Ya, I unplugged that thing early on. Mostly because I didn’t want to whack it and break it. I only had it in the picture to show y’all what it looked like.
> On Jan 10, 2024, at 6:30 PM, Jim Shorney <jimNU0C@...> wrote:
>
> ?
> Two comments here.
>
> Rule #1 of vintage radios: Never leave them running unattended, ever for "just a minute". That's all it takes to smoke an unobtanium part if something goes sideways. I'm not assuming you have done this, but just FYI. And check EVERY fuse to make sure it is the correct value. I think all of us here have probably seen gear where someone swapped in an oversize fuse because it was the only thing they had on hand and then forgot about it. That is just tempting fate.
>
> Also, the best tube tester is the circuit that you want it to operate in. Tube testers are great for sorting out tubes that are dead or very gassy but they often miss tubes that are off just far enough not to work in your circuit. This especially applies to final tubes. Your average tube tester can't test a final tube under power at 28 MHz. Also, resist the urge to re-tube the entire radio just because you can. You may find that you have more problems than you started with. Most, if not all, of the original tubes are probably just fine. Best practice is to collect a set of known good spares that you can swap in one at a time if a problem comes up.
>
> 73
>
> -Jim
> NU0C
>
>> On Wed, 10 Jan 2024 17:52:35 -0600
>> "Ryan NV5E" <ryanjones2150@...> wrote:
>>
>> You are correct, Steve, I have already put power to it. I’ve ran it a few days, mostly letting it just sit there under power.
>>
>> I had to box it up today because I had two welding jobs holding, waiting for me to get access to my fab table.
>>
>> Going to push late tonight and get this done, then see if I can pull it back out and work on it/play with it some more. I know there’s a lot for me to learn and this project will do me good.
>>
>> A friend of mine, who actually saw this post, has a tube tester, so that’s probably smart. Go ahead and test the little tubes in here and make sure they’re all choochin like they should before I move in to other things.
>>
>> Ryan
>> NV5E
>>>> On Jan 10, 2024, at 3:49 PM, Steve Wedge, W1ES/4 via groups.io <w1es@...> wrote:
>>>
>>> ?I believe that Ryan has already fired everything up, so no variacs are needed at this point. A view of the top and bottom of the chassis will be helpful. There are few mods done to the earlier Twins. I would check to see if anything needs to be done to the receiver with respect to that LF convertor. I am not familiar with its use and don't know if the receive path is interrupted when it's plugged in.
>>>
>>> The cheap variacs are useable but you need to remove the covers and make sure that all of the ground bonds are good and solid. I have one running my station for over a year and it's working fine. I would not fire up all of my rigs at the same time on it. Looking at the gauge of the wire, 10A continuous is probably fine on it.
>>>
>>> 73,
>>>
>>> Steve Wedge, W1ES/4
>>>
>>> Time flies like an arrow. Fruit flies like a banana.
>>>
>>> Sent with Proton Mail secure email.
>>>
>>>> On Wednesday, January 10th, 2024 at 2:04 PM, Lyndon VE7TFX <lyndon@...> wrote:
>>>>
>>>>
>>>> Ryan NV5E writes:
>>>>
>>>>> I don=E2=80=99t know what all else is inside. I pulled the cover off the re=
>>>>> ceiver the other day, just to take a look around. I like how it=E2=80=99s a=
>>>>> ll copper in there. And thanks for the heads up on the voltage in there.
>>>>
>>>>
>>>> Ryan, if you can, pop the covers off the tx and rx and get some
>>>> (high resolution and well lit) pictures of the top and bottom
>>>> chassis of both, then post those to the list.
>>>>
>>>> Just by eyeballing those somebody might be able to spot if a previous
>>>> owner has been golden screwdrivering in there, or if there are any
>>>> other gotchas that stand out.
>>>>
>>>> I also second the advice about putting both rigs on a variac to
>>>> start. Given their age, a little babying is in order. You can buy
>>>> variacs on fleaBay for <$100, and that is money well invested. A
>>>> 5A should do, although a 10A would give you more head room on the
>>>> transmitter. Watch how much current you pull through the variac.
>>>> If you run both the rx and tx through it concurrently, you need a
>>>> 10A.
>>>>
>>>> Do NOT buy one of the cheap chinese bright red ones you see everywhere.
>>>> They are death traps. (See the mailing list archives -- somewhere
>>>> around last spring? -- for a lively discussion on that topic.)
>>>>
>>>> Note the variac will not carry the power supply for the amp. For
>>>> that you might consider just pre-emptively recapping the power
>>>> supply. But take a look inside the PSU first, as the former owner
>>>> might have done that already.
>>>>
>>>> And finally, as others have said, buy or download the manuals for
>>>> everything and (re-)read them until you have them memorized :-)
>>>>
>>>> --lyndon
>>>>
>>>>
>>>>
>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>>
>>
>>
>
>
>
> --
>
> 73
>
> -Jim
> NU0C
>
>
>
>
>

