|
A local ham dropped in a Yaesu FL-2100Z amp tp me and said that he would like all the PA0FRI mods done to it.
See
This is no big problem, as most of the mods are common sense and they are what one would normally do to an amp.
However, there is one mod that strikes me as odd.
He suggests cutting the grounding wires on VC1, the plate tune capacitor, and running a thick wire or coax from the cold side of VC1 to a ground point at the base of one of the 572B sockets.
This seems very odd to me. I don't see how this would enhance stability, having that grounding wire running all that way.
Every amp I have seen or built, has the cold end of the capacitor bonded to the nearest point on the chassis.
Should one be doing this mod? My feeling is that it should be left alone.
Opinions appreciated.
Thanks, Alek.
VK6APK
--
From sunny Binningup
Family Businesses:
SP Electrical. www.spelectrical.net.au
The Velvet Fox.
Smart Design Electrical.
Perth Interiors.
|
GN, I've made some mods to 2100B, 2100Z, etc., several. I have never made that specific mod, all amps worked fine and stable. What I usually do is to add extra decoupling caps in plate choke base (4400 pF extra), plus one 1000 pF before glitch resistor; 15 ohm 10 watt glitch resistor at rectifiers pcb; increase grid caps upto 1000 pF; back to back 1N5408 diodes (at shunt's place). General cleaning, resolder and checking bias pcb caps and resistor values, lube fan motors, checking SWR diodes and its compensation, etc. You can add in parallel the extra, not used contacts at RL1 (I ask myself why they didn't). Don't forget to check the HV capacitors inside the tube's cage, some may be cracked (see the attached image). If you need extra parameters, ratings at half and full voltage, email me. Regards Guillermo - LU5WE. El 30/8/19 a las 21:18, Alek Petkovic vk6apk@... [ham_amplifiers] escribió: ?
A local ham dropped in a Yaesu FL-2100Z amp tp me and said that he would
like all the PA0FRI mods done to it.
See
This is no big problem, as most of the mods are common sense and they
are what one would normally do to an amp.
However, there is one mod that strikes me as odd.
He suggests cutting the grounding wires on VC1, the plate tune
capacitor, and running a thick wire or coax from the cold side of VC1 to
a ground point at the base of one of the 572B sockets.
This seems very odd to me. I don't see how this would enhance stability,
having that grounding wire running all that way.
Every amp I have seen or built, has the cold end of the capacitor bonded
to the nearest point on the chassis.
Should one be doing this mod? My feeling is that it should be left alone.
Opinions appreciated.
Thanks, Alek.
VK6APK
--
From sunny Binningup
Family Businesses:
SP Electrical. www.spelectrical.net.au
The Velvet Fox.
Smart Design Electrical.
Perth Interiors.
|
Hi
I have done an amp that had suffered multiple oscillations on 10 meters and damaged the bandswitch.?
The grounding of VC1 was done according to the article and that cured the oscillation. Amp was stable and still is without burning bandswitch contacts.
It seems not all amps have the problem with instability, but if the amp you are working on Alek, have arc marks on the bandswitch, this may be the remedy.
73 Sam HS0ZDY
toggle quoted message
Show quoted text
On Aug 31, 2562 BE, at 07:48, GGLL guiye8@... [ham_amplifiers] < ham_amplifiers@...> wrote:
?
GN, I've made some mods to 2100B, 2100Z, etc., several.
I have never made that specific mod, all amps worked fine and stable.
What I usually do is to add extra decoupling caps in plate choke base
(4400 pF extra), plus one 1000 pF before glitch resistor; 15 ohm 10 watt
glitch resistor at rectifiers pcb; increase grid caps upto 1000 pF; back
to back 1N5408 diodes (at shunt's place).
General cleaning, resolder and checking bias pcb caps and resistor
values, lube fan motors, checking SWR diodes and its compensation, etc.
You can add in parallel the extra, not used contacts at RL1 (I ask
myself why they didn't).
Don't forget to check the HV capacitors inside the tube's cage, some may
be cracked (see the attached image).
If you need extra parameters, ratings at half and full voltage, email me.
Regards
Guillermo - LU5WE.
El 30/8/19 a las 21:18, Alek Petkovic vk6apk@...
[ham_amplifiers] escribió:
> ?
>
> A local ham dropped in a Yaesu FL-2100Z amp tp me and said that he would
> like all the PA0FRI mods done to it.
>
> See
>
> This is no big problem, as most of the mods are common sense and they
> are what one would normally do to an amp.
>
> However, there is one mod that strikes me as odd.
