Static zaps Sangean (R/S radios)

[David Silver]

Well, it's that time of year ago in the upper portion of
the USA when our good fried STATIC ELECTRICITY comes back to
haunt people with Sangean (read Radio Shack also) radios.

So here are some of the posts that have been made to this
newsgroup over the past year regarding that problem. Hope it
helps someone.

If anybody wants to try to wake up Sangean to this problem,
and to get them to officially recognize the problem, their
address is:
Sangean America, Inc
2651 Troy Ave.
South El Monte, CA 91733
Phone: (818) 579-1600
Fax: (818) 579-6806

----------------------------------------
I have a RS DX-390 (Sangean ATS-818) which was destroyed by
static over the weekend when someone who shouldn't have been
touching it grabbed the antenna to adjust it without
discharging themselves of surplus static. I've read several
articles here about this problem, and wonder if anyone can
post the specifics again as to what part inside was actually
destroyed, where it is located on the board (ie: what obvious
capacitors, resistors, etc... is it close to), and where I can
get a new one to replace it.
-------------------------------------------
If DX-390 is similar to DX-400 (DX-400 is Sangean ATS-803),
then all you have to do is remove all the radio batteries,
including the backup ones for a couple of hours. This will
discharge the capacitors in the cpu and reset it. After a few
hours, replace the batteries or, better still, put in fresh
ones and see if the radio works.
-------------------------------------------
I understand that the problem is that the static electricity
zaps the FET in the unit. This has to be replaced. I don't
know how that is done, however. Sangean management insists
that the problem is only if someone uses an external antenna,
and that it will NOT happen through the whip antenna they
supply as part of the radio.

You have just confirmed what I and others have told Sangean. I
suggest that you write to Sangean in LS attn: Sales Mgr,
Sangean USA. This seems to be a major problem for some of us
in the parts of the US where static electricity is prevalent
in the cold weather.
-------------------------------------------
That would be wonderful, if it works. If what others are
saying - that the static electricity zaps the FET - then
nothing but replacement of the zapped component will do the job.
-------------------------------------------
I spent some time fiddling with my DX-440 (ATS-803A)..and
discovered something interesting.....I tried attaching an
external antenna and doing some other tests. I was switching
back and forth between the whip and connecting an external
longwire using the rear-panel phono jack and seeing what
effect the EXT/INT antenna switch had when I noticed two
things that might be of interest--they simulated the
no-sensitivity condition that the zapped radios displayed:

1) If that EXT/INT switch is not making good contact, it can
get wedged in a state where neither side is connected, it
seems. The radio then appears dead. Smartly flicking it from
one side to the other fixes this. I suspect some contact
cleaner inside the switch would also help.

2) At one point, after my repeatedly switching antenna inputs
and connecting a disconnecting the external longwire, the
radio seemed to go dead, with nothing but hiss coming out of
the audio, even when the display shoed it to be tuned to
frequencies that had had strong signals a few seconds before.
manipulating that antenna switch did nothing to cure this, but
turning the power off and on again fixed this immediately. I
found this to be particularly odd-- it seemed the
microprocessor needed resetting, but why would varying the RF
signal coming in cause it to go into an anomalous state?

Now, I haven't seen the rear panel of a DX-390 or its Sangean
equivalent (ATS808) so I don't know how similar this antenna
connection and switch is to the one on that model. But it
bears checking out. I really doubt that antenna switch is
designed for heavy use; its rear-panel location suggests the
designer expected it to be set once and then left alone. So
someone who repeatedly changes from internal to external
antennas may well wear it out, and a defective or damaged
switch could simulate a zapped front end.
-------------------------------------------
Is there any precise and specific test the user can do to
determine if their Sangean ATS-803A or Radio Shack DX-440 (or
other Sangean model or RS clone) has had this zapping? There
were such tests fro diagnosing the zapped FET front-end in the
Sony 2010, so it would help if the equivalent for the Sangean
line could be posted.

After reading all these posts, I am beginning to wonder about
my DX-440. It still has excellent medium-wave reception....
But maybe the thing is zapped? When the 2010 was zapped, the
medium-wave reception was the first thing to go.

