|
I was trying to re-seat the LSB bulb to the chassis because the bulb was intermittent. In doing so I think the positive side of the bulb housing touched ground some how because when I turned the TR-4CW back on and the amp meter light, frequency light, LSB, and USB lights were not lit. Then the filament fuse blew! I replaced the wire with #26 AWG and pulled both LSB and USB out and re-seated them and made sure nothing was shorting to ground. I quickly turned on the rig but still those lights would not light. The only light that I get is the round red light on the right side of the frequency read out. I connected my power supply to my other TR-4CW and that rig works OK so the power supply is still good. Not sure what is going on?
?
Mark
|
Did you check the filament fuse?
73
Mike W5RKL
On 5/26/25 4:33 PM, Mark N2DMI via
groups.io wrote:
toggle quoted message
Show quoted text
I was trying to re-seat the LSB bulb to the chassis because
the bulb was intermittent. In doing so I think the positive side
of the bulb housing touched ground some how because when I
turned the TR-4CW back on and the amp meter light, frequency
light, LSB, and USB lights were not lit. Then the filament fuse
blew! I replaced the wire with #26 AWG and pulled both LSB and
USB out and re-seated them and made sure nothing was shorting to
ground. I quickly turned on the rig but still those lights would
not light. The only light that I get is the round red light on
the right side of the frequency read out. I connected my power
supply to my other TR-4CW and that rig works OK so the power
supply is still good. Not sure what is going on?
?
Mark
|
Filament is still in tact. Probably because I didn't give it enough time to blow again.
Mark
|
Out of curiosity I left the rig on for a little longer (for like 5 seconds) and that filament fuse blew again! I don't know how to figure out how it keeps blowing?
Mark
|
I suggest using a DBT (Dim Bulb Tester) while checking the rig. It will save fuses, transformers, diodes, etc. If you aren't familiar with?it just use your favorite search engine and learn about it, how to use it, and how to build an inexpensive version of this very handy test device.
GL!?
Ken
WA2LBI
???
Out of curiosity I left the rig on for a little longer (for like 5 seconds) and that filament fuse blew again! I don't know how to figure out how it keeps blowing?
Mark
|
Hey Ken I will do a search on that.
Tnx!
Mark
?
|
The filament fuse runs the ...?? FILAMENTS.
?
I would unplug all the tubes and bulbs and check the wiring with an ohmmeter.
If it looks good (no shorts to ground), put them back in checking after each one or batch.
?
73,
Gary
WB6OGD
|
Ken I looked for a dim bulb tester on youtube and I don't see how that would help me?
It looks like you put the AC line cord into one end and a light bulb tells you if you have a short or not.
I believe the filament fuse circuit is on the 12.6VAC circuit.
I need something that will tell me what is causing the fuse to blow. Or guidance on how to troubleshoot.
The rig was working beautifully except for one of the USB or LSB not making good contact. When I moved the bulb?
around to make better contact is when the fuse first blew. I don't see either of the bulb sockets touching
anything so I can't figure out why the filament keeps popping?
Mark
|
Yeah I thought the same thing FILAMENT fuse. But I wasn't sure on how to approach finding the culprit.
But yeah, pull all the tubes and bulbs out and ohm out them all out! Or it could be the stupid LSB or USB socket that is somehow shorting?
Gotta be something simple?
Mark
|
Not familiar with the rig but is the original fuse a slow blow or a fast blow and if slow are you using a slow blow ?
Ralph ku4pt
On Tuesday, May 27, 2025 at 08:15:00 PM EDT, Mark N2DMI via groups.io <markkiziuk1@...> wrote:
Yeah I thought the same thing FILAMENT fuse. But I wasn't sure on how to approach finding the culprit.
But yeah, pull all the tubes and bulbs out and ohm out them all out! Or it could be the stupid LSB or USB socket that is somehow shorting?
Gotta be something simple?
Mark
|
It should be obvious that where you messed with the bulb is the cause of the current problem.? Look for the obvious first.
?
