Locked
Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
Hi Halden again, maybe I’m flogging a dead horse, but: I sent that recent post because that specific type Kapton “颁搁”? is corona resistant, while the early basic types apparently are not. It came out in 1995, about 30 years after DuPont made the first stuff. ? I believe long ago it was mentioned that Hallicrafters said? the original transformers died due to corona. ? I am no expert; I’m just getting some education, but that sizable hole ?{whole without the W} in your picture. It must have been “eaten away” by corona which creates OZONE, and so spreads out, etc etc. ?
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of HF via groups.io
Sent: Monday, September 23, 2024 1:15 AM
To: [email protected]
Subject: Re: [HallicraftersRadios] HT-37 transformer failure due to rapid STBY-->OFF-->STBY? I have some Kapton(tm) scraps from various items of lab equipment utilizing high voltages that I have disassembled.? I think the dielectric strength of all varieties is pretty good, so I doubt it matters which kind I use.? I suppose it'd be a good idea to could put whatever I find between terminals on my HV supply to make sure. -- don??? va3drl
|
Locked
Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
Hi Don,
I have some Kapton(tm) scraps from various items of lab equipment utilizing high voltages that I have disassembled.? I think the dielectric strength of all varieties is pretty good, so I doubt it matters which kind I use.? I suppose it'd be a good idea to could put whatever I find between terminals on my HV supply to make sure.
Cheers,
Halden VE7UTS
|
Locked
Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
Halden Re: your? ?/g/HallicraftersRadios/message/30949 you mention ?Kapton ?as if you intend to buy some,? but you didn’t ?mention which type as far as I can see. ? I tried to get educated and found some stuff; this being most relevant I think. ? “Kapton? CRC has a corona resistance or voltage endurance that is significantly higher than standard Kapton? HN.” ? And ?See ??? ? Kapton? FCRC combines Kapton? 100CRC corona resistant polyimide film with a heat fusible FEP fluoropolymer film? ? there are many Kapton?’s ?see ? ? -- don??? va3drl
|
Re: HT44/SX117 Dow Key help.
I am using several RF activated relays.? Much simpler to use then the old dow-key.? Also they can be set up away from the transmitter.? They do need 12V.? Check MFJ, if they are still around.
|
Thanks guys,
Waltcoates, Michael, Floyd, John, Steve, and Riley.
With your suggestions and help I’ll get my 44/117 up and running, but I’m slow so this might take a bit.
Thanks again.
Skip Magnuson W7WGM
Spokane, WA
|
Re: HT44/SX117 Dow Key help.
Skip I have several. You can have one just for shipping once you know what you need.? Some even have the mute connection on the outside.
?
Riley, K4ZDH
|
Re: HT44/SX117 Dow Key help.
My HT44 / SX117? combo has a built in antenna relay in the transmitter.
I know that some early versions of HT44 didn't have that added, but it's an easy mod and I prefer to have an internal antenna changeover relay...
Good luck 73 Steve w8tow
Another option.
A home made box with a garden variety ice cube relay will do the job. ? With a DPDT 120V AC relay you can use the other pole to ground the Rx input on transmit as well.
John K5MO
PS: Yes on 10M there is a small impedance bump, but that's why we have a variable cap in the tank :-)
On Fri, Sep 20, 2024 at 6:41?AM Floyd - K8AC via <floydsense= [email protected]> wrote: I have an SX-117 and HT-44 station and I use a Johnson TR switch instead of a relay.? No external power or switching is needed.? A B&W TR switch also works quite well.? Note that a real TR switch is electronic - a tube does the switching, unlike some boxes that use a relay but call it a "TR Switch" when it's not.? Cost is similar to a coaxial relay.
?
73, Floyd - K8AC
|
Re: HT44/SX117 Dow Key help.
Another option.
A home made box with a garden variety ice cube relay will do the job. ? With a DPDT 120V AC relay you can use the other pole to ground the Rx input on transmit as well.
John K5MO
PS: Yes on 10M there is a small impedance bump, but that's why we have a variable cap in the tank :-)
On Fri, Sep 20, 2024 at 6:41?AM Floyd - K8AC via <floydsense= [email protected]> wrote: I have an SX-117 and HT-44 station and I use a Johnson TR switch instead of a relay.? No external power or switching is needed.? A B&W TR switch also works quite well.? Note that a real TR switch is electronic - a tube does the switching, unlike some boxes that use a relay but call it a "TR Switch" when it's not.? Cost is similar to a coaxial relay.
?
73, Floyd - K8AC
|
Re: HT44/SX117 Dow Key help.