When the Sangeans are zapped, will they still get reasonable
shortwave reception when using an external antenna, but not
with the whip? Or are they totally dead even with a longwire
connected to them? What happens to the MW reception on a
zapped Sangean? And is FM totally separate, so that FM
reception isn't affected at all?
-------------------------------------------
I posted an article a week ago about how I thought my DX-440
had been zapped. Thankfully, when I opened it up, all that had
happened was that the wire had become detached from the whip
antenna. Phew!
-------------------------------------------
It happened to me yesterday. I walked across a carpeted floor
while carrying my ATS-803A under my arm. When I reached the
other side and touched something, I got a static shock and the
Sangean is now definitely not working properly. The
sensitivity on FM is hopeless.

Can anyone please help with the FET type and precise location
on the Board??? I obviously need to replace the RF pre-amp
FET. Alternatively, does anyone know how I can contact Sangean?
-------------------------------------------
I had a problem with static electricity on my Emerson ATS-803
while on a camping trip. I had strung an external antenna up a
tree and static built up and screwed up the CPU inside.

I took it to a local Dealer, who said "I was lucky it wasn't
worse" as it turned out it was easy to fix. Just remove the
batteries until all capacitors discharged I haven't had any
problems since.
-------------------------------------------
All this talk of Sangeans getting Zapped has me kinda
concerned. I've got a 440 and a 380 and always use a reel
antenna inside and outside (strung thru trees). Am I gonna get
zapped, too?
-------------------------------------------
Your message mentioned zapping the front end of the Sangean
The front end of the Sangean 803A/DX440 has an FET which will
blow. It's Q115. Radio Shack used to sell the part which you
can use as a replacement, it's MPF102 and sells for 79 cents
(US). Hope this is useful.
-------------------------------------------
There have been numerous posts lon this newsnet regarding
zapping Sangean FETs with static electricity when using an
external antenna. Sangean admits this can happen.

Does anyone have any experiences to report of this happening
WITHOUT USE OF AN EXTERNAL ANTENNA?

Has anyone had their radio loose sensitivity when it has been
possible to have had a static electric charge go through the
radio?
-------------------------------------------
It happened to me, yes it did, I was sitting in my comfy chair
with my thinly veiled Sangean (RS DX-390) and the antenna
touched the lampstand which happened to be brass and well
grounded /******/ZAP/***********>,

Oh fabulous day, a warranty repair. (bought extended warranty
from RS""""""""Thinks: when DX390 is discontinued by the nice
Radio Shack people, there will still be a lot of static
electricity around.
-------------------------------------------
I have not had any problems with static electricity with my
2010 since I installed diodes in the antenna line, and kept my
old air-gap lightening arrestors in line (over the last 6
years or so at least). so the anecdotal evidence from you
perspective is pretty good!
-------------------------------------------
I'd imagine there is a large environmental effect to all this.
Years of reading the net has suggested to me that people in
the US have big problems with static in the colder months when
the air gets dry?
Here in Australia static is not such a big problem...this may
explain why my Sangean ATS-808 is and has been happy for quite
some time. It's a rare day in my part of the world you have
static trouble.
-------------------------------------------
When the FET blows shortwave reception goes completely dead,
even the strongest broadcasts i.e. BBC no longer can be heard
at full volume. AM sensitivity goes way down but strong
stations still come in. FM does not seem to be affected in any
way.

