|
Recently acquired a Drake L75 for which I am updating its Power Supply to be safe.
A quick question... is the main power switch on the L75 still available?
Was wondering... cause the one on my - older than me - Collins 30L-1 is no longer available. It is a pain just to reach it for service; and is really easier to fill a bottle with parrot saliva than to find one of those.
So, in order to preserve the main switch on my amp, I leave it on all the time and turn it on via an Ameritron In-Rush Current Protection Outlet (ICP-240).
If the story repeats with the Drake L75 amp, then will also take same route like I did with the old Collins.
Stay safe!
Rob
YS1RS
|
As far as I know they are similarly unobtainable. Your external switch idea is a good one!
Best 73 John K5MO
Recently acquired a Drake L75 for which I am updating its Power Supply to be safe.
A quick question... is the main power switch on the L75 still available?
Was wondering... cause the one on my - older than me - Collins 30L-1 is no longer available. It is a pain just to reach it for service; and is really easier to fill a bottle with parrot saliva than to find one of those.
So, in order to preserve the main switch on my amp, I leave it on all the time and turn it on via an Ameritron In-Rush Current Protection Outlet (ICP-240).
If the story repeats with the Drake L75 amp, then will also take same route like I did with the old Collins.
Stay safe!
Rob
YS1RS
|
Where did you source the L75 filter caps from?
.....Dave
On 3/12/21 1:28 PM, Roberto - YS1RS via
groups.io wrote:
toggle quoted message
Show quoted text
Recently
acquired a Drake L75 for which I am updating its Power Supply to
be safe.
A quick question... is the main power switch on the L75 still
available?
Was wondering... cause the one on my - older than me - Collins
30L-1 is no longer available. It is a pain just to reach it for
service; and is really easier to fill a bottle with parrot saliva
than to find one of those.
So, in order to preserve the main switch on my amp, I leave it on
all the time and turn it on via an Ameritron In-Rush Current
Protection Outlet (ICP-240).
If the story repeats with the Drake L75 amp, then will also take
same route like I did with the old Collins.
Stay safe!
Rob
YS1RS
|
I leave mine on all the time and use a pair of 25 amp light switches.? 73s Byron AC9PA? 
toggle quoted message
Show quoted text
On Mar 12, 2021, at 12:28 PM, Roberto - YS1RS via groups.io <ys1rs@...> wrote: ?Recently acquired a Drake L75 for which I am updating its Power Supply to be safe.
A quick question... is the main power switch on the L75 still available?
Was wondering... cause the one on my - older than me - Collins 30L-1 is no longer available. It is a pain just to reach it for service; and is really easier to fill a bottle with parrot saliva than to find one of those.
So, in order to preserve the main switch on my amp, I leave it on all the time and turn it on via an Ameritron In-Rush Current Protection Outlet (ICP-240).
If the story repeats with the Drake L75 amp, then will also take same route like I did with the old Collins.
Stay safe!
Rob
YS1RS
|
Hola Dave and group... Yes! I've sinned. Don't kick me off the group, please... but availability of parts is not always easy here in YS; specially 2W and higher wattage resistors or high voltage parts for applications found in tube equipment. I am using modern caps found locally 150uF x 450 VDC x 105 degrees, which thought I was not going to find but was blessed finding them. Had to modify the boards though. These amps are scarce so no upgrade boards are available for them from commercial sources. All I've done is completely reversible though.
Found one diode burned out and another disolved in my hands so practically replaced them all. Modern 2 watt resistors went in also, as all the original were high in value - out of tolerance. Looks like someone else was in here before me, cause one 1/4W resistor that belongs to the meter network was replaced by a 1/2W. All that has now been corrected.
Had problems with the push button meter switches not closing the circuits correctly.? I guess all those years standing there, on storage, without been in use pass the bill, but now has been lubricated and contact cleaner went in to clean contacts and seems to be working as they should.? This amp belonged to a good friend who became SK eight years ago and the amp has been on storage since. I acquired it from his XYL and will be loved and used in my shack.
The only resistor I have not been able to find locally has been R46, the 0.82 ohm x 2 Watt resistor, that acts as a fuse. ?Too specialized to be found here. It is cracked.? Looking for two of those at present. One to go in the amp and one spare. Apart from that, all seems to be working fine and in progress.?
Will use it as companion to a Yaesu FT-450D; with a proper soft key circuit of course. Still have my doubts how the ALC will work or will be adjusted. Have more reading to do. I do have the original manual.
