# Nice things come in SMALL packages



## MMFJ (Nov 25, 2011)

Just pulled this one out of the back end of a microwave rack system.

The rack was aluminum and made in '83, with "video" cards in the front of it (any bets they aren't HD/3D???  so not likely too much resale value here. I did find some complete systems (not rack mount, but same function) on fleabay for $19 - I won't waste my time on that one... - time to scrap it out!

Most of the tear-down was not eventful (for a telecom unit, anyway...) - a bit of gold fingers, test pins, transistors and slots, etc.



I took the rear cover off, just to see if there was anything of interest...



Not bad, plenty of gold plated connectors, as well as the wiring inside those nice 'ends' - if you can get it out of there.

Thought I'd dig a bit deeper and found something really nice under the 'spaghetti' of wires...

The SD-60729 AGC IF Amplifier is not really all that uncommon - not too difficult to make yourself (for those so inclined) - I felt like it wouldn't sell for more than about $19 by itself and so I took one apart... with a very pleasant surprise...



Now, I'm considering the best way to get it all out of there - looking through my magnifier, I can see some very, very, VERY tiny wires (that are about the size of those in an IC) that run throughout the board, interconnecting the circuits (not the ones at the edges, these are inside - picture is very hard to see them, but if you look inside the center of the 5 'squares' [which are actually loops that go around like a maze], you can see the wire going out - they are also in other places, but this is the simplest to explain). There's also some components there that I'm sure someone would want for the PMs and a super-tiny IC that may have something in it - it is tied on with several gold wires (the little 'diamond' in the top right side).

It looks like the board is attached with glue, but I couldn't get it to come off with nail polish remover or goo-gone. It may be soldered, just not sure.

Have thought of just putting it on the hotplate and seeing what pops, but don't want to lose any of those tiny wires!

I did take out one of the bigger 'wires' that are attached to the round connectors and tested it as 22K (or better) - extremely soft and flexible - just like we like it! 

Any suggestions on getting the boards and all the tiny bits out without really messing things up? 

I've got three of these (maybe four) and so there is a nice little 'haul' out of this load of JUNK after all (though I already knew it was worth something when the guy that bought it just wanted to toss all this away - he brings me the 'trash' from most of his loads and I'm very happy to accept!


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## qst42know (Nov 25, 2011)

Two choices.

1. If it's glued heat will break the bond. 

2. If it's soldered heat will break the bond.


:mrgreen:


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## goldsilverpro (Nov 25, 2011)

83 was a good year for tantalum and silver/tantalum capacitors, TO5s, decent fingers. A few wonderful, high-dollar, old CPU type packages.

In an attempt to analyze your photos:

First photo: I see some top-hat, TO-5 Transistors that run good. There are some tantalum electrolytic capacitors and those 2 in the top right board might be high silver. Of course, there are the fingers. The black plastic dips and/or dark ceramic cerdips usually have some gold in them. If they have gold (pop them open and look for yellow), maybe $.20 each.

Note: I just spotted this. On the lower left board in the 1st photo, at the top of the board, notice a silver looking electrolytic capacitor with a red plug on the left end. These have a silver casing and they run 40% silver by weight. If the plug were green, it would run 25%.

2nd Photo: Some connectors. These are pretty but sometimes they don't run as good as they look.

3rd Photo: The most interesting. These are hybrid circuits, but not the best ones I've seen. The question is, are they thick film or, are they thin film? In the photo, they could be either. Thin film is sputtered and the gold is shiny and thin. Thick film gold is a gold paste that is silk-screened and duller and about 6 to 10 times thicker than thin-film. The white hybrid alumina circuit might be brazed in with a gold bearing braze but, it really doesn't look like it in the photo. I think the days for that were about 3 years earlier, about 1979, or so.


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## MMFJ (Nov 25, 2011)

Thanks for the picking apart of the other boards - I'm still learning and that really helped me see even more value (although not likely as much as the third photo parts!



goldsilverpro said:


> 3rd Photo: The most interesting. These are hybrid circuits, but not the best ones I've seen. The question is, are they thick film or, are they thin film? In the photo, they could be either. Thin film is sputtered and the gold is shiny and thin. Thick film is a paste that is silk-screened and duller and about 6 to 10 times thicker. .



From your description, I would have to say the boards match the 'thick' description much more than 'thin'. The shiny parts are the interconnection wires (out to the round parts, which are connectors going to the outside world). There are a couple spots where the traces are shiny (in the bottom of the picture), but most of the board is quite dull looking - the shiny part looks to be more of a scratch area (I might have hit it with my screwdriver or something...).

I think I will take the earlier 'option' of just heating it up and seeing what comes loose. I did try taking a torch to the aluminum, but stopped when it got too hot to handle in the pliers I was using. I found a fully working hot plate/grill in the dumpster the other day (one leg was broken, but still works great to heat my lunch!) - it should go up to about 425F - think that is enough to pop it loose?


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