Hacker Super Sovereign RP75 - 505 Am IF board L2 Slug(s) - UK Vintage Radio Repair and Restoration Discussion Forum

Ti Pwun · 6th Apr 2016, 4:32 pm

I was at the stage of aligning thiis radio but I encountered an unmovable slug - on close inspection it was cracked and I had to perform some surgery to get out the pieces. Because the plastic was cracked as well (on both sides), I trimmed it short and using a section from a donor former, I added a solid piece back on.

I temporarily used a long slug to make sure that the thread spacing was in the right position on both halves as the glue dried, it can now be wound in and out.

I only ever use plastic trimming tools and it's easy to adjust now but as well as being cracked, the slug was chipped around the slot so I'm guessing a metal screw driver was used at some point. Replacing it isn't a problem because I have plenty of short and long spares.

But here's the question: can anyone confirm if this requires one slug or two? When I got the pieces out, it appeared to only half come out and half was left in, which looked relatively flat. Cracked as well but flat.

I got that out as well but because of how the pieces looked after carefully removing them (damaging the slug rather than anything else), I cannot be sure if it should be just a single slug.

I'm just trying to avoid putting two in and risking them clashing together in an effort to trim them if it requires just one.

I noticed that the diode in the can was damaged as well and appeared to have a blob of glue holding it together so I replaced that.

The temporary slug is still in the former while it dries fully but the threads are clear of glue so it's only maintaining the correct spacing.

Hope that all makes sense but here are the pics of the repair. Bit of a pain having to resort to this but when the slug is cracked and it can't be adjusted or removed, what can you do if you don't have a spare?

stevehertz · 6th Apr 2016, 6:10 pm

Excellent job.

Nuvistor · 6th Apr 2016, 8:34 pm

If this is the last IF transformer with the detector diode I would think one slug tuning the primary.
What does the circuit and alignment instructions state?
Frank

Ti Pwun · 7th Apr 2016, 6:48 am

Quote:

Originally Posted by stevehertz

Excellent job.

Thanks! I've had to do this on several radios now, though, so I've had a bit of practice.

Frank, the IF is set by a resonator so there isn't really a procedure to follow as such - the manual merely states that L2 (3rd IF) can be trimmed if IF adjustment is required. Feeding 470KHz in and getting a weak response made me think it needed that adjustment, which wasn't possible.

I assume it's a single slug and it dawned on me last night that oerhaps the one slug was cracked and another was then inserted from the bottom in an effort to sort things out. That cracked as well and the job was abandoned. I don't know, but that would explain there being two slugs inside the former. After getting the pieces under a strong magnifier I can definitely see a flat on both ends of one of the short pieces I first removed.

I'll go with a single slug and see how it goes. I was just trying to find out for sure to avoid putting any strain on the repair.

Nuvistor · 7th Apr 2016, 8:26 am

I think you are correct, it will be single, I don't have the manual but the detector winding will unlikely be tuned.
Frank

mhennessy · 7th Apr 2016, 11:48 am

I'd also concur with that; I've never found anything but a single slug in a detector coil. And yes, an heroic repair job

Ti Pwun · 7th Apr 2016, 4:33 pm

Thanks Mark. It is indeed supposed to be just one slug. The can is back in the radio now and it's working well - I was able to find a peak this time without effort. I had coated the slug with talc to prevent it from sticking and it turns freely but I'll seal it with a (tiny) dribble of beeswax when it's in its final position.

Thanks all.

6th Apr 2016, 4:32 pm	#1
Ti Pwun Heptode Join Date: Aug 2013 Location: Bradford, West Yorkshire, UK. Posts: 888	Hacker Super Sovereign RP75 - 505 Am IF board L2 Slug(s) I was at the stage of aligning thiis radio but I encountered an unmovable slug - on close inspection it was cracked and I had to perform some surgery to get out the pieces. Because the plastic was cracked as well (on both sides), I trimmed it short and using a section from a donor former, I added a solid piece back on. I temporarily used a long slug to make sure that the thread spacing was in the right position on both halves as the glue dried, it can now be wound in and out. I only ever use plastic trimming tools and it's easy to adjust now but as well as being cracked, the slug was chipped around the slot so I'm guessing a metal screw driver was used at some point. Replacing it isn't a problem because I have plenty of short and long spares. But here's the question: can anyone confirm if this requires one slug or two? When I got the pieces out, it appeared to only half come out and half was left in, which looked relatively flat. Cracked as well but flat. I got that out as well but because of how the pieces looked after carefully removing them (damaging the slug rather than anything else), I cannot be sure if it should be just a single slug. I'm just trying to avoid putting two in and risking them clashing together in an effort to trim them if it requires just one. I noticed that the diode in the can was damaged as well and appeared to have a blob of glue holding it together so I replaced that. The temporary slug is still in the former while it dries fully but the threads are clear of glue so it's only maintaining the correct spacing. Hope that all makes sense but here are the pics of the repair. Bit of a pain having to resort to this but when the slug is cracked and it can't be adjusted or removed, what can you do if you don't have a spare? Attached Thumbnails

6th Apr 2016, 6:10 pm	#2
stevehertz Dekatron Join Date: Sep 2011 Location: Rugeley, Staffordshire, UK. Posts: 8,834	Re: Hacker Super Sovereign RP75 - 505 Am IF board L2 Slug(s) Excellent job. __________________ A digital radio is the latest thing, but a vintage wireless is forever..

6th Apr 2016, 8:34 pm	#3
Nuvistor Dekatron Join Date: Aug 2013 Location: Wigan, Greater Manchester, UK. Posts: 9,433	Re: Hacker Super Sovereign RP75 - 505 Am IF board L2 Slug(s) If this is the last IF transformer with the detector diode I would think one slug tuning the primary. What does the circuit and alignment instructions state? Frank

7th Apr 2016, 8:26 am	#5
Nuvistor Dekatron Join Date: Aug 2013 Location: Wigan, Greater Manchester, UK. Posts: 9,433	Re: Hacker Super Sovereign RP75 - 505 Am IF board L2 Slug(s) I think you are correct, it will be single, I don't have the manual but the detector winding will unlikely be tuned. Frank

7th Apr 2016, 11:48 am	#6
mhennessy Dekatron Join Date: Jul 2007 Location: Evesham, Worcestershire, UK. Posts: 4,244	Re: Hacker Super Sovereign RP75 - 505 Am IF board L2 Slug(s) I'd also concur with that; I've never found anything but a single slug in a detector coil. And yes, an heroic repair job

7th Apr 2016, 4:33 pm	#7
Ti Pwun Heptode Join Date: Aug 2013 Location: Bradford, West Yorkshire, UK. Posts: 888	Re: Hacker Super Sovereign RP75 - 505 Am IF board L2 Slug(s) Thanks Mark. It is indeed supposed to be just one slug. The can is back in the radio now and it's working well - I was able to find a peak this time without effort. I had coated the slug with talc to prevent it from sticking and it turns freely but I'll seal it with a (tiny) dribble of beeswax when it's in its final position. Thanks all.