I have an SX-117 and HT-44 station and I use a Johnson TR switch instead of a relay.? No external power or switching is needed.? A B&W TR switch also works quite well.? Note that a real TR switch is electronic - a tube does the switching, unlike some boxes that use a relay but call it a "TR Switch" when it's not.? Cost is similar to a coaxial relay.
?
73, Floyd - K8AC
|
Re: HT44/SX117 Dow Key help.
Skip,
The answer to your question is found on page 30 "Figure 20. Partial
Schematic,
Showing Relay Installation" in the HT-44 manual.
Notice the "ANTENNA RELAY connections which is a simple "SPDT" relay
switch.
The relay switch contacts connect to the HT-44's "CONTROL OUTLET"
terminals
"2" and "3". Pins "2" and "3" connect to the HT-44's internal relay
"K1" terminals
"6" and "10". In "transmit" pins 6 and 10 short together causing the
external "ANTENNA
RELAY" to "energize" resulting in switching the ANTENNA connection
to the "receiver" to
switch to the "transmitter" output. The relay contacts should have a
high voltage rating
as it will pass RF from the transmitter to the antenna in transmit
Most relay have the
relay contact voltage and current ratings stamped on the relays.
You will need an external relay that has the appropriate SPDT relay
contacts as shown
in Figure 20 on page 30 in the HT-44 manual. The relay circuit is
built on the "UNUSED
LUGS ON TERMINAL STRIP". The components you will need are the diode
(a 1N3193 is
stated but a simple 1N4005 diode will work), a 2.7ohm 2W resistor
and a 100ufd 25VDC
capacitor. Do not use a lower capacitance value cap as it can cause
the relay coil to
"Buzz" and not function properly. Use the 100ufd or if you have a
300VDC 25VDC cap,
that will work as well.
The diode, resistor and capacitor form a "1/2 wave" rectifier to
rectify the 12VAC
into a DC voltage that powers the relay. The relay coil needs to be
12VDC.
I've used this type of relay circuit in a number of Heathkit DX-60
Function switch modification
fed off the 6VAC filament feeding a 1/2 wave rectifier powering a
6VDC relay. It's a simple circuit
and easy to build.
73
Mike W5RKL
On 9/19/24 4:26 PM, waltcates via
groups.io wrote:
toggle quoted message
Show quoted text
You can use any type of R/T relay, DC or AC. Pins 2 and 3 of
J3 go to a set of relay contacts in the 44. Pins 2 and 3 are
open in receive mode and close in transmit. I have used 12v dc
and 12vac relays to perform the function. The contacts of the
relay are rated to 260v ac/dc @ 3 amps. The rt relays from the
SR series radios work fine.
Walt Cates, WD0GOF
?
A majority of acceptance is not proof of correctness.
I’m trying to reconnect my 44/117 station to use again after
several years. I don’t see a Dow Key in the wiring between the
two. I don’t want to transmit into my receiver (of course). The
44 manual shows a typical interconnection (Fig. 5, page 5). It
shows the 117v coaxial relay connected in series with the 44
power which seems odd plus no showing of a control to the relay.
Help unraveling the connections will be appreciated. eBay shows
lots of Dow Key relays (6, 12, 24, 120 v) and lots of prices.
I’ll probably need to buy one so a recommendation there would
help too. I have a vague recollection that I might have sold
mine quite some time ago.
Thanks guys for the help.
Skip Magnuson
Spokane, WA
|
Re: HT44/SX117 Dow Key help.
More on the relay. To use a 12vdc relay.
You could also use a 12v wall wart to drive the relay
Walt Cates, WD0GOF
?
A majority of acceptance is not proof of correctness.
toggle quoted message
Show quoted text
I’m trying to reconnect my 44/117 station to use again after several years. I don’t see a Dow Key in the wiring between the two. I don’t want to transmit into my receiver (of course). The 44 manual shows a typical interconnection (Fig. 5, page 5). It shows
the 117v coaxial relay connected in series with the 44 power which seems odd plus no showing of a control to the relay.
Help unraveling the connections will be appreciated. eBay shows lots of Dow Key relays (6, 12, 24, 120 v) and lots of prices. I’ll probably need to buy one so a recommendation there would help too. I have a vague recollection that I might have sold mine quite
some time ago.
Thanks guys for the help.
Skip Magnuson
Spokane, WA
|
Re: HT44/SX117 Dow Key help.