Watch out for static when connecting the antenna I have gotten
zapped twice. In the future I plan to onlyu use inductive
coupling in the winter months or even year around, the small
improvement in reception on the weak stations is just not
worth the risk. The whip on the 390 actually does a very good
job for the radio in my experience, the advantage provided by
the antenna is small. In fact I believe the external antenna
connection does not get any attenuation so a strong antenna
can actually overload the selectivity of the tune actually
making reception worse with the strong broadcasts dominating
the bands.
-------------------------------------------
I really like my DX-390. The whip doesn't seem to bring in the
stations as well as my DX350 but I ran a 140 foot 22 guage
solid copper horizontal antenna to a big tree outside and put
an aligator clip to the whip and it REALLY improved my
reception.
-------------------------------------------
I wast just notified that an UNGROUNDED longwire antenna
attached to the whip of a DX390 with an aligator clip can
cause electrostatic DAMAGE to the radio.....Be advised
-------------------------------------------
TRUE, I had my Sangean 803A blow an FET one winter storm,
heard all this cracking noise, and all of the signals went
down, blow the recv FET transistor inside it. I fixed it my
self, only a few minutes to do it, but a pain to find the same
type of FET.
-------------------------------------------
I bought a Sangean Ant-60 Portable Shortwave Reel Antenna
awhile back and haven't used it much. I don't want to plug it
into my DX-380 for two reasons. First, it tends to mute MW
reception and seond, I've heard some horror stories on the net
from 808/380/818 radio owners who experienced reception
problems after prolonged plugging and unplugging of this
antenna.

My solution is to use the optional mast antenna clip.
However,having the plug joined to the clip is rather awkward
and too tempting to just use the plug. I've cut the plug from
the antenna wire and have done likewise to the female
receptacle on the Mast clip wire. What I now have are two bare
wires that I want to join together so I can then use the Mast
clip and clip to my SW mast antenna.
-------------------------------------------
I HAVE DETERMINED BY SAD EXPERIENCE THAT USING THE ANTENNA
CLIP INSTEAD OF THE PLUG WILL NOT PROTECT YOUR RADIO.
`
After the external randon-wire antenna ruined MW reception on
my Sangean 818cs, I thought the plug was the problem. While
waiting for a replacement radio from the very gragious Grove
Enterprises, I used my somewhat older Sangean 808 with that
same antenna, this time confidently fastening the antenna to
the built-in whip with an alligator clip instead of using the
plug. Now MW reception is ruined on the 808 as well, and that
one it beyond warranty.

Apparently, the problem was never the plug but rather some
evil things called "electrostatic damage". Maybe this is why
they tell you to connect the antenna or the radio to a "good
ground", whatever the hell that is anyway.

The upshot for all us non-nerd radiophiles: Be wary of all the
"experts" who encourage us to use external antennas, yet who
say nothing about electrostatic damage.

I am going to miss using the external antenna. It was a clear
improvement over the built-in whip. For those who may have
missed previous episodes of this saga, my external antenna is
an 80-foot fire tacked to the baseboards around the living
room,. the dining room, and half the bedroom.

Here are some ideas I am considering. I hope to see your
comments on these ideas, as I am fairly in the dark on all
matters electrical.

o I should probably run the antenna along the edges of the
ceiling, rather than along the edges of the floor. Someone
suggested it would be best not to have the antenna fitted
snugly along the edges of my wall-to-wall carpet.

o Maybe I should put a capacitor or some such gizmo bewteen
the antenna and the radio.

o Maybe I should go on avoiding the antenna jack and use the
alligator clip on the built-in whip.

o To indicate how desparate I am for information on this
matter, I often listed with headphone with a 20-foot extension
cord. As I wander around I occasionally (more likely in the
winter) hear clicks and pops as the earphone cord slinks
across the carpeting. I presume by static electricity. Maybe I
should never use the headphone extension cord.
-------------------------------------------
I'm just using a portable reel antenna. I connect it to the
built-in antenna and throw it up high around the room. I use
inside and when I'm outside in the summertime. I just connect
the reel antenna to the whip. Really pulls in the signals.
Works great!
-------------------------------------------
Actually I am a little confused after reading the posts --
does the damaging static charge build up while the external
antenna is connected, or while it is just lying around not
connected? If it happens when the antenna is still connected
to the radio>(and the radio is on), then what can be done to
avoid the problem?
-------------------------------------------
I suppose it can happen either way. I think it's more likely
to cause damage when the antenna is first connected, but a
spark to an already connected antenna can also cause trouble
(even with the whip).

