Antique Radios Forum

This is the temporary home of the Antique Radio Forums while a new server to host it is being found. You will have to register here to post. Please Note: None of these topics will be preserved when the original forums are back.
 
HomeCalendarFAQSearchMemberlistUsergroupsRegisterLog in

Share | 
 

 hallicrafters SX-71 acting up again

View previous topic View next topic Go down 
AuthorMessage
smeezekitty

avatar

Posts : 49
Join date : 2010-10-12
Location : Washington/USA

PostSubject: hallicrafters SX-71 acting up again   Wed Oct 13, 2010 9:08 pm

I finally got it working exactly as it should and now its acting up again.
All caps are new ceramic, polyfilm and electrolytic.
All new caps are rated atleast 400v
All resistors more then 15% off are replaced with carbon film and metal oxide rated at 600v.
The problem is when listening to music and some SSB signals, there is a distinct distortion and click sound on bass notes. Also It does not do this all the time
Question
Any help is appreciated.

edit: The sound _APPEARS_ clean when using input from the phono input.
Back to top Go down
View user profile
tubes4life



Posts : 33
Join date : 2010-10-12
Location : northern Florida

PostSubject: Re: hallicrafters SX-71 acting up again   Wed Oct 13, 2010 9:13 pm

Did you check the tubes? I've found that tubes with loose elements can do some mighty strange things...
Back to top Go down
View user profile
smeezekitty

avatar

Posts : 49
Join date : 2010-10-12
Location : Washington/USA

PostSubject: Re: hallicrafters SX-71 acting up again   Wed Oct 13, 2010 9:15 pm

tubes4life wrote:
Did you check the tubes? I've found that tubes with loose elements can do some mighty strange things...
All tubes are tested for shorts and emission.
The rectifier has nearly zero emission but everything else checks out.
Maybe intermittent short in audio output tube?
Back to top Go down
View user profile
tubes4life



Posts : 33
Join date : 2010-10-12
Location : northern Florida

PostSubject: Re: hallicrafters SX-71 acting up again   Wed Oct 13, 2010 9:19 pm

Nah, not if you're getting clean sound from the phono input. But it could definitely be one of the receiving tubes, no doubt. I'd try lightly tapping the tubes with a pencil while the set is running; sometimes that's all it takes to bring out the gremlins.
Back to top Go down
View user profile
smeezekitty

avatar

Posts : 49
Join date : 2010-10-12
Location : Washington/USA

PostSubject: Re: hallicrafters SX-71 acting up again   Wed Oct 13, 2010 9:23 pm

tubes4life wrote:
Nah, not if you're getting clean sound from the phono input. But it could definitely be one of the receiving tubes, no doubt. I'd try lightly tapping the tubes with a pencil while the set is running; sometimes that's all it takes to bring out the gremlins.
Tapping the 6C4 made the volume waver.
Tapping the the voltage regulator made a pop and brief loud hum.
Back to top Go down
View user profile
tubes4life



Posts : 33
Join date : 2010-10-12
Location : northern Florida

PostSubject: Re: hallicrafters SX-71 acting up again   Wed Oct 13, 2010 9:26 pm

Sounds like you've found the culprit(s). Do you have spares to put in there?
Back to top Go down
View user profile
smeezekitty

avatar

Posts : 49
Join date : 2010-10-12
Location : Washington/USA

PostSubject: Re: hallicrafters SX-71 acting up again   Wed Oct 13, 2010 9:27 pm

tubes4life wrote:
Sounds like you've found the culprit(s). Do you have spares to put in there?
No.
I know the socket for the vr150 is questionable (wiggles and the contacts are loose).
Back to top Go down
View user profile
tubes4life



Posts : 33
Join date : 2010-10-12
Location : northern Florida

PostSubject: Re: hallicrafters SX-71 acting up again   Wed Oct 13, 2010 9:36 pm

You could try wiggling the socket terminals to see if that reproduces the problem...if it doesn't, it's most likely the tube.

And I wouldn't be surprised if the miniature tube sockets needed retensioned; those miniature sockets were the worst.
Back to top Go down
View user profile
smeezekitty

avatar

Posts : 49
Join date : 2010-10-12
Location : Washington/USA

PostSubject: Re: hallicrafters SX-71 acting up again   Wed Oct 13, 2010 9:39 pm

tubes4life wrote:
You could try wiggling the socket terminals to see if that reproduces the problem...if it doesn't, it's most likely the tube.

