Forums :: Resources :: Features :: Photo Gallery :: Vintage Radio Shows :: Archives :: Books
Support This Site: Contributors :: Advertise


It is currently Feb Tue 28, 2017 12:03 am


All times are UTC [ DST ]





Post New Topic Post Reply  [ 12 posts ] 
Author Message
 Post subject: Hallicrafters SX-115 Repair Tips
PostPosted: Jan Wed 18, 2017 4:19 am 
Member
User avatar

Joined: Jan Wed 20, 2016 7:43 pm
Posts: 56
Today I had an opportunity to pick up a SX-115. Overall appearance is pretty good although the cabinet top is a bit out of alignment. The chassis was a bit dirty with crud building up around the tube sockets, transformer, etc. Cleaned most of that up. Replaced the tubular caps (only a few) and one electrolytic. Ordered a new filter cap can and will replace once it arrives. The radio has been on for past 6 hours and seems to be playing quite nicely.

One issue I noticed is when turning the Tuning knob I hear a repeated clicking...actually clicking with a twang. Something is amiss but not sure what. Will look into it when I replace the can. Any thoughts on what it may be would be appreciated. I noticed the tuning mechanism (gears) have some crud and may need to be lubricated. Tips on doing this appreciated.

Finally if anybody has info on the SX-115 serial numbers and production runs that would be great. The number of this particular SX-115 is 115002 214752

Thanks...

Harry


Top
 Profile  
 
 Post subject: Re: Hallicrafters SX-115 Repair Tips
PostPosted: Jan Wed 18, 2017 3:59 pm 
Member

Joined: Jan Mon 28, 2013 9:35 pm
Posts: 663
Location: Santa Rosa, CA
The clicking could be crud on the variable cap plates causing an intermittent
short or more likely poor contact to the rotor.

A while back I restored an SX-117 and HT-44 which are from the same
period. One problem I had was poor grounds due to very minor corrosion
under many of the riveted tube sockets and terminal strips.
Wasn't visible until I removed some of the rivets. Star washers
should have been used. If you start having strange problems keep this
in mind.
Steve


Top
 Profile  
 
 Post subject: Re: Hallicrafters SX-115 Repair Tips
PostPosted: Jan Wed 18, 2017 4:28 pm 
Member
User avatar

Joined: Jun Sun 19, 2011 2:31 pm
Posts: 3841
Harry,

Is the clicking mechanical or is it coming through the receiver audio system? If mechanical take a close look at the dial lock/cal set mechanism to see if it is releasing completely in the free position. Note that the VFO mechanism also tunes the variable first IF so don't overlook that when tracking down the noise.

Rodger WQ9E


Top
 Profile  
 
 Post subject: Re: Hallicrafters SX-115 Repair Tips
PostPosted: Jan Wed 18, 2017 4:44 pm 
Member
User avatar

Joined: Jan Wed 20, 2016 7:43 pm
Posts: 56
Steve and Roger,

It's a mechanical sound. Will tinker with the CAL/Lock and see if that's it. The sound is coming from the tuning knob area so that could be it.

Thanks,

Harry


Top
 Profile  
 
 Post subject: Re: Hallicrafters SX-115 Repair Tips
PostPosted: Jan Wed 18, 2017 8:26 pm 
Member
User avatar

Joined: Jan Wed 20, 2016 7:43 pm
Posts: 56
Well after some exploration using my XYL's razor sharp hearing (she can hear a conversation 4 tables away at a crowded restaurant on a Saturday night) we located the source of the clicking. It's coming from the housing for the C33A and C33B trimmers. Will check it out further when I replace the electrolytic can. Hopefully I can remove that housing without too much fuss.


Top
 Profile  
 
 Post subject: Re: Hallicrafters SX-115 Repair Tips
PostPosted: Jan Wed 18, 2017 11:53 pm 
Member
User avatar

Joined: Jun Sun 19, 2011 2:31 pm
Posts: 3841
Hopefully that will be a simple repair. Make sure it isn't just a clearance issue where the shaft enters the housing; there is a little play available in placing the coupler to avoid having it to close to the housing.

