DX-160 Please help identify this mod

[Retroradio]

Ive used Google (yes I know Google is my friend….lol) and have located all the mods I want to do. The primary being the Frequency counter mod.
It is done by R12 et…. Using a piece of coax, capacitors, BNC connector(sometimes a transitor), etc.. Most are done dead bug style.

Now the question. I opened up my new to me DX-160 and there is a mod with the aforementioned parts. It is however in the wrong area of the board. I have looked for a schematic etc…but no luck. Anyone confirm that this or is or is not for a Frequency counter. The top of the board pic is to show the coax cable by C56 going trough the board from the BNC to the added/modded parts.
Thanks

 

[VK3RX]

Can't help with the mod but I downloaded the service manual here:

https://elektrotanya.com/realistic_dx160.pdf/download.html

And one of the mods:

VK5TM DX160 MODS

 

[Retroradio]

Thanks for their mods link. I have that site and another with the mods I want to do. The mod for the frequency counter shown is the one I have seen but doesn't seem to match the mod on mine. Hence i am confused.

 

[a417]

what's on far end of the coax? and which version do you have...the newer or the older DX-160?

 

[Retroradio]

The end is a BNC connector w/ coax and with similar parts as per the mod instruction. Just at the wrong location. It clearly looks like a Frequency counter mod as what else could it be?
I was not about to just plug in a counter and hope for the best….lol

 

[a417]

Can you see where that circuit is tapped into? I'll see what the inside of my DX-160 looks like compared to that one.

 

[W1KNE]

Whoever did that mod on your radio did a real sloppy job with it too.

 

[Boombox]

Just by looking at the pics and a few of the parts on the PCB, it looks like whatever the 'mod' is connected to is somewhere near, or on, the IF strip. Looking at all those extra parts wheedled together like that, it's just odd to me how much work guys will put into attempts to improve a perfectly good radio. The only 'mod' I did to my DX-160 was to the RF/IF gain, and I undid it a few years later because it simply didn't improve anything -- in fact, it made the RF Gain performance worse.

Good luck in working with the radio. I've found the DX-160 is excellent especially for MW DXing.

 

[Retroradio]

Its quite the mod in the dead bug style. One of the most common mods I have found is the chassis ground issue and add a Frequency counter. There are quite a few mods out there apparently .
Many thanks for your input on the IF strip.

 

[a417]

Its quite the mod in the dead bug style. One of the most common mods I have found is the chassis ground issue and add a Frequency counter. There are quite a few mods out there apparently .
Many thanks for your input on the IF strip.

Have either of you relocated/shielded the ferrite bar?

 

[Retroradio]

Its quite the mod in the dead bug style. One of the most common mods I have found is the chassis ground issue and add a Frequency counter. There are quite a few mods out there apparently .
Many thanks for your input on the IF strip.

Have to make a small correction, when I referred to the chassis ground issue I was thinking of another vintage shortwave receiver I’m rebuilding.

 

[Retroradio]

Have either of you relocated/shielded the ferrite bar?

Not yet but thats a mod I have heard of.

 

[Boombox]

There is one minor mod I made to my DX-160 that I kept.

My uncle, who was a ham and a radio officer on Naval ships, once he saw the schematic, he suggested the mod. It adds a little to the MW performance. It's R-62, a 33K resistor that on some DX-160 schematics is across the MW antenna coil. My uncle said it was placed there to reduce MW signal strengths, and if I removed it, it would sharpen the performance.

I disconnected it, and the sensitivity and selectivity improved on MW noticeably. Being that both DX-160 schematics I've got are different (one has R62, the other one, in the service manual available online, doesn't), your DX-160 may or may not have this resistor across the coil.

 

[Retroradio]

For example if I set the main dial on CB - In order to receive that band the Band-Spread dial is way past the that portion of the dial and well over 1/2 way to the other end of the dial.
Mechanical it is set up as per the service manual. The dial is where it should be at each end point and middle….
This negates a mechanical adjustment.
A re-alignment would only improve reception methinks…

So how do I get the Band-Spread dial to read in the correct portion?

 

[Engine104]

This should probably be moved from the RS Scanners section to the HF Receiver section on here...It sounds like it needs a serious realignment. The DX-160 was THE SW receiver back in the day. I'd suggest that you also pose this question on eham.net and/or qrz.com. I found a copy of the service manual online Realistic DX-160 Service Manual | RigReference.com ,but you will probably need test gear to complete the job. Good luck restoring this classic old rig.

 

[Retroradio]

Ill check out the other sites as i never thought of posting it there.
It certainly needs a re-alignment but the big question is would it solve that big of a deviation on the mechanical reading?
Its like 3/4 of the Band-spread dial out….

 

[ko6jw_2]

The term "band-spread" is really a sort of fine tuning control which consists of a small air variable capacitor in parallel with the main tuning capacitor. They can be of limited value. Why? Because the front end if the receiver is tuned to whatever frequency the main tuning is set for. This means that the band-spread control actual de-tunes the front end. The farther it is set from the center frequency the more sensitivity will be lost. It won't be fixed by aligning the receiver because it is secondary to the main tuning. My experience is that they were never very accurate and should be zeroed during the alignment process to make sure that everything is in synch.

 

[Retroradio]

Fully I understood. The issue is that yes it needs an alignment but the Band-Spread is already zeroed hence my question. Alignment will not fix this visual mechanical issue I think.

 

[Boombox]

I wouldn't worry about the Bandspread much. It never correlated exactly even when new. I used the Log scale at the top of the Bandspread instead of the actual markings. Also, the 'stars' on the main tuning dial (which one would use to start using the Bandspread) were off on my DX-160, even when new. I quickly learned to use the log scale for that also. As long as the radio was functioning well otherwise, it didn't bother me once I got used to it.

When I was 'good enough' to adjust my DX-160, the only adjustment I made (if I remember correctly) was to ensure that the MW dial was reasonably accurate. But I don't think it was off by much, if off at all.

If the radio works well, just use the Log Scales. I think that's what a lot of guys did back in the day anyway.