Re: HT-37 parts For Sale

I am also going to the Sussex hamfest? I can bring it there also.

Re: HT-37 parts For Sale

开云体育

I also have a complete HT-37 for parts or repair, untested unless someone wants me to variac it up. $100 in Middletown / Goshen NY deliver within 20 miles

Show quoted text

From:[email protected] <[email protected]> on behalf of RILEY HOLLINGSWORTH <K4zdh@...>
Sent:?Wednesday, July 3, 2024 9:07 AM
To:[email protected] <[email protected]>
Subject:?Re: [HallicraftersRadios] HT-37 parts For Sale

?

If you are definitely going to part it out, I'd like the relay. Thanks K4ZDH

Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY

#30465

Thanks Don.? That makes sense!

73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com

Show quoted text

On 7/1/2024 5:16 PM, don Root wrote:

Jeff, as a guess, your likely insulation breakdown was enough to continue building a carbon track between windings even though the 5v was isolated; and must have eventually destroyed the T-T [turn to turn] insulation on a winding and eventually became a real short. Any T-T short in a transformer is fatal . don

From: [email protected] [mailto:[email protected]] On Behalf Of Jeff AC0C
Sent: Monday, July 1, 2024 5:55 PM
To: [email protected]
Subject: Re: [HallicraftersRadios] HT-37 transformer failure due to rapid STBY-->OFF-->STBY

Two the fellow's earlier comment on not using the 5V line, when
reworking my 32A, that was the first thing I did - move to SS
specifically to idle the 5V line and avoid the risk of the well reported
short involving the 5V line. Toward the end of the process, I was
getting ready to finish up alignment and had let the transmitter run
overnight to ensure it had reached stable temp across the chassis. When
I came down the next morning, the rig was dead. Painfully confirmed
later that some amount of windings on the primary or secondary had
shorted (there were no detectable winding-to-winding shorts at idle -
and I did not have a spare HVPS available at that time to test higher).
However, as the variac was ramped up, the current draw of the
disconnected transformer soared. So the 5V to HV short is apparently
not the only transformer failure mode with this model, unfortunately.

I solved the problem by cannibalizing another HT32. But assuming Murphy
may like to come see me soon, I bought one of those shiny Dahl
transformers and it's here on the bench ready to run to the rescue when
the current transformer eventually dies. Of course, with my luck,
simply having bought the Dahl transformer may keep Muphy away allowing
the current transformer to run the rest of my days. ha ha.

73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com

Re: HT-37 parts For Sale

#30464

Shipping would probably $50+.?

I'm in Southwest Ohio near Cincinnati.

Re: HT-37 parts For Sale

#30463

If it includes shipping we have a deal.

73

Dave

Show quoted text

On Wed, Jul 3, 2024 at 10:14?AM Terry ONeill via <cpa599=[email protected]> wrote:

Is $100 fair for a parts unit.? No finals.

Re: HT-37 parts For Sale

#30462
Edited

Is $100 fair for a parts unit.? No finals.

Shipping would be extra of course.?

Re: HT-37 parts For Sale

#30461

If you are definitely going to part it out, I'd like the relay. Thanks K4ZDH

Re: My HT-45 HP-45 project.

#30460

That's right in the "zone"

I measured mine with a Bird 43 at the input (250W slug )? and one on the output (1000W slug) into a Bird 500W load.

With the power supply wired for 120, it did about 500W and wired for 240, it did around 600W

Now onto the HT33 (Mark-I)? power supply!?

I have another Drake L-4PS transformer + Harbach L-4B board that I will install in it removing the old (110 only) transformer, swinging choke and oil cap.

There's nothing wrong with the old PS except that I cannot pick up the amp @ 125lbs! ?(I'll save all the old parts and I will not drill any new holes!)?

I expect about a 50lb reduction in weight!! (and an increase in plate voltage from 2100V-2600V)

Cheers,?? Rick

Show quoted text

On Tue, Jul 2, 2024 at 09:33 AM, Bob ah7i wrote:

ah7i

?
--
73/Rick
W4XA
__________________________________
All posts are created using OpenSuSE Leap 15.5 x64 Linux

Re: HT-37 parts For Sale

#30459

What do you want for the HT-37.? We have a few HT-37 owners in the area that might rest better at night knowing there is a spare parts unit nearby.

73
dave
wa3gin

Re: My HT-45 HP-45 project.

#30458

Thanks Rick!

With 40W drive it's making ~500W per the drake meter and a dummy load. Meter is within about ~10% of reality.
I'm happy. Just need to get the relays set up for RF and bias switching.?

73, -bob ah7i

Re: HT-37 parts For Sale

#30457

Let me know what you need.

HT-37 parts For Sale

#30456
Edited

SX-101 A Drift

#30455

No they were for drift . used to keep the vfo section warm to cut down
drift check the manual.
Dampp-Chaser's were used in some gear .
73 Tony WA4JQS

Show quoted text

At 01:54 PM 7/1/2024 -0700, you wrote:

That thing was probably a Dampp-Chaser (with two P's). They were
used in some receivers and in other equipment to keep moisture out.

Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY

#30454

I have been buying my SSR's from eBay.? Most of them were for around $10 each.? I bought 4? OPTO22? 240A45 models for $40 a few months ago and they were all new old stock as were the 240A25's

I've also bought Crydom SSRs too.? I stay away from the imported knockoffs that are sold on Amazon and eBay.? It was a real stroke of luck when I found the OPTO's for $10 each.? I don't care if they're used.? They either work or they don't

If you buy them at retail, they're quite expensive!

--
73/Rick
W4XA
__________________________________
All posts are created using OpenSuSE Leap 15.5 x64 Linux

Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY

#30453

开云体育

Rick,

?

Great info, especially the selection table based on transformer KVA rating.? I’ll order a few of the Opto22-120D10 SSRs and give it a try. For others on the list, here’s the noteworthy part from the Opto22 datasheet:

?

“Careful consideration should be given to the selection of the proper SSR for driving a given transformer. Transformers are driven from positive saturation of the iron core to negative saturation of the core each half cycle of the alternating voltage. Large inrush currents can occur during the first half cycle of line voltage if a zero-voltage SSR happens to turn on during the positive half cycle of voltage when the core is already in positive saturation. Inrush currents greater than 10 times rated transformer current can easily occur. The following table provides a guide for selecting the proper SSR for a given transformer rating.”

?

Paul, W9AC

Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY

#30452

开云体育

Jeff, as a guess, your likely insulation breakdown was enough to continue building a carbon track between windings even though the 5v was isolated; and must have eventually destroyed the T-T [turn to turn] insulation on a winding and eventually became a real short. Any T-T short in a transformer ?is fatal . don

?

Show quoted text

From: [email protected] [mailto:[email protected]] On Behalf Of Jeff AC0C
Sent: Monday, July 1, 2024 5:55 PM
To: [email protected]
Subject: Re: [HallicraftersRadios] HT-37 transformer failure due to rapid STBY-->OFF-->STBY

?

Two the fellow's earlier comment on not using the 5V line, when
reworking my 32A, that was the first thing I did - move to SS
specifically to idle the 5V line and avoid the risk of the well reported
short involving the 5V line.? Toward the end of the process, I was
getting ready to finish up alignment and had let the transmitter run
overnight to ensure it had reached stable temp across the chassis.? When
I came down the next morning, the rig was dead.? Painfully confirmed
later that some amount of windings on the primary or secondary had
shorted (there were no detectable winding-to-winding shorts at idle -
and I did not have a spare HVPS available at that time to test higher).?
However, as the variac was ramped up, the current draw of the
disconnected transformer soared.? So the 5V to HV short is apparently
not the only transformer failure mode with this model, unfortunately.

I solved the problem by cannibalizing another HT32.? But assuming Murphy
may like to come see me soon, I bought one of those shiny Dahl
transformers and it's here on the bench ready to run to the rescue when
the current transformer eventually dies.? Of course, with my luck,
simply having bought the Dahl transformer may keep Muphy away allowing
the current transformer to run the rest of my days.? ha ha.

73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com
?

--
don??? va3drl

Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY

#30451

开云体育

If I were wanting to minimize the ?first excursion of current to a choke or transformer, I would want a switch that closes near the plus or minus crest of the incoming voltage, and not one that switches at zero crossings. ??Switching capacitors is another matter as is switching other loads. ?don

?

Show quoted text

From: [email protected] [mailto:[email protected]] On Behalf Of Paul Christensen
Sent: Monday, July 1, 2024 5:15 PM
To: [email protected]
Subject: Re: [HallicraftersRadios] HT-37 transformer failure due to rapid STBY-->OFF-->STBY

?

>”In addition, if you choose the "right" SSR, it will turn-on at "Zero-Crossing" meaning it will activate when the sine-wave passes zero volts (they're designed that way).”

?

Be careful when using zero-crossing (ZC) SSRs to switch extra-large power transformers.? I recently tried ZC type in my Collins 516F-2 and Drake PS-7 power supplies.? In each case, it resulted in pulsing high current surges.? In one instance, the 4A fuse blew open in my Collins power supply during a high-surge event.?

?

The attached Tyco Application Note warns against using ZC type SSRs with highly inductive loads.

?

The problem was fixed by changing to a random-switching type SSR from Crydom.? The AC load is switched from antiparallel SCRs.? Datasheet attached.? I know others have used ZC type SSRs to switch large transformers without any problems. ?I’m only offering this advice out of caution from my own experience.? ?

?

