Electronics

This is an epic video on all my efforts to fix my radio out of my 1994 Jeep Grand Cherokee. It is a limited edition Jeep with a very nice CD/Radio sound system but for about 10 years now the vacuum fluorescent display (VFD) has been dead although the radio and CD work fine. This meant my only headache was I never knew what station I was on. But after setting the stations who cares, right? Well it drove my daughter nuts because she likes to channel surf and after having the battery disconnected it was a challenge to find and set the stations again.

This is the radio/CD player that I need to fix. Only the display is broke so how challenging could that be? VERY! I guess I’m not too good at fixing VFDs.

This is the display that does not seem to be getting power or functioning.

After unplugging the display panel PCB I had access to the board headers off the main radio. The silk screening on the display panel PCB had labels that told me the pins that were for 5v and 12v.  I powered up the radio using my 12v supply to simulate the car battery being connected then used some jumper wires to probe 5v and 12v pins going to the display panel PCB. All checked just fine.

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In this video I teardown and cleanup a 20 year old Swintec 401DP printing desk calculator.  It was still working and I needed a good desk calculator for my bench.

I cover how some of the electronics work as well as the mechanics and of course my efforts cleaning and greasing it up into perfect working order. Good for another 20 years I say.

I picked this one up at Goodwill for $3.00 with 10 rolls of paper. It might have worked but it was in horrible condition and filthy as you can imagine, it had a hard life. Still Goodwill is a great place to score old electronics.  Normally I don’t fix stuff I get from Goodwill I just tear it down for fun and for spare parts. The old parts are still the best for hacking.

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I was working on my 1994 Jeep Grand Cherokee today. Just changing oil and replacing an upper radiator hose. I put my hand on my cruise control module and leaned a bit too hard on it – “SNAP”. I broke off the vacuum nipple at the base of the plastic molded housing. That’s the end of that! Well, my cruise hasn’t work for over 10 years so I wasn’t too sad.   I thought I might as well do an autopsy to see how it worked and if it didn’t work then what went wrong so long ago.

Here is the full module with vacuum diaphragm canister control and throttle cable.

Below are the control solenoids that dial in just the right vacuum to pull the diaphragm and throttle cable back to a selected cursing speed.

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