Re: SX-110 2nd IF Circuit Design
The SX-42 schematic shows a 7H7 as the third IF, printed on the diagram. ? 73 – Steve, KW4H ? Hello n7qmm25 and others YES; Depending on font etc and goobers in printing C and G look quite similar Let’s just say the C ?that I see in Dachis was a poor print of a G ?or my eyes are really tired so the second tube is REALLY a? 6SG7. that agrees with most and just now I am reading ??James’s …sx-42 repair ?which lists?? ….edited
6SK7 - 1st IF
6SG7 - 2nd IF
6H6 - 2nd detector / Noise Limiter
7H7 (two) - FM Limiters? ……… Now ?I just looked at the BAMA schematic ?again and see that the 7H7’s are called “Limiters” [for the FM] and don’t see any sign of a “3rd IF” …But … Dachis ?says ?????“7H7 3rd IF Amp “
Osterman ?says ?“7H7 IF Amp “ … Beginning not to believe the gurus. Don VA3DRL?
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Re: SX-110 2nd IF Circuit Design
Hello n7qmm25 and others YES; Depending on font etc and goobers in printing C and G look quite similar Let’s just say the C ?that I see in Dachis was a poor print of a G ?or my eyes are really tired so the second tube is REALLY a? 6SG7. that agrees with most and just now I am reading ??James’s …sx-42 repair ?which lists?? ….edited
6SK7 - 1st IF
6SG7 - 2nd IF
6H6 - 2nd detector / Noise Limiter
7H7 (two) - FM Limiters? ……… Now ?I just looked at the BAMA schematic ?again and see that the 7H7’s are called “Limiters” [for the FM] and don’t see any sign of a “3rd IF” …But … Dachis ?says ?????“7H7 3rd IF Amp “
Osterman ?says ?“7H7 IF Amp “ … Beginning not to believe the gurus. Don VA3DRL? =======trimd
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Re: SX-110 2nd IF Circuit Design
My 62 has 7H7 , and the 62a has 6SG7 in it's place
On Oct 30, 2022 4:40 PM, n7qmm25 <n7qmm25@...> wrote:
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My SX 42 has 6SK7, 6SG7 and 7H7. Clearly stamped into the metal chassis. Do you supposed one had tired eyes and thought he saw a C instead of a G?
On 10/30/2022 12:48 PM, don Root wrote:
?
Scott, and ?Steve and the gang:
I think Steve clarified a mistake re the sx-110 , but he listed IF tubes for others ?and never said anything about my comment on the sx-42 .
he listed?? “SX-42 (1947-50) 6SK7, 6SG7”?
?my? ?1996 Dachis ?book and my ?Osterman? book says ?6SK7,? 6SC7, 7H7
I also said “Wonder if we have the same printing…”
?
Now I wonder if ? my? ?1996 Dachis ?book and my ?Osterman[ second edition]? books ?are wrong ??about the 42
?
For the 62 you mentioned ?,Osterman ?lists the same IF tubes as it lists for the 42, [6SK7,? 6SC7, 7H7] and also says the A version seems to be the same except for the speaker impedance,, BUT Dachis says? 6SK7?6SG7?6SG7?
I guess I must be off-track, and/or cant read these details so maybe somebody else can check these books?
Don VA3DRL
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Re: SX-110 2nd IF Circuit Design
It was tired eyes and a transcription error.? The 7H7 is the third IF. ? 73, ? Steve, KW4H ? My SX 42 has 6SK7, 6SG7 and 7H7. Clearly stamped into the metal chassis. Do you supposed one had tired eyes and thought he saw a C instead of a G?
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On 10/30/2022 12:48 PM, don Root wrote: ? Scott, and ?Steve and the gang: I think Steve clarified a mistake re the sx-110 , but he listed IF tubes for others ?and never said anything about my comment on the sx-42 . he listed?? “SX-42 (1947-50) 6SK7, 6SG7”? ?my? ?1996 Dachis ?book and my ?Osterman? book says ?6SK7,? 6SC7, 7H7 I also said “Wonder if we have the same printing…” ? Now I wonder if ? my? ?1996 Dachis ?book and my ?Osterman[ second edition]? books ?are wrong ??about the 42 ? For the 62 you mentioned ?,Osterman ?lists the same IF tubes as it lists for the 42, [6SK7,? 6SC7, 7H7] and also says the A version seems to be the same except for the speaker impedance,, BUT Dachis says? 6SK7?6SG7?6SG7? I guess I must be off-track, and/or cant read these details so maybe somebody else can check these books? Don VA3DRL =======trimd
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Re: SX-110 2nd IF Circuit Design
My SX 42 has 6SK7, 6SG7 and 7H7. Clearly stamped into the metal
chassis. Do you supposed one had tired eyes and thought he saw a C
instead of a G?