And I wouldn't be surprised if the miniature tube sockets needed retensioned; those miniature sockets were the worst.
I got blasted with a very loud hum when wiggling contacts.
Back to top Go down
View user profile
tubes4life



Posts : 33
Join date : 2010-10-12
Location : northern Florida

PostSubject: Re: hallicrafters SX-71 acting up again   Wed Oct 13, 2010 9:48 pm

Looks like the first order of business will be either retensioning the tube socket, or replacing it if it's too far gone. Just my opinion, but I wouldn't mess with that set again until the tube socket is fixed; if you're getting a loud hum, something is making contact with something it shouldn't be.
Back to top Go down
View user profile
smeezekitty

avatar

Posts : 49
Join date : 2010-10-12
Location : Washington/USA

PostSubject: Re: hallicrafters SX-71 acting up again   Wed Oct 13, 2010 9:53 pm

tubes4life wrote:
Looks like the first order of business will be either retensioning the tube socket, or replacing it if it's too far gone. Just my opinion, but I wouldn't mess with that set again until the tube socket is fixed; if you're getting a loud hum, something is making contact with something it shouldn't be.
What does retention mean?
Nothing is shorting, its just loosing contact and humming.
Back to top Go down
View user profile
tubes4life



Posts : 33
Join date : 2010-10-12
Location : northern Florida

PostSubject: Re: hallicrafters SX-71 acting up again   Wed Oct 13, 2010 9:58 pm

I said "retension", not "retention" Laughing

I'm working on the assumption that this is a miniature socket; if so, pull the tube and using a small screwdriver, gently push each half of the contact inwards, until they are almost touching. Do that with all 7/9 contacts (not sure how many that tube has) and put the tube back in; if it still is loose, you'll have to replace the socket.
Back to top Go down
View user profile
smeezekitty

avatar

Posts : 49
Join date : 2010-10-12
Location : Washington/USA

PostSubject: Re: hallicrafters SX-71 acting up again   Wed Oct 13, 2010 10:01 pm

tubes4life wrote:
I said "retension", not "retention" Laughing

I'm working on the assumption that this is a miniature socket; if so, pull the tube and using a small screwdriver, gently push each half of the contact inwards, until they are almost touching. Do that with all 7/9 contacts (not sure how many that tube has) and put the tube back in; if it still is loose, you'll have to replace the socket.
Its octal.
6C4 is 9 pin but the socket seems fine.
Back to top Go down
View user profile
tubes4life



Posts : 33
Join date : 2010-10-12
Location : northern Florida

PostSubject: Re: hallicrafters SX-71 acting up again   Wed Oct 13, 2010 10:07 pm

If it's octal, you'll have to replace the socket; it's not a tension issue, it's a worn-out socket issue.

The 6C4 sounds like it has loose elements, and should probably be replaced. At least it's a cheap tube; about $5.
Back to top Go down
View user profile
Hemingray



Posts : 5
Join date : 2010-10-12

PostSubject: Re: hallicrafters SX-71 acting up again   Wed Oct 13, 2010 11:32 pm

Quote :

6C4 is 9 pin but the socket seems fine.

6C4 is a 7 pin....
Back to top Go down
View user profile
smeezekitty

avatar

Posts : 49
Join date : 2010-10-12
Location : Washington/USA

PostSubject: Re: hallicrafters SX-71 acting up again   Wed Oct 13, 2010 11:32 pm

Hemingray wrote:
Quote :

6C4 is 9 pin but the socket seems fine.

6C4 is a 7 pin....
Yep Embarassed
Back to top Go down
View user profile
Sponsored content




PostSubject: Re: hallicrafters SX-71 acting up again   

Back to top Go down
 
hallicrafters SX-71 acting up again
View previous topic View next topic Back to top 
Page 1 of 1
 Similar topics
-
» The Awesome Acting Club! - CLOSED
» UNLEASHED Voice Actor Auditions! (Now with PICTURES!)
» Pillars of Eternity
» My paint tool sai is acting like a butt
» Everything Wrong With Sonic Adventure 1 & 2

Permissions in this forum:You cannot reply to topics in this forum
Antique Radios Forum :: Antique Radio Forums :: Electrical/Mechanical Restoration-
Jump to: