One for the Electronics Gurus... Please

[Charlie]

D*mn, but my run of bad luck is continuing with a vengeance...
...ho, hum. Never mind.

Anyway, I'm trying to resurrect an old project. I have a fully made PCB that I'd like to 'reverse engineer'.

Photo(s)

of the bits

From the bottom-up we have a beige two-pinned box that I believe is a metalised polythene capacitor - correct?
The only markings on it say: <inverted triangle> .1363
Not a familiar marking to me. What value does this work out as?

Next we have a 9-pinned blue 'thing' just North of the IC...
...what is it?
Markings say: CTS8522 770 91 2.7K
I assume it's a multi-legged 2.7K resistor - where to get some from?

Finally the IC, It's code says DM74LS245N. An Octal Bus Transceiver I believe...
...a real bugger to find - even DigiKey doesn't stock them. Any idea where to source these or a pin-compatible equivalent?

Many thanks.

[Zetr0]

the 74ls254N is a common IC m8y.

http://www.futurlec.com/IC74LS00Series.shtml 23pence each

blue thing = 9 pin 2.7k resistor network.

http://www.futurlec.com/ResNetworks.shtml about 15pence each, closest they have is 2.2k

tip:
you can find the value of these using a multi-meter and tying off both ends

the block with "Delta.1363" looks like a high voltage polyester film capacitor, perhaps mylar?. Again you can use a multi-meter with a current to work its capacitance.

http://www.futurlec.com/CapPolyFilm.shtml


what circuit did you get this from?

[Charlie]

Thanks Zetr0.

Doh! 74ls254N common, eh? Just goes to show how rubbish I am @ searching for IC's...

I'm 'collecting' hacks + upgrades for RiscOS computers - I've pretty well exhausted the ones for which plans exist, so now I'm going to try recreating plans for the boards I have or can get hold of.
This one is for turning the serial socket on an A3000 into a joyport.
The next will be for turning the parralel port into two joyports.
After that I'll try for a econet to SCSI card.
Maybe try one of the simpler ARM3 boards too (if I can find any ARM3's)

Hmm,
I've hit a bit of a speed bump with testing of hacks - I've got two A3000's: One with ARM3 & one with ARM2. I've just replaced the ARM2 in the second with a PLCC socket and bought another ARM3 board off fleaBaby to put in it. I put it in my newly ARM3-enabled A3000 for testing (fine with a socketed ARM2) - nothing...
...like a fool I tried it in place of the ARM3 in my main A3000 - nothing...
...now neither will work in their original state. I guess I now have two dead motherboards!
The new ARM3 board must have been a dud.

[Charlie]

Serial Port JoyStick interface layout done in case any were wondering.

Hey! Quite neat considering it's hand drawn

I can't guarantee this will print 1:1 - Quick conversion to an allowed format could have messed things up.