easy peasy pcb

[vvvv]

Made a pcb in my cellar today.No big deal considering I have been making them for the past 30 years.

BUT,in the last year I have been having many problems especially developing the pcb.Usually it refused to develop even in hot commercial caustic soda solution.So tried other developers,still no go.I even thought the PCB coating was faulty or maybe there was too much chlorine and fluoride in the water supply?.Or the PCB photo resist specification has been changed by the manufacturers in the past few years? Or.......

So,first thing I did was rebuild my homemade UV box which was 30 years old!

Trip down to B&Q and bought a 120 mm Fluorescent light fitting ,about £12, then ordered a UV 'Backtube' from Farnells (come in pairs) £20, and relpaced the 1 tube in the light box.Also gave the glass lid a clean.

THen ordered some PCB FEC part No.320 4923 and some new developer part No.320 4996.

This developer is not caustic soda based and is some fancy polymer which didn't exist 30 years ago.


So, trip down to cellar and made up the developer 1 part to 4 parts water @ room temperaure.

Exposed the pcb for 5 minutes in UV and then dipped the board into the developer.All at once (few seconds)purple dye was given off as the deveoper did it's job.No agitation tank so I just rubbed off the residue with a finger not forgetting to wear vynil gloves!

THe beauty of this developer is that it is not time dependant and you can leave the pcb in the developer indefinately without seeing the artwork disappear before your eyes as is the case when using too strong caustic soda.

Rinse with water and etch in hot ferick chloride.Job done.


Still left with the problem of the bubble jet printer refusing to print in blacker thaan black,so I have to resort to over printing twice and usually I get correct registration -The printer slider which adjust for paper size has been glued in for A4 size so that my transparency is always correctly located.

Being promising to buy a lazer printer for years1

[bigclive]

I've been using an old Laserjet 6L for my transparencies for many years and recently switched to using a Samsung ML-2010R laser printer due to the need to use a different computer with no legacy parallel port.

The new laser printer does not print such a dense image and I had problems with the transparencies. I ended up using my old Canon Pixma IP4000 inkjet to print onto tracing paper. It seems to register very accurately for multiple passes from the paper tray and if you use the "glossy paper" setting it lays down a decent amount of ink. The transparencies have been very good for UV exposure.

(But I'd still like a PCB router.)