EPROM frustration and great surprise in the hybrid

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stingray

Member
Joined
Jan 2, 2016
Messages
20
I opened few EPROM`s and hybrid circuit. Is there any pm in EPROM ?? I assume that wires are aluminium.
In turn the hybrid was wery good. Lots of dull gold. And all components are wired with goldwires.
P1030267.JPGP1030266.JPGP1030265.JPG
 
The question is not which chip is good. The question is how many of each can you get at one time?

I will just give you my opinion on the matter.

The eprom with aluminum bond wires and a gold center is not worth much. There is to much weight to gold ratio. The hybrid has thick film circuit gold traces plus gold leads and gold bond wires.

In my opinion I would pay about $20.00 a pound for the hybrid chips versus paying about $4.00 a pond for the eproms
 
richard2013 said:
Those are the ceramic EPROM, but what about the plastic cased EPROM?


Generally speaking, there haven’t been any plastic cased EPROM’s due to the difficulties of combining a quartz window with a plastic casing and their different expansion rates. There are one-time programmable chips in plastic packages with no window, or EEPROM’s which are electrically erasable and reprogrammable so don’t need a window. According to the CPU Shack website though, there are a few Russian EPROMS now which are made with a plastic case and a clear resin window.

http://www.cpushack.com/EPROM.html

Macfixer01
 
What i actually wanted to know is if there is gold at all in those eproms.

If you see no yellow once you split it open, I would say the answer is no. I know that is true with the ceramic DIPs and would guess it's the same with the Eproms. In the ceramic DIPs, the gold was on the tips of the internal "fingers" and on the entire base, where the chip is mounted. If I recall, about a 16 lead ceramic dip, with gold, from the 80s-90s, was worth about 15 cents in gold. With no yellow, you might find silver, which is white and nearly worthless, or epoxy, which is totally worthless. The one at the bottom of the last (4th) photo, seems to have no PM value, unless you used chemicals on it.

I once played around with the ceramic DIPs, with Kovar leads, by heating them to a fairly low temp (the lowest temp that would work is best), maybe about 700F, and then quenching them in water. The 2 ceramic layers (which contain about 5% glass frit) are held together by heating them. When fired, the glass frit in each layer melts and bonds. I think they also add a thing layer of extra glass between the ceramic. When heated and quenched, the glass pulverizes and everything falls apart with a little assistance in a tumbler and maybe some balls or weights, like in a cement mixer. The idea was then to remove all the Kovar with a magnet, strip the gold from the Kovar with cyanide, and used AR on the gold on the ceramic. I never did this in bulk, but the experiments proved it worked. It's been about 45 years and I can't remember the details.
 
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