Comments are welcome.
73 Rob YS1RS
toggle quoted message
Show quoted text
On Mar 12, 2021, at 13:29, Dave Edwards < kd2e@...> wrote:
Where did you source the L75 filter caps from?
.....Dave
On 3/12/21 1:28 PM, Roberto - YS1RS via
wrote:
Recently
acquired a Drake L75 for which I am updating its Power Supply to
be safe.
A quick question... is the main power switch on the L75 still
available?
Was wondering... cause the one on my - older than me - Collins
30L-1 is no longer available. It is a pain just to reach it for
service; and is really easier to fill a bottle with parrot saliva
than to find one of those.
So, in order to preserve the main switch on my amp, I leave it on
all the time and turn it on via an Ameritron In-Rush Current
Protection Outlet (ICP-240).
If the story repeats with the Drake L75 amp, then will also take
same route like I did with the old Collins.
Stay safe!
Rob
YS1RS
|
Those Resistors are available on e-Bay.
73, Dick, W1KSZ
toggle quoted message
Show quoted text
Hola Dave and group...
Yes! I've sinned. Don't kick me off the group, please... but availability of parts is not always easy here in YS; specially 2W and higher wattage resistors or high voltage parts for applications found in tube equipment.
I am using modern caps found locally 150uF x 450 VDC x 105 degrees, which thought I was not going to find but was blessed finding them.
Had to modify the boards though. These amps are scarce so no upgrade boards are available for them from commercial sources. All I've done is completely reversible though.
Found one diode burned out and another disolved in my hands so practically replaced them all.
Modern 2 watt resistors went in also, as all the original were high in value - out of tolerance.
Looks like someone else was in here before me, cause one 1/4W resistor that belongs to the meter network was replaced by a 1/2W. All that has now been corrected.
Had problems with the push button meter switches not closing the circuits correctly.?
I guess all those years standing there, on storage, without been in use pass the bill, but now has been lubricated and contact cleaner went in to clean contacts and seems to be working as they should.?
This amp belonged to a good friend who became SK eight years ago and the amp has been on storage since. I acquired it from his XYL and will be loved and used in my shack.
The only resistor I have not been able to find locally has been R46, the 0.82 ohm x 2 Watt resistor, that acts as a fuse. ?Too specialized to be found here. It is cracked.?
Looking for two of those at present. One to go in the amp and one spare.
Apart from that, all seems to be working fine and in progress.?
Will use it as companion to a Yaesu FT-450D; with a proper soft key circuit of course.
Still have my doubts how the ALC will work or will be adjusted. Have more reading to do.
I do have the original manual.
Comments are welcome.
73
Rob
YS1RS
On Mar 12, 2021, at 13:29, Dave Edwards < kd2e@...> wrote:
Where did you source the L75 filter caps from?
.....Dave
On 3/12/21 1:28 PM, Roberto - YS1RS via wrote:
Recently acquired a Drake L75 for which I am updating its Power Supply to be safe.
A quick question... is the main power switch on the L75 still available?
Was wondering... cause the one on my - older than me - Collins 30L-1 is no longer available. It is a pain just to reach it for service; and is really easier to fill a bottle with parrot saliva than to find one of those.
So, in order to preserve the main switch on my amp, I leave it on all the time and turn it on via an Ameritron In-Rush Current Protection Outlet (ICP-240).
If the story repeats with the Drake L75 amp, then will also take same route like I did with the old Collins.
Stay safe!
Rob
YS1RS
|
Yes, found them there.? I just placed a small order of three. Will take 15 days to come. Now the sweet waiting with patience.?
73 de Rob YS1RS?
toggle quoted message
Show quoted text
On Mar 12, 2021, at 16:23, Dick <w1ksz@...> wrote:
?
Those Resistors are available on e-Bay.
73, Dick, W1KSZ
Hola Dave and group...
Yes! I've sinned. Don't kick me off the group, please... but availability of parts is not always easy here in YS; specially 2W and higher wattage resistors or high voltage parts for applications found in tube equipment.
I am using modern caps found locally 150uF x 450 VDC x 105 degrees, which thought I was not going to find but was blessed finding them.
Had to modify the boards though. These amps are scarce so no upgrade boards are available for them from commercial sources. All I've done is completely reversible though.
