Help with HQ-110C

[wa2pow]

I recently picked up a DOA HQ-110C as a project radio for use with an "entry level" AM station. I managed to get it working and aligned on 40/20/10m, but still have a problem with the 160/80m, specifically with the 455kc IF Can (T2). Some previous owner decided it would be a good idea to remove several of the IF Cans, and did a rather messy job of re-installing them. Also, the Band Switch wafers were seriously mis-aligned.  I dissected the T2 can, something I never saw a reason to do before. I have identified the Plate and Grid coil connection points, and measured continuity. The Plate side should have a 330pF cap in parallel, while the Grid side should have a 330pF cap on the "hi" side of the coil, with the other end of the cap being brought out to a pin. With a value of 330pF, I expected to see physical caps, but there were none. I could not find any diagram showing the proper connection points of the coild and/or caps.

There are several other things I noticed, but this should get it going on 80m.

Any help , suggestions, or comments would be greatly appreciated.

TNX es 73, Bob  WA2POW

[w3jn]

Many times the caps are micas that are integral to the base of the IF can.  However, if it works on the top bands the problem isn't the IF, look in the oscillator, mixer, or RF stage.

[WQ9E]

W3JN is correct on the micas being integral to the base and they can be a major pain.  My HQ-170 had these and they are not sealed so over time they get enough dust and moisture to develop carbon tracks and arc over.  I ended up having to remove all of mine and replace with modern dipped micas to make the 170 reliable.  However as the previous post stated, these IF cans are not your problem if it is working on the higher bands.

As I recall, the 110 becomes dual conversion on 40 and up so check your bandswitch area again to make sure that there is not a wiring issue there.  You might also listen for the HFO in another receiver to make sure that it is oscillating (and somewhere near the correct frequency) on 160 and 80.

73, Rodger WQ9E

[wa2pow]

TNX fer the info. I did notice some metal "plates" in the bottom of the Can, but couldn't figure out exactly where they are connected to the two coils. In a "standard" tuned circuit, it would be easy to locate the connection points. However, in the particular configuration, the Plate side is a tuned circuit. However, the grid side has THREE connection points: A coil-only lead, a coil/cap lead, and a cap-only lead. This is shown on the schematic. There are six leads on the bottom of the Can. Four are identified with numbers 1 through 4.

Here's my concern: Since a previous owner made it obvious that this Can was removed, I am not convinced it was re-installed correctly. Can either of you (or anyone else!) somehow let me know which numbers go to which circuit points?

Secondly, I noticed that several of the fingers on the Band Switch are rather deformed, if not entirely bent beyond repair. This is next, and I do agree with the suggestions that were made.  But I have to get this Can back in correctly to get B+ to the Mixer.

I also noticed that there may be a problem with the 22k Grid Resistor of the Converter being connected to the Function Switch instead of the Grid coil/cap lead of the T2 Can.

Ahhhhhh.

TNX agn es 73, Bob  WA2POW

[w3jn]

Again, if it's working correctly on the top bands, there's NOTHING wrong with the IF.

[WQ9E]

Bob,

Later tomorrow I will take some high res photos of the underside of my HQ-110 and I will mail them to you; hopefully this will help with any remaining wiring issues.

73, Rodger WQ9E