Re: L4/L4B/L7 power switch alternative
I have a simple solution for the power switch.? While I have
replaced the back end of the switch and I have a spare kit I got
from Nationwide Radio, KE9PQ. I leave the power switch on all the
time. My L-4B switch has odd rockers. Both are white. Not red and
black. No idea why, but it appears to be the same switch as the one
with the red and black rockers. To power the amp on I use an
external DPDT switch and 15A 250 volt receptacle mounted in a 4" x
4" box. Easy to find 15A 250 volt receptacles and DPDT switches of
the proper rating.? I also have an ES4L-4B in my L-4B.? I don't know
if Harbach still offers the ES4L-4B.
73
Stan
KM4HQE
On 5/7/24 21:39, Rick W4XA wrote:
toggle quoted message
Show quoted text
On Tue, May 7, 2024 at 03:25 PM, Steve Bookout, NR4M wrote:
Hello
all,
I
use these solid state relays, as well, and they are great!
One
thing to be aware of I'm told, as I've never experienced it
myself, there is a small amount of leakage thru the
switching transistor inside the SSR.? When using HV
supplies, this -could- put a few hundred volts on the output
of a 'turned off' power supply.? Don't need any surprises.
-Go
Drake-
73
de Steve NR4M
Hi Steve,
Yesterday, I finished rewiring the? Loudenboomer PSU ( L-4B
transformer) from 120 to 240AC using 2 SSR's.
I know they have a little leakage but it really isn't much.?
Just now, I measured 0.7V AC on the primary and 3VDC on the high
voltage line.
I'm? thinking it's probably not anything to worry about!
?
--
73/Rick
W4XA
*Every post is created
using Linux
|
Re: L4/L4B/L7 power switch alternative
Regardless of the amount of “leakage”, it becomes irrelevant when one considers safety concerns, which dictate that any high voltage amp or power supply should be disconnected from the AC line and preferably have its power connector encased in a lock-out box.
Since my near-death-experience with a Collins 30L-1, I will NEVER put a hand into an amp or power supply without the lockbox. I don’t need a padlock because I am the only one around the work but the lookout box is now an essential for me. I use a Carabiner to secure it.
Gary
toggle quoted message
Show quoted text
On May 7, 2024, at 9:39?PM, Rick W4XA <myr748@...> wrote:
On Tue, May 7, 2024 at 03:25 PM, Steve Bookout, NR4M wrote:
Hello all, I use these solid state relays, as well, and they are great! One thing to be aware of I'm told, as I've never experienced it myself, there is a small amount of leakage thru the switching transistor inside the SSR.? When using HV supplies, this -could- put a few hundred volts on the output of a 'turned off' power supply.? Don't need any surprises. -Go Drake- 73 de Steve NR4M
Hi Steve, Yesterday, I finished rewiring the? Loudenboomer PSU ( L-4B transformer) from 120 to 240AC using 2 SSR's. I know they have a little leakage but it really isn't much.? Just now, I measured 0.7V AC on the primary and 3VDC on the high voltage line. I'm? thinking it's probably not anything to worry about! ? --
73/Rick
W4XA
*Every post is created using Linux
|
Re: L4/L4B/L7 power switch alternative
On Tue, May 7, 2024 at 03:25 PM, Steve Bookout, NR4M wrote:
Hello all,
I use these solid state relays, as well, and they are great!
One thing to be aware of I'm told, as I've never experienced it myself, there is a small amount of leakage thru the switching transistor inside the SSR.? When using HV supplies, this -could- put a few hundred volts on the output of a 'turned off' power supply.? Don't need any surprises.
-Go Drake-
73 de Steve NR4M
Hi Steve, Yesterday, I finished rewiring the? Loudenboomer PSU ( L-4B transformer) from 120 to 240AC using 2 SSR's. I know they have a little leakage but it really isn't much.? Just now, I measured 0.7V AC on the primary and 3VDC on the high voltage line. I'm? thinking it's probably not anything to worry about! ? --
73/Rick
W4XA
*Every post is created using Linux
|
Re: L4/L4B/L7 power switch alternative
Hello all,
I use these solid state
relays, as well, and they are great!
