RS Wall Wart

[Tony Duell]

> Are batteries that expensive?  Seems to me you should be able to pick  
> up some cheap drug-store C cells for under $10.

I don't know about the States, but over here, 'Pound shops' (the 
equivalent of your Dollar stores, I guess) sell standard batteries. The 
quality is not great, but a couple of packs of C cells from there would 
probably do for testing an electronic game.

> 
> Lastly, it seems like it is almost a requirement that anybody who is  
> interested in collecting classic hardware invest in a good laboratory  
> power supply with variable current-regulated output.  6 C batteries 

I certainly agree. The 3 insturemnts that get used _a lot_ on my bench 
are (in no particular order) : 

1) A Multimeter. Actually a Fluke 85. I'd prefer an 87, but I found a 
second-hand 85 at a good price becasue some display segements were out. 
Cleaning the Zebra strips fixed that. I have to clean them again from 
time to time, but it's very obvious when it needs doing, and it gives 
accurate readings. The only thinkg I don't like about it is the fucntion 
swithc (including power on/off) partly formed by a wiping contact on PCB 
traces.

2) An HP LogicDart. Need I say more?

3) A bench PSU. I built a Velleman kit one -- 30V 8A continuous, 10A 
peak. The advantage of the kit is, even if I say so myself, I know it's 
been built properly, that safety earths are in place, and so on. Which is 
more than I can say about some commercial Far-eastern supplies at a place 
I was working.
  
> 9 VDC.  I'd set my lab supply to 8.9V, clip alligator clips to the  
> battery terminals, and play away.  Similarly, somebody who hasn't  

Another very useful thing that I bought (from Maplin) was a set of all 
hose little 2-pin plug to power-connector adapters (the Adaptaplugs you 
mentioned, I think) and a cable with a socket to take those moulded on 
one end and, IIRC, spade lugs on the other. I cut the latter off and 
fitted 4mm plugs to go on the bench supply, fitting them so that if I put 
the red plug in the +ve socket of the supply, the polarity of the final 
power plug would be as indicated on it. 

That set-up has been very useful for powering up all sorts of things 
fitted which were supposed to use wall-warts.

Another useful cable is a car cigar lighter socket to 4mm plugs. To run 
in-car adapters, etc, off the bench supply.

-tony