>
> He suggests cutting the grounding wires on VC1, the plate tune
> capacitor, and running a thick wire or coax from the cold side of VC1 to
> a ground point at the base of one of the 572B sockets.
>
> This seems very odd to me. I don't see how this would enhance stability,
> having that grounding wire running all that way.
>
> Every amp I have seen or built, has the cold end of the capacitor bonded
> to the nearest point on the chassis.
>
> Should one be doing this mod? My feeling is that it should be left alone.
>
> Opinions appreciated.
>
> Thanks, Alek.
> VK6APK
>
> --
> From sunny Binningup
>
> Family Businesses:
> SP Electrical.
> The Velvet Fox.
> Smart Design Electrical.
> Perth Interiors.
>
>
|
Alek, I’d?check and see what Tom W8JI recommends at his web page for those amps. ?I’d also consider if any of the rest of the mods are a good idea as well. ?I know some are ok but some are also questionable. ?Lou Sent from AOL Mobile Mail
Get the new AOL app:
?
A local ham dropped in a Yaesu FL-2100Z amp tp me and said that he would
like all the PA0FRI mods done to it.
See http://www.pa0fri.com/
This is no big problem, as most of the mods are common sense and they
are what one would normally do to an amp.
However, there is one mod that strikes me as odd.
He suggests cutting the grounding wires on VC1, the plate tune
capacitor, and running a thick wire or coax from the cold side of VC1 to
a ground point at the base of one of the 572B sockets.
This seems very odd to me. I don't see how this would enhance stability,
having that grounding wire running all that way.
Every amp I have seen or built, has the cold end of the capacitor bonded
to the nearest point on the chassis.
Should one be doing this mod? My feeling is that it should be left alone.
Opinions appreciated.
Thanks, Alek.
VK6APK
--
From sunny Binningup
Family Businesses:
SP Electrical. www.spelectrical.net.au
The Velvet Fox. https://www.facebook.com/TheVelvetFox/
Smart Design Electrical. https://www.facebook.com/smartdesignelectrical/
Perth Interiors. https://www.instagram.com/perthinteriors/
|
Thanks Lou.
Yes, with every amp that passes through here, particularly the Yaesu
and Ameritron models, the first thing I do is get the filament volts
down from 6.8v or 6.9V, to as close as possible to 6.3V.
Then a glitch resistor and the back to back diodes.
I always check the filter caps, bleeders and rectifier diodes and
replace the lot, if there are signs of trouble.
A check of the parasitic suppressor resistors is always done and in the
older, more well used amps, these resistors need replacing.
This particular 2100Z, is the most pristine I've ever seen. Original
Cetron tubes, without a mark or speck of dust on them. The outside and
inside of the amp, are like the thing has never been used. The fan
blades are spotless. Just everything is spotless.
So, that's all I've done with this particular amp. I'll let the guy
pick it up, as is.
Oh, it had a 2 wire mains power lead, with a US plug on it. I changed
it for a 3 wire, so it could be properly earthed, to comply more
closely with Aussie rules.
Thanks and 73, Alek.
On 31/08/2019 6:44 PM, Gudguyham@... [ham_amplifiers] wrote:
Alek, I’d?check and see what Tom W8JI recommends at his web page for
those amps. ?I’d also consider if any of the rest of the mods are a
good idea as well. ?I know some are ok but some are also questionable.
?Lou
Sent
from AOL Mobile Mail
Get the new AOL app:
?
A local ham dropped in a Yaesu FL-2100Z amp tp me and said that
he would
like all the PA0FRI mods done to it.
See
This is no big problem, as most of the mods are common sense and they
are what one would normally do to an amp.
However, there is one mod that strikes me as odd.
He suggests cutting the grounding wires on VC1, the plate tune
capacitor, and running a thick wire or coax from the cold side of VC1
to
a ground point at the base of one of the 572B sockets.
This seems very odd to me. I don't see how this would enhance
stability,
having that grounding wire running all that way.
Every amp I have seen or built, has the cold end of the capacitor
bonded
to the nearest point on the chassis.
Should one be doing this mod? My feeling is that it should be left
alone.
Opinions appreciated.
Thanks, Alek.
VK6APK
--
From sunny Binningup
Family Businesses:
SP Electrical.
The Velvet Fox.
Smart Design Electrical.
Perth Interiors.
--
From sunny Binningup
Family Businesses:
SP Electrical.
The Velvet Fox.
Smart Design Electrical.
Perth Interiors.
|
Very interesting Sam. Thanks for that info.
Cheers, Alek.
On 31/08/2019 10:50 AM, Svante Nordenstrom sm3dyu@...
