun Dec 09, 2018 12:30 am

4.38V is well outside the specification :shock:

I’m surprised there were no other problems!

I’m glad to hear that you are back up and running 8)

Thanks for reporting back =D>

Have fun :D

Mark

Post Reply