On Jan 10, 2024, at 6:30 PM, Jim Shorney <jimNU0C@...> wrote:

?
Two comments here.

Rule #1 of vintage radios: Never leave them running unattended, ever for "just a minute". That's all it takes to smoke an unobtanium part if something goes sideways. I'm not assuming you have done this, but just FYI. And check EVERY fuse to make sure it is the correct value. I think all of us here have probably seen gear where someone swapped in an oversize fuse because it was the only thing they had on hand and then forgot about it. That is just tempting fate.

Also, the best tube tester is the circuit that you want it to operate in. Tube testers are great for sorting out tubes that are dead or very gassy but they often miss tubes that are off just far enough not to work in your circuit. This especially applies to final tubes. Your average tube tester can't test a final tube under power at 28 MHz. Also, resist the urge to re-tube the entire radio just because you can. You may find that you have more problems than you started with. Most, if not all, of the original tubes are probably just fine. Best practice is to collect a set of known good spares that you can swap in one at a time if a problem comes up.

73

-Jim
NU0C

On Wed, 10 Jan 2024 17:52:35 -0600
"Ryan NV5E" <ryanjones2150@...> wrote:

You are correct, Steve, I have already put power to it. I’ve ran it a few days, mostly letting it just sit there under power.

I had to box it up today because I had two welding jobs holding, waiting for me to get access to my fab table.

Going to push late tonight and get this done, then see if I can pull it back out and work on it/play with it some more. I know there’s a lot for me to learn and this project will do me good.

A friend of mine, who actually saw this post, has a tube tester, so that’s probably smart. Go ahead and test the little tubes in here and make sure they’re all choochin like they should before I move in to other things.

Ryan
NV5E

On Jan 10, 2024, at 3:49 PM, Steve Wedge, W1ES/4 via groups.io <w1es@...> wrote:

?I believe that Ryan has already fired everything up, so no variacs are needed at this point. A view of the top and bottom of the chassis will be helpful. There are few mods done to the earlier Twins. I would check to see if anything needs to be done to the receiver with respect to that LF convertor. I am not familiar with its use and don't know if the receive path is interrupted when it's plugged in.

The cheap variacs are useable but you need to remove the covers and make sure that all of the ground bonds are good and solid. I have one running my station for over a year and it's working fine. I would not fire up all of my rigs at the same time on it. Looking at the gauge of the wire, 10A continuous is probably fine on it.

73,

Steve Wedge, W1ES/4

Time flies like an arrow. Fruit flies like a banana.

Sent with Proton Mail secure email.

On Wednesday, January 10th, 2024 at 2:04 PM, Lyndon VE7TFX <lyndon@...> wrote:


Ryan NV5E writes:

I don=E2=80=99t know what all else is inside. I pulled the cover off the re=
ceiver the other day, just to take a look around. I like how it=E2=80=99s a=
ll copper in there. And thanks for the heads up on the voltage in there.

Ryan, if you can, pop the covers off the tx and rx and get some
(high resolution and well lit) pictures of the top and bottom
chassis of both, then post those to the list.

