Homebrew Bench Supply Resto...pt1

 This is a cool home brew bench supply I got from a friend. It was built 50ish years ago, and was pretty cool in its time. Regulation and output current is in bad condition, but I think it has potential, especially since it was built by my friend. This is the 1st part of the restoration.

Sansui 4000

 This is a beautiful Sansui 4000 I got from a friend. It was built in 1969, sports a Walnut cabinet, and pumps out a very conservative 65 watts per channel into 4 ohms. It is labeled as the Solid State 4000, considering that there were still many high end sets of that era with vacuum tubes. 

This one is very clean and works well. I've cleaned and serviced the controls and switches, and will be recapping this later. Here's a few pics and video...

Heathkit HR-10

 This is a Heathkit HR-10 I got from a friend. It was his original receiver, and was paired with a Heathkit DX-40. I have a DX-40 (see it in my blog listing on the rh side of this page), so this it the perfect lashup for my novice nostalgia station :-) .

This was in pretty good shape. I buffed out the original paint on the cabinet, replaced a few caps and resistors, serviced the switches and controls, tested the tubes and cleaned their pins and sockets, replaced a lamp, and gave it an alignment. Wow, its a pretty good receiver for it's era. Here's a few setup videos and pics...

Yaesu FL2100B Repairs

 This is a Yaesu FL-2100B I repaired for a friend. He was using this on 29.600 FM with high carrier, around 600W out. He noticed power beginning to sag, then an arc under the hood, and the magic smoke was released. 

I found the plate choke burned from a hot-spot, the plate choke bypass cap on the dc hot side blown, grid resistors blown, and a shorted tube. 

I replaced the shorted tube, replaced the blown grid resistors, replaced the bypass doorknob, and coated the rf choke in the hot area. I used the grid dip meter and found a resonance around 29.700...very close to where he operates on 10m fm simplex. That's probably what burned the plate choke. I added a 2.5 mH choke between the main rf choke and the plate caps, and that pushed the resonance past 30mhz. After I tested the amp, I added an additional fan to aid in cooling when operating on 10m FM at 600w carrier. 

The completed repairs...

Grid resistors replaced...

The hv cap below the choke was replaced...

I coated the burned area. The shellac on the wire was darkened, and was coated with transformer shellac. A 2.5 mH choke was installed between the rf plate choke and the tube caps.

The additional choke moved the resonance well above the region used for 10m FM.

Idle current now at 50mA. 

Plate voltage at 2500vdc.

100w in yields abt 700 out. 70 watts in yields about 550, a safe level for short transmissions on 10 FM.

The tuned input was optimized for 29.600. 

Running it a bit after repairs.

Tempo CL-220

 I picked up this Tempo CL-220 in a batch of items, and had never seen one before. After a bit of research, I uncovered an interesting story on this radio. Watch the video below to hear more about that. This is a crystal controlled radio. It has no crystals for frequencies in my area, and considering the high cost of custom crystals, I opted to not restore it. It's an interesting rig, here's a video and a few pics...