A/V Problem (inFuze) and introducing myself to the group.

[Stephen N]

Hello everybody,

    my name is Stephen, I'm 33 years old, and I bought and built an RS Components FIGnition inFuze in May of this

year (2014). I made a video of the build and posted it to You Tube as Birth Of A Computer - Can A Beginner Build One?.

Firstly, I'd like to give you a quick history of me so, here goes: in 1988 I was given a wood panelled Atari 2600,

which - although a legendary system - did not advance my programming skills one bit. It wasn't until 1992 that

I was given a ZX Spectrum 48k +, with the QL-style keyboard that finally allowed me to start learning BASIC.

Unfortunately, the 8-bit industry decided to do a disappearing act in the following year, 1993. I continued to use

the Spectrum throughout the 90's and learned to program BASIC to a fairly reasonable standard, though I

never wrote any original programs worthy of mention. I also spent 2 years on a fairly disappointing programming

apprenticeship, where they mostly had me making coffees and sending faxes.

Fast forward to 2012 and I spotted a ZX Spectrum +2B in a second hand shop and after a few days decided to

buy it , when I realised it was still there. I was at college as a mature student, and my cat had jumped on the

Spectrum a couple of times so, I put it back in it's box and there it stayed until 2014 (the Speccy, not the cat).

Anyway, earlier this year I caught the retro bug, and after a while, decided that I wanted to know how the hardware

worked as well as the software (ooh, ooh, ooh, I wanna be like you...). I tried to track down a ZX81 kit, only to find

that they are becoming more and more rare in their unbuilt state, and it would cost £99 for a replica ZX81 from a

seller in Bulgaria. With all the politics going on at the moment in that part of the world, I wondered if it would ever

get here and what returning it would be like if it turned out to be a dud.

Then I happened on the FIGnition, with its low price tag and rating as suitable for beginners, I ordered one from

RS Components, built it, and - to my surprise - I didn't have to redo any of the soldering to get it running!

Now, after all that waffling, for the shocking truth - I've only used the FIGnition twice. I've been so busy doing other

things, that I haven't been able to get around to learning FORTH, joining this group, etc.

I mention this, because - on only the third time that I got the FIGnition out of it's box - it has been in a project

box that is screwed together, and I never got around to drilling holes for the ports into, cushioned with anti-static

foam on the inside -  there now seems to be an A/V problem.

The FIGnition worked perfectly the first two times but now, I get white lines and hissing - I can still load

and use programs and see them on the TV screen but, only with this interference.

I ordered some new RCA Phono ports online. Unfortunately, it was a random selection, and when they finally

arrived on import from the far east, they were all 2-pin, not the 3-pin ports used on the FIGnition PCB.

I also tried re-heating the solder, yesterday (10/10/2014), which has not solved the problem.

I've tried different cables and both the RCA ports and the SCART port with an adapter so, it is looking

like it may well be the FIGnition itself.

So, before I order a 3-pin RCA port - is there anything else I could try to get my FIGnition working again?

Stephen N

[Julian Skidmore]

Hi Stephen,

Well done with your FIGnition build!

I've watched quite a bit of that video now - excellent! Great to see how people receive their FIGnitions from RS. I can see how it really helps to have a whole stack of programs you can run immediately (you can also edit the individual sectors to see how they work as they all contain source code).

White lines and hissing? It seems to me that sounds like a physical hardware issue, but since the programs still work, the CPU must be OK :-) . A few things to check:

1. Do you take the FIGnition out of the anti-static foam when you run it? anti-static foam works by kinda shorting whatever's touching it (that's how it dissipates the static charge). If there are bits on the bottom of the PCB, that could still be an issue.

2. You'll want to check D1, D2, R5 and R6 connections as well as U1.3 and U1.5. If there's a short from D1 to D2 or R5 to R6 you could get white lines. That's because in the image part of a scan line the Sync signal will be high and the video signal will vary. However, in the Sync part, the video signal will be low and the Sync will vary. This means it's likely the video would look stable, but with white lines.

3. I had a problem with part of the phono connector getting worn out a while back; from my earliest RevE FIGnition after a couple of years of plugging and unplugging.

4. If you send photos of the rear of the FIGnition and the front, then people may be able to see the problem more easily.

-cheers from Julz

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                  The DIY 8-bit computer from nichemachines™

[Stephen N]

Hi Julian,

       thanks for your speedy reply, in answer to your first question I always remove the FIGnition from the foam, although

I have yet to secure the PCB to a base of any description, as I'm having trouble finding 2mm screws.

