An unused Garrard RC70B - UK Vintage Radio Repair and Restoration Discussion Forum

dalgwcobl · 16th Feb 2018, 12:05 am

I've just 'won' an RC70B on eBay. It's boxed (although the label on the box says it's an RC75A). The unit is as new and unused. Having applied a few drops of light machine oil to the turntable main bearing, which was seized, the changer mechanism works perfectly. It even came with a small cloth bag containing mounting hardware, including little coil springs.
The only problem, as usual, is the magnetic pickup. The damping rubber, which is a piece of flattened red tubing, is still pliable, but probably too stiff, while the armature is sitting too close to one pole-piece. I have attempted to centralise the armature using the two grub-screws, but there's not enough thread to get it centred. The pickup produces an output, but it is distorted. I'm sure the armature is rattling against the pole piece, which doesn't help, and I'm using a small transistor amp, which will not be a good match. The output is at quite a good level, so magnet and coil seem OK. I'm just working up to trying to sort it out without damaging anything. Incidentally, looking at previous posts, the head unplugs easily from the arm, which is not surprising given the unit's condition.
Has anyone managed to get one of these pickups to work well? It's in such good condition, it would be a shame not to get it working properly. I could use it as part of a talk on the history of recorded music.

electrogram · 16th Feb 2018, 12:42 am

i have repaired a couple of these in the past, they work well. repalcing the rubber parts got mine going. iirc i used two layers of cycle inner tube glued together for the armature centreing. I expect the rc75 box was for the new rc75(new fangled 3-speed) that was fitted to the radiogram the rc70b(old 78rpm only) was removed from.

Hartley118 · 16th Feb 2018, 8:21 am

Yes, the Garrard head does unplug from the arm, though mine didn't do so particularly readily, requiring the removal of a set screw and warming up some adhesive that was holding in the old head, followed by gentle brute force!

What I was then delighted to find is that arm will accept a Decca XMS plugin head of the 'club head' style, as used in the Decola and Deccalian. These give some of the best available reproduction of 78s and the sapphire stylus relieves you of the need to keep changing needles.

Martin

Techman · 16th Feb 2018, 2:53 pm

That deck would have probably had not a lot more than a couple or three years use in a gram bought new in the late forties due to the technology changing so fast as to make it quickly obsolete with the 33 and 45 rpm records starting to become available by the end of the decade. A deck with the new speeds would have been fitted and the hardly used old deck put in the box the new deck came in. I would have said that the deck could have had only 18 months use if the box for the replacement deck had been labeled RC72, which was the first three speed deck made by Garrard, the RC75 coming out a year or two later.

Techman · 16th Feb 2018, 3:00 pm

As I've also posted in the Marconi radiogram thread, the pickup head will need re-building. If you do a forum search you'll find a number of past threads describing how to re-build these magnetic heads and replace the age hardened rubber suspension. Remember, don't attempt to play any good 78 records on it as it is as it'll seriously damage them!

Techman · 16th Feb 2018, 3:08 pm

And again, I keep remembering things about this particular deck - It doesn't have much of a weight counterbalance, other than a sort of clothes peg type spring if I remember rightly, so be careful if you try to run it with different pickup heads. I've seen them with bits of wood such as match sticks jammed under this spring so as to try to decrease the tracking weight.

dalgwcobl · 16th Feb 2018, 6:42 pm

Thanks for that chaps. The comment about the box being for its replacement makes a lot of sense! There was no mains lead attached (the connector terminals looked unused) but there was a piece of twisted pair lead soldered (badly) to the pickup terminal board.
I'll certainly have a go at resurrecting the pickup - but in the meantime, does anyone have a Decca XMS going begging?!!

dalgwcobl · 16th Feb 2018, 11:09 pm

Success! With extreme care, under a bright light and magnifier, I managed to dismantle the pickup and withdraw the armature. The red rubber suspension tubes were still quite soft, but had been 'pinched' in place. By rotating them 90 degrees to put the softest parts in position, I was able to re-insert the armature into place and position it precisely in between the pole pieces. For the top damper, I tried two thickness of Royal Mail's best rubber band, pending some silicon tubing. Result? It burst into life and produced a stonking output to my little transistor amplifier, and the sound quality was amazingly good. I'll source some suitable tubing for a more permanent repair, but the result was amazingly good. The changer mechanism works beautifully, so it looks like a good result.
I'll report on progress with some silicon tubing.

