Stuck Scan Coils - UK Vintage Radio Repair and Restoration Discussion Forum

brianc · 4th Oct 2008, 9:14 pm

Hi all.
I am restoring a Pye LV30 which is in a very poor state and nowhere near powering up but I needed to get the scan coils off the tube and they were impossible to get off. One thread on the forum suggested that the set be run for a while to warm up the coils - impossible in my case. So I attached my variable bench PSU to the line coils (nearest to the tube neck) and passed 1 amp through them, feeling the winding temperature frequently. After about 2 minutes, the coils were very easy to twist and remove with little or no stress applied to the neck of the tube. I had to clean the inside of the coils as there was a sticky mess - I have no idea what, but the coils now slide up the neck easily.
Cheers
Brian

Framer Dave · 4th Oct 2008, 10:09 pm

Hello Brian,

There should be a prize for an idea like that! Noted for future use.

Regards,

Dave

murphyv310 · 10th Oct 2008, 11:45 am

Hi.
Sounds a good idea.
How hot did the coils get?
Trevor

brianc · 12th Oct 2008, 10:46 am

Quote:

Originally Posted by murphyv310

Hi.
Sounds a good idea.
How hot did the coils get?
Trevor

Hi Trevor
The coils were just warm to the touch but evidently warm enough to soften the grunge that was causing the problem. IMHO, there was absolutely no danger of overheating but keeping an eye (or finger!) on the temperature is obviously vital. Limiting the current to 1A is a good safeguard against overheating.
Cheers
Brian

4th Oct 2008, 9:14 pm	#1
brianc Rest in Peace Join Date: Jun 2004 Location: Burghfield, Reading, Berkshire, UK, Posts: 1,055	Stuck Scan Coils Hi all. I am restoring a Pye LV30 which is in a very poor state and nowhere near powering up but I needed to get the scan coils off the tube and they were impossible to get off. One thread on the forum suggested that the set be run for a while to warm up the coils - impossible in my case. So I attached my variable bench PSU to the line coils (nearest to the tube neck) and passed 1 amp through them, feeling the winding temperature frequently. After about 2 minutes, the coils were very easy to twist and remove with little or no stress applied to the neck of the tube. I had to clean the inside of the coils as there was a sticky mess - I have no idea what, but the coils now slide up the neck easily. Cheers Brian

4th Oct 2008, 10:09 pm	#2
Framer Dave Rest in Peace Join Date: Dec 2006 Location: Near Wrecsam, North Wales Posts: 356	Re: Stuck Scan Coils Hello Brian, There should be a prize for an idea like that! Noted for future use. Regards, Dave

10th Oct 2008, 11:45 am	#3
murphyv310 Dekatron Join Date: Sep 2006 Location: Kilmarnock, Ayrshire, UK. Posts: 5,422	Re: Stuck Scan Coils Hi. Sounds a good idea. How hot did the coils get? Trevor __________________ Cheers, Trevor. MM0KJJ. RSGB, GQRP, WACRAL, K&LARC. Member