BSR UA8 turntable - velocity trip issue - UK Vintage Radio Repair and Restoration Discussion Forum

awc · 3rd Oct 2015, 12:40 pm

Although fully serviced, I couldn't get the velocity trip on this deck to operate consistently.

After much unsuccessful playing around with the trip, I noticed that the pawl on the turntable is in fact a sort of cut off grub screw and the face fronting the trip had become worn into a slope.

The effect of this was that the trip was sliding off the grub screw instead of engaging with it and operating the arm lift.

Turning the grub screw round 180 degrees so it presented a unused side to meet the trip completely sorted the problem.

Alex

Nickthedentist · 3rd Oct 2015, 4:10 pm

Useful tip, Alex. Could we have a pic please?

awc · 4th Oct 2015, 9:40 am

Well here they are, difficult to get the screw completely in focus but P1 is the before and P2 the after.

Alex

Radio_Dave · 4th Oct 2015, 11:25 am

Hi Alex,

I've never seen a screw there before. I imagine somebody's put it there because the cam has worn away.

David

Mike Phelan · 4th Oct 2015, 11:52 am

David's right. The alloy can get worn in time.

awc · 4th Oct 2015, 3:01 pm

Well, all I can say is that the grub screw has a domed end, rather than the usual flat one and the hole in the cam has a matching hollow. I guess we need someone with the same model deck to check their one and report.

Alex

awc · 14th Oct 2015, 5:12 pm

I've had the opportunity of examining another UA8 and Radio Dave was quite right, the grub screw must have been inserted at a later date to compensate for wear on the cam as lack of adjustment elsewhere meant it was the only option.

I've also noticed that a blob of solder was put on the pointed end of the operating lever in an attempt to get it to push the velocity trip over a bit further!

Many thanks to all who offered advice .

Alex

rswanborough · 15th Oct 2015, 1:06 pm

In the mid 60's I was told that BSR stood for British Standard Rumble. Horrible decks.

3rd Oct 2015, 12:40 pm	#1
awc Retired Dormant Member Join Date: Jul 2005 Location: Somerset, UK. Posts: 334	BSR UA8 turntable - velocity trip issue Although fully serviced, I couldn't get the velocity trip on this deck to operate consistently. After much unsuccessful playing around with the trip, I noticed that the pawl on the turntable is in fact a sort of cut off grub screw and the face fronting the trip had become worn into a slope. The effect of this was that the trip was sliding off the grub screw instead of engaging with it and operating the arm lift. Turning the grub screw round 180 degrees so it presented a unused side to meet the trip completely sorted the problem. Alex

3rd Oct 2015, 4:10 pm	#2
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,844	Re: BSR UA8 turntable - velocity trip issue Useful tip, Alex. Could we have a pic please?

4th Oct 2015, 9:40 am	#3
awc Retired Dormant Member Join Date: Jul 2005 Location: Somerset, UK. Posts: 334	Re: BSR UA8 turntable - velocity trip issue Well here they are, difficult to get the screw completely in focus but P1 is the before and P2 the after. Alex Attached Thumbnails

4th Oct 2015, 11:25 am	#4
Radio_Dave Nonode Join Date: Jun 2004 Location: Norwich, Norfolk, UK. Posts: 2,543	Re: BSR UA8 turntable - velocity trip issue Hi Alex, I've never seen a screw there before. I imagine somebody's put it there because the cam has worn away. David __________________ http://www.youtube.com/ My Nixie Clocks

4th Oct 2015, 11:52 am	#5
Mike Phelan Dekatron Join Date: Nov 2003 Location: Near Leeds, West Yorkshire, UK Posts: 4,609	Re: BSR UA8 turntable - velocity trip issue David's right. The alloy can get worn in time. __________________ Mike.

4th Oct 2015, 3:01 pm	#6
awc Retired Dormant Member Join Date: Jul 2005 Location: Somerset, UK. Posts: 334	Re: BSR UA8 turntable - velocity trip issue Well, all I can say is that the grub screw has a domed end, rather than the usual flat one and the hole in the cam has a matching hollow. I guess we need someone with the same model deck to check their one and report. Alex

14th Oct 2015, 5:12 pm	#7
awc Retired Dormant Member Join Date: Jul 2005 Location: Somerset, UK. Posts: 334	Re: BSR UA8 turntable - velocity trip issue I've had the opportunity of examining another UA8 and Radio Dave was quite right, the grub screw must have been inserted at a later date to compensate for wear on the cam as lack of adjustment elsewhere meant it was the only option. I've also noticed that a blob of solder was put on the pointed end of the operating lever in an attempt to get it to push the velocity trip over a bit further! Many thanks to all who offered advice . Alex

15th Oct 2015, 1:06 pm	#8
rswanborough Retired Dormant Member Join Date: May 2011 Location: Johannesburg, South Africa. Posts: 32	Re: BSR UA8 turntable - velocity trip issue In the mid 60's I was told that BSR stood for British Standard Rumble. Horrible decks.