On 10/30/2022 12:48 PM, don Root wrote:
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?
Scott,
and ?Steve and the gang:
I think
Steve clarified a mistake re the sx-110 , but he listed IF
tubes for others ?and never said anything about my comment
on the sx-42 .
he listed??
“SX-42 (1947-50) 6SK7, 6SG7”?
?my? ?1996
Dachis ?book and my ?Osterman? book says ?6SK7,? 6SC7, 7H7
I also said
“Wonder if we have the same printing…”
?
Now I wonder
if ? my? ?1996 Dachis ?book and my ?Osterman[ second
edition]? books ?are wrong ??about the 42
?
For the 62
you mentioned ?,Osterman ?lists the same IF tubes as it
lists for the 42, [6SK7,? 6SC7, 7H7] and also says the A
version seems to be the same except for the speaker
impedance,, BUT Dachis says? 6SK7?6SG7?6SG7?
I guess I
must be off-track, and/or cant read these details so maybe
somebody else can check these books?
Don VA3DRL
=======trimd
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Re: SX-110 2nd IF Circuit Design
Don, ? I just checked, and yes – there’s a third IF tube for the SX-42 – the 7H7.? I overlooked that.? FYI, my Osterman book is the fourth edition. ? 73 – Steve, KW4H ? ? Scott, and ?Steve and the gang: I think Steve clarified a mistake re the sx-110 , but he listed IF tubes for others ?and never said anything about my comment on the sx-42 . he listed?? “SX-42 (1947-50) 6SK7, 6SG7”? ?my? ?1996 Dachis ?book and my ?Osterman? book says ?6SK7,? 6SC7, 7H7 I also said “Wonder if we have the same printing…” ? Now I wonder if ? my? ?1996 Dachis ?book and my ?Osterman[ second edition]? books ?are wrong ??about the 42 ? For the 62 you mentioned ?,Osterman ?lists the same IF tubes as it lists for the 42, [6SK7,? 6SC7, 7H7] and also says the A version seems to be the same except for the speaker impedance,, BUT Dachis says? 6SK7?6SG7?6SG7? I guess I must be off-track, and/or cant read these details so maybe somebody else can check these books? Don VA3DRL =======trimd
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Re: SX-110 2nd IF Circuit Design
? Scott, and ?Steve and the gang: I think Steve clarified a mistake re the sx-110 , but he listed IF tubes for others ?and never said anything about my comment on the sx-42 . he listed?? “SX-42 (1947-50) 6SK7, 6SG7”? ?my? ?1996 Dachis ?book and my ?Osterman? book says ?6SK7,? 6SC7, 7H7 I also said “Wonder if we have the same printing…” ? Now I wonder if ? my? ?1996 Dachis ?book and my ?Osterman[ second edition]? books ?are wrong ??about the 42 ? For the 62 you mentioned ?,Osterman ?lists the same IF tubes as it lists for the 42, [6SK7,? 6SC7, 7H7] and also says the A version seems to be the same except for the speaker impedance,, BUT Dachis says? 6SK7?6SG7?6SG7? I guess I must be off-track, and/or cant read these details so maybe somebody else can check these books? Don VA3DRL =======trimd
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SX-71 RF sensitivity knob
Hi, I am wondering if my RF sensitivity control is working correctly, possibly it may have been modified?
When you turn the gain down from the click, the signal seems to be muted from the bottom, as though it is a squelch, while the signal meter will rise to full scale as the gain is lowered. when the control is advanced it mutes the output completely at some pont.
Most radios that I have used the RF sensitivity works similar to a volume control, with the signal meter lowering as the gain is lowered, and the signal and noise level is lowered to the point of not receiving a signal.
Thanks,
Scott
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A recent posting got me to looking through my archives. I found the following short discussion that may be of interest to some.
In this discussion we will be looking at the high voltage bleeder resistors and the metering ckt resistor. Also, the discussion is related to the following; P-500, PS-500-120, PS-500-AC, PS-500A-AC and the PS-150-120.?
?
First the metering resistor. The metering resistor in the 150 series and the 500 series power supplies is R207. In all the power supplies except the PS-500A-AC it is documented as a 10ohm 1watt resistor. In the PS-500A-AC is documented
as a 10ohm 5watt resistor.?