[ham_amplifiers] wrote:
Hi
I have done an amp that had suffered
multiple oscillations on 10 meters and damaged the bandswitch.?
The grounding of VC1 was done according
to the article and that cured the oscillation. Amp was stable and still
is without burning bandswitch contacts.
It seems not all amps have the problem
with instability, but if the amp you are working on Alek, have arc
marks on the bandswitch, this may be the remedy.
73
Sam
HS0ZDY
?
GN, I've made some mods to 2100B, 2100Z, etc., several.
I have never made that specific mod, all amps worked fine and stable.
What I usually do is to add extra decoupling caps in plate choke base
(4400 pF extra), plus one 1000 pF before glitch resistor; 15 ohm 10 watt
glitch resistor at rectifiers pcb; increase grid caps upto 1000 pF; back
to back 1N5408 diodes (at shunt's place).
General cleaning, resolder and checking bias pcb caps and resistor
values, lube fan motors, checking SWR diodes and its compensation, etc.
You can add in parallel the extra, not used contacts at RL1 (I ask
myself why they didn't).
Don't forget to check the HV capacitors inside the tube's cage, some may
be cracked (see the attached image).
If you need extra parameters, ratings at half and full voltage, email
me.
Regards
Guillermo - LU5WE.
El 30/8/19 a las 21:18, Alek Petkovic vk6apk@...
[ham_amplifiers] escribió:
> ?
>
> A local ham dropped in a Yaesu FL-2100Z amp tp me and said that he
would
> like all the PA0FRI mods done to it.
>
> See
>
> This is no big problem, as most of the mods are common sense and
they
> are what one would normally do to an amp.
>
> However, there is one mod that strikes me as odd.
>
> He suggests cutting the grounding wires on VC1, the plate tune
> capacitor, and running a thick wire or coax from the cold side of
VC1 to
> a ground point at the base of one of the 572B sockets.
>
> This seems very odd to me. I don't see how this would enhance
stability,
> having that grounding wire running all that way.
>
> Every amp I have seen or built, has the cold end of the capacitor
bonded
> to the nearest point on the chassis.
>
> Should one be doing this mod? My feeling is that it should be left
alone.
>
> Opinions appreciated.
>
> Thanks, Alek.
> VK6APK
>
> --
> From sunny Binningup
>
> Family Businesses:
> SP Electrical.
> The Velvet Fox.
> Smart Design Electrical.
> Perth Interiors.
>
>
--
From sunny Binningup
Family Businesses:
SP Electrical.
The Velvet Fox.
Smart Design Electrical.
Perth Interiors.
|
?
I have worked on numerous 2100Z amps including some
converted to 6M and have had not needed any special mods other than to the bias
supply for Svetlana tubes.
?
I have looked at his mostly off the wall mods for
the SB-200 as real Hammy Hambone technology.
?
Carl
----- Original Message -----
Sent: Saturday, August 31, 2019 6:44
AM
Subject: Re: [ham_amplifiers] FL-2100Z
Mods
?
Alek, I’d?check and see what Tom W8JI recommends at his web page for
those amps. ?I’d also consider if any of the rest of the mods are a good
idea as well. ?I know some are ok but some are also questionable.
?Lou
Sent
from AOL Mobile Mail
Get the new AOL app:
?
A local ham dropped in a Yaesu FL-2100Z amp tp me and said that he would
like all the PA0FRI mods done to it.
See http://www.pa0fri.com/
This is
no big problem, as most of the mods are common sense and they
are what one would normally do to an amp.
However, there is one mod that strikes me as odd.
He suggests cutting the grounding wires on VC1,
the plate tune
capacitor, and running a thick wire or coax
from the cold side of VC1 to
a ground point at the base of
one of the 572B sockets.
This seems very odd to
me. I don't see how this would enhance stability,
having that
grounding wire running all that way.
Every amp
I have seen or built, has the cold end of the capacitor bonded
to the nearest point on the chassis.
Should one be doing this mod? My feeling is that it should be
left alone.
Opinions appreciated.
Thanks, Alek.
VK6APK
--
From sunny Binningup
Family Businesses:
SP Electrical.
www.spelectrical.net.au
The Velvet Fox.
https://www.facebook.com/TheVelvetFox/
Smart Design
Electrical. https://www.facebook.com/smartdesignelectrical/
Perth Interiors. https://www.instagram.com/perthinteriors/
|
Hi Alek,
I trust you are well. Have you done the step start mod ?“A simple but effective delay can be done with an NTC resistor. The primary winding of the transformer is only a few Ohm, so that a 1Ohm/20A NTC is sufficient to limit the large momentary switching currents of uncharged HV elco's and cold filaments.”