Paul, W9AC

--
don??? va3drl

Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY

#30450

Two the fellow's earlier comment on not using the 5V line, when
reworking my 32A, that was the first thing I did - move to SS
specifically to idle the 5V line and avoid the risk of the well reported
short involving the 5V line.? Toward the end of the process, I was
getting ready to finish up alignment and had let the transmitter run
overnight to ensure it had reached stable temp across the chassis.? When
I came down the next morning, the rig was dead.? Painfully confirmed
later that some amount of windings on the primary or secondary had
shorted (there were no detectable winding-to-winding shorts at idle -
and I did not have a spare HVPS available at that time to test higher).?
However, as the variac was ramped up, the current draw of the
disconnected transformer soared.? So the 5V to HV short is apparently
not the only transformer failure mode with this model, unfortunately.

I solved the problem by cannibalizing another HT32.? But assuming Murphy
may like to come see me soon, I bought one of those shiny Dahl
transformers and it's here on the bench ready to run to the rescue when
the current transformer eventually dies.? Of course, with my luck,
simply having bought the Dahl transformer may keep Muphy away allowing
the current transformer to run the rest of my days.? ha ha.

73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com

Show quoted text

On 7/1/2024 4:15 PM, Paul Christensen wrote:

"In addition, if you choose the "right" SSR, it will turn-on at
"Zero-Crossing" meaning it will activate when the sine-wave passes zero
volts (they're designed that way)."

Be careful when using zero-crossing (ZC) SSRs to switch extra-large power
transformers. I recently tried ZC type in my Collins 516F-2 and Drake PS-7
power supplies. In each case, it resulted in pulsing high current surges.
In one instance, the 4A fuse blew open in my Collins power supply during a
high-surge event.

The attached Tyco Application Note warns against using ZC type SSRs with
highly inductive loads.

The problem was fixed by changing to a random-switching type SSR from
Crydom. The AC load is switched from antiparallel SCRs. Datasheet
attached. I know others have used ZC type SSRs to switch large transformers
without any problems. I'm only offering this advice out of caution from my
own experience.

Paul, W9AC

Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY

#30449

On Mon, Jul 1, 2024 at 02:15 PM, Paul Christensen wrote:

>”In addition, if you choose the "right" SSR, it will turn-on at "Zero-Crossing" meaning it will activate when the sine-wave passes zero volts (they're designed that way).”

?

Be careful when using zero-crossing (ZC) SSRs to switch extra-large power transformers.? I recently tried ZC type in my Collins 516F-2 and Drake PS-7 power supplies.? In each case, it resulted in pulsing high current surges.? In one instance, the 4A fuse blew open in my Collins power supply during a high-surge event.?

?

The attached Tyco Application Note warns against using ZC type SSRs with highly inductive loads.

?

The problem was fixed by changing to a random-switching type SSR from Crydom.? The AC load is switched from antiparallel SCRs.? Datasheet attached.? I know others have used ZC type SSRs to switch large transformers without any problems. ?I’m only offering this advice out of caution from my own experience.? ?

?

Paul, W9AC

?Hi Paul,

Thanks for that info.....I seem to? remember you mentioning this before and I cannot disagree!

I'm using 2-OPTO22 240A25's in the Loudenboomer power supply which is essentially a complete L-4B (L-4PS) power supply with the exception of using 2 Semtech 5000v diode stacks and 8-330uF 450V? (parallel) caps instead of the original 220uF caps.

I have switched it on and off multiple times trying to get it to "fault" and so far it works flawlessly!

I used OPTO22 120A25 SSR's in the AC-4's and same.? no problems yet.

I suppose I could stick a 1ohm 1% precision resistor in the AC line and directly measure the actual instantaneous? currents with a scope.

OPTO22 does mention what one should do to mitigate this and based on the information on page 17 in their specifications, It's close using the 240A25 for the L-4PS plate transformer and I am well over the requirements using the 120A25 for the AC-4 transformer.

My final plan is to change to the 240A45 in both the Loudenboomer and L-4B power supplies,
--
73/Rick
W4XA
__________________________________
All posts are created using OpenSuSE Leap 15.5 x64 Linux

OPTO22_Solid_State_Relays_data_sheet-5.pdf

Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY

#30448

开云体育

>”In addition, if you choose the "right" SSR, it will turn-on at "Zero-Crossing" meaning it will activate when the sine-wave passes zero volts (they're designed that way).”

?

Be careful when using zero-crossing (ZC) SSRs to switch extra-large power transformers.? I recently tried ZC type in my Collins 516F-2 and Drake PS-7 power supplies.? In each case, it resulted in pulsing high current surges.? In one instance, the 4A fuse blew open in my Collins power supply during a high-surge event.?

?

The attached Tyco Application Note warns against using ZC type SSRs with highly inductive loads.

?

The problem was fixed by changing to a random-switching type SSR from Crydom.? The AC load is switched from antiparallel SCRs.? Datasheet attached.? I know others have used ZC type SSRs to switch large transformers without any problems. ?I’m only offering this advice out of caution from my own experience.? ?

?

Paul, W9AC

Crydom SSR.pdf

Solid State Relays - ENG_CS_13C3206_AppNote_0513_Beware_of_Zero-Crossover_Switching_of_Transformers_13c3206r[1].pdf