16th Feb 2018, 12:05 am	#1
dalgwcobl Pentode Join Date: Dec 2008 Location: Royston, Hertfordshire, UK. Posts: 131	An unused Garrard RC70B I've just 'won' an RC70B on eBay. It's boxed (although the label on the box says it's an RC75A). The unit is as new and unused. Having applied a few drops of light machine oil to the turntable main bearing, which was seized, the changer mechanism works perfectly. It even came with a small cloth bag containing mounting hardware, including little coil springs. The only problem, as usual, is the magnetic pickup. The damping rubber, which is a piece of flattened red tubing, is still pliable, but probably too stiff, while the armature is sitting too close to one pole-piece. I have attempted to centralise the armature using the two grub-screws, but there's not enough thread to get it centred. The pickup produces an output, but it is distorted. I'm sure the armature is rattling against the pole piece, which doesn't help, and I'm using a small transistor amp, which will not be a good match. The output is at quite a good level, so magnet and coil seem OK. I'm just working up to trying to sort it out without damaging anything. Incidentally, looking at previous posts, the head unplugs easily from the arm, which is not surprising given the unit's condition. Has anyone managed to get one of these pickups to work well? It's in such good condition, it would be a shame not to get it working properly. I could use it as part of a talk on the history of recorded music. Attached Thumbnails

16th Feb 2018, 12:42 am	#2
electrogram Heptode Join Date: Jul 2008 Location: Hereford, UK. Posts: 719	Re: An unused Garrard RC70B i have repaired a couple of these in the past, they work well. repalcing the rubber parts got mine going. iirc i used two layers of cycle inner tube glued together for the armature centreing. I expect the rc75 box was for the new rc75(new fangled 3-speed) that was fitted to the radiogram the rc70b(old 78rpm only) was removed from.

16th Feb 2018, 8:21 am	#3
Hartley118 Nonode Join Date: Aug 2015 Location: Cambridge, Cambs. UK. Posts: 2,198	Re: An unused Garrard RC70B Yes, the Garrard head does unplug from the arm, though mine didn't do so particularly readily, requiring the removal of a set screw and warming up some adhesive that was holding in the old head, followed by gentle brute force! What I was then delighted to find is that arm will accept a Decca XMS plugin head of the 'club head' style, as used in the Decola and Deccalian. These give some of the best available reproduction of 78s and the sapphire stylus relieves you of the need to keep changing needles. Martin __________________ BVWS Member

16th Feb 2018, 2:53 pm	#4
Techman Dekatron Join Date: Nov 2009 Location: Lincolnshire, UK. Posts: 5,000	Re: An unused Garrard RC70B That deck would have probably had not a lot more than a couple or three years use in a gram bought new in the late forties due to the technology changing so fast as to make it quickly obsolete with the 33 and 45 rpm records starting to become available by the end of the decade. A deck with the new speeds would have been fitted and the hardly used old deck put in the box the new deck came in. I would have said that the deck could have had only 18 months use if the box for the replacement deck had been labeled RC72, which was the first three speed deck made by Garrard, the RC75 coming out a year or two later.

16th Feb 2018, 3:00 pm	#5
Techman Dekatron Join Date: Nov 2009 Location: Lincolnshire, UK. Posts: 5,000	Re: An unused Garrard RC70B As I've also posted in the Marconi radiogram thread, the pickup head will need re-building. If you do a forum search you'll find a number of past threads describing how to re-build these magnetic heads and replace the age hardened rubber suspension. Remember, don't attempt to play any good 78 records on it as it is as it'll seriously damage them!

16th Feb 2018, 3:08 pm	#6
Techman Dekatron Join Date: Nov 2009 Location: Lincolnshire, UK. Posts: 5,000	Re: An unused Garrard RC70B And again, I keep remembering things about this particular deck - It doesn't have much of a weight counterbalance, other than a sort of clothes peg type spring if I remember rightly, so be careful if you try to run it with different pickup heads. I've seen them with bits of wood such as match sticks jammed under this spring so as to try to decrease the tracking weight.

16th Feb 2018, 6:42 pm	#7
dalgwcobl Pentode Join Date: Dec 2008 Location: Royston, Hertfordshire, UK. Posts: 131	Re: An unused Garrard RC70B Thanks for that chaps. The comment about the box being for its replacement makes a lot of sense! There was no mains lead attached (the connector terminals looked unused) but there was a piece of twisted pair lead soldered (badly) to the pickup terminal board. I'll certainly have a go at resurrecting the pickup - but in the meantime, does anyone have a Decca XMS going begging?!!

16th Feb 2018, 11:09 pm	#8
dalgwcobl Pentode Join Date: Dec 2008 Location: Royston, Hertfordshire, UK. Posts: 131	Re: An unused Garrard RC70B Success! With extreme care, under a bright light and magnifier, I managed to dismantle the pickup and withdraw the armature. The red rubber suspension tubes were still quite soft, but had been 'pinched' in place. By rotating them 90 degrees to put the softest parts in position, I was able to re-insert the armature into place and position it precisely in between the pole pieces. For the top damper, I tried two thickness of Royal Mail's best rubber band, pending some silicon tubing. Result? It burst into life and produced a stonking output to my little transistor amplifier, and the sound quality was amazingly good. I'll source some suitable tubing for a more permanent repair, but the result was amazingly good. The changer mechanism works beautifully, so it looks like a good result. I'll report on progress with some silicon tubing.