What would you rescue and why?

discuss both original and modern hardware for the bbc micro/electron
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msknight
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What would you rescue and why?

Post by msknight »

What else would you rescue from these two boards (issue 3 and 4) and why?
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danielj
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Re: What would you rescue and why?

Post by danielj »

81LS95s, SAA5050 and 6850 - all the rest I think are pretty much easy to get.
sP1d3r
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Re: What would you rescue and why?

Post by sP1d3r »

A working motherboard is worth keeping although socketing all the chips could cause damage to the board, the tracks and/or the components.

Neither of those boards would be suitable for desoldering practice because they both look like they could work, both in need of a good clean also.
GoodToGo!
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Re: What would you rescue and why?

Post by GoodToGo! »

It depends, if you are going to stash the boards for bits, then like danielj said, plus that 2764 EPROM. However if you are going to turf the boards in the bin (which if you were in Oz I would more than happily take off your hands) then me being me, I would remove almost everything. All the IC's and transistors, all the connectors, the modulators, the jumpers, crystals, pots, etc. The only bits I personally wouldn't bother with are the resistors, capacitors, IC sockets (unless maybe they are turned pin or 'unique') and headers.
But that's just me...... BBC bits seem to be hard to come by down here, and they can be pricey.

Cheers!
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Re: What would you rescue and why?

Post by sP1d3r »

If you look at the pictures of my issue 7 motherboard in this post:

viewtopic.php?f=9&t=22853

and then the attached picture, you can see that it's possible to repair quite damaged motherboards.

Total time spent is so far a bit less than 150 minutes plus some thinking time.

I can see that IC62 on the issue 4 seems to have a lifted track, but otherwise no obvious damage, the power connector may come off if you put a drop of WD40 on it, wait a while and then push it further on first to loosen it before trying to pull it off.

The issue 3 motherboard can be fitted with an econet clock BTW.
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marcelaj1
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Re: What would you rescue and why?

Post by marcelaj1 »

In the past I used a couple of scans of a motherboard, top and bottom, as layers in Gimp. This allowed me to trace the physical path of connections around the board and find a cracked track without having to take the board out and constantly keep flipping it over.
The problem I have/had was that the image of the top of the board I got from the internet and was an "angled" image of an issue 7 board. The bottom was a 2 part scan on my issue 4 board. With a lot of Gimp tools I managed to twist and distort the images so that they sort of aligned if I kept shifting the layers about while tracing.
I never got a good enough image to publish but I thought at the time how little difference there seemed to be between an issue 4 and 7. Then I thought what would be great is if this could be put into some sort of PCB design package and used as a general fault finding thing, then had the idea that if we had a PCB design thing it would be possible to have a new board made........then my brain ran away with itself and I thought we could have a board made with integrated new stuff like the VideoNuLA solution and a proper clock and, and, and........drag the Beeb into the 21st century :D (it begs the question when does the beeb stop being one)
To do this we would need to capture the original board. If there is a board that can be stripped back to nothing and scanned converted maybe this is a place to start.

Ashley.
Ronin47
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Re: What would you rescue and why?

Post by Ronin47 »

I'd personally keep the boards and salvage as I needed stuff, the parts are safe whilst on the board. It's what I do with my ST mainboards.

I learned a while back that chucking stuff can bite you later, though it's a difficult call when you also have to keep the wife sweet :)

At least having moved house I have the space these days.
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daveejhitchins
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Re: What would you rescue and why?

Post by daveejhitchins »

msknight wrote:
Wed Sep 15, 2021 3:38 pm
What else would you rescue from these two boards (issue 3 and 4) and why?
If you do decide to continue saving parts (?) I can provide a good home for the modulators :D

Dave H.
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1024MAK
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Re: What would you rescue and why?

Post by 1024MAK »

I’d remove the electrolytic capacitors so that I could connect them with reverse polarity to blow them up! :lol:

On a serious note, the hardest to get item, after a good condition case, IS THE PCB.

Issue three boards have a small number of design errors for some of the extra I/O circuitry (details in the service manual) but other than that, work fine.

As said above, there are no significant differences between the issue four and issue seven boards (issue five and six boards were never put into production).

Hence either keep them and if needed carefully remove parts as required. Or if you don’t want to store them, or don’t have the space, let someone on here have them.

Mark
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msknight
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Re: What would you rescue and why?

Post by msknight »

I've continued to take the parts off that I can. I'll remove the Econet chips also, although I'm not sure I'll use them.

I was trying to go through my e-mails of ten years ago to see what I was told about the old boards that I was given, but can't find the e-mails. It is possible that they were working boards, but just the person didn't want the Issue 3 and 4 boards at the time as there were plenty of 7 boards around. So I might have just butchered working boards.

However, here I have limited space and already have three BBC micros in various states of... er... repair? So it makes sense for me to have the spare chips and repair the issue 7's as they go wrong... as I happen to have the boards. All the RAM chips were tested OK, so that was a bonus.

Thanks for your help on this. I'm slowly understanding things. Have a long way to go.
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msknight
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Re: What would you rescue and why?

Post by msknight »

1024MAK wrote:
Thu Sep 16, 2021 9:43 am
Hence either keep them and if needed carefully remove parts as required. Or if you don’t want to store them, or don’t have the space, let someone on here have them.
I'm up for that. I've already PM'd Dave about the modulators, but after that I'll stop.

If the empty PCBs are really of use to people, even after I've messed them up, (some already had some wire on the back) I'm happy to get them to someone rather than throw them.
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Re: What would you rescue and why?

Post by marcelaj1 »

msknight wrote:
Thu Sep 16, 2021 9:53 am
If the empty PCBs are really of use to people, even after I've messed them up, (some already had some wire on the back) I'm happy to get them to someone rather than throw them.
Happy to have a go at scanning a board, does not matter if some tracks are shot, Gimp has enough tools to fix some pretty messed up images, may be of use to people as a resource, could make a searchable image to help locate components along with the searchable schematics.

PM me with P&P and I will give it a shot.

One other thing maybe worth recovering, on some boards the "latch lugs" on the IDE sockets at the bottom of the board can be recovered by pushing out the retaining pins. These can be refitted to other beebs with the same style socket as they have a habit of snapping, I have swapped mine from the printer port to the floppy port as the floppy ones were broken and I don't use the printer one.

Ashley.
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msknight
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Re: What would you rescue and why?

Post by msknight »

Ok - only the issue 3 board is available now, but it's pretty sparse. The modulator has been taken off and most of the socketed chips, all the ram and a few of the others. It's looking pretty bare. Let me know if interested and I'll post an updated picture.
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