Stereo Repair

My hobby is electronics and the repair of most home appliances. Doing repairs “Under the table” nets me a nice income, really all those years of training paid for by Uncle Sam should be used, and I do enjoy a challenge from time to time. Well My most recent challenge is a Stereo Amplifier, It Is a Knight KA-40.

This piece was given to me to keep from having to pay for it to be recycled. It came with with several large boxes, with other items and parts.  I really did not want it in the beginning.

The Knight KA-40 was sold from the mid 60's to the early 70's as a kit, the buyer assembled and then used the amp. Considering that this is 50 years old, came from an attic, was a kit, and has vacuum tubes in it finding parts would be difficult. The common ailment I found while researching this model was the voice coils would burn out.

So I opened the case and find the fuse is still good, I used my home made ESR Meter to test the capacitors in the power supply and they are long dead. I checked the voice coils, and found one was open. There is not a chance of finding another coil available, The options at this point is to try to repair the coil, wind a new coil, or hope to find a replacement......

I decided to gently unwind the outer wrapping of the coil. On the 3^rd turn I found a break! I tested with my multimeter and had continuity! This coil was repaired! So after a good cleaning, replacement of all the electrolytic capacitors, and replacing a few screen resisters Also I found about 80 cold solder joints from either age or was just bad to begin with. I replace the fuse, plug the unit into my Variac, set the voltage low and turned the power on. Slowly I increased the voltage and the amp came to life. Plugging in an older Cassette player I soon had music drifting through the shop. Some work on the cosmetics and I'll have a good Stereo Amp. Sometimes we are just fortunate to have simple repairs.

The pictures are the before  repairs started pics.  I still need to work on cosmetics.   Total cost to repair this Amp was  15.75$ US. 

McDonalds Meal

This evening I stopped at a local McDonald's  for dinner and some Wi FI time.  So i ordered 2 burgers and a large Tea.  The first burger was the 1.00 buffalo thing, it was quite good, the second was the grilled onion and cheddar burger.  When I picked it up and unwrapped it I though it felt light.  I bit into it and chewed, and chewed some more. yep cheese, onions, and bread, but no beef that I could taste.  I opened the bun and there was no burger patty.  What!  I looked at it for a moment, then went to the counter,  the crew leader asked if there was a problem.  Well, I said,  I ordered the burger and it does not have a patty in it.  and held it out to show her.  She snatched it and said she would fix it.  I was trying to joke about the value menu the worker was having none of the conversation, but other customers pipe in.   And these are people that want a 15.00 dollar an hour minimum wage?   Well they made another burger and it was complete. 

another day in my paradise.   Blake.

Wireless keyboard repair

Recently I stopped by a friends home, while there the conversation swung around to their wireless keyboard had quit working. Knowing that I have a Amateur Radio license they asked if I would look it over. So I sat at the desk and listen to them explain how it is suppose to work. Pressing buttons I saw none of the leds like up. I picked up the keyboard, looking for the power cord. There is not one. So I turned it over to check for a battery compartment. I found and opened it, out came 2 AA batteries. I took 2 from my tool box and replaced them. Still no power. I checked to see if I may have installed them backwards, nope they were in correctly. So I looked for a power button. All I could find was a channel open button. I pressed it and the keyboard functioned properly.

I have found most repairs are just very simple items that are sometimes overlooked because they are so simple. My friend do not have to buy a new keyboard, so they saved a handful of cash. Also on the other hand I found that 95 % of all electrical items that are in the dumpster work well, Of that 5 % only 98% of those only need a fuse or a minor part replacement. Often the cost of the part/s is under 10 dollars.  So if you want to save some money check the item before you toss it or have someone look at it.   Blake.