One thing to be aware
of I'm told, as I've never experienced it myself, there is a
small amount of leakage thru the switching transistor inside the
SSR.? When using HV supplies, this -could- put a few hundred
volts on the output of a 'turned off' power supply.? Don't need
any surprises.
-Go Drake-
73 de Steve NR4M
On 5/6/2024 7:24 PM, Rick W4XA wrote:
toggle quoted message
Show quoted text
I think either are fine of course...
I found a seller on eBay that was selling those 240A45's for about
$10 each (new old stock) I couldn't pass them up!? so I bought 6
of them!
Then I found a different seller with the 240A25's for about the
same price so I grabbed them too!?
On another completely unrelated note, I have a Viking Valiant that
has a REALLY clunky DC powered relay that is activated by the PTT
line.? EF Johnson thought it a good idea to key the finals by
keying the actual plate transformer AC!? (and other stages with a
separate set of contacts)
The relay uses about 200V DC and that 200V is on the PTT line in
the microphone. (really safe huh?)
I'm changing that one to an SSD also? (already have low voltage DC
in there for a T/R relay so I'll use it!)
I love these SSD's!
Their only problem is cost if you have to buy them new at retail.?
Mouser gets about $82 for new Opto22 240A45 SSR's......? and
Digikey gets about $80 for the 240A25 models.
It probably wouldn't be worth it if I had to pay retail for them.
--
73/Rick
W4XA
*Every post is created
using Linux
|
On 2024-05-07 10:31, Kevin Kampman wrote: Usually they are sequenced front to rear (A, B, C) then front or back. So "A" is closest to the metal panel? I have an ulterior motive. Another "old radio" project. It's a Collins KWM-2. I made up a circuit to fix its abysmal CW support. That little board mounts behind the VFO. To activate it, I need a signal that's grounded for CW mode. There is an unused lug on wafer "G" of the mode switch that will supply just that. - Jerry, KF6VB
|
Usually they are sequenced front to rear (A, B, C) then front or back. Study/follow the schematic to prove this out. They can be a bear to replace, but it can be done.?
--
73, Kevin, K8KVN
|
Re: L4/L4B/L7 power switch alternative
I think either are fine of course...
I found a seller on eBay that was selling those 240A45's for about $10 each (new old stock) I couldn't pass them up!? so I bought 6 of them!
Then I found a different seller with the 240A25's for about the same price so I grabbed them too!?
On another completely unrelated note, I have a Viking Valiant that has a REALLY clunky DC powered relay that is activated by the PTT line.? EF Johnson thought it a good idea to key the finals by keying the actual plate transformer AC!? (and other stages with a separate set of contacts)
The relay uses about 200V DC and that 200V is on the PTT line in the microphone. (really safe huh?)
I'm changing that one to an SSD also? (already have low voltage DC in there for a T/R relay so I'll use it!)
I love these SSD's!
Their only problem is cost if you have to buy them new at retail.?
Mouser gets about $82 for new Opto22 240A45 SSR's......? and Digikey gets about $80 for the 240A25 models.
It probably wouldn't be worth it if I had to pay retail for them.
--
73/Rick
W4XA
*Every post is created using Linux
|
Re: L4/L4B/L7 power switch alternative
On Mon, May 6, 2024 at 11:15 AM, Rick W4XA wrote:
You might have missed it.? I'm not running DC controlled SSR's.? I used AC controlled SSR's
Rick; I did note that you were using AC controlled SSR's... Using an AC-controlled SSR for a "switch-saver" installation inside an L-4PS (or L-7PS) looks to be simpler and cleaner than my solution using a 12VDC power supply. However, I already had a vetted 50 Amp DC-controlled SSR, and the 12V power supply I sourced was significantly less expensive than a suitable AC-controlled SSR. Mark - AD7EF
|
Does anyone have an MN-75 meter bezel that is surplus to requirements?