The cure is to bleed it away somehow. I use a transformer (one
side attached to ground) to couple my outdoor antenna to its
coaxial feedline: this effectively prevents static buildup.
You can also ground the antenna itself, as I suggest above.
-------------------------------------------
WARNING! Some receivers (Sangean, early Sonys, etc) do not
have overload protection for reasonable voltage transients on
external antennas! Put back-to-back diodes in parallel between
the external antenna lug and the external ground lug on the
radio. Most any silicon diodes will do. Then your front end
FET won't burn out as easily next time. (This includes damage
from static electricity when you touch the antenna terminals
in the dry wintertime.)

And yes, be sure to disconnect the antenna when you're not
listening to the radio.
-------------------------------------------
My suggestion is...Don't plu in an external antenna. Get an
antenna for SW that clips to your mast antenna and buy
yourself a select-a-tenna for MW. I do this with my DX- 380 and
DX-440 and both methods work wonderfully###
-------------------------------------------
It seemed the problem developed after I started using an
external antenna (for shortwave reception). My external
antenna consists of just an 80-foot wire tacked around the
baseboards. At the radio end, the wire is attached to the 1/8"
jack supplied with the 818cs. The external antenna degrades AM
reception (which I am told is not unusual), so I frequently
plu/unplug the antenna. My theory is that the external antenna
plug (jack) on the radio is damaged, probably as a result of
plugging/unplugging the antenna. I have had trouble before
with 1/8" headphone jacks wearing out (on packe-sized Sony
radios). AM reception sometimes improves with the antenna
plugged part-way in.

Has anyone on the net experienced similar problems, only with
the headphone jacks on Sangean receivers, or is this a problem
limited to the external antenna jack? How many plu-in/plug-out
cycles are we talking about before the failure occcurs?
-------------------------------------------
My boss recommended a picofarad size capacitor between the
longwire and the radio. He said that picofarad size would have
minimal electrical effects on the antenna and front end but
still protect the FET.
-------------------------------------------
Don't overlook the possiblity of a static discharge on the
external antenna zapping the front-end circuits of the receiver.

I believe this is exactly what happened to my Sangean ATS-808
when I went away for a weekend and left the outdoor antenna
connected. On return, the AM reception was dismal and only
strong local stations could be received. Yet FM and SW
reception was OK.

It is always a good idea to disconnect any external antenna
when not in use or during bad weather.

Since getting the radio replaced, I have had no further
trouble and I have repeatedly connected and disconnected
external antennas through the antenna jack.

In fact, I prefer to use the antenna jack instead of clipping
onto the whip antenna if only because the latter causes the
whip to become loose and "scratchy". With an antenna connected
through the jack, the whip is electrically removed along with
the "scratch".
-------------------------------------------
Well, there are some of the comments that we made on this
newsgroup regarding the static electric problems with Sangean
radios.

Hope this information helps you.

Dave


Subj: thanks for ATS-803 help

Return-path: <pacs!jba...@delphi.com>
Received: from mcs.drexel.edu (king.mcs.drexel.edu)
by delphi.com (PMDF V4.3-9 #7804) id <01HGGUL74...@delphi.com>; Mon,
29 Aug 1994 03:56:19 -0400 (EDT)
Received: from pacs.UUCP by mcs.drexel.edu (4.1/SMI-4.0) id AA02080; Mon,
29 Aug 94 03:56:05 EDT
Received: by pacs.pha.pa.us (/\==/\ Smail3.1.21.1 #21.16)
id <m0qezAO...@pacs.pha.pa.us>; Mon, 29 Aug 94 01:22 EDT
Date: Mon, 29 Aug 1994 01:21:57 -0400 (EDT)
From: John Baxter <jba...@pacs.pha.pa.us>
Subject: thanks for ATS-803 help
To: dsi...@delphi.com
Message-id: <m0qezAO...@pacs.pha.pa.us>
X-Mailer: ELM [version 2.3 PL11]
Content-transfer-encoding: 7BIT

Hi Dave,

You don't know me, but your kindness has helped me a lot.

I have a Sangean ATS-803 shortwave set, and it got zapped while
connected to an attic antenna during a thunderstorm. This was really a
bummer, because I am very pleased with the radio.

