What I've Been Up To....

Started this post on Monday, then came down with a head cold, which is now progressing South. Feeling better, but still a bit woozy......

Tonight's cold and blustery, a Good Night to stay downstairs, drink hot cocoa, and continue the work on the Fisher stereo for my friend. Since I've scaled back garage operations for the year, and everything's been "Winterized" outside, I'm able to spend several hours or more on it daily.  I'm really embarrassed about taking so long on this, but I don't generally take in any outside work until mid-October or so. He brought this to me in mid-April, and I was only out of the Hospital for a month or so from the Dental Emergency that almost turned off my lights, and was just getting back on my feet.

It was a mess, having been (sloppily) worked on by several people before me.

This is the back side of the front panel. All the yellow, orange, and white wires connected to the brown circuit board are for the fourteen individual little light bulbs that were glued into the back of the panel to light the indicator when that function was activated. I tried really hard earlier this year to find a replacement bulb with lead wires attached. I'd seen them before in various modeling supply magazines, as they're used to light up the insides of scale buildings and such. Reasonably priced, too. BUT....they're all 12 Volts. The bulbs in the receiver are 8 Volts. If you run a 12V bulb on 8 Volts, it ain't gonna be very bright! It had three different kinds of bulbs in it, most were crudely soldered on to the original wires, and the connection wrapped with a bit of electrical tape. Some were dead, some were very dim, and a couple had fallen out of the panel, leaving the indicator for that function in the dark.

All of the wiring on this board had to be removed, the pins cleaned, the main harness wires put back on, and then the bulbs get soldered in. Whoever built this for Fisher didn't pay attention the the details. The soldered the leads for the bulbs to the pins on the board, and then they wire wrapped the main harness wires on! Changing a bad bulb just went from ~15 minutes to over an hour.

Per bulb.

And it turns out that most of the wire wraps weren't done properly, and they slid right off the pin! Wire wrapping is capable of producing a very reliable "gas tight" seal between the wire and the pin. It normally takes a special tool to unwrap the wire from the pin, but not here. Not wrapping them tight enough will cause intermittent connections at some time in the future, and they're NOT fun to troubleshoot. BTDT, DAMHIK!

Looks much better now that it's cleaned up.

This is the gut pile...

....and these are the lamp assemblies I made to replace them. Lamps are rated at at 8VAC, and expected life is 10,000 hours.

Since this receiver is loaded with wire wraps on all the boards, I'm going to add a drop of soldering flux to each of them, and then solder them. Problems solved, and future problems averted.

Early bedtime tonight. Still not running at 100%. I blame Well Seasoned Fool for the cold!