On Fri, Mar 14, 2025 at 12:38 PM, Jordan wrote:
Is there anything connected to the ACC2 cable, or is it just the plug...?
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Jordan VE6ZT
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Jordan, it was a DIN cable with plugs at both ends. I did check that there were no shorts between the pins.
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The cable appears to be of good quality but the plug required a lot of effort to mate with the ACC2 socket. I tried it with another socket and it was much easier.
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When I bought the radio it had the original Kenwood silver sticker over the ACC2 socket so I'm guessing it has never been used before.
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--
Mike G8GYW
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Is there anything connected to the ACC2 cable, or
is it just the plug...?
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Jordan VE6ZT
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----- Original Message -----
Sent: Friday, March 14, 2025 6:27
AM
Subject: Re: [Kenwood-Amateur-Radio]
TS-870S no TX
After allowing radio to warm up (let sit for 15 minutes turned on), take a
#2 type pencil (with a new eraser), and press down on every component on the
board (or boards), while the radio is in the mode that is malfunctioning.
Watch your meter or indicators closely, that show intermittent problem. This
method is great for finding breaks in components and solder traces. Take your
time, not getting in a hurry.
Gary
On 3/14/2025 7:17 AM, Mike via groups.io
wrote:
I managed to get the fault to return by inserting a plug into the ACC2
socket, which was a tight fit and required a lot of effort. When I removed
the DIN cable normal operation returned.
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Something on that board is obviously intermittent.
?
--
Mike G8GYW
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After allowing radio to warm up (let sit for 15 minutes turned
on), take a #2 type pencil (with a new eraser), and press down on
every component on the board (or boards), while the radio is in
the mode that is malfunctioning. Watch your meter or indicators
closely, that show intermittent problem. This method is great for
finding breaks in components and solder traces. Take your time,
not getting in a hurry.
Gary
On 3/14/2025 7:17 AM, Mike via
groups.io wrote:
toggle quoted message
Show quoted text
I managed to get the fault to return by inserting a plug into
the ACC2 socket, which was a tight fit and required a lot of
effort. When I removed the DIN cable normal operation returned.
?
Something on that board is obviously intermittent.
?
--
Mike G8GYW
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I managed to get the fault to return by inserting a plug into the ACC2 socket, which was a tight fit and required a lot of effort. When I removed the DIN cable normal operation returned.
?
Something on that board is obviously intermittent.
?
--
Mike G8GYW
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toggle quoted message
Show quoted text
Sam
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I checked that the relay and PCB connectors were secure but the only screws I disturbed were those on the top shield. I left the radio on for several hours and tested it in TX periodically and it was OK.
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It certainly does look good on the inside ?.
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Mike G8GYW
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Sam
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I checked that the relay and PCB connectors were secure but the only screws I disturbed were those on the top shield. I left the radio on for several hours and tested it in TX periodically and it was OK.
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It certainly does look good on the inside ?.
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Mike G8GYW
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Mike,
Did you torque any screws on the board containing the Rx/Tx relay, or any metal shield covering portions of the circuitry?
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Sometimes these kinds of issues are caused by hairline fractures on a ckt board, and mechanically or thermally connections become intermittent. Mechanical Flakey.
Sometimes these kinds of issues are caused by cold solder joints, also impacted my mechanical or thermal stress. (Thermal Flakey).
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Now, it could be the Rx/Tx has pitted contacts such that the Common (c) center connection (Armature) does not shuttle between Normally Open (nc), and Normally Closed (nc) positions.
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Did you at least verify the Rx/Tx relay was firmly seated?
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Glad you got it working. Maybe it just wanted you to admire it from the inside.
Sam
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Ok Mike...No problem...have fun with the rig and
feel free to ask questions should you have any....73...Jordan VE6ZT
----- Original Message -----
Sent: Thursday, March 13, 2025 9:21
AM
Subject: Re: [Kenwood-Amateur-Radio]
TS-870S no TX
Thanks Jordan. All the board screws were tight and I couldn't see or feel
any loose connectors but if/when it fails again I will follow your
advice.
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This radio is immaculate and shows no signs of having been opened before.
I think it may have been a demo model the dealer forgot about years ago and I
may actually be its first owner.
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Mike G8GYW
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Thanks Jordan. All the board screws were tight and I couldn't see or feel any loose connectors but if/when it fails again I will follow your advice.
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This radio is immaculate and shows no signs of having been opened before. I think it may have been a demo model the dealer forgot about years ago and I may actually be its first owner.
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Mike G8GYW
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P.S.....
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Should read "...control line
connectors."
----- Original Message -----
Sent: Thursday, March 13, 2025 7:55
AM
Subject: Re: [Kenwood-Amateur-Radio]
TS-870S no TX
All I can suggest is that you tighten all the
screws fixing the board to the chassis, then pull and then reseat the dc and
control like connectors...It could simply be an oxidized interconnection
contact. If it's a cold solder joint, that might require a little more work to
determine.?Intermittents can be a PITA...I use a Philips head screw
driver. Use one that fits snugly with no play...
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73...Jordan VE6ZT
----- Original Message -----
Sent: Thursday, March 13, 2025 7:25
AM
Subject: Re: [Kenwood-Amateur-Radio]
TS-870S no TX
Well this is frustrating ...
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I removed the screen cover from the Final unit to access the TX/RX
relay and now it's working again ?.
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I couldn't see anything loose so I'm in the dark as to what's causing
it.
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Maybe I just put it back together and see if it fails again.
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Incidentally what is the correct type of screwdriver for this radio?
Posidriv, Philips or something else? I don't want to damage the pristine
screws.
?