Found one diode burned out and another disolved in my hands so practically replaced them all.
Modern 2 watt resistors went in also, as all the original were high in value - out of tolerance.
Looks like someone else was in here before me, cause one 1/4W resistor that belongs to the meter network was replaced by a 1/2W. All that has now been corrected.
Had problems with the push button meter switches not closing the circuits correctly.?
I guess all those years standing there, on storage, without been in use pass the bill, but now has been lubricated and contact cleaner went in to clean contacts and seems to be working as they should.?
This amp belonged to a good friend who became SK eight years ago and the amp has been on storage since. I acquired it from his XYL and will be loved and used in my shack.
The only resistor I have not been able to find locally has been R46, the 0.82 ohm x 2 Watt resistor, that acts as a fuse. ?Too specialized to be found here. It is cracked.?
Looking for two of those at present. One to go in the amp and one spare.
Apart from that, all seems to be working fine and in progress.?
Will use it as companion to a Yaesu FT-450D; with a proper soft key circuit of course.
Still have my doubts how the ALC will work or will be adjusted. Have more reading to do.
I do have the original manual.
Comments are welcome.
73
Rob
YS1RS
On Mar 12, 2021, at 13:29, Dave Edwards < kd2e@...> wrote:
Where did you source the L75 filter caps from?
.....Dave
On 3/12/21 1:28 PM, Roberto - YS1RS via wrote:
Recently acquired a Drake L75 for which I am updating its Power Supply to be safe.
A quick question... is the main power switch on the L75 still available?
Was wondering... cause the one on my - older than me - Collins 30L-1 is no longer available. It is a pain just to reach it for service; and is really easier to fill a bottle with parrot saliva than to find one of those.
So, in order to preserve the main switch on my amp, I leave it on all the time and turn it on via an Ameritron In-Rush Current Protection Outlet (ICP-240).
If the story repeats with the Drake L75 amp, then will also take same route like I did with the old Collins.
Stay safe!
Rob
YS1RS
|
Harbach also has them. Not that these are failsafe safety resistors. 73 -Jim NU0C On Fri, 12 Mar 2021 17:18:08 -0600 "Roberto - YS1RS via groups.io" <ys1rs@...> wrote: Yes, found them there.
I just placed a small order of three.
Will take 15 days to come.
Now the sweet waiting with patience.
73 de Rob
YS1RS
On Mar 12, 2021, at 16:23, Dick <w1ksz@...> wrote:
?
Those Resistors are available on e-Bay.
73, Dick, W1KSZ
From: [email protected] <[email protected]> on behalf of Roberto - YS1RS via groups.io <ys1rs@...>
Sent: Friday, March 12, 2021 3:16 PM
To: [email protected] <[email protected]>
Subject: Re: [DRAKE-RADIO] L75 Amp Main Power Switch Availability
Hola Dave and group...
Yes! I've sinned. Don't kick me off the group, please... but availability of parts is not always easy here in YS; specially 2W and higher wattage resistors or high voltage parts for applications found in tube equipment.
I am using modern caps found locally 150uF x 450 VDC x 105 degrees, which thought I was not going to find but was blessed finding them.
Had to modify the boards though. These amps are scarce so no upgrade boards are available for them from commercial sources. All I've done is completely reversible though.
Found one diode burned out and another disolved in my hands so practically replaced them all.
Modern 2 watt resistors went in also, as all the original were high in value - out of tolerance.
Looks like someone else was in here before me, cause one 1/4W resistor that belongs to the meter network was replaced by a 1/2W. All that has now been corrected.
Had problems with the push button meter switches not closing the circuits correctly.
I guess all those years standing there, on storage, without been in use pass the bill, but now has been lubricated and contact cleaner went in to clean contacts and seems to be working as they should.
This amp belonged to a good friend who became SK eight years ago and the amp has been on storage since. I acquired it from his XYL and will be loved and used in my shack.
The only resistor I have not been able to find locally has been R46, the 0.82 ohm x 2 Watt resistor, that acts as a fuse. Too specialized to be found here. It is cracked.
Looking for two of those at present. One to go in the amp and one spare.
Apart from that, all seems to be working fine and in progress.
Will use it as companion to a Yaesu FT-450D; with a proper soft key circuit of course.
Still have my doubts how the ALC will work or will be adjusted. Have more reading to do.
I do have the original manual.
Comments are welcome.
73
Rob
YS1RS
.
