Back coated tape - UK Vintage Radio Repair and Restoration Discussion Forum

Roy · 3rd Apr 2011, 10:14 pm

Back coated tape shouldn't be used on domestic machines employing fixed pressure pads, but what about those rotating pressure pads as seen on some Grundigs?

I haven't seen one for a while, but I think the erase head has no pad at all, and the record/replay head has the rotary pad. For the benefit of anyone unfamiliar with these, a plastic wheel with a foam tyre is held against the head face under light spring pressure, and the wheel rotates as the tape passes, so it doesn't drag on the tape in the way that the fixed felt pad does.

Any thoughts from the reel-to-reel specialists? Has anyone tried it?

Roy

ricard · 4th Apr 2011, 7:39 am

Since there's nothing dragging against the back of the tape on those Grundigs, I would expect back coating or not would not make a difference.

But aren't those machines in question very old? I have these rotary pads on my TK819 (mid-50's single motor reversing machine), and I suspect they'd be used on all other members of that family (TK9, TK820, TK830...), but didn't Grundig switch to 'pressure bands' (i.e. a clear strip of plastic (mylar?) with a felt coating) soon afterwards, like on the TK30,35,54 et al and the ever popular TK14 and friends? I don't even remember the similar-vintage (to the TK819) TK5 having that type of rotary pad though I could be wrong there.

/Ricard

DOFFERY · 4th Apr 2011, 9:00 am

The rotary wheels finished after the TK 830/3D the last of the range 9/12/819/820/830, when pressure pads were introduced for the TK5/8, TK20/24/25/30/35 etc. etc. pressure bands came in with the TK 14 range.

Colin.

Roy · 5th Apr 2011, 9:29 am

Agreed, only a few early machines had the rotary pads. I haven't tried using back coated tape on one of these, but I can see no reason why it wouldn't work.

Thanks

Roy

3rd Apr 2011, 10:14 pm	#1
Roy Hexode Join Date: May 2003 Location: Hertfordshire, UK Posts: 258	Back coated tape Back coated tape shouldn't be used on domestic machines employing fixed pressure pads, but what about those rotating pressure pads as seen on some Grundigs? I haven't seen one for a while, but I think the erase head has no pad at all, and the record/replay head has the rotary pad. For the benefit of anyone unfamiliar with these, a plastic wheel with a foam tyre is held against the head face under light spring pressure, and the wheel rotates as the tape passes, so it doesn't drag on the tape in the way that the fixed felt pad does. Any thoughts from the reel-to-reel specialists? Has anyone tried it? Roy

4th Apr 2011, 7:39 am	#2
ricard Octode Join Date: Mar 2006 Location: Lund, Sweden Posts: 1,632	Re: Back coated tape Since there's nothing dragging against the back of the tape on those Grundigs, I would expect back coating or not would not make a difference. But aren't those machines in question very old? I have these rotary pads on my TK819 (mid-50's single motor reversing machine), and I suspect they'd be used on all other members of that family (TK9, TK820, TK830...), but didn't Grundig switch to 'pressure bands' (i.e. a clear strip of plastic (mylar?) with a felt coating) soon afterwards, like on the TK30,35,54 et al and the ever popular TK14 and friends? I don't even remember the similar-vintage (to the TK819) TK5 having that type of rotary pad though I could be wrong there. /Ricard

4th Apr 2011, 9:00 am	#3
DOFFERY Retired Dormant Member Join Date: Aug 2004 Location: Blackpool, Lancashire, UK. Posts: 1,488	Re: Back coated tape The rotary wheels finished after the TK 830/3D the last of the range 9/12/819/820/830, when pressure pads were introduced for the TK5/8, TK20/24/25/30/35 etc. etc. pressure bands came in with the TK 14 range. Colin.

5th Apr 2011, 9:29 am	#4
Roy Hexode Join Date: May 2003 Location: Hertfordshire, UK Posts: 258	Re: Back coated tape Agreed, only a few early machines had the rotary pads. I haven't tried using back coated tape on one of these, but I can see no reason why it wouldn't work. Thanks Roy