I found a stringy piece of solder connecting R5.1 and R6.1, which looked very likely to be the culprit, so I've filed away at the

connection with a small blade, until the offending solder was removed.

Unfortunately, I decided to look at the board first thing this morning, when I was quite tired, and consequently

dislodged another resistor R10 which I will have to re-solder now, I guess I'd better not power up until that is done.

I didn't get around to taking photos but, I'll take some if I have any more trouble.

Thanks again for your help!

Stephen

[Stephen N]

Hi Julian,

    still having some trouble. I've got a value of 1.465 (Amps?) across R5.1 and R6.1, after removing what I thought was the short circuit.

The buzzer on my multimeter (I have a better, digital one now, rather than the analogue in the video) did not sound at any point.

I've included some photos - the underside of my PCB looks like a complete mess now that it has been enlarged into a photograph,

I'm massively embarrassed but, if I can save this FIGnition by posting images of my awful beginners soldering efforts here, then I may as well try.

The metal collar of the yellow AV port was also quite far forward and loose, until pushed it back into position.

Stephen

[Julian Skidmore]

Hi Stephen,

FWIW, about a decade or so ago my experience of soldering made me think that although I could do software, I was just hopeless at hardware, couldn't solder for toffee! However, you have a near 100% working FIGnition; that's pretty awesome and before this thread is over, it'll be even better :-) .

OK, before  you resolder anything else, can I see an image of the top of your solder reel (or whatever it is that identifies the solder you have)? Did you get it from Maplin? Also, what kind of soldering iron do you have?

-cheers from Julz

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[Stephen N]

Here are the photos you requested.

 

Both the solder and the soldering iron I was given as presents are from Maplin. 

 

[david richards]

Hi Stephen,

Have a close look at the position of R4, the right hand terminal is soldered into the wrong hole.

I haven't yet studied the schematic yet for you to try to find what a difference it would make but it cant be helping.

Kind regards, David,

[Si Brindley]

The soldering isn’t *that* bad - it’s the flux residue that makes it look messy - and you can clean that off.  I think you can by specific fluid for it but I just used methylated spirit. I agree with David though - the way that R4 is straining awkwardly back on itself to reach the wrong hole is probably a clue ;)

On Tue, Oct 14, 2014 at 4:53 PM, Stephen N <stephen...@gmail.com> wrote:

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<FIGnitionDisplay-SoundIssues.gif><FIGnitionRevEStephenN01.gif><FIGnitionRevEStephenN02.gif><FIGnitionRevEStephenN03.gif>

[david richards]

I'm not looking forward to the day I run out of my present roll of lead/tin solder with fairly nice flux in it.

Every roll I use seems to be different, mostly worse than the one I use at home which I have had for more than 30 years!

I have yet to learn lead free soldering, but I bet it isn't as easy as lead/tin.

I understand it is not too bad if everything is clean and the iron is quite hot.

[Stephen N]

Thanks David and Si,

    I can see exactly what you are talking about with R4 now. I'll sort that out as soon as I can tomorrow.

David, I'm a complete newbie to soldering but, I did have my soldering station temperature set very high, 

and at one point I had to turn everything off and clean the tip of my soldering iron as it was rejecting

the lead free solder.

Si, I had no idea whether it was possible to clean off the flux residue or not, so thanks for the tip, I'll

definitely give my PCB a good wipe down now.

Thanks to you both again, you've really brightened up my evening with your advice!

[Julian Skidmore]

Hi Si,

Actually - take a look at the Solder reel: it says: Sn 99.3% Cu 0.7%, type N29AR from Maplin. I knew it!

Consistently I've found that that kind of solder is absolute garbage!!! All it ever does is squidge around and fail to stick to anything you want. If you look at the original building guide:

https://sites.google.com/site/libby8dev/fignition/documentation/build-it

It says the kind of solder I use is the Ag 5%, Sn 95.5%, Cu 0.5% type from Maplin, which works quite nicely. 

Unfortunately, when I produced the one-page guide for RS, I forgot to specify the type of solder (note how it's the only item without an RS code). My bad, sorry.

So, anyway, you deserve a medal for managing to build a mostly working FIGnition using that stuff. Now I would recommend binning it and buying some of the better solder. It's about twice as expensive, but it'll prevent you from bursting a blood vessel with rage!

http://www.maplin.co.uk/p/lead-free-silver-solder-roll-100g-n32ar

Two other good things: your soldering iron looks top and at least the solder you have will be fairly easy to heat up and flick off. Remember to remove the integrated circuits first whenever you try to resolder parts of your FIGnition! This can be done quite easily with a small flat-head screwdriver, gently wiggling and levering up the chips from the keypad end of the FIGnition. Steady the chips with your finger on the top of the packaging; avoid touching the pins and when they're loosely sitting on the socket, use your fine pliars to transfer them to the antistatic sponge*.

Also Dave Richards is right about R4, you've managed to fit one of the leads through a via, connecting ground to ground. R4 is part of the 3.6v regulator it sinks enough current from 3.6v to 0v for the diodes to operate correctly to step down the voltage.

Although it might work (and appears to so far), what will happen is that when neither the external SRAM and Flash are being selected, then the current between the 3.6v regulator and ground will drop to near zero (micro-amperes kind of thing) and this will cause the diodes to drop less voltage, and those two chips aren't rated above 3.6v. On the positive side the current might be so low it won't damage the chips; the capacitors will help smooth out the rise in voltage and finally, the firmware can only turn off both of the chips for at most 40 microseconds at a time (occasionally) and for <1 microsecond more often.

To find out more about the hardware check out the Hardware manual from this page:

https://sites.google.com/site/libby8dev/fignition/fuze/usermanual

Hope this helps!

-cheers from Julz

*FIGnition users whose chips are delivered in antistatic tubes should replace the chips in the tube and tape both ends of the tube.

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[Stephen N]

Hello again Julian,

        I had to do my de-soldering in a different room yesterday, and consequently

managed to snap off one of the legs of R4 as there was a lot of unwanted background

 noise near that room. 

R4 is off the board now but, I'll have to pop out and buy some more resistors of that type, 

and I may as well buy some of the solder that you recommended as well, while I'm at the shops.

It's currently been pouring with rain for hours upon hours here, and I can think of numerous

excuses not to go out so, it may be a day or two before I actually get to the shops.

As soon as I have the replacement resistor on the board, I'll update you on whether my

FIGnition is working or not.

Thanks! :)

[Stephen N]

Hello again,

        I got out to Maplin and bought a reel of the solder recommended by Julian.

It cost about 3x as much as the solder I had already.

Unfortunately, when I asked about the 1k resistors, the person behind the counter,

said they only had 3 left. I bought all 3 but, upon returning home discovered the

bands seem to be wrong. 

I am attaching a photo of the resistors. 

The blue 5-band resistors sold to me by Maplin, are at the top of the photo.

The brown 4-band resistors at the bottom are some I had already from a 

electronics starter kit I bought earlier this year. I think I'm right in saying

they are 1k but, with a 5% tolerance instead of the ones supplied with

the FIGnition which had 1% tolerance.

Could I use these brown ones, or should I just try again?

Thanks

Stephen N 

[Bob]

Maybe, you could measure each of the 5% resistors with your ohmmeter, and select the one closest to 1k?

Those black-brown-brown-gold-brown resistors might be 10ohm 1%.

--

[david richards]

I'm sure the 5% tolerance 1k will be just fine in this application.

hth David.

[Julian Skidmore]

Hi Stephen,

They'll be fine, all my prototype FIGnition work was done with maplin 5% tolerance resistors and the design certainly allows for that. The key thing for R4 anyway is that it can sink enough current for the diodes to be fully on. 950 to 1050 ohms won't make any difference to that :-)

Also, and you may be shocked to find out: maplin don't usually stock more than 2 of any kind of basic component. I used to pop along to my local one during development and totally clean them out of whatever I needed ;-)

-cheers julz

--

[Stephen N]

I'm back again.

Replacing R4 has not corrected the problem. I got myself a digital multimeter and

went through all the tests again, and my attention ended up on resistor 6.

Am I right in thinking I have the wrong resistor where the 470R should be?

I can't see any other resistors on the board that I could have mixed it up with.

(The brown bodied resistor now in R4 is the only one that I supplemented myself.) 

[Julian Skidmore]

Hi Stephen,

To me it looks like your 470R is in the right place - it's the only one with a yellow band and that's where I'd expect it to be. Have you tried this:

1. Remove the ICs & stick them in the antitstatic foam.

2. Resolder pins 3 and 5 of U1, on the AVR socket, perhaps adding a little bit of the new (good, but expensive) solder would help the whole of the solder joint melt, making it easier to redo them.