With the 1-watt resistor in place, during tune-up or if you experience an antenna problem, you can easily see in excess of .450ma of plate current. That is over 2 watts dumped into R207. When that resistor opens you lose transmitter
power and get a rather strange indication. When you turn the unit on with that resistor open, while in receive mode, you will get slowly increasing plate current indication on a meter plugged into the metering jacks on the power supply.?
When the power supply for the 400A was produced, that resistor was changed to a 5-watt resistor. My personal choice is the square, ceramic, 10-watt 10-ohm resistor?
?
Now for the high voltage bleeder resistors. This issue is complicated by the variations in the Hallicrafters documentation. Some documentation for the 500 series supplies calls out 15k 10watt resistors. Some documentation calls
out 20k 10watt resistors. ?
Over the years I have repaired hundreds of the 150 and 500 power supplies. In power supplies with the 15k 10watt resistors, with a lot of hours of service, you will find three common degradations. First the insulation on the red
wires from the resistors to the capacitors will be melted and blackened at the resistor end. You will also find the platting on the resistor leads flaky and pealing. Then you will notice the solder connection on the terminal strips have crystalized and coated
with lead oxide. In some cases, continuity is lost.?
In the factory units that were produced with the 20k 10watt resistors you do not find the degradations. I personally stocked 20k 20watt replacements?
?Walt Cates,
WD0GOF
?
Your past has no control over your future. Only your NOW can impact your future.
|
A recent posting got me to looking through my archives. I found the following short discussion that may be of interest to some.
In this discussion we will be looking at the high voltage bleeder resistors and the metering ckt resistor. Also, the discussion is related to the following; P-500, PS-500-120, PS-500-AC, PS-500A-AC and the PS-150-120.?
?
First the metering resistor. The metering resistor in the 150 series and the 500 series power supplies is R207. In all the power supplies except the PS-500A-AC it is documented as a 10ohm 1watt resistor. In the PS-500A-AC is documented
as a 10ohm 5watt resistor.?
With the 1-watt resistor in place, during tune-up or if you experience an antenna problem, you can easily see in excess of .450ma of plate current. That is over 2 watts dumped into R207. When that resistor opens you lose transmitter
power and get a rather strange indication. When you turn the unit on with that resistor open, while in receive mode, you will get slowly increasing plate current indication on a meter plugged into the metering jacks on the power supply.?
When the power supply for the 400A was produced, that resistor was changed to a 5-watt resistor. My personal choice is the square, ceramic, 10-watt 10-ohm resistor?
?
Now for the high voltage bleeder resistors. This issue is complicated by the variations in the Hallicrafters documentation. Some documentation for the 500 series supplies calls out 15k 10watt resistors. Some documentation calls
out 20k 10watt resistors. ?
Over the years I have repaired hundreds of the 150 and 500 power supplies. In power supplies with the 15k 10watt resistors, with a lot of hours of service, you will find three common degradations. First the insulation on the red
wires from the resistors to the capacitors will be melted and blackened at the resistor end. You will also find the platting on the resistor leads flaky and pealing. Then you will notice the solder connection on the terminal strips have crystalized and coated
with lead oxide. In some cases, continuity is lost.?
In the factory units that were produced with the 20k 10watt resistors you do not find the degradations. I personally stocked 20k 20watt replacements?
?Walt Cates,
WD0GOF
?
Your past has no control over your future. Only your NOW can impact your future.
|
Re: SX-110 2nd IF Circuit Design
I may be in error, I have both the SX-62 and SX-62A, and everywhere I read, said there was a SX-42 version, so I "assumed" , yep there's that word.. there was a SX-42A, My mistake.
The SX-62 and 62A have the 2 different front ends you mentioned for the SX-42. Maybe the SX-42 has different runs to capture the differences?
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Scott, Steve and the gang:
it seems strange that both Osterman and Dachis mention the 42 ?but ?neither ??mentions 42A; are we gathering that the IF tubes listed are for? the A version?? ?
I see the ?BAMA manual for the 42 shows
6SK7??6SG7 ?and? ?antiqueradios says the same
When I search for a 42A ,I get only 42 ,, seems that even BAMA does not have a 42A.? Somebody must have dug out the differences.
Don VA3DRL?
?
?
?
???????? I think the 42 vs the 42A have the different front end
?
