AN EPIC REPAIR UPDATE

[Ron Buchwald]

:D Thanks Pete for letting me post this on the forum, I feel it is important to all simmers who use the EPIC System. While wiring my over head panel, I shorted a connection. I put 12vdc to one of the button rows and it failed. while checking all the rest of the button rows I found that row 4 the one I shorted and row 15 were no good. I removed the expansion card and began to trouble shoot the board. I found that row 4 on the 40 pin ribbon cable was tied to one of 5 ic's. the chip is a MC74AC138. it is a 1 of 8 decoder/demultiplexer. my thinking was that it must be blown. I found and ordered 20 of them from ON Semiconductor. http://onsemi.com

they were free samples. they came today and i carefully removed the two I felt were bad. YES!, fixed the board now all 32 rows are good. hope this will help any one if they find a row/ rows are bad. I know a good bit about the EPIC hardware so If you need help, maybe I can.

Next a problem I had was with the rotory encoders not working and several of the analog channels. Ralph repaired my main USB board for me. However several months later it failed again. The problem was, and is caused by the weather, yes the weather. I am in florida, very humid and hot. seems as there is a problem with several chips on the board that did not like this. I have seen this on a lot of GrassVally production switchers (television). the chips and board allow fungis to grow between the pins and short the chip. a good cleaning with flux remover will slove this if done before the short. again I hope this will help. Ron.

PS if you can't for some reason get them I have 10 I will part with. :P