--lyndon
|
Re: L4/L4B/L7 power switch alternative
On Mon, May 6, 2024 at 10:15 AM, Mark Davis wrote:
Your continuously running "wall wart in a box" won't cause any ground-fault problem if it's wired from line to line on a 240VAC service, or from line to neutral on a 120VAC service.?
Mark - AD7EF
You might have missed it.? I'm not running DC controlled SSR's.? I used AC controlled SSR's specifically? so I wouldn't have to have a separate powered DC supply.? The switch still switches AC but at only a "few" mA. Either way, They work great in the Loudenboomer supply and will be easy to install in the L-4B supply. I'll take some pictures when I do it so everyone can see! Cheers, Rick Here's one of the Loudenboomer supply!? I used the original L-4PS transformer & terminal block? (note the 120VAC jumpers) The yellow box holds the the 2-100K bleeders, (2) 5000V Semtech diode stacks and the Harbach SB-220?? 8x330uF-450V cap board. Yesterday, I rewired it for 240V  ? --
73/Rick
W4XA
*Every post is created using Linux
|
Re: L4/L4B/L7 power switch alternative
On Mon, May 6, 2024 at 08:00 AM, Rick W4XA wrote (on the "L7 fails to Key" topic):
On a side note, It appears that the HT-45 wired for 240 might trip a 240 GFI since it uses 1-side of the AC line to run the 120 AC blower, and filament transformers......if they trip on unequal current
Rick; The 2-pole (240VAC) GFCI breakers trip on leakage from either side to - ground-. I have it on good authority that a 240VAC GFCI will not trip on imbalanced loads from either side to - neutral-. Your continuously running "wall wart in a box" won't cause any ground-fault problem if it's wired from line to line on a 240VAC service, or from line to neutral on a 120VAC service.? On the L-4B I modified per the "L-4B Adventure" topic, instead of a constantly powered "wall-wart", I've installed a small CE-listed 12VDC power supply that operates on 120VAC - 240VAC input inside the L4PS. The 12VDC power supply input is wired across the AC line... no connection to ground ?anywhere on the AC-input side. Mark - AD7EF
|
Re: L4/L4B/L7 power switch alternative
I guess my reply on the other thread should have been here!
This would be essentially turning the L-4/L-7 front panel switch into a front panel "Hood Ornament"
On another note, Isn't MFJ "disappearing from the scene"?
--
73/Rick
W4XA
*Every post is created using Linux
|
Mark, yeah I agree? having powered circuit running all the time can present problems. (like having a wall-wart installed inside the box)
I referred to the "ZR" article to mention the SSR's in general as a way to get the "spark" away from the unobtanium switch.
I didn't use a DC controlled SSR in mine so I didn't test with a GFI protected circuit .?? I don't have GFI "protected" outlets in my "roomful" of radios!? However I do have an adjoining restroom that does and am currently running my TR-4 off the outlet right now.? Works just great and doesn't trip the GFI (at least on 120AC with the SSR switched AC-4)
I also must confess, I? didn't try using DC controlled SSR's because I did not like the idea of a small DC power supply being powered all the time (like a "wall-wart) .... so I used AC controlled SSR's in both the AC-4 and the and the L-4PS (Hallicrafters Loudenboomer ) power supply.? Interesting though wall-warts do not seem to "trip" GFI's.?
In the L-4PS, I started with 120 AC power and because I was getting a bit of voltage drop on the 120 line, I decided to rewire it for 240AC.? I also tried it initially with a single SSR for 120 operation and added a second SSR so it would be in place if and when I rewired it for 240.? (ZR used only 1 SSR on the 240 wired L-4PS.... I like the Command Technologies method of 2 (AC controlled)? SSRs so I did that)
The HT-45 power supply switching uses one side of the 240 AC line to power the blower , 3-400? filament transformer and the previously installed tube rectifiers.? There was also a separate 120AC line sent back into the power supply to trigger the previously installed electro-mechanical relay used to power the plate transformer.?
