Date: Sun, 17 Mar 2013 18:32:26 -0500 Subject: Resurrecting a Bendix G-15 From: craig at solomonson.net To: cctech at classiccmp.org I was going through some boxes of old documents as I prepare to thin out my computer collection and ran across a couple leads that I had 30+ years ago on a couple early vacuum tube era computers--one was a Bendix G-15 and the other was a Royal Precision LGP-30. Thought it would be fun to see if either computer was still there and turns out that the Bendix G-15 is buried in a storage unit yet! I haven't heard back on the LGP-30 yet. When the weather warms up, I will get a chance to help dig out the Bendix and hopefully make a deal on it. Apparently, the Bendix was operational before going into storage in the mid-1970's. So, what are the chances that after sitting for almost 40 years that it would still be operational? I know that vaccum tubes can deteriorate but those are easy to replace. What about the capacitors, resistors, and diodes? I do not know if the storage unit was climate controlled, but if not, I assume corrosion could be a problem with all the contacts. What other issues might one expect with an old system like this? Unfortunately, I am not an electronics expert but always like a challenge. I now regret selling my Bendix Diode tester a few years ago on eBay! Maybe I will have to rent in some day if I make the deal! Electrolytics will be the biggest issue. Most will fail ( if they even can be revived )when you apply voltage. There are a number of web pages on reforming these.Paper capacitors will often be leaky. The worst ones are the ones that lookthe best. Some of black plastic ones are the worst. I've seen some wax coveredones that look really bad that work fine with no leakage.Resistor will most likely be carbon comp types. In most cases, these willstill work when quite a bit off tolarence. Still measure any that look tobe over heated or cracked. I've seen them as much as 2 time the valueof the band. I would guess that even though it is tube, it most likely useddiodes for gate expansion. Diodes are usually OK but don't be surprisedto find one of two that are shorted.Keep a log of every part you replace with a newer one for historic purposes.Dwight