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Re: SX-110 2nd IF Circuit Design
Scott, Steve and the gang: it seems strange that both Osterman and Dachis mention the 42 ?but ?neither ??mentions 42A; are we gathering that the IF tubes listed are for? the A version?? ? I see the ?BAMA manual for the 42 shows 6SK7??6SG7 ?and? ?antiqueradios says the same When I search for a 42A ,I get only 42 ,, seems that even BAMA does not have a 42A.? Somebody must have dug out the differences. Don VA3DRL? ? ?
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Re: SX-110 2nd IF Circuit Design
Correct.? I made a typo when copying the information over.
73 - Steve, KW4H
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Thanks Walt.? One less thing to worry about. ? 73, ? Gary H. Harmon, Jr. K5JWK 6003 Archwood San Antonio, TX 78239 (210) 657-1549 gharmon@... ? Grroup and List Moderator “Real radios glow in the dark” “Too many projects not enough time” “Just think my sons, some day this will all be yours” “Retirement-Every day is a Saturday except Sunday” ? http://www.grissomroadcoc.org ?
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From: [email protected] < [email protected]> On Behalf Of waltcates Sent: Saturday, October 29, 2022 12:22 PM To: [email protected]Subject: Re: [HallicraftersRadios] Test ? Hi Gary, it works to my house.. Your past has no control over your future. Only your NOW can impact your future.
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Hi Gary, it works to my house..
?Walt Cates,
WD0GOF
?
Your past has no control over your future. Only your NOW can impact your future.
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Just testing to see if my access to this group is working.
?
73,
?
Gary H. Harmon, Jr.
K5JWK
6003 Archwood
San Antonio, TX 78239
(210) 657-1549
gharmon@...
?
Grroup and List Moderator
“Real radios glow in the dark”
“Too many projects not enough time”
“Just think my sons, some day this will all be yours”
“Retirement-Every day is a Saturday except Sunday”
?
http://www.grissomroadcoc.org
?
|
Just testing to see if my access to this group is working. ? 73, ? Gary H. Harmon, Jr. K5JWK 6003 Archwood San Antonio, TX 78239 (210) 657-1549 gharmon@... ? Grroup and List Moderator “Real radios glow in the dark” “Too many projects not enough time” “Just think my sons, some day this will all be yours” “Retirement-Every day is a Saturday except Sunday” ? http://www.grissomroadcoc.org ?
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If it is a 2w resistor that is probably why it is open. The bleeder resistors are 15K 10-watt. I replace them with 20K 10-watt resistors, which reduces the heat dissipated in the chassis. It still bleads off the charge fast enough to be safe.
?Walt Cates,
WD0GOF
?
Your past has no control over your future. Only your NOW can impact your future.
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All great information and thank you.?
I have found that R201 one of two wirewound 15k 2W bleeder resistors is open. R202 is good at 14.7k.? I wouldn't have thought an open bleeder could result in high DC out.?
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30K at 575v is a pretty decent pre-load!
About 20ma.?
That’s 6 watts for each resistor and a total load of 12 watts.?
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All great information and thank you.?
I have found that R201 one of two wirewound 15k 2W bleeder resistors is open. R202 is good at 14.7k.? I wouldn't have thought an open bleeder could result in high DC out.?
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Re: SX-110 2nd IF Circuit Design
The hallicrafters manual in my hand says SX-110 first IF = 6SG7 and the second IF = 6SK7
?Walt Cates,
WD0GOF
?
Your past has no control over your future. Only your NOW can impact your future.
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I think the 42 vs the 42A have the different front ends
Sent from my Verizon 4G LTE Tablet
On Oct 28, 2022 7:28 PM, don Root <drootofallevil@...> wrote:
Steve, ?good work on all this!
I think you originally said? “a 6SK7 was used for the 2nd IF, while a 6SG7 is used for the 1st IF.”? == ??6SG7 then 6SK7
But now you show from Osterman ….
SX-110 (1960-63) 6SG7, 6SH7? ???so I had a look at mine
?
SX-110 (1960-63) 6SG7, 6SH7? >> ???while don’s ?1996 Osterman? book says 6SG7, 6SK7?? ??
Also I noticed…
SX-42 (1947-50) 6SK7, 6SG7?? ?>>??? while don’s ?1996 Osterman? book says ?6SK7,? 6SC7? , 7H7
Wonder if we have the same printing or I need to get back to the eye fixer?
i did not check? all you listed; only those with a 6SG7?
don va3drl
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don Root
waltcates
Bruce Collins