On Mar 12, 2021, at 13:29, Dave Edwards <kd2e@...> wrote:
Where did you source the L75 filter caps from?
.....Dave
On 3/12/21 1:28 PM, Roberto - YS1RS via groups.io wrote:
Recently acquired a Drake L75 for which I am updating its Power Supply to be safe.
A quick question... is the main power switch on the L75 still available?
Was wondering... cause the one on my - older than me - Collins 30L-1 is no longer available. It is a pain just to reach it for service; and is really easier to fill a bottle with parrot saliva than to find one of those.
So, in order to preserve the main switch on my amp, I leave it on all the time and turn it on via an Ameritron In-Rush Current Protection Outlet (ICP-240).
If the story repeats with the Drake L75 amp, then will also take same route like I did with the old Collins.
Stay safe!
Rob
YS1RS
|
The ones I ordered are from NTE electronics.... maybe are not the ones needed for safety....?
Ups
Rob
YS1RS
toggle quoted message
Show quoted text
On Mar 12, 2021, at 19:36, Jim Shorney <jshorney@...> wrote:
?
Harbach also has them. Not that these are failsafe safety resistors.
73
-Jim
NU0C
On Fri, 12 Mar 2021 17:18:08 -0600
"Roberto - YS1RS via groups.io" <ys1rs@...> wrote:
Yes, found them there.
I just placed a small order of three.
Will take 15 days to come.
Now the sweet waiting with patience.
73 de Rob
YS1RS
On Mar 12, 2021, at 16:23, Dick <w1ksz@...> wrote: ?
Those Resistors are available on e-Bay.
73, Dick, W1KSZ
From: [email protected] <[email protected]> on behalf of Roberto - YS1RS via groups.io <ys1rs@...>
Sent: Friday, March 12, 2021 3:16 PM
To: [email protected] <[email protected]>
Subject: Re: [DRAKE-RADIO] L75 Amp Main Power Switch Availability
Hola Dave and group...
Yes! I've sinned. Don't kick me off the group, please... but availability of parts is not always easy here in YS; specially 2W and higher wattage resistors or high voltage parts for applications found in tube equipment.
I am using modern caps found locally 150uF x 450 VDC x 105 degrees, which thought I was not going to find but was blessed finding them.
Had to modify the boards though. These amps are scarce so no upgrade boards are available for them from commercial sources. All I've done is completely reversible though.
Found one diode burned out and another disolved in my hands so practically replaced them all.
Modern 2 watt resistors went in also, as all the original were high in value - out of tolerance.
Looks like someone else was in here before me, cause one 1/4W resistor that belongs to the meter network was replaced by a 1/2W. All that has now been corrected.
Had problems with the push button meter switches not closing the circuits correctly.
I guess all those years standing there, on storage, without been in use pass the bill, but now has been lubricated and contact cleaner went in to clean contacts and seems to be working as they should.
This amp belonged to a good friend who became SK eight years ago and the amp has been on storage since. I acquired it from his XYL and will be loved and used in my shack.
The only resistor I have not been able to find locally has been R46, the 0.82 ohm x 2 Watt resistor, that acts as a fuse. Too specialized to be found here. It is cracked.
Looking for two of those at present. One to go in the amp and one spare.
Apart from that, all seems to be working fine and in progress.
Will use it as companion to a Yaesu FT-450D; with a proper soft key circuit of course.
Still have my doubts how the ALC will work or will be adjusted. Have more reading to do.
I do have the original manual.
Comments are welcome.
73
Rob
YS1RS
.
On Mar 12, 2021, at 13:29, Dave Edwards <kd2e@...> wrote:
Where did you source the L75 filter caps from?
.....Dave
On 3/12/21 1:28 PM, Roberto - YS1RS via groups.io wrote:
Recently acquired a Drake L75 for which I am updating its Power Supply to be safe.
A quick question... is the main power switch on the L75 still available?
Was wondering... cause the one on my - older than me - Collins 30L-1 is no longer available. It is a pain just to reach it for service; and is really easier to fill a bottle with parrot saliva than to find one of those.
So, in order to preserve the main switch on my amp, I leave it on all the time and turn it on via an Ameritron In-Rush Current Protection Outlet (ICP-240).
If the story repeats with the Drake L75 amp, then will also take same route like I did with the old Collins.
Stay safe!
