Took a Week, But I'm Feeling OK....

 Thought I was feeling better, but then it smacked me again on it's way out the door...

ANYWHOO....work continues on numerous things. I'm making up an "Electrical Experiments Board" for grandson #!, although I'm sure his younger brother will enjoy it, too.

It will use one of the LiMH batteries from the small R/C trucks we have, and an assortment of switches, lights, bells, buzzers, and motors. Kind of like an "Electrical LEGO Set" that they can use to learn how to hook things together using wire and "Fahnestock Clips" for the connections.

And of course I'm rolling along on the Fisher RS-2010 receiver. The next post about it will be on the rebuild of the Power Amplifier Board. Had some bad diodes that threw all the voltages off, and clobbered a couple of transistors. Looks like another trip down "Substitution Lane" to see what modern parts are suitable.

Oh, Lord.....What Hit Me?.....

 Picked up SLW about half-past midnight at DIA on (early) Friday morning from a trip to see one of her friends in SoCal. She'd been sick her last day there, and was wiped out the next two days "going at both ends", as it were.

Then it hit me Sunday night.

Flat on my back all day Monday, and even now that I'm up and moving, I'm still kinda 'shaky'.

We got our first measurable snowfall last night.  Looks like about 3~4", about 22* outside right now, with an expected low of 5* by early morning.

Time for a mug of hot cocoa, a blanket, and some TV watching time with a nice fire going in the fireplace.

The Fisher Saga Continues....It's ALIVE!

 Well, at least it didn't go up in smoke when I brought it up on the variac!

And now we go into troubleshooting the Power Amplifier Board, the original problem that brought the receiver here.

This board has six undocumented changes from the schematics in the Service Manual.

1 - Four 10uF capacitors, two each on the STK-0080 "Darlington Power Packs".

2 - Two small inductors on the bottom of the board.

3- An "extra" transistor on each driver transistor

4- An extra resistor in each channel.

5 - A resistor that doesn't go to the designated pad in each channel.

6 - A capacitor/resistor network mounted to the chassis, with "flying leads" going to the board. The capacitor is the out-of-focus blue cylinder handing in midair.

Things like this, along with the haphazard layout of the board (parts are scattered everywhere, part numbering is odd, etc) makes troubleshooting tedious.

This shows "Q17" with an extra resistor, and an extra transistor stuck into some of the holes for Q17. Resistor "R03" is also not going to where it looks like it should go. These are most of the major changes Sanyo made that I have to figure out.

Yes, it needed a lot more work than I anticipated, but that's why people bring me these things to fix. At least I'm down to one circuit board, which to me is the Light At The End Of The Tunnel.

Happy New Year!

 I'll be among the legions of those who will go to bed early. Just getting too old to stay up as late as I used to.

Been very windy here, and the fence on the North side of the backyard has come loose from the rotted posts it was attached to. Looks like we'll be getting together with our neighbors to split the cost of getting it replaced. The fence is the original one from the late 1970's when the houses were built. Our previous neighbor and I replaced a few of the old posts, but several of the others have since rotted away at ground level, and now the fence panels are loose. I rigged them up with some paracord and some "MILSPEC" antenna stakes, but it's time to rebuild that section of fence.

Been cold, too, with the low last night in the high teens, and very dry. We've had two light dustings of snow, and about 1/4" of rain since Halloween way below normal. Looks like the Great Push to get the snowblower serviced has kept the snow away.

Be safe, checketh thy six regularly, and hope 2025 will be what we need.

Merry Christmas - He Is Born -

I'd like to wish my friends here a very Merry Christmas, and a very Happy New Year.

We'll be having our Christmas Dinner with family and friends tomorrow, but tonight is a small gathering for our Christmas Tradition of Sloppy Joes, French Fries, and the ritual tearing of wrapping paper.

No, we haven't had any snow this year, but we might have 40* and raining for Christmas Day.

Peace to all.....

The Fisher Saga Continues - Act III -

 Been working on this post since right after Thanksgiving. I'm making very good progress on the Fisher, and will most likely power it up this weekend.

I have to admit that this receiver needed more work than I expected. It showed signs of being repaired at least twice before, and while the work was of acceptable quality, two of the transistors were a substitute type with different specs. Then I found the under-rated capacitors. A couple of them were open, ten or so were leaky, some showed signs of heat distress, and one appeared to have lost a very tiny amount of dielectric fluid.