You can use any type of R/T relay, DC or AC. Pins 2 and 3 of J3 go to a set of relay contacts in the 44. Pins 2 and 3 are open in receive mode and close in transmit. I have used 12v dc and 12vac relays to perform the function. The contacts of the relay are
rated to 260v ac/dc @ 3 amps. The rt relays from the SR series radios work fine.
Walt Cates, WD0GOF
?
A majority of acceptance is not proof of correctness.
toggle quoted message
Show quoted text
I’m trying to reconnect my 44/117 station to use again after several years. I don’t see a Dow Key in the wiring between the two. I don’t want to transmit into my receiver (of course). The 44 manual shows a typical interconnection (Fig. 5, page 5). It shows
the 117v coaxial relay connected in series with the 44 power which seems odd plus no showing of a control to the relay.
Help unraveling the connections will be appreciated. eBay shows lots of Dow Key relays (6, 12, 24, 120 v) and lots of prices. I’ll probably need to buy one so a recommendation there would help too. I have a vague recollection that I might have sold mine quite
some time ago.
Thanks guys for the help.
Skip Magnuson
Spokane, WA
|
I’m trying to reconnect my 44/117 station to use again after several years. I don’t see a Dow Key in the wiring between the two. I don’t want to transmit into my receiver (of course). The 44 manual shows a typical interconnection (Fig. 5, page 5). It shows the 117v coaxial relay connected in series with the 44 power which seems odd plus no showing of a control to the relay.
Help unraveling the connections will be appreciated. eBay shows lots of Dow Key relays (6, 12, 24, 120 v) and lots of prices. I’ll probably need to buy one so a recommendation there would help too. I have a vague recollection that I might have sold mine quite some time ago.
Thanks guys for the help.
Skip Magnuson
Spokane, WA
|
Re: Help Tweaking in New IF Can in S-120
That is true...
Justin B. - KI5GKD
On 9/19/2024 12:12 PM, barry marks
wrote:
toggle quoted message
Show quoted text
Justin
?? but when all goes well it's a onetime experience filled with
satisfaction.? Besides, it gives you a chance to play with
otherwise dormant equipment.
????????????????????????????????? barry
Yeah, I find the alignments a bit tedious...
--
Justin B.
KI5GKD
--
Justin B.
KI5GKD
|
Re: Help Tweaking in New IF Can in S-120
Justin
?? but when all goes well it's a onetime experience filled with satisfaction.? Besides, it gives you a chance to play with otherwise dormant equipment.
????????????????????????????????? barry
toggle quoted message
Show quoted text
Yeah, I find the alignments a bit tedious...
--
Justin B.
KI5GKD
|
I’m still looking for any coils or tuning units for my HT-9. If you have anything available please email me what you have and what you are asking for them with shipping.
Thanks,
Tom N5AMA
713-417-5959
|
FW: [heathkit] Need IM-5228 VTVM Parts
Knobs and large thumbnut have been resolved.? Unit is working fine and is awaiting a the installation of the battery eliminator once I receive it. ? What I need now is one of the switchable probes.? I think I have one but it is hiding, ? Anyone have an extra for sale or trade? ? Best 73, ? Gary H. Harmon Jr 6003 Archwood San Antonio, TX 78239-1504 (210) 657-1549 home (210) 884-6926 cell gharmon@... k5jwkgary@... ?
toggle quoted message
Show quoted text
|
Re: Help Tweaking in New IF Can in S-120
Yeah, I find the alignments a bit tedious...
--
Justin B.
KI5GKD
|
Re: Help Tweaking in New IF Can in S-120
if i may add my 2c worth.
?? may i assume you first, with radio off turn dial end to end to be sure pointer correctly ends up at same but opposite places on dial.? if not the first adj would to be to make it so. i believe band spread needs to be at O plate closed.
??????????? almost all AA5 circuits have similar realignment instr.? so if the pointer is off where it should be on the dial after you have realigned all if"s the next step is to tune radio to known local station on lower end of am dial. if its spot on to local station fine. if not you need to? tweak local osc coil? to match station to pointer. Next on to high end of dial.? if the station freq and pointer don't match
you now adjust osc padder of smaller section of tuning cap to match up. sometimes there is 'interaction between these adjustments causing you to redo dial adj a few times. such is life :+)
??????????
????????????????????????????????? barry
|
Need one of the large black knobs and one of the thumbnuts that fastens the bracket to the case. ? Best 73, ? Gary H. Harmon Jr 6003 Archwood San Antonio, TX 78239-1504 (210) 657-1549 home (210) 884-6926 cell gharmon@... k5jwkgary@... ?
|
don Root
Steve Marquie
Floyd - K8AC
waltcates