Yaesu FT-900 VCO Repairs

 This is a Yaesu FT-900 with a VCO problem I repaired for a friend. Beautiful rigs, lots of goodies crammed in a mid-sized package. This radio intermittently stopped working on some bands. 

For coverage of all bands from 100khz (receive) through 30mhz, and transceive from 160 meters through 10 meters, it uses 4 voltage controlled oscillators. This method allows better broadband performance and is switched by the processor via diode matrix. 

After a little digging, I discovered the coils are made of steel, soldered into copper through-hole pcb. They had developed a poor connection (dissimilar metals). Removal, scraping, tinning, and resoldering corrected the issue. A little alignment and reassembly, and she was up and running. Here's some video and pics...

GRC 615-B Restored

 This is an old GRC 615-B SWR bridge / low power hf wattmeter by General Radiotelephone Company that I restored and calibrated for a friend. If you dig around on eBay, you'll find some cool stuff by them. I have a noise bridge from GRC, they even made a multiband HF rig. Anyway, here's a few pics of this sweet piece...

Alinco DX-70TH Repair

 This is an Alinco DX-70TH hf rig I repaired for a local friend. He bought it at a hamfest as a "non-worker". Good receive, no transmit, VERY high idle current. I suspected finals... When I cracked it open, there were loose screws all over, main board loose, cables disconnected, etc. Oh well, sure enough, the n-channel FETs in the PA were hosed. 

I put everything back together, removed the FETs, and bypassed them with .01uF caps as a quick test. Nice QRP rig, did about 4 watts out. Beautiful signal, and proved the rest of the rig to be OK. I replaced the FETs, and it was a new rig. Here's a few pics...

Lafayette Comstat 35 Restoration

 This is a Lafayette Comstat 35 tube-type CB radio base station from about 1975. These were pretty popular and were high end 23 channel radios in their heyday. 

I saw this at a yard sale and couldn't help myself. It was lonely, dirty, and needed some love :-).

I gave this radio a full massage, replaced some tubes, capacitors, a few out of spec resistors, serviced all controls and switches, padded the pa output load trimmer to load correctly, replaced the internal speaker, gave It a full alignment, and added 2 more crystals to give it channel groups 26-35 (the AM channels). 

It has some character marks (scratches, etc), but overall looked very good for a 49 year old radio, see the photos. Power output is about 3 watts.  Receiver sensitivity is very good, .15uV @ 10dB. This is a very solid radio!

Icom IC-720 Repairs...

 This is an Icom IC-720 I bought in an estate sometime back. This was built around 1980. I don't have a clue what this poor radio went through, as it was in the basement and covered in mud. 

Expecting the worst, I started on the internals first (before wasting a lot of time cleaning). To my surprise. It was just the typical stuff...dirty switches, noisy controls, etc. The motorized band switch was seized up, but cleaning and lube fixed that. I replaced all of the 6vdc caps, a couple of larger electrolytics, and touched up the alignment. This old girl came to life and played like a new radio!

A bit of cleaning, and it went on to pull time in the shack of a new ham. Some of these old radios are real gems. Here's a video and a few pics...