Introducing myself

In this forum you can write about anything that does not fit in other forums.
This includes generic Oric talkings and things that are totaly unrelated but want to share with people here :)
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mikeb
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Re: Introducing myself

Post by mikeb » Sun Sep 01, 2019 5:05 pm

Chema wrote:
Sat Aug 31, 2019 10:53 pm
Mmmmmm.... I don't remember if the Oric 1 rom performed a memory test.
It does -- not an extensive one, but that's why you get a wipe-down of black-white fine bars (looks grey) about 2 secs after bootup, just before the text screen appears, and why unused memory is filled with UUUUU -- the test writes 0xAA = 10101010 then 0x55 = 01010101 to each location (and reads it back, obviously!)

@kaydav

You have good (enough) RAM for it to boot and get that far.

The expansion port looks like someone's tried to kick it in, so probably a small child tried quite hard to insert a coin or something :(

When you do straighten it out, make sure you can insert/remove a 34-way IDC connector (if you don't have a handy Oric peripheral or lead, a 34 way floppy drive lead would do -- with the power off, and just for mechanical testing of the fit!)

The speaker may well be damaged due to impact into the voice coil. Whether the VIA (6522) and 8912 (sound chip) are working or not, you should be able to hear a soft purring from the speaker once it is powered on. Put your ear right on it. If dead silence, speaker is probably toasted, but fortunately it is not a critical part and any small speaker that will physically fit would work -- it doesn't even have to be PCB mounting (like the original) if you are prepared to mount it to the case with two short flying leads.

Good luck, hope you don't find more horrors inside!

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kaydav
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Re: Introducing myself

Post by kaydav » Sun Sep 01, 2019 8:49 pm

Thank you all :)
What I know about the damage is that it spent a decade or so in a cardboard box in my brother's loft, then was transported 75 miles when he moved house - and then another decade later transported the 75 miles back to me. When I got it, it was in among tapes and ZX hardware and other bits and pieces, and there wasn't any protective wrapping at all *scowls at brother*. It's possible these bits and pieces have slid around and bashed into each other. Or a stack of boxes fallen .. eek!
mikeb wrote:
Sun Sep 01, 2019 5:05 pm
When you do straighten it out, make sure you can insert/remove a 34-way IDC connector (if you don't have a handy Oric peripheral or lead, a 34 way floppy drive lead would do -- with the power off, and just for mechanical testing of the fit!)
That's a great idea. Used gently enough it could help realign the pins. I have tiny jeweller's needle-nosed and flat-nosed pliers too, they'll come in handy. Ok, I'll check it over some more later in the week and fingers crossed it turns out all fixable.

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mikeb
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Re: Introducing myself

Post by mikeb » Mon Sep 02, 2019 5:19 pm

kaydav wrote:
Sun Sep 01, 2019 8:49 pm
I have tiny jeweller's needle-nosed and flat-nosed pliers too, they'll come in handy.
You should get by okay with those. There's a tool that music-box repairers/clock fixers use that is designed for this, for slipping over a pin and levering it straight (a hollow stainless steel tube closely matched to the pin size, with a handle, or held in a pin-vice).

e.g. http://www.nancyfrattimusicboxes.com/tools1.html

I wonder if there's an electronics equivalent? If not, you might need to make one :)

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Steve M
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Re: Introducing myself

Post by Steve M » Mon Sep 02, 2019 6:12 pm

I think that's basically a pin vice with a tube in its jaws. You can get the pin vice a lot cheaper elsewhere.
https://www.ebay.co.uk/itm/Swivel-Pin-V ... SwpONZVwvy

Then you just need to find a metal tube small enough to fit over the pin. A bit of brass tube should do the trick.

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Re: Introducing myself

Post by mikeb » Tue Sep 03, 2019 5:08 pm

Steve M wrote:
Mon Sep 02, 2019 6:12 pm
Then you just need to find a metal tube small enough to fit over the pin. A bit of brass tube should do the trick.
I linked that tool as an example of what I was talking about, not necessarily a recommendation to buy :)

Brass tube is probably no good -- you need something that is stiffer than the thing you are trying to bend, hence stainless steel tube for brass-copper pins, and it needs to be a good fit, otherwise you can't really get it to straighten the pin.

Maybe if you can find a fat enough diameter of *blunt* hypodemic nerdle ...