Is it effective? Other soft step start arrangements seem more complex.
I look forward to hearing from you.
Best wishes
Angus
?
|
G'day Angus.
Sorry for the delay. I missed your email and I'm just cleaning up
my emails and noticed this one.
Yes, the NTC works. I use them in this form for a lot of amps
that I build. See Ebay Item number 402565661699.
They are compact
and work extremely well.
I've never bothered
with soft starts for the little Yaesu amps, as all the Yaesus
I've worked on, have excessive filament voltage at the filament
pins when connected to our AC mains.
A low value of
resistance made up of 5W wirewound resistors in parallel in
series with the filaments brings the volts back from around 6.9
- 7.0V back down to the nominal 6.3V. This resistance, usually
around 0.15 Ohms, also provides a measure of inrush protection
to the filaments. This is very important when using Chinese
valves, which hate excessive volts on the filament.
Cheers from sunny
Binningup, Western Australia.
Alek VK6APK
On 16/11/2024 5:06 am, AngusGM6AGC via
groups.io wrote:
toggle quoted message
Show quoted text
Hi Alek,
I trust you are well. Have you
done the step start mod ?“A
simple but effective delay can be done with an NTC resistor.
The
primary winding of the transformer is only a few Ohm, so
that a 1Ohm/20A NTC is sufficient to limit the large
momentary switching currents of uncharged HV elco's and cold
filaments.”
Is
it effective? Other soft step start arrangements seem more
complex.
I
look forward to hearing from you.
Best
wishes
Angus
?
|
Alek, Angus, I couldn't make those ebay numbers work but if you do a search on ebay for "NTC resistor" you get several. I had to use one in my 50 amp Astron (RS-50) linear power supply. It would sometimes trip the breaker. at start up The one I used is... SL322R025. It solved?the problem. It's been at least 7 years with no problems. Here's a link...
I originally got the info from "repeater builder"?
73, Bob W4JFA
G'day Angus.
Sorry for the delay. I missed your email and I'm just cleaning up
my emails and noticed this one.
Yes, the NTC works. I use them in this form for a lot of amps
that I build. See Ebay Item number 402565661699.
They are compact
and work extremely well.
I've never bothered
with soft starts for the little Yaesu amps, as all the Yaesus
I've worked on, have excessive filament voltage at the filament
pins when connected to our AC mains.
A low value of
resistance made up of 5W wirewound resistors in parallel in
series with the filaments brings the volts back from around 6.9
- 7.0V back down to the nominal 6.3V. This resistance, usually
around 0.15 Ohms, also provides a measure of inrush protection
to the filaments. This is very important when using Chinese
valves, which hate excessive volts on the filament.
Cheers from sunny
Binningup, Western Australia.
Alek VK6APK
On 16/11/2024 5:06 am, AngusGM6AGC via
wrote:
Hi Alek,
I trust you are well. Have you
done the step start mod ?“A
simple but effective delay can be done with an NTC resistor.
The
primary winding of the transformer is only a few Ohm, so
that a 1Ohm/20A NTC is sufficient to limit the large
momentary switching currents of uncharged HV elco's and cold
filaments.”
Is
it effective? Other soft step start arrangements seem more
complex.
I
look forward to hearing from you.
Best
wishes
Angus
?
|
I have mixed emotions about NTC resistors.? I tried one on my SB-220 and found that the resistance would change between idle and full plate current.? The large current change caused the filament voltage to change since it uses the same transformer.? Because of the filament voltage change under load, I took it out.?
Bill K3HZP
|
The SB220 has a separate filament transfomer but since the line feeding it and the plate transformer is the same, any sag on the line voltage due to plate primary current drawn by the plate transformer will affect the filament voltage.
On Monday, December 9, 2024, 10:04 AM, Bill K3HZP via groups.io <hzp_electronics@...> wrote: I have mixed emotions about NTC resistors.? I tried one on my SB-220 and found that the resistance would change between idle and full plate current.? The large current change caused the filament voltage to change since it uses the same transformer.? Because of the filament voltage change under load, I took it out.?
Bill K3HZP
|
In the soft start device I'm talking about, it gets switched out
of circuit by the 100A relay, just like the resistor in a normal
slow start.
Alek VK6APK
On 9/12/2024 11:04 pm, Bill K3HZP via
groups.io wrote:
toggle quoted message
Show quoted text
I have mixed emotions about NTC resistors.? I tried one on my
SB-220 and found that the resistance would change between idle
and full plate current.? The large current change caused the
filament voltage to change since it uses the same transformer.?
Because of the filament voltage change under load, I took it
out.?