A friend of mine was helping me try to figure out what got zapped. I
happened to see your post in rec.radio.shortwave, and passed along the
info about the FET Q115. I suspected a FET getting zapped, but had no
idea where it was on the board. My friend Stew got the part you
specified (MPF102) at Radio Shack and fixed the radio.

It is so great to have it working again. Thanks very much.

73,

John Baxter, N3FPZ (yes, I'm a ham and should be fixing my own gear !!!)
228 Manor Drive
Richboro, PA 18954
jba...@pacs.pha.pa.us
-----------------------------------------------------------
Re: [Need Help]: External Antenna for ATS 803A
From: "Paul J Bricmont" <pa...@Birdsong.Sunnyvale.CA.US>
Date: Wed, 07 Sep 94 20:11:58 PDT (Page 1 of 1)

mal...@newstand.syr.edu (Marie A. Lamb) writes:

>lo...@fourier.oac.uci.edu wrote:
>
>: Hi everyone:
>: I have one problem that I need your help. I had an ATS 803 A and I
>: decide to set up an external antenna for it. I followed the
direction in
>: PASSPORT TO WORLD BAND RADIO. I went to Radio Shack to purchase the
>SW Antenna Kit ( 278-758), but the claw clip ( 270-349) is out of
>stock. I followed the procedure in the kit, it says I have to connect the
>ground terminal of the radio to ground, but I could not find out where is
>the ground terminal on the ATS 803A. So could you guy help me how to
>set this SW Antenna Kit up, other wise I waste $9.99 :-)))
>: Thanks a lot
>: LOng ( Just a novice shortwave listener)
>
>No, you haven't wasted your $9.99. When I was new in 1991, I got a
>Sangean ATS-803A, and my dad very kindly set up the very same kind
> of antenna for me.
>While some people have had trouble with very long external antennas
>with this radio, the antenna in the kit you describe is about 20 meters
>and works fine with this radio. Don't worry about the ground terminal,
>since there is none. If you wish to ground this radio, simply attach a
>ground wire to the metal foot of the radio, and then attach the wire to
>a ground rod. Just make sure to disconnect both your external antenna
>and the ground wire if a storm is coming, since you don't want lightning
>or (more likely) static to damage your radio.
>
>Also, you should be told that this radio has a place to connect an
>external antenna, so you don't need the claw clip. I work for Passport,
>so I know that the claw clip is suggested only for radios that cannot
>have an antenna directly plugged into them. The receptacle for an
>antenna plug is on the back of the radio, and it has a switch next to
>it for one's choice of the external antenna or the radio's own whip
>antenna. Instead of using a claw clip or alligator clip, get a phono
>plug (also called an RCA plug) from Radio Shack, and solder it to the
>lead-in of your antenna instead of using a claw clip. Once you get the
>antenna plugged in, put the antenna switch on the external setting, and
>you'll be fine. However, if you're listening to strong stations, you
>may want to cut back a bit on the RF gain control to avoid overloading,
>which will give you "ghost" signals from stations other than the one you
>want to hear. The wire will help with the weaker stuff, though.
>
>(By the way, if your ATS-803A is like mine, it may have come with this
>very odd antenna connector, which I found very bothersome. Just buying
>an RCA plug and soldering it onto your lead-in is cheap and also much
>easier.)

deleted

>73--
>Marie Lamb
>Editorial Contributor, Passport to World Band Radio
>(and longtime ATS-803A owner)
>mal...@mailbox.syr.edu
----------------------------------------------------
The following is quote from the manual that came with my Realistic
DX-440 (a.k.a Sangean ATS-803A):

To ensure the best reception, always connect a ground wire to the
external antenna jack. Connect the single wire lead-in to the center
terminal of the RCA plug. Connect a suitable earth ground to the outer
terminal of the plug.


I did this about two weeks ago and immediately noticed a reduction in
the amount of noise on Shortwave bands. I would not recommend
connecting the ground wire to the metal support on the back of the
radio because, as far as I can tell, this support is not connected to
the electronics in any way.

