OT--Actual elecytronics repair question

No, tapping on it will not induce micro-phonics but will often lessen the howl. Once the radio is on, the howl goes away, maybe after 10 minutes. I'm no newbie to micro-phonics. Some of the old PLL-02a chassis CB radios would howl if you turned up the volume. But you could also hear a high pitch whine in the howl if you tapped on the chip.

No kidding LOL!

We have it here due to severe thunderstorms with large hail, damaging winds, localized flooding, micro-bursts and tornadoes. In April of 2002 a tornado narrowly missed my place. Winds took out windows, ripped siding off houses one street down, took down large trees behind my property, then jumped a 1/4 mile and continued. The same tornado traveled about 15 miles landing then rising taking out a whole neighborhood 8 miles before it got here. So we have the potential for some damaging storms. I remember in 1999 I had just purchased a Dodge 4x4 in the spring. I was out chasing a storm around and got pelted by some golf ball sized hail. That ended my chasing days. I don't have a beater that I care about looking like someone took a hammer to it.

Well, if it were "grounding", then banging on the case would have no effect (unless there were some screws loose).

Incidentally, I tried my VX-5 turn on/off times. It took about 1 second to turn on, and the same to turn off. Pushing the button to turn off was *NOT* instantaneous. I had to hold it for 1 sec. It's been like that since new, so there's been no deterioration. At this point, I don't know if it's a firmware issue, settings issue, or dirty keyboard. Save, reset and reload seems the easiest to do first.

Something is getting warm perhaps?

That's why I like California. Other than earthquakes and government, we don't have much in the way to disasters here.

Ouch. I've never even seen a tornado, so I have no idea what it might be like. Raining golf balls sounds like no fun. Yes, Skywarn has its place in your part of the country.

From what I've read these radios, maybe the first batch had grounding issues and the fix was to provide a better ground. If you have some time google VX-5 grounding issue. I haven't done it yet so I can't post any reference links.

Yeah by immediately I meant within a second. Compared to 10 sometimes 30 seconds to get it to come on it seemed pretty immediate to me :)

Another couple things; if the radio if left off for a couple days it takes more button-play to get it to come on. Also when I charge it off the cig lighter cord, the words 'now charging' appear and when done the RX/TX light turns amber and 'charge complete' is displayed. This tells my some micro processing is going one when the radio is off. I guess you could call it a soft-off/soft-on. Obviously with a touch pad some standby processing is needed to interpret the call for on. But without delving into the operating theory it's hard to tell exactly but easy to guess.

The RF out device sinks on the back but I think the warming and expanding of the radio in general creates a better ground for whatever is not getting a good ground. The radio does not have to be transmitted, it can just RX during this period and eventually the howl will stop. And the howl is only on .70cm. This would indicate problems other than grounding. Or not :) It's only a minor annoyance and I actually do a lot of SW QSX on that radio and only use it moderately on VHF. And it's been doing the howl for years. Neither the howl or delayed on are a big issue until either interfere completely with the operation.

I urge non-hams to listen to skywarn on a scanner if they have one when weather threatens. Anyone in Skywarn gets a text when watches/advisories are put out by the NWS.

On 1/14/2011 12:58 PM Jeff Liebermann spake thus:

Hmm, tell that to all those folks who live "up the hill" from you off 17 whose houses perennially slip-slide away in the rainy season ...

But yeah, I guess apart from that, a few houses falling into the ocean each year, and those houses that got blown up/burned up in San Bruno, we're relatively disaster-free here.

Jeff Liebermann Inscribed thus:

This thing doesn't have a backup battery does it ? If so have you replaced it !

Oh, you mean like my house?

My guess(tm) is I'm on a 45 degree slope. However, I'm not worried about sliding down the hill. I've gone through some effort to divert water around the house and check for hydraulic and geological hazards. What worries me is having one of the huge trees land on my house or getting caught in a forest fire.

Little lightning, no tornados, no hurricanes, minimal flooding, etc. Yeah, I like it here (except for the government disasters).

I think it stores in erasable prom but can't be sure. I had it open once and don't recall seeing anything big enough to be a supercap or battery. It's really miniaturized.

Meat Plow Inscribed thus:

A friend of mine had a HT, Icom I think, with a 2021 battery in it. It went bananas changing channels when you pressed TX. Turned out that the battery was the problem. Now I don't know whether it was low voltage or corrosion because it was repaired by the supplier.

Sadly he's now silent key, so I can't go and ask him. Come to think about it my FT290 has a battery in it... I'll have to check that !

I'm too lazy to dig out the schematic, but I guess(tm) it's NVRAM of some sort. I don't see a coin cell inside. Some inside photos:

Registration required to see them full size.

Note the big white circle that is silk screen to the PCB. That's where the speaker magnet is positioned. I suspect that if you place some foam tape to put some pressure on the PCB, it might reduce the microphonics.

Also, two reasons it's only on 440Mhz. It might be a seperate VCO oscillator for each band, and the LO multiplier ratio is higher for

Incidentally, I sorta blundered across this BNC to SMA adapter made specifically for various Yaesu handhelds. Looks better than the easily broken adapters I've been using.

There a bunch of others with similar design available.

I'll have another look when I pull it apart to clean the conductive pad on the power button. I'm sure there are no 3 volt lithium cells in it in the 20xx size.

Yeah I got the schematic around somewhere, to lazy to dig it up.

I think i read that suggestion a long time ago too.

Understood.

Yeah I have a couple SMA - BNC adapters. Bought them at a ham fest a good while back. If you are going to use the SMA with an external antenna in your home or vehicle they make an adaptor with coax inbetween connectors. I have one that has an SMA on one end, a couple feet of very thing 50 ohm coax (not sure the number but it's half as thin or more as RG58/U) and a SO239 on the other. Beats using a BNC - SO239 adapter.

RG-174?

Could have been. About the right diameter.

I have a 1000 foot spool under my main workbench to make custom probes with.

I prefer LMR100, RG316, or RG188. Most of the pigtails I've bought use RG-316. I don't have a 1000ft roll but do have a tangled mess of indeterminant length buried under the bench.

I paid $20 for it, and it works fine for that use. I also have rolls of silver plated double shielded teflon coax, but why waste it?

I've had this HT apart a half dozen times to clean the contacts and buttons . It seemed each time the cleaning effort worked for less than the previou s time. This last time was desperate. I put a tiny piece of copper foil o n the bottom of the rubber button, held in place by a drop of Elmer's glue. So far, it's working well. KB1KXJ

Yes, that's the way it works. Every time you clean them, you remove some more of the conductive coating.

They sell small conductive rubber pads intended to be glued onto the existing pads. I have never tried them, though. Using metal might be hard on the contacts.

Do "they" even sell "conductive paint" to repair rear window defoggers anymore? They came viz a little finger nail polish bottle and brush. I came across an old, dried up bottle of the stuff in the back of one of my junque drawers recently...

Jonesy