If the fuse didn't blow quickly, the short you caused may have removed insulation from that wire (supplying Voltage to those items you stated were not lit.? Again, look for the obvious.
?
73, Bill, K8TE
|
For those who don't know how the TR4/TR4C/TR4CW filament circuit is
fused,
I have all 4 Drake TR3, TR4, TR4C, and TR4CW HF series transceiver
manuals
on my website for downloading. Click the following link then scroll
down to the
Drake manual listing and click the appropriate TR3/4 series manual.
The Drake TR3 has a physical "pigtail" fuse in series between pin 4
of the power
connector and the lamp and filament wiring.
Drake changed the "pigtail" fuse in the TR4, TR4C, and TR4CW to a 1
& 1/2" length
of #26 tinned wire in series with pin 4 of the power connector to
the lamp and filament
wiring. This is stated in the TR4, TR4C, and TR4CW schematics.
73
Mike W5RKL
On 5/27/25 7:09 PM, Mark N2DMI via
groups.io wrote:
toggle quoted message
Show quoted text
Ken I looked for a dim bulb tester on youtube and I don't see
how that would help me?
It looks like you put the AC line cord into one end and a
light bulb tells you if you have a short or not.
I believe the filament fuse circuit is on the 12.6VAC
circuit.
I need something that will tell me what is causing the fuse
to blow. Or guidance on how to troubleshoot.
The rig was working beautifully except for one of the USB or
LSB not making good contact. When I moved the bulb?
around to make better contact is when the fuse first blew. I
don't see either of the bulb sockets touching
anything so I can't figure out why the filament keeps
popping?
Mark
|
I did some more reading about the dim bulb tester and I agree that it is a good method to prevent my filament fuse wire from opening and instead make a light bulb glow! Now that I have a better understanding on what it actually does I will look into building one.
Thank you very much for your suggestion!
Mark
|
Glad you understand it now. Sorry I couldn't be more help last night but I was with my grandkids and on my cell phone. I only had a couple minutes to send that DBT suggestion.?
On Wed, May 28, 2025 at 6:35?AM Mark N2DMI via <markkiziuk1= [email protected]> wrote: I did some more reading about the dim bulb tester and I agree that it is a good method to prevent my filament fuse wire from opening and instead make a light bulb glow! Now that I have a better understanding on what it actually does I will look into building one.
Thank you very much for your suggestion!
Mark
|
Mark,
I disagree using the dim bulb test.
You clearly said you tested your power supply with another TR4C and
it worked fine.
That test was enough to eliminate the power supply as the source of?
your problem.
The RED indicator on the upper right corner of the front panel is
the "VFO" indicator
and it is not connected to the filament string like the meter, dial,
and side band bulbs
are. That indicator is a NE2-E neon bulb that's connected across
Q3's Emitter and Collector
indicating the TR4CW internal VFO is in use (see the TR4CW schematic
and manual).
Your problem started when you were messing with the side band bulb
sockets. That's
where you need to start troubleshooting.
Using the dim bulb test in series with the power supply primary is
not going to tell you
where your problem is within your TR4CW.
73
Mike W5RKL
On 5/28/25 5:35 AM, Mark N2DMI via
groups.io wrote:
toggle quoted message
Show quoted text
I did some more reading about the dim bulb tester and I agree
that it is a good method to prevent my filament fuse wire from
opening and instead make a light bulb glow! Now that I have a
better understanding on what it actually does I will look into
building one.
Thank you very much for your suggestion!
Mark
|
It is likely that the centre contacting of the bulb connector is touching something that’s grounded. It’s crowded in that area!
Steve Wedge, W1ES
Time flies like an arrow. Fruit flies like a banana.
On Wed, May 28, 2025 at 09:04, Mike W5RKL via groups.io < mikew5rkl@...> wrote: Mark,
I disagree using the dim bulb test.
You clearly said you tested your power supply with another TR4C and it worked fine.
That test was enough to eliminate the power supply as the source of? your problem.