To connect the antenna and ground wire to the radio try a right angle
RCA plug from Radio Shack. Connect the center wire of your coax feed
line to the screw on the center terminal of the RCA connecter. Then
connect a length of stranded copper wire to the metal clip which is
part of the outer terminal of the plug. Connect this wire to a ground
rod or cold water pipe. After you connect both the wires to the plug
the plastic cover will probably not fit very well on the connecter. Try
wrapping the cover with tape to help hold it on.

Hope this helps,

Paul Bricmont

San Jose, CA

DX-440 with 35 ft long wire
--------------------------------------------------------
Re: [Need Help]: External Antenna for ATS 803A
From: Marie A. Lamb <mal...@newstand.syr.edu>
Date: 8 Sep 1994 18:46:55 GMT (Page 1 of 1)
Responding to: <NeDBsc...@Birdsong.Sunnyvale.CA.US>

Paul J Bricmont (pa...@Birdsong.Sunnyvale.CA.US) wrote:
: The following is quote from the manual that came with my Realistic
: DX-440 (a.k.a Sangean ATS-803A):
:
: To ensure the best reception, always connect a ground wire to the
: external antenna jack. Connect the single wire lead-in to the center
: terminal of the RCA plug. Connect a suitable earth ground to the outer
: terminal of the plug.
OK. I don't recall this being in the manual for the ATS-803A, even though
it is identical to the DX-440 aside from a few minor details.
: I would not recommend
: connecting the ground wire to the metal support on the back of the
: radio because, as far as I can tell, this support is not connected to
: the electronics in any way.
True. I heard this suggestion for portables without a ground terminal
on a shortwave show some years back. Although it's not connected to the
electronics, the idea is more to help bleed static charge off the body of
the radio.
:
: To connect the antenna and ground wire to the radio try a right angle
: RCA plug from Radio Shack. Connect the center wire of your coax feed
: line to the screw on the center terminal of the RCA connecter. Then
: connect a length of stranded copper wire to the metal clip which is
: part of the outer terminal of the plug. Connect this wire to a ground
: rod or cold water pipe. After you connect both the wires to the plug
: the plastic cover will probably not fit very well on the connecter. Try
: wrapping the cover with tape to help hold it on.
Sounds to me like it would work.

73--
Marie Lamb
mal...@mailbox.syr.edu
-------------------------------------------------------------
Re: realistic DX-390 = Sangean ?
From: JBStrick <jbst...@aol.com>
Date: 8 Sep 1994 02:12:09 -0400 (Page 1 of 1)
Responding to: <CvsAM...@freenet.carleton.ca>

In article <CvsAM...@freenet.carleton.ca>, ap...@FreeNet.Carleton.CA
(John Hamilton) writes:

>Does anyone know the Sangean model of the Realistic DX-390 ?
>There has been some info on JFET replacement due to external ant
>connection problems, and I would like to know if we're talking about the
>same unit

I believe the model number is ATS-818
------------------------------------------------------
Re: realistic DX-390 = Sangean ?
From: Brent Shaw <bls...@lamar.ColoState.EDU>
Date: 8 Sep 1994 13:13:10 -0600 (Page 1 of 1)
Responding to: <CvsAM...@freenet.carleton.ca>


I have a DX-390, and I believe the Sangean model # is ATS-818.
================================================================================

Brent L. Shaw I never represent anyone's
1st Lt, USAF opinions but my own, and
Department of Atmospheric Science mine are always right! :-)
Colorado State University
Fort Collins, CO 80523
sh...@tachu.atmos.colostate.edu
(303) 491-8540
================================================================================
------------------------------------------------------
Re: 803A + Long Wire = POP! Bewarned.
From: Zack Lau (KH6CP) <zl...@arrl.org>
Date: Thu, 8 Sep 1994 17:21:27 GMT (Page 1 of 1)
Responding to: <34ffmj$s...@usenet.INS.CWRU.Edu>

David Toste VE3TOS (da...@cleveland.Freenet.Edu) wrote:

: Well it happened to me TWICE already. Went camping this long weekend and
: I like to cover the forest in wire and then hook up to the radio. Well I
: must of let out about 400 feet of wire if not abit more. I had it up about
: 7 feet above the ground.