--
Mike G8GYW
|
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All I can suggest is that you tighten all the
screws fixing the board to the chassis, then pull and then reseat the dc and
control like connectors...It could simply be an oxidized interconnection
contact. If it's a cold solder joint, that might require a little more work to
determine.?Intermittents can be a PITA...I use a Philips head screw driver.
Use one that fits snugly with no play...
?
73...Jordan VE6ZT
----- Original Message -----
Sent: Thursday, March 13, 2025 7:25
AM
Subject: Re: [Kenwood-Amateur-Radio]
TS-870S no TX
Well this is frustrating ...
?
I removed the screen cover from the Final unit to access the TX/RX relay
and now it's working again ?.
?
I couldn't see anything loose so I'm in the dark as to what's causing
it.
?
Maybe I just put it back together and see if it fails again.
?
Incidentally what is the correct type of screwdriver for this radio?
Posidriv, Philips or something else? I don't want to damage the pristine
screws.
?
--
Mike G8GYW
|
Well this is frustrating ...
?
I removed the screen cover from the Final unit to access the TX/RX relay and now it's working again ?.
?
I couldn't see anything loose so I'm in the dark as to what's causing it.
?
Maybe I just put it back together and see if it fails again.
?
Incidentally what is the correct type of screwdriver for this radio? Posidriv, Philips or something else? I don't want to damage the pristine screws.
?
--
Mike G8GYW
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Sorry - I now see you are asking about the 870s, not 570S.?
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Mike,
([A=B] + POWER ON) should be a full reset, so you should be good there.
In your image what am I looking at (discolorization on the RF shielding); is that a burn mark?
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Random thoughts // questions:
1). Do you have an undervoltage situation (unit needs a bit more current to xmit, than rcv).? Maybe your PS is in need of a rest...
I'd carry the radio out to the car and see if I could get it into xmit into some dummy load at low power.
2). Or maybe your antenna feedline has a short.
3). Have you the right antenna selected?
4). I'd try removing and replacing the battery, then doing another FULL reset. I had read some posts in other places about this fixing similar problems.
5). Make sure all connectors (particularly the tiny coax ones are connected to their boards firmly).
6). Rx/Tx relay?
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This is a pretty interesting and informative video on troubleshooting the TS-570:
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Sam.
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On Thu, Mar 13, 2025 at 12:44 PM, Jordan wrote:
What is that scorched discolored area...?? Looks like something arced or burned...
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Jordan...
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That's a reflection in the screening can ?.
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--
Mike G8GYW
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Thanks Jordan, yes that was helpful.
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I found a good quality set of schematics on mods.dk and have identified the TX/RX relay which is switched by a TXB line.
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Time to start probing ...
--
Mike G8GYW
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What is that scorched discolored area...??
Looks like something arced or burned...
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Jordan...
----- Original Message -----
Sent: Thursday, March 13, 2025 6:15
AM
Subject: Re: [Kenwood-Amateur-Radio]
TS-870S no TX
Manuals sometimes show a partial reset and a full or complete
reset.
Bob W4JFA
On Wed, Mar 12, 2025 at 04:39 PM, Bob wrote:
If you haven't already, try a factory full reset. I'm not a
professional tech but I've fixed 2 radios in the past year and a half
doing a full reset.
Bob W4JFA
Thanks Bob. I tried the Full Reset described in the instruction manual
([A=B] + POWER ON) to no effect.
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Is that the same as the factory reset?
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The Mic socket and ACC2 are wired to the TX-RX Unit X57-4620-00.
Unfortunately the schematic in my downloaded copy of the service manual is
very fuzzy. Is there a better one somewhere?
?
--
Mike G8GYW
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Manuals sometimes show a partial reset and a full or complete reset. Bob W4JFA
On Wed, Mar 12, 2025 at 04:39 PM, Bob wrote:
If you haven't already, try a factory full reset. I'm not a professional tech but I've fixed 2 radios in the past year and a half doing a full reset.
Bob W4JFA
Thanks Bob. I tried the Full Reset described in the instruction manual ([A=B] + POWER ON) to no effect.
?
Is that the same as the factory reset?
?
The Mic socket and ACC2 are wired to the TX-RX Unit X57-4620-00. Unfortunately the schematic in my downloaded copy of the service manual is very fuzzy. Is there a better one somewhere?
?
--
Mike G8GYW
|
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Get the service manual and read the portion that
deals with the RX/TX change-over. I'm pretty sure you'll find a description as
to how the change-over is implemented. Normally there are voltages such as RXB
and TXB or similar, which are switched on the transition.
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Clearly that process is not working since RX
doesn't turn off when you try to transmit...That's likely your first
clue...
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I hope this helps....73...Jordan VE6ZT
----- Original Message -----
Sent: Wednesday, March 12, 2025 9:51
AM
Subject: Re: [Kenwood-Amateur-Radio]
TS-870S no TX
On Wed, Mar 12, 2025 at 03:12 PM, David Frechette wrote:
You should be able to find a schematic and trace the circuit, at
least in theory!
I have the schematic, just hoping for some pointers. Nothing happens when
I operate PTT, it stays in RX.
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Mike G8GYW
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On Wed, Mar 12, 2025 at 04:39 PM, Bob wrote:
If you haven't already, try a factory full reset. I'm not a professional tech but I've fixed 2 radios in the past year and a half doing a full reset.
Bob W4JFA
Thanks Bob. I tried the Full Reset described in the instruction manual ([A=B] + POWER ON) to no effect.
?
Is that the same as the factory reset?
?
The Mic socket and ACC2 are wired to the TX-RX Unit X57-4620-00. Unfortunately the schematic in my downloaded copy of the service manual is very fuzzy. Is there a better one somewhere?
?
--
Mike G8GYW
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Bob