3. Resolder both pins on diodes D1 and D2 using the technique above.

4. Resolder both pins on R5 and R6.

Check continuity from IC1.3 to D1.1, D1.2 to R5.1 and R5.2 to its connection on the Video phono socket. Check that there's no continuity from D1.1 to D2.1 and from R5.1 to R6.1.

Sorry if it's a bit of a trial, debugging hardware is part of the learning & of course your board does mostly work - it will run programs for example :-) !

-cheers from Julz

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[Stephen N]

That's okay - in a way I'm learning from the mistakes I've made.

I'll get that soldering done in the next one to two weeks, and then

let you know if my FIGnition is working properly.

Thanks again for the help.

Stephen N

[Julian Skidmore]

Great, we'll look forward to it :-)

-cheers from Julz

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[David Richards]

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470R colour code is either:
yellow purple brown tolerance, or, yellow purple black black tolerance
The resistor on your board looks very much like the one on my board.

Why do you suspect it is wrong?
If you would like to work on the problem one evening I could compare some voltage readings on my board to your own.

hth David,

[Stephen N]

Hi David,
thanks for your offer of assistance.

Unfortunately, each time I go back to the PCB with the soldering iron, the
connections seem to get torn off (as in the metal rings around the drilled holes). I suppose it's something to do with the cheap solder I used originally?

As such I think I've decimated the PCB for this FIGnition.

Stephen N

[Julian Skidmore]

Yes, sorry Stephen,

It probably is to do with the cheap solder. Because it's quite poor, my guess is that you end up turning up the temperature and this causes the solder pads (as they're called) to peel off the PCB.

:-(

-Cheers from Julz

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[David Buckley]

It's nothing to do with cheap solder, you are either getting the board too
hot and or tearing them off when pulling components out. Unless components
are in the wrong holes there is no need to remove them at all. Just use some
proper cored solder which has good flux. Don't use the soldering iron like
it is a paint brush or like you are dabbing glue on, it needs to be gently
but firmly pressed on the lead to be soldered touched with solder and then
the flux melts and cleans the parts and helps to transfer the heat quickly
so the solder flows into the joint. If you still can't manage a good joint
after practising on some scrap wire then buy good old fashioned lead solder,
you won't die from touching it or inhaling the fumes which are the flux,
lead only really fumes if you boil it and soldering irons are not hot enough
to do that.
David

[Julian Skidmore]

Hi David,

Although the techniques you describe are correct, if you have a look at one of the early images it shows that Stephen used some awful stuff from Maplin: N29AR; Sn 99.3%, Cu 0.7%. I've had years of doing soldering behind me, but if I've ever had the misfortune to work with this stuff it makes me feel like I've completely lost the knack as it squidges around and never sticks to anything I want; even with the best Mitch Altman inspired technique I can muster. It's like trying to solder with fine toothpaste or grouting.

But all your techniques do sound good :-)

-cheers from Julz

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[David Buckley]

Well I have without doubt been soldering for far longer than you and the way to get solder to flow is to let the flux do the work with the solder at the right temperature. If a joint has been improperly made and ends up dry the simple remedy is to use solder that flows and let it fill up the voids by capillary action, it may just need the temperature of the iron increasing or a better flux. It is not rocket science it is just a practical skill that has to be learned and dabbing around with the soldering iron as virtually all beginners do and then blaming the solder gets nowhere.

The solder from Maplin may be difficult to use, blame the green lobby for that, but it is still not necessary to rip everything apart and then try re-soldering with a different brand. One symptom of an iron with too low a temperature or wattage for the job or one which is not placed properly in contact with the joint to be made is that the solder doesn't flow and in trying, the board and components eventually get too hot and burn. Trying to do any rework like that leads to a disaster, pads fall off and in the worst case the pad doesn't fall off but breaks away from the plated through hole so even though the joint may look good from the outside, underneath it can be a dry joint and if the connection to it is by a track on the other side of the board then it can be a mystery why the board doesn't work.

David

 

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[Carl Attrill]

Slightly off topic here, but while we are talking about soldering, can anyone explain why when attempting to repair an Apple PSU (de-solder a cap)  why I could not melt the existing solder? I had to give up. It was like steel.

Back on topic,

I have a spare FIGnition PCB that Julz sent over for FIGkeys 1.1  development, I can donate this to Stephen, but I doubt his components can be reused.

Thoughts?

[David Buckley]

There was probably too much copper for your iron to heat up, it could have been soldered to a ground plane which may even have been internal to the PCB. You just need a powerful iron with a bit big enough to give a good contact area for the heat to flow through.

