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8 votes
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How do I put an RJ-45 connector on to repair a Kenwood MC-59 microphone cable?

Here's how to repair a Kenwood MC-59 microphone cable (ships with the TM-V71a, probably the 710, and a few LMR radios as well). First, if you didn’t know already, behind the rubber boot at the end of ...
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  • 1,615
6 votes

Repairing a Tecsun PL-660

I signed up here just to reply to this great (the only one I could find on the internet) question/experience that helped me with an identical problem. I was so close to giving up when I read this ...
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5 votes
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Iskra sst 2030 radio speaker plug

To me, this looks very much like a "DIN Lautsprecherstecker": Positive is the small hole, negative the wide slot. Loudspeaker, if I ask google, is zvočnik in Slovenian – so the "ZV" label makes ...
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5 votes

Repairing a Tecsun PL-660

Tecsun is very similar to Baofeng in that anybody selling them expects a certain number of DOAs and other failures. They already know that QA on those rigs is directly reflected in the price. In the ...
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  • 2,021
5 votes

How to avoid acoustic feedback while fixing radios?

You could use a headset or earphones with the receiving radio, so the received audio goes straight into your ears instead of to the microphone of the transmitting radio. Or you could use an assistant ...
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4 votes
Accepted

Presumably working FT-8900R doesn't turn on. What can be a reason?

OK, I figured it out. Turned out a little FFC cable disconnected inside the panel during the shipping. After fixing this the radio worked flawlessly!
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4 votes
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How can I replace the NiMH battery in an old RigExpert AA230 Antenna Analyzer?

With the battery case detached from the device, look at the side with the copper terminals. You should see several seams that can be exploited with a sufficiently thin shim. I carefully used a box ...
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  • 1,445
4 votes

Can an oscilloscope be used as an RF voltmeter?

One of the functions of an oscilloscope is actually to measure RF volts, just make sure to use the x 10 function to minimize loading on the circuit you are measuring, and keep in mind that some high ...
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  • 3,323
4 votes
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Globar resistor repair or alternative(s)?

This is an Inrush Current Limiter (ICL). You can still get them today, but they look quite a bit different. See Digikey for a wide range of parts. Typically, these are used for reducing the inrush ...
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  • 1,871
4 votes

How should coax be physically wired to a "stud" mag mount?

Generally on a stud mount the center conductor is connected to the threaded stud with a ring terminal, you put the bolt through the terminal, then through the hole in the mount, and screw the stud ...
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  • 252
3 votes

Can an oscilloscope be used as an RF voltmeter?

Maybe. If measuring a circuit output that expects a load impedance, such as a 50 Ohm coax or antenna, then to measure the RF voltage at that point with an oscilloscope, you should terminate that ...
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  • 12.4k
3 votes
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Identification of valve

Are you sure that you are correct in the comments about your pin 2 and pin 7? (The conventional numbering for these tubes is as in your drawing, so conventionally pins 8 and 5). If you look very ...
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  • 311
3 votes

Iskra sst 2030 radio speaker plug

LEVI means LEFT DESNI means RIGHT ZV1 is speaker one ZV2 is speaker two S this radio has connections for two pairs of 4 ohm speakers. I guess LEFT ZV1 and RIGHT ZV1 are main speakers and ZV2 are ...
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3 votes

Morse Code Key Grease

I would suggest that these were probably designed to run dry or very lightly oiled (ie: no grease) and that some previous owner took it upon them self to "fix it" using the wrong grease. There will ...
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  • 671
3 votes

How do I replace the Li-ion battery in a Kenwood TM-741A?

I found the TM-741A service manual. As shown on page 106, the battery can be seen looking into the case from the front after the display panel is removed. Luckily, the spare batteries from my dive ...
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  • 7,685
3 votes

Broken IF Transformer (tiny and 455 KHz)

The transformer is most probably a part of a critical tuned circuit. If the ferrite is broken then the radio keeps working but the filtering is worse. There a a number of ways to find a replacement ...
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  • 131
3 votes

How should coax be physically wired to a "stud" mag mount?

GodJihyo nailed it on this problem. There's definitely a piece missing. (The piece that the feed cable passes through.) The mount base should be shaped like a wedding cake with another 'layer' that'...
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  • 155
2 votes

Is preheating required before replacing an old valve?

The process is called degassing. This is done to prevent arcing in high voltage transmitting (power amplifier) tubes. It is not as important for lower voltage tubes but I am sure if done correctly ...
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  • 2,868
2 votes

Morse Code Key Grease

Once cleaned up, a simple light oil, such as 3-in-1 household oil, is sufficient. There is no need to use a real grease or heavy oil, but a light oil will prevent oxidation, reduce wear, and make the ...
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  • 11.9k
2 votes

Intermittent receive on FT-990

I have to ask the obvious question: is the antenna tuned when you are trying to receive? Briefly transmitting may activate an automatic tuner. Relay contacts sound like a reasonable hypothesis, ...
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2 votes

How to identify the mic connection pins in Heathkit SB-102?

Referring to the circuit diagram for this set www.nostalgickitscentral.com/heath/schematics/heathkit_schema_sb102.pdf The mic connector has 2 pins and the grounded body as the 3 connections. As you ...
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  • 311
2 votes

Yaesu FT-817 Won't transmit Dig, SSB or CW

Menu option for ssb filter (38?) should be "off", if no filter.
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2 votes

How to splice RG-174 coax?

At HF there are almost no limits on how bad your splice can be, as long as: there's no short circuit braid is connected to braid and inner to inner You could even use a "chocolate block" connector :)...
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2 votes
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How to handle old stuck tuning slugs?

You should never use a metal tool on powdered iron or ferrite tuning slugs, adjustment tools for them are usually some type of plastic. You should be able to find these online. The better the fit, the ...
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  • 252
2 votes

Jennings variable vacuum capacitor

Now solved (!) fact: the capacitor inner part is now totally at the out position - meaning minimum capacitance. to increase to max capacitance the brass part (see picture) must be pressed in. usually ...
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  • 47
1 vote

How to splice RG-174 coax?

Hmm. I've done this many times. Would a magnifying headband and extra light help you? That's certainly helped me to do that. The same way as we would splice larger coax.
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  • 7,485
1 vote

Heathkit SB-102 Plate Current out of control

In response to tuning the finals and grid dip: I’ve tuned a lot of IF strips as a Navaids Tech. VORs and Tacans mostly. Ham later. The procedure was always to start at the first IF and work to the ...
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1 vote

Heathkit SB-102 Plate Current out of control

The creap could be a bad capacitor or the circuit is over loaded due to excessive voltage on the plate. This sounds systematic of a component failure and requiring component isolation and L-C meters. ...
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1 vote

Motorola XT180 not charging

I will answer the final question: "Should I return them to the store?" Yes. If they are still under warranty, return them and get a replacement. If the battery is a sealed unit inside, then opening ...
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