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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc. |
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7th Sep 2020, 11:54 am | #1 |
Moderator
Join Date: Feb 2006
Location: Wembley, Middlesex
Posts: 7,224
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Tandberg TD20
I've been asked to look at a Tandberg TD20 which at some stage was modified for 110V 60Hz
The owner wants it converted back to 240V 50HZ. I presume the motor pulley will need changing unless of course it has two steps, one for 50Hz one for 60Hz. Does anyone know if that's the case or do I have to get a new pulley? |
7th Sep 2020, 2:13 pm | #2 |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
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Re: Tandberg TD20
So far as I can make out from looking at various pictures I would say that the capstan motor pulley needs to be changed, and if the original conversion was done properly the mains VDR along with all the motor capacitors and depending on the PROM IC colour code the three feed resistors for the supply and take up motors (two for the DC supplies to the supply and take up motors and the one for the AC supply to the take up motor when in playback/record mode)
Lawrence. Last edited by ms660; 7th Sep 2020 at 2:30 pm. Reason: duplicate word removed |
7th Sep 2020, 2:24 pm | #3 |
Hexode
Join Date: May 2005
Location: Greater Manchester, UK.
Posts: 496
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Re: Tandberg TD20
Hi Maurice,
Assume it is the 20A ? I believe it has a tapping on the transformer to select 115/230V While this user guide says refer to qualified technician for voltage configuration, it does state in the specification at the end of the document both 115, 230V http://sportsbil.com/tandberg/td-20a-om-english.pdf The schematic shows the transformer has two primary windings in series, so I would assume this is the means for 115/230 configuration http://sportsbil.com/tandberg/td-20a-se-circ-align.PDF All three motors seem to be fed from the secondary of the transformer through speed regulators/switches etc So seems to be just the changes to the transformer tapping Best Regards Chris |
7th Sep 2020, 2:33 pm | #4 |
Hexode
Join Date: May 2005
Location: Greater Manchester, UK.
Posts: 496
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Re: Tandberg TD20
There is a table of resistor/cap changes on the schematic (Table 2)
This shows different values for 115/230 Assume this motor is regulated by AC frequency so it will need a pulley change. There is also a varistor to change on the AC input. Best Regards Chris |
7th Sep 2020, 2:55 pm | #5 |
Moderator
Join Date: Feb 2006
Location: Wembley, Middlesex
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Re: Tandberg TD20
Thanks everyone
I wonder where i can get a pulley from? I doubt the owner would have it. |
7th Sep 2020, 10:37 pm | #6 |
Hexode
Join Date: May 2005
Location: Greater Manchester, UK.
Posts: 496
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Re: Tandberg TD20
If you can measure the motor shaft diameter and also the diameter of the portion where the belt runs then there must be somebody on the forum who has a lathe and some aluminium bar who could make one for you (with 20% increase on the diameter).
Best Regards Chris |
13th Sep 2020, 6:19 pm | #7 |
Hexode
Join Date: Mar 2008
Location: Margate, Kent, UK.
Posts: 355
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Re: Tandberg TD20
Would the pulley be the same on the series12 or 15?
Regards Paul |
13th Sep 2020, 10:50 pm | #8 |
Moderator
Join Date: Feb 2006
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Re: Tandberg TD20
No.
The owner has decided not to go ahead with the conversion. |