----- Original Message -----

From: Carl Attrill

To: fignition@googlegroups com

Sent: Friday, November 07, 2014 8:59 PM

Subject: Re: A/V Problem (inFuze) and introducing myself to the group.

[Stephen N]

Hello Julian, David, and everyone,
there's really no-one at fault here but me. In my build video on You Tube, I start off by saying I wasn't the best at soldering at school in 1996.

Back then I was also a bit naff at other skills like woodwork, which I've always put down to the fact I'm genuinely blind in one eye.

My purpose in buying a FIGnition was to find out if my soldering skills had improved over the years as I want to create more advanced hobby designs and maintain any retro computers I happen upon.

I should not have dashed into building a FIGnition computer as only my third electronics project and second to involve soldering.

Something that did not make it into the final version of my video was my absolute surprise when the FIGnition powered up and worked. Wow!

Carl, thanks for the offer of a PCB. I have a number of components lying around from Maplin lucky bags and could probably recreate the FIGnition parts list.

Stephen N

[David Buckley]

Stephen
Once we admit that it doesn't matter what day of the week it is or whether
the moon is in Jupiter or whatever then with practice at something we can
only get better. So it is great that you have built a FIGnition. Sometimes
soldering can seem tricky and like a black art and it is difficult to
discern why something doesn't work. I have used quite a number of the
HC-SR04 Ultrasonic sensors form China but the other day one of them didn't
work anymore. It has been on a robot for the last six months and then
stopped working - strange! But then I noticed that as I was testing if I
touched the sensor it started working for a few readings. Examining it with
a Jeweller's eyeglass I couldn't see anything wrong - all the solder joints
looked perfect, nice and shiny but if I flexed the board it worked so
somewhere there was a bad joint. So I decided to start with the two
Ultrasonic cans and with a freshly wiped and tinned and fluxed bit I
resoldered the four leads for the two cans - press the tip on the joint and
apply the slightest amount of solder so there was fresh flux and re-melt the
solder. The joints after resoldering looked exactly the same as before
however the sensor now worked again.
So professional electronics companies can make bad joints which fail after a
while and which are impossible to detect visually. There are thousands and
thousands of those sensors coming from China so it is not some guy in a
shack somewhere but an automated PCB assembly plant.
You have made a good start, don't get disheartened, make sure you can see
what you are soldering, the 'Helping Hands' with a magnifying glass are
good. I now use an illuminated magnifying glass and sometimes for smt work a
jewellers eyeglass - have to be careful not to burn my nose with the iron.
Also I have stopped using a wet sponge to clean the iron - it destroys the
tips, I use a stainless steel pan-scrub - dry, it works better than anything
I have used in the past.
Onwards and upwards.
David

----- Original Message -----
From: "Stephen N" <stephen...@gmail.com>
To: <fign...@googlegroups.com>

Sent: Saturday, November 08, 2014 8:49 AM
Subject: Re: A/V Problem (inFuze) and introducing myself to the group.

[Stephen N]

Hello again,

        I have some Veroboard and am planning to rebuild my damaged inFuze as a Flint.

I have the files from Github and noticed that there are various revisions.

I presume I have to use Revision J, but I'm not to sure about the mods.

Also - how do I know what to put where e.g.What specific resistor is that, which exact capacitor goes there etc?

As far as I know my chips are working okay, and I have an Atmega 168 as a backup plan if anything is wrong with the 328P

included in the kit originally.

Stephen

[Julian Skidmore]

Hi Stephen,

Good to hear from you - wow, you're gonna do a FLINT version :-) !!!!

It turns out that the stripes files on GitHub are for the original prototype version of FIGnition (attached image). That's not really a FLINT.

However, if you scroll to the bottom of:

https://sites.google.com/site/libby8dev/fignition/documentation/build-it-rev-d/fignition-flint

You'll find FIGnitionFlintRevF.zip (also attached). The file FIGnitionFlintComponentListVf.txt tells you where all the components are.

Thanks to your email, I've updated the stripes circuit to correctly include the current FIGnition as a stripes circuit and updated the component list :-)

-cheers from Julz

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[Julian Skidmore]

Hi Stephen,

I've updated the google sites FLINT page to include the newer version of the circuit and the component positions for resistors, diodes and capacitors.

https://sites.google.com/site/libby8dev/fignition/documentation/build-it-rev-d/fignition-flint

Hope this helps. If there are any more uncertainties, post them in this thread :-)

-cheers from Julz

[Stephen N]

That's brilliant, thanks :)

I'll post back here if it works out.