(On a side note, It appears that the HT-45 wired for 240 might trip a 240 GFI since it uses 1-side of the AC line to run the 120 AC blower, and filament transformers......if they trip on unequal current )
So I used that 120AC to switch AC power to the AC controlled Opto22 240A25 SSR's.
It works fine using either 120 or 240 AC and the SSR's can be controlled using either 120 or 240 AC.? So in the unmodified L-4PS wired to an L-7/L-4B.? It simplifies the wiring even more.? I will just mount the SSR's vertically, in the L-4PS on the internal side of the chassis opposite of where the Harbach board is mounted.? I won't even have to open up the RF deck.? The only difference will be using 240A45's instead of the 240A25's I? used in the HT-45 iteration of the L-4PS
I was going to apologize for the thread "hi-jack" but this is about protecting the switch so it is germane to this discussion.?
How ever it's done, it must be done or the? switch will have to be replaced with something that doesn't look original on the front panel or it will become a non-working front panel ornament and on-off switching? will have to be accomplished via an outboard switch.
--
73/Rick
W4XA
*Every post is created using Linux
|
I have clean very good working 28xxx serial number R-4C for sale. It has the noise blanker with stock filter. $400 plus shipping. ? Dan K9DTC
|
Permalink to this message thread: /g/DRAKE-RADIO/topic/93458618#msg67295On Mon, 06 May 2024 01:43:23 -0700 "Mark Davis via groups.io" <markad7ef@...> wrote: For a different approach to energizing the SSR, which addresses both of these issues, see my "L-4B Adventure" topic on this groups.io -- 73 -Jim NU0C
|
L4/L4B/L7 power switch alternative
What has worked for me for years is to use an Ameritron/MFJ ICP240 or ICP120 to turn my amps on and off; the power switches in the amps are left on. ?However, in spite of the advertising, these are NOT inrush protectors in a strict sense; my analysis of the circuit was confirmed by an Ameritron/MFJ engineer/technician. ?The circuit depends on the phase of the sine wave and pull in time for the relay. ?So the amount of onset delay varies; guess it is better than nothing but they do save wear and tear on the amps' power switches. ?Not sure how long MFJ will be carrying these switches.
Awaiting to see what the "not keying" cause is.
73 and enjoy Hamvention if you come here. ?Be sure to bring an umbrella as well as sunscreen as the historical data suggets...
Evan, K9SQG
On Monday, May 6, 2024 at 04:43:26 AM EDT, Mark Davis <markad7ef@...> wrote:
On Mon, May 6, 2024 at 12:39 AM, Rick W4XA wrote:
W8ZR has a great article on how he did it in an L-4B using a single solid state relay.
Rick, all A word of caution regarding the W8ZR SSR modification on the L-4B... the rectifier / filter circuit that author uses to energize the SSR when the L4B power switch is turned on is directly connected between one side of the input AC and chassis ground. The approximately 15mA of current drawn by this circuit pretty much eliminates the stress on the power switch, but having a "metallic" path between one side of the AC line and ground presents a safety hazard. In fact, if you have a 240V GFCI circuit breaker in the line powering your amp, the current to ground through the rectifier / filter circuit will consistently cause a ground fault. Another issue with the W8ZR rectifier / filter circuit is that it doesn't work if you wire the amp to operate off 120VAC. For a different approach to energizing the SSR, which addresses both of these issues, see my "L-4B Adventure" topic on this . Mark - AD7EF
|
Re: OT: Coax bypass switches
toggle quoted message
Show quoted text
On Fri, May 3, 2024 at 09:53 AM, Lyndon VE7TFX wrote:
I'm putting together a 6m tuner so I can get the TR-6
back on the air. I want to be able to bypass the tuner,
but I have no idea what would make a suitable switch.
Anyone have a recommendation?
Lyndon; Going back to your original post: "I'm putting together a 6m tuner so I can get the TR-6back on the air. I want to be able to bypass the tuner..."
and your later feedback: "Sorry folks, I should have been more specific.I'm looking for a mechanical switch, not a relay. And itneeds to handle at least a couple of hundred watts."