The RED indicator on the upper right corner of the front panel is the "VFO" indicator
and it is not connected to the filament string like the meter, dial, and side band bulbs
are. That indicator is a NE2-E neon bulb that's connected across Q3's Emitter and Collector
indicating the TR4CW internal VFO is in use (see the TR4CW schematic and manual).
Your problem started when you were messing with the side band bulb sockets. That's
where you need to start troubleshooting.
Using the dim bulb test in series with the power supply primary is not going to tell you
where your problem is within your TR4CW.
73
Mike W5RKL
On 5/28/25 5:35 AM, Mark N2DMI via groups.io wrote:
I did some more reading about the dim bulb tester and I agree that it is a good method to prevent my filament fuse wire from opening and instead make a light bulb glow! Now that I have a better understanding on what it actually does I will look into building one.
Thank you very much for your suggestion!
Mark
|
Steve,
It quite possible one of the side band sockets has shorted
to melt the filament fusible link.
Mark needs to start at the side band sockets first. That where
the problem started.
If the power supply fuse blew when the TR4CW was powered up
then I would agree, a dim bulb test is warranted. However, since
Mark clearly stated he tested the power supply with another TR4
radio and it worked fine, using a dim bulb test is not warranted
and will not point to the problem in his TR4CW radio.
73
Mike W5RKL
On 5/28/25 8:10 AM, Steve Wedge, W1ES/4
via groups.io wrote:
toggle quoted message
Show quoted text
It is likely that the centre contacting of the
bulb connector is touching something that’s grounded. It’s
crowded in that area!
Steve Wedge, W1ES
Time flies like an arrow. Fruit flies like a banana.
On Wed, May 28, 2025 at 09:04, Mike W5RKL via groups.io <mikew5rkl@...>
wrote:
Mark,
I disagree using the dim bulb test.
You clearly said you tested your power supply with another TR4C
and it worked fine.
That test was enough to eliminate the power supply as the source
of? your problem.
The RED indicator on the upper right corner of the front panel
is the "VFO" indicator
and it is not connected to the filament string like the meter,
dial, and side band bulbs
are. That indicator is a NE2-E neon bulb that's connected across
Q3's Emitter and Collector
indicating the TR4CW internal VFO is in use (see the TR4CW
schematic and manual).
Your problem started when you were messing with the side band
bulb sockets. That's
where you need to start troubleshooting.
Using the dim bulb test in series with the power supply primary
is not going to tell you
where your problem is within your TR4CW.
73
Mike W5RKL
On 5/28/25 5:35 AM, Mark N2DMI via
groups.io wrote:
I did some more reading about the dim bulb tester and I
agree that it is a good method to prevent my filament fuse
wire from opening and instead make a light bulb glow! Now
that I have a better understanding on what it actually does
I will look into building one.
Thank you very much for your suggestion!
Mark
|
Don't get me wrong, Mike.? I agree that a dim bulb tester is not the appropriate test equipment for this problem.? I would first do what you (I believe -- it's a long thread!) and others have suggested and run the TR-4 with no tubes in and check for shorts or high-resistance shorts in the filament circuit.? Current draw of a good AC-4 at 120 VAC input is around 400-500 mA.? A Variac with a 2A fuse and 2A capacity should be adequate to check a tubeless TR-4 running off an AC-4.? If you see significantly more current than 500 mA, you have a problem in the TR-4 (since the supply has been confirmed as good). A nicked wire touching a grounded part sounds like the issue to me because it seems to immediately blow the fuse, then later takes a couple of minutes to blow the fuse.? Further testing can be done by removing all the lamps AND tubes and testing the resistance across both legs of the 12 VAC power connection (power supply removed).
If you have a hipot tester you could try that.? The spark will be really obvious if it's intermittently touching something.
Steve Wedge, W1ES
Time flies like an arrow.? Fruit flies like a banana.
Sent with secure email.
On Wednesday, May 28th, 2025 at 9:22 AM, Mike W5RKL via groups.io <mikew5rkl@...> wrote:
Steve,
It quite possible one of the side band sockets has shorted
to melt the filament fusible link.