: Well it worked out nicely for a few hours until I heard a small pop and then
: all I got was S-5 (on the 803) of STATIC and NOISE, it sort of sounded like
: I had the radio next to a really noisey PC with the case open. At time I could

: bearly hear some of the REALLY STRONG SW stations. Anytime I tuned after
1620khz
: all I could hear is just noise. Anything below 1620 and in the FM band worked
: no probs. Got home opened up the radio and went right to the same JFET I
replaced about 2 years ago and the radio is good as new. If your into
electronics and
: have the same problem look for Q115 (2SK152-3).

Perhaps the most cost effective solution is to ground the antenna through a
high value resistor, perhaps 470 ohms to 10,000 ohms. This will drain the
charge while not noticeably degrading reception. The resistor wattage isn't
important, 1/4 watt is a common value. A 1000 ohm 1/4 watt resistor might
be a good value to ask for.

Basically, static electricity accumulates on the antenna, and it discharges
through the FET. The resistor drains the charge, preventing the voltage
from building up.


--
Zack Lau KH6CP/1 2 way QRP WAS
8 States on 10 GHz
Internet: zl...@arrl.org 10 grids on 2304 MHz
------------------------------------------------------


Almost got my DX-390 fixed, one last question....
From: David Finster <fin...@zeus.fasttax.com>
Date: Wed, 19 Oct 1994 06:08:38 GMT (Page 1 of 1)

I've gotten a lot of great info from this group, and through e-mail. The
general thread has been that some transistor close to the antenna is not well
protected from static, and tends to pop.

Armed with this info, and no schematics (shame, shame) I started testing
transistors and found that Q2 was open between the emitter and the base. I
pulled it out and verified this on the bench. One person sent me mail
explaining that actually TWO transistors in this area would tend to blow, but
if they were both bad, I would have lost my AM broadcast reception as well.
I tested the other transistors in circuit, and they all appeared to be fine.
So, I think I may have the culprit in my sights.

Now I need to find a replacement. If anyone has the Radio Shack part number
for Q2, or a cross for this, I would be most grateful. I find two set of
numbers on this component - "3330" and "2 SH". It isn't listed in my SK cross
reference.
------------------------------------------------------------
I opened up my radio (it's out of warranty, anyway) to see what
kind of damage had been done. Luckily, (and with the help of my
brother who, unlike me, is quite knowledgeable about electronics) I
found that the only thing that had been fried was a Field-Effect
Transistor labaled Q1 on the circuit board (this is in a DX-390/Sangean
818 mind you, other models could be different). I replaced this with ---------------------------------------------------------------
an MPF102 FET that I bought at Radio Shack for $.99 (Cat. No. 276-2062)
and my radio has been working fine ever since.
---------------------------------------------------------------
Subject: Re: 803A + Long Wire = POP! Bewarned.
From: zl...@arrl.org (Zack Lau (KH6CP))
Organization: American Radio Relay League
Date: Thu, 8 Sep 1994 17:21:27 GMT

Perhaps the most cost effective solution is to ground the antenna through a
high value resistor, perhaps 470 ohms to 10,000 ohms. This will drain the
charge while not noticeably degrading reception. The resistor wattage isn't
important, 1/4 watt is a common value. A 1000 ohm 1/4 watt resistor might
be a good value to ask for.

Basically, static electricity accumulates on the antenna, and it discharges
through the FET. The resistor drains the charge, preventing the voltage
from building up.

------------------------------------------------------------------------

Oops! This is how I destroyed MW reception on my Sangean 818cs, owing I
think to static discharge, a phenomenon more likely to occur when running
the antenna along the carpet, they say. Also, the danger is higher in
winter, they say. I note you said your antenna is grounded (mine was not),
and grounding does help, they say. Is there any reason to believe that
Grundig radios are less likely than Sangean radios to suffer from static
discharge?
---------------------------------------------------------------

Subject: Re: Q: Sangean ATS-803a static-sensitive transistor(s)
From: dsi...@delphi.com
Date: Fri, 19 Aug 94 19:49:08 -0500
Organization: Delphi (in...@delphi.com email, 800-695-4005 voice)

>The posts mentioned about some transistors in the Sangean ATS-803a that
>are quite sensitive to static. If I remember correctly, it/they were
>connected fairly close to the whip antenna's input on the circuit-board.

