Browsing Posts published on 08/09/2010

I think NOT!

So, as I said earlier, I built up another PC, convinced that this one had a blown serial port.  Before you mock and say it can’t happen, well, I’ve seen it happen in the past.  Granted, this was in ‘Ye Olde Days’ when there were separate boards for i/o and the like.

ANYWAY, when I’d got it built, I installed WinXP.

A long job by anyone’s standards, but particularly long for me because this machine was only a 1GHz with a paltry 256MB of memory.

I supose I could have become frustrated with its speed -or lack of it, but when faced with situations like this, I tend to take a Zen approach.

So, no less than four hours later after Service Pack 3 and all the subsequent updates after that went on, I popped the excellent ‘Microchip MPLAB’ suite of software then finished it off with the PIC programming software from Velleman.

A couple of re-boots later, I connected up the programming board with NEW 12 volt regulator and replaced diodes and…

STILL NOTHING!

%^$&***!!   (…That’s techie-speak for ‘Whoops! Oh dear me.’..)

(…It was at this point that all thoughts of ‘Zen’ and ‘communing’ with this little circuitboard swiftly evaporated…)

Thankfully, the years spent either at a computer or dead circuitboard kicked in, so rather than ‘de-fenestrate’ the circuitboard in question, I calmly turned the computer off, switched off the various power supplies, and made myself, in my opinon, some well-earned dinner.  Which I ate and washed up.

I then took a shower and changed my clothes.

Then I had another cup of tea (…it really is the Drink Of The Gods, I.M.H.O…), and sat down with the circuit diagram in front of me, cat obligingly on my knee… …and concentrated.

I won’t bore you with my thought processes, but suffice to say that after about half an hour, after running through in my head all that this circuit was telling me, I decided that it really must be a particular transistor (…TR1 to be exact…) that wasn’t behaving itself.

When I’d checked it ‘in circuit’ (…the cheats way…), it had appeared to be right, but then I noticed that there was a diode connected nearby that could in theory have been skewing the readings somewhat.

Well, there was nothing for it but to take it out -always a decidedly dodgy thing to attempt without over-heating it with the iron on double sided board.

I got it out without a fatal dose of:- ‘OUCH HOT!’, and measured it on my meter.

Something didn’t add up.

So, I checked it with the new one I’d bought earlier, side-by-side, and the two didn’t tally at all!

…A tingling down my spine and into my fingertips…

Could this be the animal?  Could I have got it right?

I hastily cleaned off the circuitboard of old solder, popped in the new one, soldered it in, and I must admit my fingers were shaking a little when I connected it all up and threw the necessary switches and pressed the right buttons on the screen…

…AND IT ONLY WORKED!

Well, words fail me when I try to describe just how good that felt.

Shouts of:- “Whose cat!!??” were pretty insufficient, I can tell you.

Anyway, anyway, anyway…

I’ll not bore you any further, Dear Reader, but suffice to say that I’m only 30+ hours behind where I should have been, but hey-ho.

…More news as it happens!

Teething troubles?

Ha!  You don’t know teething troubles.

Went down to Maplin and bought the parts, no problem.  For once, they had everything in stock!

So, got back, repaired the board, put a new 12 volt regulator on it, persuaded an old power supply to give me 20 or so volts, checked everything twice, then plugged it in, and…

Zip.

Sooooo, it looks like I’ve somehow blown the serial port on my PC!

Consequently, this afternoon I’ve been building a ‘new’ (…well, scavenged from old parts…)  PC just for programming in the kitchen.  This has no less than two serial ports on it, and while it’s more than a little slow, as I’ll only be using it for PIC prgoramming, thats not such an issue.

<…sigh…>

“Mr Nose?  Hi!  Meet Mr Grindstone here…’

Slight teething troubles…

It had to happen.

After the last couple of days’ roaring successes, yesterday afternoon saw a couple of ‘snags’ appear.

The programmer Nick had been using ‘died’.  One minute, it was happily compiling and programming, the next minute it decided that it had had enough.  For now.

SO, today Nick will be repairing this and seeing just why it died in the first place.

No worries, though.

It will be repairable because the fault is somewhere in the logic circuits that ‘glue’ the programmer to the PC.  Luckily, these are simple transistor switches and circuits, so will be easy (…Ha!..) to replace where necessary.  No big dedicated chips that are impossible to get.

There’s also the issue of the power supply input voltage for this circuit.  The board says it needs 15 volts to work correctly, but Nick has only been giving it a little less than 12 volts, but again, no worries.

Using a power supply ‘gifted’ by a local computer shop (…’Taplin Computer Services’ on Taplin Road…) and a little ‘bodgery’, Nick will be able to give the board more than enough power later on this afternoon when he’s been down to Maplin’s at Hillsborough for more parts.

No danger.


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