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kaydav
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Re: Introducing myself

Post by kaydav » Tue Sep 03, 2019 10:33 pm

I had a hunt through my jewellery tools and found a pin vice but currently no tubing that's small enough. However, I DID find an old piece of scrap copper jewellery that I'd made into a small enough tube .. and funnily enough it did work. Copper's a bit soft really, brass or steel would have been better and the blunt hypodermic would have been a great possibility. I also found some jumper pins on an old hard drive (for the slave-master settings) and they were good at aligning pairs of pins. A bit of a pain going along the rows two pins at a time but it looks much better now and I think a connector will fit. I still have to dig out a floppy cable to make sure.

I opened up the case! First, whether it has two ROMs or one - it has one, if the ROMs are located to the right of the speaker and south of the reset switch (I'll attach photos). The empty space where the second ROM would have been looks like it has never been in use.

All in all, it looks in good nick to me on a visual check-over. The peripheral ports look firm and don't seem to have been shunted when the port pins were damaged. The speaker definitely needs replaced (any recommendations?), and hmmm I do suspect kid damage having seen it now (that'd be my kids then, 20-odd years ago). But the sound chip looks ok. It seems pretty clean inside. The rotary whatchacallem where you adjust the fine tuning through a hole in the case - it's right next to a component labelled 12.000 IQDD and the nearest label on the board is IC21 - has been shunted sideways and looks to have come apart. 12.000 IQDD is also leaning over so may have been shunted too.

I tried to unscrew and lift the board off the keyboard to have a further look at that, but it didn't lift away at all so I didn't try to force it. I may have missed a screw hidden somewhere. Or it might need a firmer pull apart than I dared. I put it all back together for now and checked it still works as much as it did last time. Keyboard is pretty much the same, wrong keys happening, some keys not working, and some doing multiples. I had found one key stuck down and levered it back up but it didn't fix the issue.
Attachments
IMG_20190903_155742.jpg
rotary tuning
IMG_20190903_155517.jpg
speaker, ROM chip
IMG_20190903_155510.jpg
top right

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mikeb
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Re: Introducing myself

Post by mikeb » Wed Sep 04, 2019 4:38 pm

Good news on the pin straightening :)

Your rotary whatchamacallit is quite broken. Variable capacitor CV1, it's used to create the colour signal for the UHF output only. You can desolder it and throw it away (and have no colour UHF output) or find a replacement (2.22pF, original is Mullard 808-11229, but anything of that value and correct pin spacing ...)

The RGB output won't be affected by this. Probably better to remove it than have a broken bit abandoned to disintegrate.

If the 12.000MHz crystal had been damaged, you'd get nothing from Oric it all, it's the main system oscillator/timer. So it should be ok as long as it's not being shunted into anything else. It doesn't look to have moved very far at all.

The single ROM is a good sign, that's a proper production Oric. The concern mentioned about 2 chips is that early Orics had two chips, one (or both) was an EPROM. While this works just fine, EPROMS can fade over time and become unreliable, but more importantly, the mask programmed ROM can be "switched off" by external peripherals -- e.g. the disk interface. If you have an EPROM there (you don't) then they don't support that, they can't be moved out of the way, and disk interfaces fail to work. So you're good.

Speaker: Anything small enough to fit in the space. The original is PCB mounted on two tangs, and when the original speaker on my Oric died (too much volume on Damsel In Distress :) it was replaced with a small speaker on two short flying leads, mounted to the case with small bolts/speaker clips. Leads long enough to open the case and lay it aside, obviously.

Keyboard: I think you should only have to remove three screws to release the board (along the top edge, left-middle-right). The keyboard only connects by a 14-15 way connector, which is marked PL3, just below the two DIN connectors (cassette, video). You can see it from the top of the board. If it's stiff, you may need to rock the board, rather than brute force lift it off. Walk it up and off. I don't recall it being difficult, and there's no "lock" or anything to release (clips, catches).

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Steve M
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Re: Introducing myself

Post by Steve M » Thu Sep 05, 2019 8:42 pm

I have a load of spare boards that you could use to get a speaker or some of these other parts from.
PM me if you're interested.

