|A Mint Example That Never Worked
||Time Owned: 0 to 3 months.
|Back in the 80's I had the opportunity to use an HR-1680. A friend let me borrow it and I thought that it was very well done. Not an SB-303, but good nonetheless. It would have worked much better than the Hallicrafters S-85 that I used as a Novice.|
I had been offering (at my cost) Heathkit digital dials almost identical to the ones that the late Neil Hecht from AADE sold. Initially, I purchased (and refurbed) an SB-300 to use as the 'test bed'. Thinking that I would have no further need of the SB-300, I sold it off on eBay. However, when a couple of hams on the Yahoo Heathkit forum expressed interest in another batch of boards, I bought an HR-1680 on eBay to serve the same purpose.
The eBay seller advertised that it 'powered up', so I expected the rig to be problematic. When it arrived, it looked virtually pristine - but it didn't work. It even came with the original construction manual. Whoever built it made the last check mark in the area where the heterodyne oscillators are aligned. No more check marks after that (sigh!)
The VFO didn't work because the builder used screws that were a tad too long and they shorted out the stator in the VFO tuning capacitor (there is admonition in the manual about this). Replacing those screws got the VFO working, but still 'no joy'.
There was a problem with the voltages in the product detector section caused - believe it or not - by a shorted .1 mf ceramic bypass capacitor.
Replacing this brought the set to life for the very first time. This is the first time that I'd ever seen a shorted ceramic capacitor and I've repaired MANY radios. Guess Heathkit got a bummer.
The 20 meter heterodyne oscillator (22.895 Mhz) crystal was indeed defective. After a number of calls to a Florida based ham who sells surplus crystals, I finally gave up, took the crystal apart and resoldered the interal connections. It works now, but who knows for how long.
So, I finished the alignment and it works like a brand new HR-1680 receiver should. It's near mint.
The eBay seller was from Wisconsin. He said that he bought it from an environmentally controlled storage facility. I tried to find out exactly where, but he either couldn't or wouldn't tell me.
I would love to find out who built this radio just to tell him or her what went wrong. As a matter of fact, I would even gladly return the repaired radio to the original builder as a good will gesture if he or she could provide proof of former ownership.
Call it 'unfinished business'.
|Simple, excellent receiver
||Time Owned: 6 to 12 months.
|The Heathkit HR-1680 is an all solid-state vintage Heathkit CW/SSB (no dedicated AM) receiver. It is a dual-conversion SuperHet design with a dual-gate MOSFET RF amplifier at the front end and dual gate MOSFET mixers at its 8.66 MHz and 3.395 IFs (which include multi-pole crystal filters). In a throwback moment to earlier tube receivers, the front end also includes a continuously variable preselector circuit, in addition to the switch selected bandpass filters before the RF amplifier. The SSB product detector is IC based and followed by op-amp active filters. An FET based Hartly oscillator forms the core of its VFO. This elegant and simple design was pretty advanced for its year of introduction - 1975, and a pleasure to assemble and align with most circuits contained on four plug-in boards. It is a very sensitive and mellow-sounding receiver, and while it will never make it to the top of Sherwood's receiver performance list, it is fun and easy to use. |
Four quirks should be noted if you buy one: 1. The S-meter scale is notional, and Heathkit released a mod for it to improve performance (slightly), 2. Early power supplies ran hot and if you have this problem, search the net for mods to fix this, 3. The preselector wire must be routed away from the metal case and other circuitry on its way to the RX board, or RX sensitivity and selectivity will be reduced - if you open the case and the wire is "floating" in mid air on its way to the RX board, its fine, 4. The band switch and slider contacts can accumulate dust and oxidize over time. If you have problems with a "dead" band or switch, clean it with DeOxIt and it will likely come back to life after a few operations back and forth.
My HR-1680 is almost like new, runs as cool as a cucumber and is usually connected to my Yaesu FTDX-3000's external 2nd receiver jack. I use it for browsing second (in-band) frequencies while working a contact on the primary frequency. In this configuration, the HR-1680 can take advantage of FTDX-3000 pre-amps and attenuators, which are between the antenna and 2nd receiver output, further improving its performance.
Once calibrated using the internal crystal calibrator, the analog VFO dial of the HR-1680 is quite accurate and the VFO is very stable (for an analog 1975 design). A beautiful and elegant example of Heathkit design genius - not all Heathkits were well done, but the HR-1680 receiver is a gem, even 40+ years after introduction.
|great cw rig
||Time Owned: more than 12 months.
|I have had the hr-1680 receiver and the companinon hx-1681 for many years. I assembled it, and it has always worked great. I bought the transmitter later at a swap and spent a week getting it to work, due to an inept builder's blunders. Once I got it working, the combination has been great. I have two ten tec solid state rigs, but I still prefer the heathkits, with the tube final transmitter. Its too bulky for field day, and too susceptible from overload from all the ssb rigs on site. But it works excellent at home, and I always get as good as I give on rst reports.|
|stable, easy to use receiver
||Time Owned: more than 12 months.
|I have owned this receiver for 18 years, along with it's companion transmitter, the HX-1681.|
It is very stable,and simple to operate, and has good sensitivity. The 250hz audio filter gives the best cw note I have heard on any receiver.
On the negative side, nearby strong signals will desensitize it somewhat.
For it's used price, it is an excellent value
||Time Owned: 3 to 6 months.
|This is a nice, basic 80 to 10 Meter receiver for SSB/CW. Since its a kit radio some obvious cautions apply. The VFO is thermally stable - amazingly so for its construction - and mechanically quite good too. This radio is light years ahead of the HR-10. It is a sensitive, stable receiver even on 10 Meters. My one complaint is that the audio derived AGC has a tendancy to pop. Heath did well on this radio, and even today it offers good value given its performance and what it can be purchased for. The radio had a companion transmitter that was a hybrid (transistor/vaccuum tube final). Its one of the better basic HF receivers around, and it is very possible to do a lot worse for more money.|