Oh, and there were two resistors that had lost their smoke.

I managed to get the tuning mechanism back together, and restrung the dial cord. This had been hanging over my head since I started working on it. The service manual diagram didn't match what was in the receiver, so I used my "Before" photos to see how the gears on the main tuning capacitor fit together, along with a tabbed thrust washer, and how the dial cord was strung. This started when the shaft that goes into the main tuning capacitor came out in my hand and dropped two small parts out as I was trying to diagnose why the tuning was so sloppy. The OEM dial cord was stiff, dried out, and brittle. It made the tuning feel "gritty". AND the tuning mechanism is not documented, with the drawing in the Service Manual not matching how the receiver was built.

 

 

 And now that the front panel and knobs are cleaned and back on it, it's starting to look like a receiver again....

Among other non-documented changes were four capacitors on the Power Amp Board, along with two resistors and a capacitor attached to it, and two small inductors on the bottom of the Power Amp Board. Took a while to trace those parts out, figure out why there were there, and make notations on the schematic.

ALL of the electrolytic capacitors on the Power Supply, Power Amp, Preamp/Tone, Equalization and FM/MPX boards have been replaced. Eleven aluminum electrolytic capacitors in the FM Multiplex section were replaced with tantalum electrolytic capacitors for improved frequency response and stability, and six more on the Tone and EQ boards were changed for the same reasons.

These had failed and were very "leaky".

And while these still appeared to be OK, how many of them are on the edge of failure after 40-some years?

The gooey looking stuff on one end of the larger capacitors is NOT leaking electrolyte. It's a glue used in assembly to keep larger, heavier parts from coming loose before the board is soldered. It's also used in high-vibration environments to keep the parts moving around and cracking their soldered connections to the board.

ALL the wire wrap connections were inspected, and soldered. There were a half dozen that were coming unwrapped, and most of them showed signs of distress.

All the controls and switches were cleaned and lubed with DeoxIT D5 or Fader F5, as appropriate.

All panel lamps were replaced. Yes, I could have replaced them with LED's, but that would involve making a little Rectifier/Filter board as the lamps are fed with 8 Volts AC.

So stay tuned, kids for Act-IV..... The Power Amplifier Autopsy.....

I greatly appreciate my friend's patience and understanding in this. We never really discussed what "Fixing It" can entail. I sympathize with him, as I have numerous friends who had the I Went For A Brake Job, ANNND...experience.

Yes, there will be an Epilogue, probably called something like "Testing And Delivery"...

Big Fisher Saga Post Coming Soon!

 Rolling right along on it, and should be able to power it up this week!

Stay tuned.....

Happy Thanksgiving....and The Fisher Saga continues....

 First of all, We'd like to wish everybody who drops by here a very Happy Thanksgiving. This is our 15th Thanksgiving together, so I have 15 more things to be thankful for!

The work is proceeding quickly on the Fisher receiver now that I have sufficient time to devote to it. So far I've replaced 17 electrolytic capacitors that were under-rated. You simply don't run 24 Volts on a capacitor rated at 25 Volts. You have zero safety margin if the Line Voltage rises a few Volts, and I've seen a low of 116 Volts, and a high of 121 Volts, here at the house. Most of those were on the Power Supply Board,  six were in the Tone Amplifier Board and two were on the Equalization Board.

I soldered all of the wire wrap connections to their pins on the boards, and cleaned up some iffy areas regarding how the wiring is run inside the chassis.

A veritable forest of new lamps!

Say "Ahhhhhhhh...."

All the electrolytic capacitors removed.

And replaced with new, higher Voltage, and a higher temperature rating.

I did the same to the Tone Amplifier Board and the Equalization Board.

If I'm able to move when we get back from Dinner on Thanksgiving, I'll dress all the leads into their spaces, and replace the mini cable ties Fisher used.

And this completes the bottom side of the chassis

Drive safe be careful of any bad weather, and enjoy Thanksgiving. I have a LOT to be thankful for this year.

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!

Interesting Flight Path

 Couldn't determine which aircraft flew this, but it caught my eye...

Happy Veteran's Day

 To all who served, I am deeply in your debt. Thank you all for your service, sacrifice, dedication, and loyalty to the USA.

I am humbled to count you as friends....