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My reaction exactly. The connections in question _look_ OK, though obviously aren't. There are some others on the front panel that look even worse than what I can do with what I've got right now, and my questionable soldering skills. Is there any way to check for either of these problems? Well, once I got the face plate off yesterday I was able to wiggle the LED itself in its 'socket' and it would come on. Oh, wonderful. I just took both the scope and the logic probe to both E46 and E39. They both gave the same results, the chip looks to be good. Something tells me this system is going to drive me crazy! But it means that what the scope told me a couple days ago is correct. I cleaned the edge fingers before even turning it on, though I think I'll clean them again. I'll have to take a look at the PSU connectors. I blew out the backplane slots with canned air, how can you do a better job of cleaning them? Not since I got it a couple weeks ago, before that I've no idea. I suspect it might have spent a short amount of time outside as I found a couple pine needles in it. Sounds about like the one I was going to buy last weekend, but they were out of ALL of their Weller's except one really cheap looking model at the local electronics store. I know Fry's has a whole cabinet of different models, but I didn't fell like going down there twice in one week. Sounds like I need to plan on that Saturday. On a possitive note, either Saturday or Monday I'll have a 4k Core Stack and a 8k Core Stack. So I can see what happens with different a different core stack in place. I think I'll also be getting the spare M8330 at the same time, the pair of CPU boards will be coming later, probably in a week or to. Zane | Zane H. Healy | UNIX Systems Adminstrator | | healyzh(a)aracnet.com (primary) | Linux Enthusiast | | healyzh(a)holonet.net (alternate) | Classic Computer Collector | +----------------------------------+----------------------------+ | Empire of the Petal Throne and Traveller Role Playing, | | and Zane's Computer Museum. | | http://www.aracnet.com/~healyzh/ |

OK, both you and Joe seem to have misunderstood what I meant by 'socket', but then that really isn't a good word for it. The LED's are soldered to the circuit board, there is a plastic 'socket strip' that keeps them in position, and it's bolted to the circuit board. Well, don't know if that's any clearer. Let's just say they aren't sockets you actaully plug something into. Me to. I got a fairly good look in there today, and the contacts definitely need cleaned. I'm going to have to do something to try and clean them up. I'll have to give the soaked chunk of cardboard trick a try. I think I'm going to have to hold off on this until this weekend though, this sounds like something that will take quite a while. Zane

I just vacuumed my backplane, but most of the gunk in my pdp8/e appears to be a result of deteriorating foam. I forgot, what was generally considered the best compound to use for cleaning pdp8/e edge connectors? I think it had 'gold' in its name... I used what I thought was a good quality contact cleaner once on some Terak boards (LSI-11 based computer) and though it worked, the boards sort of glued themselves into the backplane or something, making it extremely difficult to pull the boards at a later date. Obviously I wouldnt want to repeat this problem on a PDP8/e, it was bad enough with only a 4-slot quad backplane... -Lawrence LeMay

At 01:22 PM 12/2/99 -0800, Zane wrote: You may have corroded LED sockets, specially since you said it had been left outside. I use an old punch card and fold it in half a couple of times till it fits snugly in the gap and then dampen it with alcohol and work it around in the slots to clean them. Of course if you had a HP you wouldn't have these problems. :-) I agree. I have a Weller and it works perfect. I've been told that they no longer make the magneticly operated irons so you may have to find a used one. BTW the number on the back of the tip (7, 8, 9, etc) indicates the temperature that it regulates at. 7 = 700d F, 8 = 800d F, etc. The local surplus place has a large variety of tip styles and temperatures so I have plenty of different ones to work with. I like to use a hot one (800d) for unsoldering so I can heat the joint up and get the iron off of it quickly. But I use a 500 to 600d one for general use. Same here in the eastern US. FWIW I also have a couple of PACE solder/ desoldering stations but I never use them. Too big and ackward and they don't work a bit better than the Weller. Joe

At 11:34 PM 12/2/99 +0000, you wrote: It wouldn't hurt. But I was told they had quit making them a year or so ago so that may not be right. You're right. I meant to add that the solder that I'm using is a very low temperature solder with silver in it. 500 or 600 degrees would be too cold for standard solder. I love this silver stuff, it expensive but it flows beautifully. Most of the stuff that I work on is tiny so a one ounce roll will last for a couple of years. Joe

Tony Duell wrote: I believe it does contain silver indeed. It is _very_ expensive. And you need acethylene+O2 in order to use it. -- Carlos Murillo-Sanchez email: cem14(a)cornell.edu 428 Phillips Hall, Electrical Engineering Department Cornell University, Ithaca, NY 14853

At 02:32 PM 12/3/99 -0800, you wrote: That's the same kind of stuff that they sell here for soldering copper water pipes. NO LEAD ALLOWED! The last time I checked it costs about $16/pound. That's cheaper than good electrical solder. What I You have to watch out for any solder and make sure it's for electrical work. There are many other kinds of solder and many (most?) of them have acid fluxs. You can use it on electrical stuff but you'll be replacing everything in about six months! That's an interesting idea. But I certain that you'd have to heat the joint to the melting pont of the old solder before this stuff would alloy with it. If that's the case then you could just take the part off then and not go through all the rest of the procedure. I've mixed various lead alloys for casting bullets and you have to heat the mix to the melting point of the element with the highest melting point before they will all melt and alloy together. This is true even if the alloy has a lower MP than the individual elements. Joe

At 12:59 AM 12/4/99 +0000, Tony wrote: Hmmm. Well I guess that's one way of doing it. But I take stuff like this off by heating the pins one at time and slipping a piece of very thin metal under them so that they don't restick to the circuit board. I take off 20 something pin surface mount devices this way in a matter of minutes. It doesn't mess up the board or part (I reuse both). Joe

At 06:45 PM 12/3/99 +0000, Tony wrote: I'm not sure either but they sure charge an arm and a leg for it! They use it here for air conditioning work. It takes a LOT of heat to melt that stuff. Even a propane torch won't work. You have to use Oxy-Actylene or MAPP gas. Joe