Re: L7 makes alot of smoke
Don't lose hope. They were loud on 10m a little while ago but working EU. I scored Chad for ATNO and two bands yesterday with someone else's L7. This one suffered a flashover in a Chinese 3-500z a couple of weeks ago. That is an event that I don't want to experience again... You would probably know if the safety resistor in the PS went. They go off like a M80 and leave shrapnel inside the PS. On Fri, 19 Apr 2024 08:12:38 -0700 "K6OXN Bob via groups.io" <bobk6oxn@...> wrote: So much for trying to contact Easter Island as they were on strong last night at 221262.00. I could hear them very well about a 58 here and would have liked to have that contact. -- 73 -Jim NU0C
|
A golden screwdriver even less so. 73 -Jim NU0C On Fri, 19 Apr 2024 10:19:48 -0400 "Mike Bryce via groups.io" <prosolar@...> wrote: Must have been the same old tech that told me, ¡°A screwdriver will never fix a broken radio.¡±
Mike, WB8VGE
SunLight Energy Systems
The Heathkit Shop
|
Yes his xyl still sells the files but not CD¡¯s. The info in his web site is good. Just send an email
73, Jim VE1RB
Hi,
I wanted to purchase the Drake 2-B info from K4OAH, but I found that he's an SK. RIP,? Garey.
Did anyone continue on supplying Garey's Drake rig information?
73,
Larry? K3PEG?
|
Re: Another TR7 Journey begins
I just ordered 10 turn pots for the power supply board from Mouser.? Seems that if I just look at the damn things they change so a bit over $35 shipped will be well worth it IMO.
73, Bill NZ0T
|
Hi,
I wanted to purchase the Drake 2-B info from K4OAH, but I found that he's an SK. RIP,? Garey.
Did anyone continue on supplying Garey's Drake rig information?
73,
Larry? K3PEG?
|
Re: L7 makes alot of smoke
Both of the Parasitic Choke resistors were kind of burnt. That may be because of parasitics as C39 and 40 were the blown capacitors. I don't think the breakers blew as it seems when the caps went I lost HV. Haven't checked the PS to see if the .82 resistor blew, been cleaning up the area around the tubes.? All the RFC's look ok, no burn marks and check out with an ohm meter.? I have fully grounded grids as I did that not too long ago.? Resistance between grid and filaments check ok. Along with resistance between grid and plate. I really think some type of parasitic oscillation took place while on 15 meters.? I will carefully clean and replace those bad components and then bring it up gradually.
So much for trying to contact Easter Island as they were on strong last night at 221262.00. I could hear them very well about a 58 here and would have liked to have that contact.
73? Bob
|
Peter Thanks for the info, ok on it being for the RR1 RR2.?? Great picture of the LN4 in the RR1. Sure don't remember seeing anything like that. I was not that familiar?with their marine line products as much as their 4 line. Thanks Rex WB8TDG
You are the winner of this thread.
On Thu, 18 Apr 2024 19:53:57 +0000
"Steve Wedge, W1ES/4 via " <w1es=[email protected]> wrote:
> I'm going to go take a shower now...
>
>
>
> Steve Wedge, W1ES/4
--
73
-Jim
NU0C
|
Must have been the same old tech that told me, ¡°A screwdriver will never fix a broken radio.¡±
Mike, WB8VGE
SunLight Energy Systems
The Heathkit Shop
J e e p
o|||||||o?
A man with one clock knows what time it?is. A man with two clocks is never sure.
toggle quoted message
Show quoted text
On Apr 18, 2024, at 11:10 PM, Jim Shorney < jimNU0C@...> wrote:
An old tech once told me that "it's almost never the alignment". If it is equally deaf on all bands you have a fault in the common parts. Follow the signal chain and see where you lose it. 73 -Jim NU0C On Thu, 18 Apr 2024 21:40:18 -0500 "Ed KG5UN via " < maikranze@...> wrote: The jumper made no difference. It appears this rig just is a little deaf.?
I am going to see if I can return it.?
Ed?
|
Re: L7 makes alot of smoke
Bob,
Could you provide a few extra details?
Were all of the parasitic choke resistors "fried"? ?If so, that might be symptomatic of a self-oscillation or parasitic. ?. ?With the strapping as a DC path it is unlikely that they failed due to a B+ or tube problem.
If the entire amp went dead, then that means the circuit breakers probably tripped. ?
What two capacitors exploded?
73,
Evan, K9SQG
On Friday, April 19, 2024 at 12:47:40 AM EDT, K6OXN Bob <bobk6oxn@...> wrote:
Earlier this evening, while trying to tune my L7 up on 15 meters, there was a large flash and bang.? The L7 went dead and alot of smoke came out.? Opened it up and found the 47 ohm plate resistors fried and the 2? capacitors exploded. I have ordered a couple of new door knob caps and some resistors. Does anyone have any more ideas as too what else might be effected?? Much thanks in advance.
73? Bob
|
Re: L7 makes alot of smoke
Sounds like a plate-grid short. Check the tubes for shorts. Check the plate choke to see if it opened. Look under the chassis and check the grid chokes.
In the power supply check the .82 ohm resistor as it will act as a fuse. Hopefully it didn't take out any rectifiers.
It could also be one of the plate caps shorted. Check RFC6.
Those are the most common failures but these events can be quite catastrophic so hopefully none of the metering got damaged.
--
73 de Mike, W1NR
THAT was the equation. EXISTENCE!... SURVIVAL... must cancel out... programming!
- Ruk -
|
Earlier this evening, while trying to tune my L7 up on 15 meters, there was a large flash and bang.? The L7 went dead and alot of smoke came out.? Opened it up and found the 47 ohm plate resistors fried and the 2? capacitors exploded. I have ordered a couple of new door knob caps and some resistors. Does anyone have any more ideas as too what else might be effected?? Much thanks in advance.
73? Bob
|
An old tech once told me that "it's almost never the alignment". If it is equally deaf on all bands you have a fault in the common parts. Follow the signal chain and see where you lose it. 73 -Jim NU0C On Thu, 18 Apr 2024 21:40:18 -0500 "Ed KG5UN via groups.io" <maikranze@...> wrote: The jumper made no difference. It appears this rig just is a little deaf.?
I am going to see if I can return it.?
Ed
|
The jumper made no difference. It appears this rig just is a little deaf.? I am going to see if I can return it.?
toggle quoted message
Show quoted text
On Apr 18, 2024, at 9:35?PM, Paul Christensen via groups.io <w9ac@...> wrote:
?On Thu, Apr 18, 2024 at 06:25 PM, Jim Shorney wrote:
Check that the internal RX antenna jumper has not been removed (Item C. on page 3-2 of the manual).
Or temporarily connect a male-male RCA cable between the rear panel EXT RCVR and EXT ANT jacks.? With the RCA cable, capacitive coupling is still maintained through C702. If the receiver comes alive, the internal soldered jumper was removed by a prior owner.?? Paul, W9AC
|
On Thu, Apr 18, 2024 at 06:25 PM, Jim Shorney wrote:
Check that the internal RX antenna jumper has not been removed (Item C. on page 3-2 of the manual).
Or temporarily connect a male-male RCA cable between the rear panel EXT RCVR and EXT ANT jacks.? With the RCA cable, capacitive coupling is still maintained through C702. If the receiver comes alive, the internal soldered jumper was removed by a prior owner.?? Paul, W9AC
|
Thanks for the info.
I think I will let this mic go and try to find something better.
I will dig into the manual and have a look at that jumper.
73,
Ed
KG5UN
toggle quoted message
Show quoted text
On Apr 18, 2024, at 8:25?PM, Jim Shorney via groups.io <jimNU0C@...> wrote:
?
Check that the internal RX antenna jumper has not been removed (Item C. on page 3-2 of the manual).
Your 600 Ohm mic may not have enough output. The manual specifies a high impedance mic. You would need a "matching" transformer to step up the voltage or a preamp to use your mic.
73
-Jim
NU0C
On Thu, 18 Apr 2024 13:46:58 -0700
"Ed KG5UN via groups.io" <maikranze@...> wrote:
Ok I have the rig powered up and running.
not hearing much but it appears to be band conditions more than anything I hope.
I did tune down below 160 to the top of the AM broadcast band and stations that are 10 over on my other rig are barely S-3 on the Drake. Is this normal?
The mic that can with it is a low impedance Astatic and will barely drive the rig. It shows decent output on CW.
Ed
|
Check that the internal RX antenna jumper has not been removed (Item C. on page 3-2 of the manual). Your 600 Ohm mic may not have enough output. The manual specifies a high impedance mic. You would need a "matching" transformer to step up the voltage or a preamp to use your mic. 73 -Jim NU0C On Thu, 18 Apr 2024 13:46:58 -0700 "Ed KG5UN via groups.io" <maikranze@...> wrote: Ok I have the rig powered up and running.
not hearing much but it appears to be band conditions more than anything I hope.
I did tune down below 160 to the top of the AM broadcast band and stations that are 10 over on my other rig are barely S-3 on the Drake. Is this normal?
The mic that can with it is a low impedance Astatic and will barely drive the rig. It shows decent output on CW.
Ed
|
You are the winner of this thread. On Thu, 18 Apr 2024 19:53:57 +0000 "Steve Wedge, W1ES/4 via groups.io" <w1es@...> wrote: I'm going to go take a shower now...
Steve Wedge, W1ES/4 -- 73 -Jim NU0C
|
Re: T-4XB No carrier oscillator
On 2024-04-18 14:34, Steve Wedge, W1ES/4 via groups.io wrote: Pulling my hair out here. Anyone see anything I may have overlooked?
This is a simple circuit that's a bear to get at!
*** That reminds me of a deal I got on a Galaxy V transceiver. It was absolutely mint condition. The flea market vendor said that he had removed the packing tape from the tubes. Lacking a power supply, I rewound a big low-voltage transformer. Got the rig up & running, but the carrier oscillator would not adjust to frequency. Apparently, the crystal had aged. And it was really buried in a little tiny compartment that was hard to get to. I gave up and sold it at a later flea market. - Jerry, KF6VB
|
Re: T-4XB No carrier oscillator
Bad solder joint, open solder joint.
toggle quoted message
Show quoted text
On Apr 18, 2024, at 4:34?PM, Steve Wedge, W1ES/4 via groups.io <w1es@...> wrote:
? I've taken V1 half-apart and metered out components.? All I've found is the 220k resistor being slightly out of tolerance.? Capacitors within tolerance.? C2 value is good and changes as I turn it.? Pins 2 & 3 have different voltages compared with a good transmitter or the chart.? I've changed the crystal.? Crystals test good on my homebrew crystal tester.? Tube has been changed.? S1 appears to be working.
Pulling my hair out here.? Anyone see anything I may have overlooked?? This is a simple circuit that's a bear to get at!
73,
Steve Wedge, W1ES/4
Time flies like an arrow.? Fruit flies like a banana.
Sent with secure email.
|
Yeah,
I guess you're right!
Links always look pretty strange.......
--
73/Rick
W4XA
*Every post is created using Linux
|
Jim Shorney
Ed KG5UN
Paul Christensen