Bill K3HZP
|
Hi Bob
Search for
100A 4000W High-Power
Soft Start Circuit Power Board for Class A Amplifier Amp
73, Alek.
On 9/12/2024 10:00 pm, Bob via
groups.io wrote:
toggle quoted message
Show quoted text
Alek, Angus, I couldn't make those ebay numbers
work but if you do a search on ebay for "NTC resistor" you get
several.
I had to use one in my 50 amp Astron (RS-50) linear power
supply. It would sometimes trip the breaker. at start up The
one I used is...
SL322R025. It solved?the problem. It's been at least 7
years with no problems. Here's a link...
I originally got the info from "repeater builder"?
73, Bob W4JFA
G'day Angus.
Sorry for the delay. I missed your email and I'm just
cleaning up my emails and noticed this one.
Yes, the NTC works. I use them in this form for a lot of
amps that I build. See Ebay Item number 402565661699.
They are compact and work extremely well.
I've never bothered with soft starts for the little
Yaesu amps, as all the Yaesus I've worked on, have
excessive filament voltage at the filament pins when
connected to our AC mains.
A low value of resistance made up of 5W wirewound
resistors in parallel in series with the filaments
brings the volts back from around 6.9 - 7.0V back down
to the nominal 6.3V. This resistance, usually around
0.15 Ohms, also provides a measure of inrush protection
to the filaments. This is very important when using
Chinese valves, which hate excessive volts on the
filament.
Cheers from sunny Binningup, Western Australia.
Alek VK6APK
On 16/11/2024 5:06 am, AngusGM6AGC via wrote:
Hi Alek,
I trust you are well.
Have you done the step start mod ?“A
simple but effective delay can be done with an NTC
resistor. The
primary winding of the transformer is only a few
Ohm, so that a 1Ohm/20A NTC is sufficient to limit
the large momentary switching currents of uncharged
HV elco's and cold filaments.”
Is
it effective? Other soft step start arrangements seem
more complex.
I
look forward to hearing from you.
Best
wishes
Angus
?
|
Akek, That worked! Thanx. My Kenwood has a soft start in it already (Kessler). My Henry (2K-3) about once every three months will trip the breaker when turned on. I can live with that I guess. The amp was built in 1968 so I guess it can stay the way it is. Plus for my "test" amp, I use the MFJ external step start, ICP-240. I think the Henry is about maximum for that MFJ.
So you're using the NTC in place of a resistor in the soft start. I never thought of that but obviously it works.
The NTC in my Astron RS-50 is always in the circuit. 7 years or so used just about everyday and it's obviously holding up. Yep, different than an amp though.
73, Bob W4JFA
Hi Bob
Search for
100A 4000W High-Power
Soft Start Circuit Power Board for Class A Amplifier Amp
73, Alek.
On 9/12/2024 10:00 pm, Bob via
wrote:
Alek, Angus, I couldn't make those ebay numbers
work but if you do a search on ebay for "NTC resistor" you get
several.
I had to use one in my 50 amp Astron (RS-50) linear power
supply. It would sometimes trip the breaker. at start up The
one I used is...
SL322R025. It solved?the problem. It's been at least 7
years with no problems. Here's a link...
I originally got the info from "repeater builder"?
73, Bob W4JFA
G'day Angus.
Sorry for the delay. I missed your email and I'm just
cleaning up my emails and noticed this one.
Yes, the NTC works. I use them in this form for a lot of
amps that I build. See Ebay Item number 402565661699.
They are compact and work extremely well.
I've never bothered with soft starts for the little
Yaesu amps, as all the Yaesus I've worked on, have
excessive filament voltage at the filament pins when
connected to our AC mains.
A low value of resistance made up of 5W wirewound
resistors in parallel in series with the filaments
brings the volts back from around 6.9 - 7.0V back down
to the nominal 6.3V. This resistance, usually around
0.15 Ohms, also provides a measure of inrush protection
to the filaments. This is very important when using
Chinese valves, which hate excessive volts on the
filament.
Cheers from sunny Binningup, Western Australia.
Alek VK6APK
On 16/11/2024 5:06 am, AngusGM6AGC via wrote:
Hi Alek,
I trust you are well.
Have you done the step start mod ?“A
simple but effective delay can be done with an NTC
resistor. The
primary winding of the transformer is only a few
Ohm, so that a 1Ohm/20A NTC is sufficient to limit
the large momentary switching currents of uncharged
HV elco's and cold filaments.”
Is
it effective? Other soft step start arrangements seem
more complex.
I
look forward to hearing from you.
Best
wishes
Angus
?
|
Bob
Bill K3HZP