Rob
YS1RS
|
Maybe, maybe not. You may be able to find out on the NTE web site. The originals are IRC SPH 0.82Ω 2W 73 -Jim NU0C On Fri, 12 Mar 2021 20:45:03 -0600 "Roberto - YS1RS via groups.io" <ys1rs@...> wrote: The ones I ordered are from NTE electronics.... maybe are not the ones needed for safety....?
Ups
Rob
YS1RS
On Mar 12, 2021, at 19:36, Jim Shorney <jshorney@...> wrote:
?
Harbach also has them. Not that these are failsafe safety resistors.
73
-Jim
NU0C
On Fri, 12 Mar 2021 17:18:08 -0600
"Roberto - YS1RS via groups.io" <ys1rs@...> wrote:
Yes, found them there.
I just placed a small order of three.
Will take 15 days to come.
Now the sweet waiting with patience.
73 de Rob
YS1RS
On Mar 12, 2021, at 16:23, Dick <w1ksz@...> wrote: ?
Those Resistors are available on e-Bay.
73, Dick, W1KSZ
From: [email protected] <[email protected]> on behalf of Roberto - YS1RS via groups.io <ys1rs@...>
Sent: Friday, March 12, 2021 3:16 PM
To: [email protected] <[email protected]>
Subject: Re: [DRAKE-RADIO] L75 Amp Main Power Switch Availability
Hola Dave and group...
Yes! I've sinned. Don't kick me off the group, please... but availability of parts is not always easy here in YS; specially 2W and higher wattage resistors or high voltage parts for applications found in tube equipment.
I am using modern caps found locally 150uF x 450 VDC x 105 degrees, which thought I was not going to find but was blessed finding them.
Had to modify the boards though. These amps are scarce so no upgrade boards are available for them from commercial sources. All I've done is completely reversible though.
Found one diode burned out and another disolved in my hands so practically replaced them all.
Modern 2 watt resistors went in also, as all the original were high in value - out of tolerance.
Looks like someone else was in here before me, cause one 1/4W resistor that belongs to the meter network was replaced by a 1/2W. All that has now been corrected.
Had problems with the push button meter switches not closing the circuits correctly.
I guess all those years standing there, on storage, without been in use pass the bill, but now has been lubricated and contact cleaner went in to clean contacts and seems to be working as they should.
This amp belonged to a good friend who became SK eight years ago and the amp has been on storage since. I acquired it from his XYL and will be loved and used in my shack.
The only resistor I have not been able to find locally has been R46, the 0.82 ohm x 2 Watt resistor, that acts as a fuse. Too specialized to be found here. It is cracked.
Looking for two of those at present. One to go in the amp and one spare.
Apart from that, all seems to be working fine and in progress.
Will use it as companion to a Yaesu FT-450D; with a proper soft key circuit of course.
Still have my doubts how the ALC will work or will be adjusted. Have more reading to do.
I do have the original manual.
Comments are welcome.
73
Rob
YS1RS
.
On Mar 12, 2021, at 13:29, Dave Edwards <kd2e@...> wrote:
Where did you source the L75 filter caps from?
.....Dave
On 3/12/21 1:28 PM, Roberto - YS1RS via groups.io wrote:
Recently acquired a Drake L75 for which I am updating its Power Supply to be safe.
A quick question... is the main power switch on the L75 still available?
Was wondering... cause the one on my - older than me - Collins 30L-1 is no longer available. It is a pain just to reach it for service; and is really easier to fill a bottle with parrot saliva than to find one of those.
So, in order to preserve the main switch on my amp, I leave it on all the time and turn it on via an Ameritron In-Rush Current Protection Outlet (ICP-240).
If the story repeats with the Drake L75 amp, then will also take same route like I did with the old Collins.
Stay safe!
Rob
YS1RS
|
Rob - The Power Switch used on the Drake L75 HF Amplifier was Very Common in 1960s and 1970s. I was used as the Power Switch on Window Air Conditioners (240 VAC) in North America. Numerous Rocker Switch manufacturers (Eaton, Carling, etc.) Eaton still manufacturers this Rocker Switch series: Rockette (page 56-57 of catalog)
—
Look at 1960s Star Trek episodes, and you will see that switch.
Used ones can be “Harvested” from Junk Yards where old Air Conditioners are sent, OR
you can find NOS switches at HVAC contractors with historic parts inventory.
==
For those with DIY Skills, disassembly can repair many (corrosion, carbon from Arc).
