Recap or not - UK Vintage Radio Repair and Restoration Discussion Forum

zooterman · 5th Apr 2011, 5:55 pm

Hi All.
Been sorting out a Teac X7r today, new belts, lube and demag, Rw seems a bit slow though, wondering if a full recap will help or will it be a waste of money on this machine, it's a nice clean machine with good heads and light use going by it's condition.
Can't make up my mind what to do

HamishBoxer · 5th Apr 2011, 7:18 pm

Rather than a full recap i would find out first whats causing poor rewind.Is it indeed mechanical?

David

zooterman · 5th Apr 2011, 11:12 pm

I don't think it's mechanical as I have done a complete clean and lube job, and everything is free, will I get the cost of parts and labour back when I try to sell it, that's my question.

Lucien Nunes · 6th Apr 2011, 12:18 am

These decks use DC reel motors, faulty wind can be caused by brush trouble or carbon build-up between the commutator segments. I can't remember how the wind speed is regulated in the X7, but if it is an FG servo then a fluctuating voltage across the motor when running at constant speed is usually a sign that the motor rather than the electronics is at fault.

Lucien

zooterman · 6th Apr 2011, 5:20 pm

Hi Lucian.
Is it poss to strip and clean the motor or best leave it alone. I'm waiting for PCB boards to come from the US for the X1000r, will be in touch when they arrive.
Wal

Lucien Nunes · 7th Apr 2011, 9:34 am

Yes ISTR they're quite easy to service but like many PM DC motors they can be a little bit fiddly to reassemble. Take off the back end, watching out for any nylon shims on the end of the shaft, and being careful not to let the armature hit the magnets as this can cause loss of magnetism. Clean the comm and remove all carbon dust, reassemble using a thin tool to guide the brushes over the comm. Do not let the flat brush springs twist.

Check the motor is receiving full volts first, and that the back tension and arm positions are normal, before going to the trouble of pulling it apart. I can't picture how the motor speed is controlled in the 7" decks, probably not at all during wind as they don't have low-speed search. Only the back-tension is under servo control from the arm positions.

Lucien

5th Apr 2011, 5:55 pm	#1
zooterman Retired Dormant Member Join Date: Jan 2007 Location: Lampeter, Dyfed, Wales, UK. Posts: 369	Recap or not Hi All. Been sorting out a Teac X7r today, new belts, lube and demag, Rw seems a bit slow though, wondering if a full recap will help or will it be a waste of money on this machine, it's a nice clean machine with good heads and light use going by it's condition. Can't make up my mind what to do

5th Apr 2011, 7:18 pm	#2
HamishBoxer Dekatron Join Date: Aug 2007 Location: W.Butterwick, near Doncaster UK. Posts: 8,932	Re: Recap or not Rather than a full recap i would find out first whats causing poor rewind.Is it indeed mechanical? David

5th Apr 2011, 11:12 pm	#3
zooterman Retired Dormant Member Join Date: Jan 2007 Location: Lampeter, Dyfed, Wales, UK. Posts: 369	Re: Recap or not I don't think it's mechanical as I have done a complete clean and lube job, and everything is free, will I get the cost of parts and labour back when I try to sell it, that's my question.

6th Apr 2011, 12:18 am	#4
Lucien Nunes Rest in Peace Join Date: Apr 2008 Location: London, UK. Posts: 2,508	Re: Recap or not These decks use DC reel motors, faulty wind can be caused by brush trouble or carbon build-up between the commutator segments. I can't remember how the wind speed is regulated in the X7, but if it is an FG servo then a fluctuating voltage across the motor when running at constant speed is usually a sign that the motor rather than the electronics is at fault. Lucien

6th Apr 2011, 5:20 pm	#5
zooterman Retired Dormant Member Join Date: Jan 2007 Location: Lampeter, Dyfed, Wales, UK. Posts: 369	Re: Recap or not Hi Lucian. Is it poss to strip and clean the motor or best leave it alone. I'm waiting for PCB boards to come from the US for the X1000r, will be in touch when they arrive. Wal

7th Apr 2011, 9:34 am	#6
Lucien Nunes Rest in Peace Join Date: Apr 2008 Location: London, UK. Posts: 2,508	Re: Recap or not Yes ISTR they're quite easy to service but like many PM DC motors they can be a little bit fiddly to reassemble. Take off the back end, watching out for any nylon shims on the end of the shaft, and being careful not to let the armature hit the magnets as this can cause loss of magnetism. Clean the comm and remove all carbon dust, reassemble using a thin tool to guide the brushes over the comm. Do not let the flat brush springs twist. Check the motor is receiving full volts first, and that the back tension and arm positions are normal, before going to the trouble of pulling it apart. I can't picture how the motor speed is controlled in the 7" decks, probably not at all during wind as they don't have low-speed search. Only the back-tension is under servo control from the arm positions. Lucien