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Re: Introducing myself

Post by Steve M » Thu Sep 05, 2019 8:51 pm

mikeb wrote:
Tue Sep 03, 2019 5:08 pm
Brass tube is probably no good -- you need something that is stiffer than the thing you are trying to bend, hence stainless steel tube for brass-copper pins, and it needs to be a good fit, otherwise you can't really get it to straighten the pin.

Maybe if you can find a fat enough diameter of *blunt* hypodemic nerdle ...
I think brass would work as a tube will have more structural strength than a pin.

A fat enough needle would be something like a biopsy punch. They come in various sizes. The body is usually plastic though so you can't put too much pressure on it.
Personally I'd drill a hole in the end of a bit of drill rod using my lathe - but not everyone has an engineers lathe and a stock of drill rod.

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iss
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Re: Introducing myself

Post by iss » Thu Sep 05, 2019 9:42 pm

Guys, be more practical - why not to use small metal ballpoint-pen refill as tube. :)
Mini-Ballpoint-Pen-Refill.jpg
Mini-Ballpoint-Pen-Refill.jpg (8.59 KiB) Viewed 274 times

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Re: Introducing myself

Post by mikeb » Fri Sep 06, 2019 4:41 pm

As long as it can fit between the 0.1" spaced pins -- that's a mighty small pen, and, importantly, has a fairly constant sized hole drilled up the middle (not just a little hole at the end that widens out inside!) then that would work too.

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Re: Introducing myself

Post by Steve M » Fri Sep 06, 2019 6:18 pm

iss wrote:
Thu Sep 05, 2019 9:42 pm
Guys, be more practical - why not to use small metal ballpoint-pen refill as tube. :)
Because it's full of ink!?
I wouldn't have thought it was strong enough.

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kaydav
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Re: Introducing myself

Post by kaydav » Fri Sep 06, 2019 7:34 pm

Thanks guys :) The pen idea made me laugh, it might just work too. I've been inside a couple of old PCs today and they have the right kind of floppy/CD cable that might fit. Didn't have time to do anything with the Oric though.
mikeb wrote:
Wed Sep 04, 2019 4:38 pm
Your rotary whatchamacallit is quite broken. Variable capacitor CV1, it's used to create the colour signal for the UHF output only. You can desolder it and throw it away (and have no colour UHF output) or find a replacement (2.22pF, original is Mullard 808-11229, but anything of that value and correct pin spacing ...)

The RGB output won't be affected by this. Probably better to remove it than have a broken bit abandoned to disintegrate.
I think I may well remove the broken part, and probably stick a label inside to remind future-me that I did it.
mikeb wrote:
Wed Sep 04, 2019 4:38 pm
Speaker: Anything small enough to fit in the space. The original is PCB mounted on two tangs, and when the original speaker on my Oric died (too much volume on Damsel In Distress :) it was replaced with a small speaker on two short flying leads, mounted to the case with small bolts/speaker clips. Leads long enough to open the case and lay it aside, obviously.
Steve M wrote:
Thu Sep 05, 2019 8:42 pm
I have a load of spare boards that you could use to get a speaker or some of these other parts from.
PM me if you're interested.
Thank you for the offer, Steve. I looked up electronics sites and small speakers seem quite easy to get hold of. It's been a while (30 years) since I did any electronics soldering so I'm thinking of getting a hobbyist kit of some sort just to get a bit of practice before I touch the Oric. If I feel really ambitious I'll source another of the CV1 capacitors and replace that too.
mikeb wrote:
Wed Sep 04, 2019 4:38 pm
Keyboard: I think you should only have to remove three screws to release the board (along the top edge, left-middle-right). The keyboard only connects by a 14-15 way connector, which is marked PL3, just below the two DIN connectors (cassette, video). You can see it from the top of the board. If it's stiff, you may need to rock the board, rather than brute force lift it off. Walk it up and off. I don't recall it being difficult, and there's no "lock" or anything to release (clips, catches).
Thanks, I'll give it another try as soon as I can.

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kaydav
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Re: Introducing myself

Post by kaydav » Sat Sep 14, 2019 4:53 pm

After soldering yesterday, I tested the Oric today. Big smiles :D
IMG_20190914_153556.jpg
sound, colour, keyboard .. it works!
Many thanks to everyone who helped :)

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Re: Introducing myself

Post by Dbug » Sat Sep 14, 2019 5:07 pm

Good!
It's alive :)

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