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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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22nd Jan 2019, 1:58 pm | #1 |
Retired Dormant Member
Join Date: Jun 2018
Location: Durham, County Durham, UK.
Posts: 2
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Grundig CR 485 Transformer Replacement
Hi,
My portable stereo cassette player will not now function on mains. I have tested on battery without problem(6x 1.5v C cell ). I have tested and replaced the T630ma fuse without success. I do not own a multi meter as yet. Concluding the transformer not working. Can't see any markings on the transformer but concluding output is 9v AC. Can somebody advise what amp. rating I should use for either replacing the transformer or using a DC power brick connected to the battery terminals. |
22nd Jan 2019, 2:57 pm | #2 |
Moderator
Join Date: Jun 2003
Location: Oxford, UK
Posts: 27,936
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Re: Grundig CR 485 Transformer Replacement
9V stabilised at 500mA should be fine. In fact 250mA should be OK if there isn't a CD player built in. Just make sure you connect the supply the right way round.
Replacing the transformer won't be trivially easy if you don't have the right skills and equipment, so a wall wart is the best solution. |
22nd Jan 2019, 4:12 pm | #3 | |
Octode
Join Date: Apr 2007
Location: Hampshire, UK.
Posts: 1,576
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Re: Grundig CR 485 Transformer Replacement
Quote:
To save of space and weight, transformers are usually made to give an excess of voltage output 'off load', this drops down through resistive losses in the windings when you begin to draw current. Therefore, avoid using a transformer which is too big or again you will end up with a surplus of voltage. What is wrong with the original one? Is there a thermal fuse in the primary winding? You need a meter to check this out, do that first. |
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22nd Jan 2019, 4:42 pm | #4 |
Moderator
Join Date: Jun 2003
Location: Oxford, UK
Posts: 27,936
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Re: Grundig CR 485 Transformer Replacement
I agree that it's unlikely the transformer itself has failed, but the OP doesn't appear to have the skills or facilities to do any fault finding, so an external power supply is the simplest solution in the circumstances.
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