Need to Replace the Drake L75 Band Switch?
gb
|
Great info!!! Will save it.? Thanks for sharing.
Rob
toggle quoted message
Show quoted text
On Mar 13, 2021, at 07:44, Gregory Beat via groups.io <w9gb@...> wrote:
? [Edited Message Follows]
Rob - The Power Switch used on the Drake L75 HF Amplifier was Very Common in 1960s and 1970s. I was used as the Power Switch on Window Air Conditioners (240 VAC) in North America. Numerous Rocker Switch manufacturers (Eaton, Carling, etc.) Eaton still manufacturers this Rocker Switch series: Rockette (page 56-57 of catalog)
—
Look at 1960s Star Trek episodes, and you will see that switch.
Used ones can be “Harvested” from Junk Yards where old Air Conditioners are sent, OR
you can find NOS switches at HVAC contractors with historic parts inventory.
==
For those with DIY Skills, disassembly can repair many (corrosion, carbon from Arc).
Need to Replace the Drake L75 Band Switch?
gb
|
Hello Yes the switches can been had. My Elmer set his amps up with the 25 amp light switches. I just bought 2 for $10 at local hardware store for second operating position. Takes 10 -15 minutes to wire up . Lot easier than taking all those little screws out of L7 ! Hihi? 73s Byron AC9PA?
toggle quoted message
Show quoted text
On Mar 13, 2021, at 7:43 AM, Gregory Beat via groups.io <w9gb@...> wrote: ?Rob - The Power Switch used on the Drake L75 HF Amplifier was Very Common in 1960s and 1970s. I was used as the Power Switch on Window Air Conditioners (240 VAC) in North America. Numerous Rocker Switch manufacturers (Eaton, Carling, etc.) Eaton still manufacturers this Rocker Switch series: Rockette (page 56-57 of catalog)
—
Look at 1960s Star Trek episodes, and you will see that switch.
Used ones can be “Harvested” from Junk Yards where old Air Conditioners are sent, OR
you can find NOS switches at HVAC contractors with historic parts inventory.
==
For those with DIY Skills, disassembly can repair many (corrosion, carbon from Arc).
Need to Replace the Drake L75 Band Switch?
gb
|
Regarding the Collins 30L-1 Power (Rocker) Switch, as noted earlier, MANY Rocker Switch manufacturers produced this rocker switch type. == Collins sourced their switch from McGill Manufacturing Company.
Mc Gill Mfg Co.?
907 N. Lafayette St.?
Valparaiso, IN 46383?
Collins OEM Vendor P/N C811-113010109?
That "C" in the part number may mean it was special-ordered?by Collins.?
==
In 1990, McGill Mfg. was purchased by Emerson Electric.
The McGill?Electrical Division was merged with Emerson’s Appleton Electric Division
and continues to exist today under the Emerson umbrella.
|
0852/0862?Series Rocker Switches are available in single pole (0852) and double pole (0862), unlighted and lighted models. Unlighted versions are available with white, black and red rockers. Lighted versions are available with white, black or red rockers with either a clear, red or green lens. These switches are equipped with nylon snap-in brackets. They are Vac rated switches also suitable for low voltage Vdc applications.
|
Those .82 ohm? @? 2 watt? resistors? are a bad joke when used for a.... 'HV fuse'.?
I found surplus? BUSS? ?HVB.75? ?HV fuses? at? SSON.? ?
Scroll? way down to? very bottom left hand? corner.?
The? HVB-.75? ?is? ?3/8"? diam x 4.4"? long.? The end caps are? .41"? diameter. (13/32") .? They are rated at? 750 ma? CCS? @? 2.5 kv .? ?That? 2.5 kv rating is the AC? rating.? The actual DC rating is
3535 vdc...which is ample for the? drake amps.?
The correct? mating? ?3/8" fuse? clip? is found here.? ?
Scroll? way down the left side till? you find?
(CLP) FC-21CF
Silver plated 3/8" - 7/16" clip fits 15 watt carbon resistors. End stop retainer. Also fits F09 (3/8"D) fuses.
##? ?These are? things of beauty !? All silver plated, and include the all important end stop retainers.? Once the? BUSS? HVB-.75 is installed, it can not migrate out.? ?Fuse can be mounted? either horz or vert.?
