____________________________Hi JMcG, well I am far from an expert in anything, but Johnson stuff I know for a good reason, aside from working for them for a while, we service most of their assemblies daily.
Moving these treads stresses the little service loop cable lengths and we find cable conductors pulled from housings leaving open signal paths, power loss, no safety key working.
The quickest way to get you back up would be to swap the board, and send that dead one to me and we look at it closer. I have seen the old 32k oscillators fail when we used the MSP430, and many of the newer CPU choices don't use the 32k or even the watch type, and appear more robust overall, so I might check to see it's running if you have a scope, if not, run your fingers across the leads of the oscillator, and watch or listen for that cpu to change states, as in the past I have seen my body capacitance spike a timing pin and a powered CPU advance an instruction or change states, telling me no valid crystal was working, rare find but possible. More likely, we may have an open resistor on the upper board disabling a power supply as there are a few smaller power supplies up there for the CPU and display. We could also have a failed CPU itself, quite hard to 100% that until you literally hot air a suspect and replace it with a known good pull, which we've done to verify failures and trends.
No schematics available for Johnson products, but I have found a few quazi schemo's on their websites over the years for Matrix stuff. Engineers in the States had to make their own as China wouldn't release them after initial designs were sent and cobbled or costed-down so only the few nerds out there knew the circuits, intents, restrictions and abilities of the Johnson groups, designs, formats.
The safety key click may be the precharge relay, as when lift is engaged, the CPU would prefer to return it to where it started, down .5 degree, relays click, lift up .5 degree, and the upper just verified dual drive as well as Hall-Effect ticks in each direction instead of the potentiometer showing the throw position of the lift, now the console gets to count, add, subtract, and recall, silly change and added part-count(cost).
I will try to message you thru this blog and we get address info, and I zip out a board if we have one. You give it a spin, if it works, you're all set, if not, we forge forward on another course ;o)
I also purchased the 7.0AT and experienced the dead console issue. Used it maybe 5 times and the console died. Was able to get customer service to send me a new upper console board, installed it and about 5 more uses and the same thing ... dead console. My bank was able to secure a refund from Horizon, and I still have the inoperable machine in my garage.
Found an upper console board on ebay for about $200. However, seems to me that the source of the problem could be: 1) a defective manufacturing process for the boards per se; or 2) another root cause that is knocking out the boards. Use of the refurbished boards mentioned by Iamjetinah would help rule out the defective manufacturing process possibility. If the problem persists after using a refurbished board, then it seems that there is a another problem source that is knocking out the boards.
Iamjatinah, I have two defective boards that I would gladly swap for one refurbished board if you are willing. I gotta believe there are several 7.0AT owners with this same problem, and a refurb swap would help pave the way for a solution to this problem Happy to cover all costs to make this deal work. Please contact me on this forum or at <snip> if you are interested. Thank you!
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