Mark needs to start at the side band sockets first. That where
the problem started.
If the power supply fuse blew when the TR4CW was powered up
then I would agree, a dim bulb test is warranted. However, since
Mark clearly stated he tested the power supply with another TR4
radio and it worked fine, using a dim bulb test is not warranted
and will not point to the problem in his TR4CW radio.
73
Mike W5RKL
On 5/28/25 8:10 AM, Steve Wedge, W1ES/4
via groups.io wrote:
It is likely that the centre contacting of the
bulb connector is touching something that’s grounded. It’s
crowded in that area!
Steve Wedge, W1ES
Time flies like an arrow. Fruit flies like a banana.
On Wed, May 28, 2025 at 09:04, Mike W5RKL via groups.io <mikew5rkl@...>
wrote:
Mark,
I disagree using the dim bulb test.
You clearly said you tested your power supply with another TR4C
and it worked fine.
That test was enough to eliminate the power supply as the source
of your problem.
The RED indicator on the upper right corner of the front panel
is the "VFO" indicator
and it is not connected to the filament string like the meter,
dial, and side band bulbs
are. That indicator is a NE2-E neon bulb that's connected across
Q3's Emitter and Collector
indicating the TR4CW internal VFO is in use (see the TR4CW
schematic and manual).
Your problem started when you were messing with the side band
bulb sockets. That's
where you need to start troubleshooting.
Using the dim bulb test in series with the power supply primary
is not going to tell you
where your problem is within your TR4CW.
73
Mike W5RKL
On 5/28/25 5:35 AM, Mark N2DMI via
groups.io wrote:
I did some more reading about the dim bulb tester and I
agree that it is a good method to prevent my filament fuse
wire from opening and instead make a light bulb glow! Now
that I have a better understanding on what it actually does
I will look into building one.
Thank you very much for your suggestion!
Mark
|
*centre contact
I hate autocorrect sometimes...
Steve Wedge, W1ES
Time flies like an arrow.? Fruit flies like a banana.
Sent with secure email.
On Wednesday, May 28th, 2025 at 9:22 AM, Mike W5RKL via groups.io <mikew5rkl@...> wrote:
Steve,
It quite possible one of the side band sockets has shorted
to melt the filament fusible link.
Mark needs to start at the side band sockets first. That where
the problem started.
If the power supply fuse blew when the TR4CW was powered up
then I would agree, a dim bulb test is warranted. However, since
Mark clearly stated he tested the power supply with another TR4
radio and it worked fine, using a dim bulb test is not warranted
and will not point to the problem in his TR4CW radio.
73
Mike W5RKL
On 5/28/25 8:10 AM, Steve Wedge, W1ES/4
via groups.io wrote:
It is likely that the centre contacting of the
bulb connector is touching something that’s grounded. It’s
crowded in that area!
Steve Wedge, W1ES
Time flies like an arrow. Fruit flies like a banana.
On Wed, May 28, 2025 at 09:04, Mike W5RKL via groups.io <mikew5rkl@...>
wrote:
Mark,
I disagree using the dim bulb test.
You clearly said you tested your power supply with another TR4C
and it worked fine.
That test was enough to eliminate the power supply as the source
of your problem.
The RED indicator on the upper right corner of the front panel
is the "VFO" indicator
and it is not connected to the filament string like the meter,
dial, and side band bulbs
are. That indicator is a NE2-E neon bulb that's connected across
Q3's Emitter and Collector
indicating the TR4CW internal VFO is in use (see the TR4CW
schematic and manual).
Your problem started when you were messing with the side band
bulb sockets. That's
where you need to start troubleshooting.
Using the dim bulb test in series with the power supply primary
is not going to tell you
where your problem is within your TR4CW.
73
Mike W5RKL
On 5/28/25 5:35 AM, Mark N2DMI via
groups.io wrote:
I did some more reading about the dim bulb tester and I
agree that it is a good method to prevent my filament fuse
wire from opening and instead make a light bulb glow! Now
that I have a better understanding on what it actually does
I will look into building one.
