OK. I've removed 2 diodes, a section of PCB track and a chunk of my index finger.
Only one of the diodes survived. When I said at the start that the boards looked like they had been soldered by hand, I think I may have been absolutely spot on. All the component leads have been passed through the board and bent over before the solder has been applied. They are an absolute pain to remove. Years ago, I replaced my chisel shaped soldering iron with a more delicate pointed one. It's absolutely useless for this sort of job - it takes forever to transfer enough heat to melt the solder boulders holding the components in place.
And to make it worse, I can't find my thin-nosed pliers. I have 3 pairs. They've all gone. I had to go next door and borrow some from my neighbour. I'll have to do a small re-equip when I go to Maplins tomorrow. And heaven knows where the solder sucker has gone. Found the box and the spare nozzle, but the tool iself has gone awol.
And all the bl**dy lights just went out...
Back soon.
That was how I was taught to mount components for flow soldering before automatic insertion machines came along!
If you know a component is duff then cut the lead on the non-solder side and the remnant will fall out when you melt the solder.
What voltage is printed on the fattest capacitor in the middle of the board? [edit](Have found out by Googling that it is 2200uF 50V so you shouldn't need wonder-diodes) BTW the IRxA/B are probably circuit references on the board? not component part no.[/edit]
Sorry, not been at the computer.
Nearly right - it's actually 2000µF and the voltage is 63WV. "WV" is new to me, and Google eventually revealed that it means Working Voltage. The two smaller ones are 1500µF at 50WV. Not that I know anything about it, but I'd more or less come to the same conclusion about the IR numbers. TBH, I couldn't actually see the markings - my son told me there was something there and I had to get a magnifying glass to confirm what he could read.
The soldering technique is that which I used when I used to put together kit radios as a teenager - never been an outdoor type and I needed a more interesting hobby than stamp collecting. I'd forgotten how to remove components - used to cannibalise stuff I bought from the War Surplus shops on the Edgware Road.
I'll go and get the diodes, some pliers, a new soldering iron and a solder sucker, just in case I have to remove the big capacitors. As somebody on here said the other day, the best way to find something is to buy a replacement for it.
Thanks once again for all the help.
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Topic: 34 years of faithful service (Read 5154 times)