I believe the "ANT. SELECTOR SWITCH" in the Drake MN-2000 tuner is an excellent example of how you could accomplish your objectives with a 2-pole 3-position ceramic-wafer rotary switch. Here's the schematic of that 2000W 80M - 10M tuner:  This schematic is a page from the MN-2000 manual posted at The shown "ANT. SELECTOR SWITCH" has five positions, to support matching (tuned) or direct (bypass) operation with 2 antennas, and a dummy load in the "ALT." position. If you eliminate the second "matching" and "direct" positions, a 3-position switch will do the job. Here's a 2-pole ceramic-wafer switch on eBay (for under $15, including shipping) that can be configured for 2 to 5 positions: . I think this switch would be "just the ticket" for your application. Mark - AD7EF
|
Evan,
Okay on the rain.
Chuck
|
On Mon, May 6, 2024 at 12:39 AM, Rick W4XA wrote:
W8ZR has a great article on how he did it in an L-4B using a single solid state relay.
Rick, all A word of caution regarding the W8ZR SSR modification on the L-4B... the rectifier / filter circuit that author uses to energize the SSR when the L4B power switch is turned on is directly connected between one side of the input AC and chassis ground. The approximately 15mA of current drawn by this circuit pretty much eliminates the stress on the power switch, but having a "metallic" path between one side of the AC line and ground presents a safety hazard. In fact, if you have a 240V GFCI circuit breaker in the line powering your amp, the current to ground through the rectifier / filter circuit will consistently cause a ground fault. Another issue with the W8ZR rectifier / filter circuit is that it doesn't work if you wire the amp to operate off 120VAC. For a different approach to energizing the SSR, which addresses both of these issues, see my "L-4B Adventure" topic on this . Mark - AD7EF
|
Bob, The switch rebuild kits are indeed no longer available. The L-7 ON/OFF switch like the L-4B switch doesn't actually get "dirty".? The contacts? burn when opening and closing at the sine-wave (+/-)? peak of the line voltage.? It happens every time you open or close the switch if the voltage is at or near the peak AC voltage.? You can install a step-start circuit but it only partially protects during "turn-on",?? and does nothing for "turn-Off" And if you're running on 240AC line voltage that peak voltage is pretty high.  If you're "fast" you can open or close the switch at 0V at 0, 180, or 360 degrees.?? I'm not very successful at that but there is an easy way to mitigate the problem.? Install either an electro-mechanical relay which transfers the contact burn to the relay, or solid state relay that doesn't actually "turn-on" (or off) until "zero-crossing" of the sine-wave.? Either way, the switch no longer bears the brunt of the "spark". W8ZR has a great article on how he did it in an L-4B using a single solid state relay. Command technologies used 2 SSR's in their Commander 2500? I used 2 OPTO22? 240A25 solid state relays in my Hallicrafters HT-45 power supply (built from an L-4B power transformer and similar voltage doubling rectifier/filter circuit to the L-7 / L-4B ) You can find the relays on ebay.? There are 2 types available.? DC controlled (Like W8ZR used)? and AC controlled. I opted for AC control eliminating the need for DC power to control the relays.? The On/OFF switch is still switching (120V) AC power but because the SSR control input resistance is on the order of 33K the switched current is less than 8 mA? (3.6mA each)? and will not cause much if any spark with make or break of the switch. In addition, I put a single SSR in a Drake AC-4 too.? It protects the switch and there's no "thump" in the power supply when I turn on the TR-4
On Sun, May 5, 2024 at 11:31 AM, K6OXN Bob wrote:??? Yes Mike does not have the rebuild kits anymore. I was able to remove the switches and thoroughly cleaned them and checked connections, they now work fine. Still unable to key.?
73? Bob
?
--
73/Rick
W4XA
*Every post is created using Linux
|
Mark Davis
Jim Shorney
Robin K4IDC