These are the capacitors that cause the tuning of the variable first IF to follow the VFO so make sure that you record the setting of these capacitors versus the VFO tuning before removing the coupling to avoid lots of alignment/tracking fun.

Rodger WQ9E


Top
 Profile  
 
 Post subject: Re: Hallicrafters SX-115 Repair Tips
PostPosted: Jan Thu 19, 2017 12:08 am 
Member
User avatar

Joined: Jan Wed 20, 2016 7:43 pm
Posts: 56
Rodger, thanks.

The top of the housing is dimpled. I'm wondering whether rotors are hitting that. Won't really know until I remove the housing. Hopefully that's straight forward.


Top
 Profile  
 
 Post subject: Re: Hallicrafters SX-115 Repair Tips
PostPosted: Jan Sat 28, 2017 4:00 am 
Member
User avatar

Joined: Jan Wed 20, 2016 7:43 pm
Posts: 56
So I've gone through the SX-115 and replaced a number of resistors, the filter caps, and most of the tubular mylar caps (.0022, .047 and .22). I say most because the schematic and parts list show four 0.22mf mylars (C42, C82, C100 and C130), yet I found and replaced only three and a 0.22 mylar cap is not easy to miss. I cannot find C130 and wondering if (a) it's hiding somewhere or (b) there was a manufacturing update and only three mylar 0.22s were used.

Thoughts?

Thanks...Harry


Top
 Profile  
 
 Post subject: Re: Hallicrafters SX-115 Repair Tips
PostPosted: Jan Sat 28, 2017 2:15 pm 
Member
User avatar

Joined: Jun Sun 19, 2011 2:31 pm
Posts: 3841
Harry,

C-130 bypasses the RF gain control line and would normally be mounted near the RF gain pot. It has been too long since I have been inside my SX-115 to remember a location. There isn't much connected to the manual gain bus in the SX-115 so at worst case tracing the line shouldn't be too difficult.

However as long as the RF gain control is working normally you needn't worry about C130. If it shorts or goes leaky the worst that will happen is that reducing the RF gain control will no longer reduce gain and the receiver will no longer fully mute when in the standby position; there won't be any collateral damage like there is when some capacitors short.

Rodger WQ9E


Top
 Profile  
 
 Post subject: Re: Hallicrafters SX-115 Repair Tips
PostPosted: Jan Sat 28, 2017 2:29 pm 
Member
User avatar

Joined: Jan Wed 20, 2016 7:43 pm
Posts: 56
Rodger,

Thanks. Yes, found it on the schematic but nowhere to be found in the receiver. More curious than anything else. Radio plays fine albeit could use an alignment. Have a few more resistors to replace (1 and 2 watts I didn't have).

Harry


Top
 Profile  
 
 Post subject: Re: Hallicrafters SX-115 Repair Tips
PostPosted: Jan Sat 28, 2017 3:06 pm 
Member
User avatar

Joined: Jun Sun 19, 2011 2:31 pm
Posts: 3841
You are welcome Harry. Did you cure the mechanical clicking issue?

Rodger WQ9E


Top
 Profile  
 
 Post subject: Re: Hallicrafters SX-115 Repair Tips
PostPosted: Jan Sat 28, 2017 8:14 pm 
Member
User avatar

Joined: Jan Wed 20, 2016 7:43 pm
Posts: 56
Rodger,

I think so. There were vibrations on the capacitor housing as I turned the tuning knob. Now whether the shaft and/or capacitor was hitting the housing or vibrations were traveling from the source up there is unclear. I oiled the capacitor / shaft bearings and that seemed to help a great deal. However, from time to time the click and vibration returns. So I'm beginning to think it may be in the gearing.

Harry


Top
 Profile  
 
Post New Topic Post Reply  [ 12 posts ]  Moderator: Sandy

All times are UTC [ DST ]


Who is online

Users browsing this forum: Google [Bot], MSNbot Media, wrnewton and 8 guests



Search for:
Jump to:  




















Privacy Policy :: Powered by phpBB