Just by eyeballing those somebody might be able to spot if a previous
owner has been golden screwdrivering in there, or if there are any
other gotchas that stand out.

I also second the advice about putting both rigs on a variac to
start. Given their age, a little babying is in order. You can buy
variacs on fleaBay for <$100, and that is money well invested. A
5A should do, although a 10A would give you more head room on the
transmitter. Watch how much current you pull through the variac.
If you run both the rx and tx through it concurrently, you need a
10A.

Do NOT buy one of the cheap chinese bright red ones you see everywhere.
They are death traps. (See the mailing list archives -- somewhere
around last spring? -- for a lively discussion on that topic.)

Note the variac will not carry the power supply for the amp. For
that you might consider just pre-emptively recapping the power
supply. But take a look inside the PSU first, as the former owner
might have done that already.

And finally, as others have said, buy or download the manuals for
everything and (re-)read them until you have them memorized :-)

--lyndon

--

73

-Jim
NU0C

Be sure to keep track of which tubes go where. It can make a difference with the alignment. Your transmitter seems to already be working fine.



Steve Wedge, W1ES/4

Time flies like an arrow. Fruit flies like a banana.

Sent with Proton Mail secure email.

On Wednesday, January 10th, 2024 at 6:52 PM, Ryan NV5E ryanjones2150@... wrote:

You are correct, Steve, I have already put power to it. I’ve ran it a few days, mostly letting it just sit there under power.

I had to box it up today because I had two welding jobs holding, waiting for me to get access to my fab table.

Going to push late tonight and get this done, then see if I can pull it back out and work on it/play with it some more. I know there’s a lot for me to learn and this project will do me good.

A friend of mine, who actually saw this post, has a tube tester, so that’s probably smart. Go ahead and test the little tubes in here and make sure they’re all choochin like they should before I move in to other things.

Ryan
NV5E

On Jan 10, 2024, at 3:49 PM, Steve Wedge, W1ES/4 via groups.io w1es@... wrote:

I believe that Ryan has already fired everything up, so no variacs are needed at this point. A view of the top and bottom of the chassis will be helpful. There are few mods done to the earlier Twins. I would check to see if anything needs to be done to the receiver with respect to that LF convertor. I am not familiar with its use and don't know if the receive path is interrupted when it's plugged in.

The cheap variacs are useable but you need to remove the covers and make sure that all of the ground bonds are good and solid. I have one running my station for over a year and it's working fine. I would not fire up all of my rigs at the same time on it. Looking at the gauge of the wire, 10A continuous is probably fine on it.

73,

Steve Wedge, W1ES/4

Time flies like an arrow. Fruit flies like a banana.

Sent with Proton Mail secure email.

On Wednesday, January 10th, 2024 at 2:04 PM, Lyndon VE7TFX lyndon@... wrote:

Ryan NV5E writes:

I don=E2=80=99t know what all else is inside. I pulled the cover off the re=
ceiver the other day, just to take a look around. I like how it=E2=80=99s a=
ll copper in there. And thanks for the heads up on the voltage in there.

Ryan, if you can, pop the covers off the tx and rx and get some
(high resolution and well lit) pictures of the top and bottom
chassis of both, then post those to the list.

Just by eyeballing those somebody might be able to spot if a previous
owner has been golden screwdrivering in there, or if there are any
other gotchas that stand out.

I also second the advice about putting both rigs on a variac to
start. Given their age, a little babying is in order. You can buy
variacs on fleaBay for <$100, and that is money well invested. A
5A should do, although a 10A would give you more head room on the
transmitter. Watch how much current you pull through the variac.
If you run both the rx and tx through it concurrently, you need a
10A.

Do NOT buy one of the cheap chinese bright red ones you see everywhere.
They are death traps. (See the mailing list archives -- somewhere
around last spring? -- for a lively discussion on that topic.)

Note the variac will not carry the power supply for the amp. For
that you might consider just pre-emptively recapping the power
supply. But take a look inside the PSU first, as the former owner
might have done that already.

And finally, as others have said, buy or download the manuals for
everything and (re-)read them until you have them memorized :-)

--lyndon

You are correct, Steve, I have already put power to it. I’ve ran it a few days, mostly letting it just sit there under power.

I had to box it up today because I had two welding jobs holding, waiting for me to get access to my fab table.

Going to push late tonight and get this done, then see if I can pull it back out and work on it/play with it some more. I know there’s a lot for me to learn and this project will do me good.

A friend of mine, who actually saw this post, has a tube tester, so that’s probably smart. Go ahead and test the little tubes in here and make sure they’re all choochin like they should before I move in to other things.

Ryan
NV5E

On Jan 10, 2024, at 3:49 PM, Steve Wedge, W1ES/4 via groups.io w1es@... wrote:

I believe that Ryan has already fired everything up, so no variacs are needed at this point. A view of the top and bottom of the chassis will be helpful. There are few mods done to the earlier Twins. I would check to see if anything needs to be done to the receiver with respect to that LF convertor. I am not familiar with its use and don't know if the receive path is interrupted when it's plugged in.

The cheap variacs are useable but you need to remove the covers and make sure that all of the ground bonds are good and solid. I have one running my station for over a year and it's working fine. I would not fire up all of my rigs at the same time on it. Looking at the gauge of the wire, 10A continuous is probably fine on it.

73,

Steve Wedge, W1ES/4

Time flies like an arrow. Fruit flies like a banana.

Sent with Proton Mail secure email.

On Wednesday, January 10th, 2024 at 2:04 PM, Lyndon VE7TFX lyndon@... wrote:

Ryan NV5E writes:

I don=E2=80=99t know what all else is inside. I pulled the cover off the re=
ceiver the other day, just to take a look around. I like how it=E2=80=99s a=
ll copper in there. And thanks for the heads up on the voltage in there.

Ryan, if you can, pop the covers off the tx and rx and get some
(high resolution and well lit) pictures of the top and bottom
chassis of both, then post those to the list.

Just by eyeballing those somebody might be able to spot if a previous
owner has been golden screwdrivering in there, or if there are any
other gotchas that stand out.

I also second the advice about putting both rigs on a variac to
start. Given their age, a little babying is in order. You can buy
variacs on fleaBay for <$100, and that is money well invested. A
5A should do, although a 10A would give you more head room on the
transmitter. Watch how much current you pull through the variac.
If you run both the rx and tx through it concurrently, you need a
10A.

Do NOT buy one of the cheap chinese bright red ones you see everywhere.
They are death traps. (See the mailing list archives -- somewhere
around last spring? -- for a lively discussion on that topic.)

Note the variac will not carry the power supply for the amp. For
that you might consider just pre-emptively recapping the power
supply. But take a look inside the PSU first, as the former owner
might have done that already.

And finally, as others have said, buy or download the manuals for
everything and (re-)read them until you have them memorized :-)

--lyndon

On Jan 10, 2024, at 3:49 PM, Steve Wedge, W1ES/4 via groups.io <w1es@...> wrote:

?I believe that Ryan has already fired everything up, so no variacs are needed at this point. A view of the top and bottom of the chassis will be helpful. There are few mods done to the earlier Twins. I would check to see if anything needs to be done to the receiver with respect to that LF convertor. I am not familiar with its use and don't know if the receive path is interrupted when it's plugged in.

The cheap variacs are useable but you need to remove the covers and make sure that all of the ground bonds are good and solid. I have one running my station for over a year and it's working fine. I would not fire up all of my rigs at the same time on it. Looking at the gauge of the wire, 10A continuous is probably fine on it.

73,

Steve Wedge, W1ES/4

Time flies like an arrow. Fruit flies like a banana.

Sent with Proton Mail secure email.