The? .410"? diameter? end pieces fit the mating above? Fuse clips? good and tight.? ? ?I mounted one? ?HVB-.75? ?fuse in the? L4PS? power supply.? ? I used a 50 ohm @? 50 watt? wire wound resistor? for the? 'glitch resistor'.?
##? B+? 1st goes through the? fuse....? THEN the? 50 ohm? glitch resistor..then to? RF deck.? ? The? 50 ohm resistor LIMITS the? fault current to a safe value...? and the? HV fuse? INTERUPTS the fault current..and does so in
< 2 msecs... event? over.? ?With? 2650 vdc on the L4PS, fault current is just? 2650 /? 50 ohms? = 53 amps.? ? 53? amps? will indeed? open off a? 750 ma rated? HV fuse? in? < 2 msecs.? ?Buddy tested this in his lab, with repeatable? results.? ?IF u don't have
room for a 50 ohm? @? 50 watt? wire? wound,? you can series? 2 x 25 ohm? @? 25 watt? wire wounds.?
##? The? surplus? BUSS? HVB- .75? ?is a bargain price.? ?I use the bigger? HVU-3? for the? bigger amps..and mating 3/4"? silver plated? fuse clips ( made by the same outfit as the smaller? 3/8"? clips). They too, open off? in? <? 2 ,msecs? every time. ( bigger 50 ohm glitch resistor assy used,? comprised of 4 x 200? ohm, typ? AS? globars).
Jim? ?VE7RF
##? what I would? NOT recommend is? ? Microwave? oven? 5 kv rated? fuses.? They are? NOT? ?UL? /? CSA rated.? ?W8ZR had a B+? arc... and the? chinese microwave oven 5 kv rated? glass? fuse exploded with glass everywhere !? ? ?Those? 5 kv rated MO? fuses are a bit longer than a 3AGC? fuse.??
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Hmm... They survived through three engineering generations and served the purpose over the decades of real world use. Real HV fuses are expensive for a new build. Even the great W8JI espouses the use of fault limiting resistors, although he prefers higher values. 73 -Jim NU0C On Sun, 14 Mar 2021 12:03:51 -0700 "Jim VE7RF" <jim.thom@...> wrote: Those .82 ohm? @? 2 watt? resistors? are a bad joke when used for a.... 'HV fuse'.
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Emerson still has the McGill / Appleton 811 series Rocker switch (on product list),
Made to Order. ?
gb
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On Sun, Mar 14, 2021 at 08:21 PM, Jim Shorney wrote:
<Hmm... They survived through three engineering generations and served the purpose over the decades of real world use. Real HV fuses are expensive for a new build. Even the great W8JI <espouses the use of fault limiting resistors, although he prefers higher values.
<73
<-Jim
<NU0C
##? ?You won't see any amps other than drake, using a .82 ohm? @? 2 watt? resistor.....for a... 'hv? fuse'.? ?New, correctly sized? HV? fuses are cheap, and meet? ?UL /? CSA? standards.? ?Drake could have bought thousands of em? at whole sale prices.? ?W8JI? typ will use 10 ohm,? or? 20? ohm max, for the? current limiting resistor (aka...'glitch resistor').? ?ARRL handbook? sez to use? 10-15 ohms? per KV.? ?After building? 38? x hb? B+? supplies over the years, and experimenting with different value glitch resistors,? I settled on? 50 ohms, regardless of the? actual? B+? value.? ?But it's a two edged sword.? ?Higher values will limit fault current to a lower value.... BUT dissipate more heat, depending on? mode, and how much average plate current involved.? ?Higher value? glitch resistors? also have a higher? V drop? across them...? ( which will increase even more, with higher plate currents).?
##? In? L4B? size amps,? ?with say? 2650 vdc no load..and a fault occurred,? it's then just 2650 /? 50 ohms =? ? 53 amps of fault current.? And? ?53 amps of fault current will open off that? BUSS? 750 ma HV fuse in? < 2 msecs? every time.? ?On a L4B, with? 800 ma peaks on? ssb,? the? V drop on peaks is .8? X? 50 ohms? = 40 vdc? V drop on the loaded? B+.? ? Average plate current on ssb mode is? typ? 400 ma( with processing).? ?(.4 X.4 )? ?X 50 ohms =? ? 8 watts dissipation? in the? 50 ohm glitch R.? ?( and? 32 watts if a? 800 ma? dead cxr, like tuning up with a cxr).? ?Hence my use of a? simple? 50 ohm, 50 watt wire wound? for the glitch? R.?