You bet they are sensitive to static electricity entering from the antenna
circuit. One good static electric zap and the sensitivity of the unit went
down drastically. Sangean officially does not admit the problem, but it's
there. Especially in the winter. That's when there were several posts to
this board about the problem.

I don't remember if the exact component that failed was noted in any
of the posts, but it is in the FET. I'll check to see if I saved any of those
posts. If so, I'll send them to you.

---------------------------------------------------------------
--

[Chris Brewster]

David Silver reposted some messages concerning static zapping of Sangean
808/818 and Radio Shack DX-390/440. FYI I have the closest thing to an
FAQ for these sets (until the real thing comes along), which I've sent
to many on this list. It's an edit bunch of postings on lots of
subjects, including some that were in David's post. Write me for a
copy. (Last revision was 10/28.)
--

Chris Brewster Cray Research, Inc.

[Dan Sterio]

Hi Chris, I would appreciate receiving your "FAQ" on the Sangean 808 radio. I
love this little job which performs so well. If only it had SSB.

Thanks for your kind offer.

Dan_S...@magic.ca

[Franklin Q. SWL]

On Fri, 29 May 2020 15:53:26 GMT
"Mr. Cold Shower" <em...@address.here> wrote:

> kerry.ma...@gmail.com wrote in
> news:20a79a2b-51e9-42eb...@googlegroups.com:
>
> > Greetings from 2020!
> >
> > I'm in the process of moving and was going through stuff in the
> > basement to see what I wanted to keep or not. My DX-440 hasn't
> > worked in many years and was replaced ages ago with a 398. I
> > brought it upstairs and was messing around with it... power light
> > always on with 9V 300mA adapter, no audio from speaker or headphone
> > jack, AM displays signal bars, FM stations don't. I read through a
> > few of the posts from the 90's and came across one discussing
> > flipping the INT/EXT antenna switch in the rear of the radio. I
> > pulled the plug, flipped the switch a few times and plugged the 440
> > back in. The set started working! The power light is still on even
> > when the set is off, but other than that the radio seems to work
> > for now.
>
>
> WOW! All you had to say is that it's fixed, you didn't need
> to write a God Damn book about it.
>

Please ignore the above comment by Mr. Cold Shower. He's a faggot.

Thing is, so are you. Go chow down on a bowl of cold dicks, homo.

EYE NUB J00,

FQS

[Snidely Whiplash]

In article <rbhgdm$1ggq$1...@gioia.aioe.org>, "Franklin Q.SWL"

<frankl...@gmail.com> wrote:

>
>Please ignore the above comment by Mr. Cold Shower. He's a faggot.
>
>Thing is, so are you. Go chow down on a bowl of cold dicks, homo.
>

Do you prefer billy goats or nanny goats?

SW

[fred k. engels®]

That's not really a big secret, but I still puked my guts out over Keven
ALbert Strum THE convicted pedophile who continues posting fake UseNet user
names and addresses to cover his goat/Sheep Pedophilia ass!!!!!!!!!!!!!!
https://www.youtube.com/watch?v=ohegYOB9-TM
"THE convicted pedophile Keven ALbert Strum is a
batshit
CHICKENSHIT
GOATFUCKER
GOATSHIT
COCKSUCKER
CYBER STALKER SOCKPUPPET TROLL
In his native habitat, near a computer.
convicted pedophile Keven ALbert Strum deep into
goat/sheep Pedophilia!!!!!!!!!!!!!!!!!!!
https://upload.wikimedia.org/wikipedia/commons/1/1d/Internet_Troll_-_Unworded.jpg

"Snidely Whiplash" wrote in message
news:to.Fran...@goat.fuckers.gioia.aioe.barnyard...