On Wednesday, January 10th, 2024 at 2:04 PM, Lyndon VE7TFX <lyndon@...> wrote:


Ryan NV5E writes:

I don=E2=80=99t know what all else is inside. I pulled the cover off the re=
ceiver the other day, just to take a look around. I like how it=E2=80=99s a=
ll copper in there. And thanks for the heads up on the voltage in there.

Ryan, if you can, pop the covers off the tx and rx and get some
(high resolution and well lit) pictures of the top and bottom
chassis of both, then post those to the list.

Just by eyeballing those somebody might be able to spot if a previous
owner has been golden screwdrivering in there, or if there are any
other gotchas that stand out.

I also second the advice about putting both rigs on a variac to
start. Given their age, a little babying is in order. You can buy
variacs on fleaBay for <$100, and that is money well invested. A
5A should do, although a 10A would give you more head room on the
transmitter. Watch how much current you pull through the variac.
If you run both the rx and tx through it concurrently, you need a
10A.

Do NOT buy one of the cheap chinese bright red ones you see everywhere.
They are death traps. (See the mailing list archives -- somewhere
around last spring? -- for a lively discussion on that topic.)

Note the variac will not carry the power supply for the amp. For
that you might consider just pre-emptively recapping the power
supply. But take a look inside the PSU first, as the former owner
might have done that already.

And finally, as others have said, buy or download the manuals for
everything and (re-)read them until you have them memorized :-)

--lyndon

There's one thing that maybe should be kept in mind about what people may be using to drive their L-7 or L-4 /L-4B when it comes to ICOM transceivers. ??

I'm not sure that everyone who uses ICOM radios are using the IC-7600/7610 or the even IC-7800/7850/51's? for that matter.

A very large portion of them have the IC-7300 transceiver.? I don't know the actual numbers but it seems A LOT of people I talk to these days are using what one amateur I know calls the "Belly-Button" radio? (everybody has one!)

Directly connecting the IC-7300 to an L-7 or L-4 could eventually damage/destroy the send relay. Hence the "Warning" from the manual.

The below statement is taken directly from the ICOM 7300 instruction manual:
The IC-746, 7410, and others are similar

?WARNING!
??The maximum signal level of the [SEND] jack is 16 V/0.5 A DC. Use an external unit if your non-Icom linear amplifier requires a control voltage and/or current greater than specified.


I also found that my L-4B in stock configuration could not be "keyed" directly with the IC-705 or my IC-M802. Both of which use "open collector" type keying. (For the IC705, I suppose it should probably be called "open? drain" FET keying etc...)

The IC-M802 easily drives the L-4B to 1000W or more output.

Now,? before anyone laughs at? using an IC-705 to drive the L-4B, it's 10W output drives my L-4B to about 250W
(and having said that, I normally use the 705 to drive a Mercury III to about 1200-1300w on 160-40.? It's a little less above ...)

Since my C-line only drives the L-4B to around 1300w, it's a tad over a 7db difference when driving with the IC-705.

But I MUST use a keying interface with both the M802 and 705.

I'm currently using a CRYDOM MPDCD3 (opto-isolated) solid state "relay"? with a pair of 3-vdc series lithium batteries.


Of particular note is the max turn-on/turn-off time of? only 0.1ms .....? There are many other DC (and AC)? controlled solid state "relays" that will control DC and AC and switch with similar times

You could use "accy port -supplied" DC voltage for it.? The IC-705 doesn't have DC voltage available in the "SEND" line so I used the 2x3v battery holder for maximum isolation. (it only draws about 4ma from the batteries during "key-down")

Just another way to do it if desired and it works for just about any amp.


--

73/Rick

W4XA
*Every post is created using Linux

Ryan NV5E writes:

I don=E2=80=99t know what all else is inside. I pulled the cover off the re=
ceiver the other day, just to take a look around. I like how it=E2=80=99s a=
ll copper in there. And thanks for the heads up on the voltage in there.

Ryan, if you can, pop the covers off the tx and rx and get some
(high resolution and well lit) pictures of the top and bottom
chassis of both, then post those to the list.

Just by eyeballing those somebody might be able to spot if a previous
owner has been golden screwdrivering in there, or if there are any
other gotchas that stand out.