##? On the bigger? HB? B+? supplies, with a lot more filter C,? ?I use globar type AS? resistors.? The? AS types are designed for glitch service, and will handle a lot of joules of? energy...and also a lot of HV.? Typ,? 4 x 200 ohm, type? AS? resistors are wired in parallel..and also fan cooled.? ?But that's what's required for 5-8 kv dc? supplies..and tubes that? suck 1.5? to 3 amps of plate current.? ?3 amps? ccs? into 50 ohms? =? ?450 watts, which is a bunch.? The type? AS? resistors are? 18"? long x 1.5"? diam,? rated for? 225 watts each /? 900 w? total.? They run hot when used in ccs modes.? ?Lower? duty cycle modes like? ssb is a non issue,? only? ?1/4 the? dissipation...same as? the 50 ohms used in the? L4B? B+? supply.
Jim? VE7RF
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I'm not going to waste time debating trivia with you. I just don't want the audience to get the impression that the L-4B is some pathetic POS that doesn't even deserve to be on 11 Meters based on your rantings. The fact is that a countless number of these amps have been in service for decades and they do the job they were intended to do as-is. 73 -Jim NU0C On Tue, 23 Mar 2021 08:51:49 -0700 "Jim VE7RF" <jim.thom@...> wrote: On Sun, Mar 14, 2021 at 08:21 PM, Jim Shorney wrote:
<Hmm... They survived through three engineering generations and served the
purpose over the decades of real world use. Real HV fuses are expensive
for a new build. Even the great W8JI <espouses the use of fault limiting
resistors, although he prefers higher values.
<73
<-Jim
<NU0C
##? ?You won't see any amps other than drake, using a .82 ohm? @? 2 watt? resistor.....for a... 'hv? fuse'.? ?New, correctly sized? HV? fuses are cheap, and meet? ?UL /? CSA? standards.? ?Drake could have bought thousands of em? at whole sale prices.? ?W8JI? typ will use 10 ohm,? or? 20? ohm max, for the? current limiting resistor (aka...'glitch resistor').? ?ARRL handbook? sez to use? 10-15 ohms? per KV.? ?After building? 38? x hb? B+? supplies over the years, and experimenting with different value glitch resistors,? I settled on? 50 ohms, regardless of the? actual? B+? value.? ?But it's a two edged sword.? ?Higher values will limit fault current to a lower value.... BUT dissipate more heat, depending on? mode, and how much average plate current involved.? ?Higher value? glitch resistors? also have a higher? V drop? across them...? ( which will increase even more, with higher plate currents).
##? In? L4B? size amps,? ?with say? 2650 vdc no load..and a fault occurred,? it's then just 2650 /? 50 ohms =? ? 53 amps of fault current.? And? ?53 amps of fault current will open off that? BUSS? 750 ma HV fuse in? < 2 msecs? every time.? ?On a L4B, with? 800 ma peaks on? ssb,? the? V drop on peaks is .8? X? 50 ohms? = 40 vdc? V drop on the loaded? B+.? ? Average plate current on ssb mode is? typ? 400 ma( with processing).? ?(.4 X.4 )? ?X 50 ohms =? ? 8 watts dissipation? in the? 50 ohm glitch R.? ?( and? 32 watts if a? 800 ma? dead cxr, like tuning up with a cxr).? ?Hence my use of a? simple? 50 ohm, 50 watt wire wound? for the glitch? R.
##? On the bigger? HB? B+? supplies, with a lot more filter C,? ?I use globar type AS? resistors.? The? AS types are designed for glitch service, and will handle a lot of joules of? energy...and also a lot of HV.? Typ,? 4 x 200 ohm, type? AS? resistors are wired in parallel..and also fan cooled.? ?But that's what's required for 5-8 kv dc? supplies..and tubes that? suck 1.5? to 3 amps of plate current.? ?3 amps? ccs? into 50 ohms? =? ?450 watts, which is a bunch.? The type? AS? resistors are? 18"? long x 1.5"? diam,? rated for? 225 watts each /? 900 w? total.? They run hot when used in ccs modes.? ?Lower? duty cycle modes like? ssb is a non issue,? only? ?1/4 the? dissipation...same as? the 50 ohms used in the? L4B? B+? supply.
Jim? VE7RF
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Roberto - YS1RS
Dick
Jim Shorney
Greg W9GB