Thank you very much for your suggestion!
Mark
|
Steve,
He needs to study the TR4CW schematic filament and lamp wiring so he
understands
how it's wired. He also need to pay attention to the side band
switch setting and
the band switch setting as both affect which side band lamp is lit.
He should set the
rear lamp "B" or "D" switch setting to "B", this bypasses the lamp
series resistor to ground
in "D" setting to dim the meter and dial lamps. All of this is found
on the schematic.
73
Mike W5RKL
On 5/28/25 1:45 PM, Steve Wedge, W1ES/4
via groups.io wrote:
toggle quoted message
Show quoted text
Don't
get me wrong, Mike.? I agree that a dim bulb tester is not the
appropriate test equipment for this problem.? I would first do
what you (I believe -- it's a long thread!) and others have
suggested and run the TR-4 with no tubes in and check for shorts
or high-resistance shorts in the filament circuit.? Current draw
of a good AC-4 at 120 VAC input is around 400-500 mA.? A Variac
with a 2A fuse and 2A capacity should be adequate to check a
tubeless TR-4 running off an AC-4.? If you see significantly
more current than 500 mA, you have a problem in the TR-4 (since
the supply has been confirmed as good). A nicked wire touching a
grounded part sounds like the issue to me because it seems to
immediately blow the fuse, then later takes a couple of minutes
to blow the fuse.? Further testing can be done by removing all
the lamps AND tubes and testing the resistance across both legs
of the 12 VAC power connection (power supply removed).
If
you have a hipot tester you could try that.? The spark will be
really obvious if it's intermittently touching something.
Steve Wedge, W1ES
Time flies like an arrow.? Fruit flies like a banana.
Sent with secure email.
On Wednesday, May 28th, 2025 at
9:22 AM, Mike W5RKL via groups.io
<mikew5rkl@...> wrote:
Steve,
It quite possible one of the side band sockets has shorted
to melt the filament fusible link.
Mark needs to start at the side band sockets first. That where
the problem started.
If the power supply fuse blew when the TR4CW was powered up
then I would agree, a dim bulb test is warranted. However,
since
Mark clearly stated he tested the power supply with another
TR4
radio and it worked fine, using a dim bulb test is not
warranted
and will not point to the problem in his TR4CW radio.
73
Mike W5RKL
On 5/28/25 8:10 AM, Steve Wedge,
W1ES/4 via groups.io wrote:
It is likely that the centre contacting of
the bulb connector is touching something that’s grounded.
It’s crowded in that area!
Steve Wedge, W1ES
Time flies like an arrow. Fruit flies like a
banana.
On Wed, May 28, 2025 at 09:04, Mike W5RKL via groups.io <mikew5rkl@...>
wrote:
Mark,
I disagree using the dim bulb test.
You clearly said you tested your power supply with another
TR4C and it worked fine.
That test was enough to eliminate the power supply as the
source of your problem.
The RED indicator on the upper right corner of the front
panel is the "VFO" indicator
and it is not connected to the filament string like the
meter, dial, and side band bulbs
are. That indicator is a NE2-E neon bulb that's connected
across Q3's Emitter and Collector
indicating the TR4CW internal VFO is in use (see the TR4CW
schematic and manual).
Your problem started when you were messing with the side
band bulb sockets. That's
where you need to start troubleshooting.
Using the dim bulb test in series with the power supply
primary is not going to tell you
where your problem is within your TR4CW.
73
Mike W5RKL
On 5/28/25 5:35 AM, Mark
N2DMI via groups.io wrote:
I did some more reading about the dim bulb tester
and I agree that it is a good method to prevent my
filament fuse wire from opening and instead make a
light bulb glow! Now that I have a better
understanding on what it actually does I will look
into building one.
Thank you very much for your suggestion!
Mark
|
Mark N2DMI
Gary WB6OGD
Bill K8TE