I also second the advice about putting both rigs on a variac to
start. Given their age, a little babying is in order. You can buy
variacs on fleaBay for <$100, and that is money well invested. A
5A should do, although a 10A would give you more head room on the
transmitter. Watch how much current you pull through the variac.
If you run both the rx and tx through it concurrently, you need a
10A.

Do NOT buy one of the cheap chinese bright red ones you see everywhere.
They are death traps. (See the mailing list archives -- somewhere
around last spring? -- for a lively discussion on that topic.)

Note the variac will not carry the power supply for the amp. For
that you might consider just pre-emptively recapping the power
supply. But take a look inside the PSU first, as the former owner
might have done that already.

And finally, as others have said, buy or download the manuals for
everything and (re-)read them until you have them memorized :-)

--lyndon

Rob, don't put too much effort measuring the sensitivity of your TR-4C and R-4C .
If you hear an obvious increase in the noise level when connecting the antenna to the TR-4C in the AM position, while it may not be as sensitive as the R-4C, it will still be "enough"!
Cheers!
Rick
//
On Wed, Jan 10, 2024 at 12:33 PM, Rob PA9Z wrote:
Thanks folks,
Indeed, the TR-4C doesn't seem to be the ideal rig for AM. Luckily I
also have the 4C twins, and the R-4C does AM very well. ?I could
accept the 'distortion' caused by squeezing AM through the SSB
filter, but I also have the impression that the sensitivity of the
TR-4C receiver in AM is significantly less then SSB. ?I will compare
that with the R-4C. ?Meanwhile I think I need to accept the limited
AM functionality of the TR-4C.
'73 de Rob PA9Z
--
/*73/Rick*/
//*W4XA
**///Every post is created using Linux *
*/

Thanks folks,

Indeed, the TR-4C doesn't seem to be the ideal rig for AM. Luckily I also have the 4C twins, and the R-4C does AM very well. ?I could accept the 'distortion' caused by squeezing AM through the SSB filter, but I also have the impression that the sensitivity of the TR-4C receiver in AM is significantly less then SSB. ?I will compare that with the R-4C. ?Meanwhile I think I need to accept the limited AM functionality of the TR-4C.

'73 de Rob PA9Z

73/Rick

On Jan 10, 2024, at 08:40, Jim VE7RF <jim.thom@...> wrote:

?I would toss the silly 1/2 wave rectifier and at least use a FWB? or a FWD, depending on the application.? ?That 22 ohm resistor is not going to do much to speed up the RLS time, it's value is too low for that.? But for the oem 3PDT mech relay, it's good enough? and a moot point.?

Hmmmm…

?

闯辞别…奥丑测?

?

I have a TS890s and for 6 months drove my L4-B with it. Granted I did use an Ameritron ARB704 as an intermediary. The only mod to the amplifier was running a Peter Dahl transformer in the Power Supply, which upped the high voltage a wee (sic) bit.

?

Joe – W7RKN

?

From: [email protected] [mailto:[email protected]] On Behalf Of Joe KI5O
Subject: Re: [DRAKE-RADIO] New to me drake 4 twins

?

Ryan it sounds like you have a great set. My only worries are making sure you have a soft key board installed on the L4B if you are using a newer radio to drive the amp.?

These lots of fun to learn with, and we are fortunate to have such a great group here as a resource.

Joe ki5o?

The drake (both the L4 and the L7) use a 22 volt ac transformer winding for the relay shown below is part of the filament transformer, and showing the winding that is used for the PTT relay power supply.

22 VAC X 1.41 (from converting AC to DC) is 31 volts DC.

Most if not all modern radios can easily handle 40 volts DC on their PTT relays and MOSFETs (like the 7610)
In addition of CR5 and R30 shown on the schematic below, also helps to quash any voltage spikes generated by the relay coil collapsing when voltage is removed from it.

So the bottom line... It's not needed.


Let me know if you have questions.

73, Jim W7RY