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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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Old 28th Apr 2017, 3:14 pm   #1
Hammonds
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Default Brenell Mk5 series 2 deck heads o/c?

I have this Brenell Mk5 series 2 deck, which I need to sell on behalf of three sisters, whose father was a BBC engineer and who has just died.

What is the best way, please, of checking the continuity in the heads with my Fluke without risking damaging them?

Any help would be welcome.

Thanks

Dave
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Old 28th Apr 2017, 6:02 pm   #2
julie_m
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Default Re: Brenell Mk5 series 2 deck heads o/c?

Set the meter to a resistance range and apply the probes to the terminals.

The potential danger to tape heads with analogue meters was never burning out the coil (there is more power going through the heads during recording than any normal multimeter puts out), but magnetising the core. Which then leaves your precious tapes getting quieter with every listen ..... No prizes for guessing how I discovered this
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Old 29th Apr 2017, 9:49 am   #3
lesmw0sec
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Default Re: Brenell Mk5 series 2 deck heads o/c?

Even if you use AC to check head continuity, there is a danger of magnetising the core unless the signal can be initiated and removed slowly. In either case if you have access to a head de-magnetiser (basically a solenoid powered from 50c/s, which gives a strong field), this should clear the heads.
The method is to switch on the de-mag a foot or so away from the heads, bring it into close contact with the head for a few seconds, then slowly move it away before switching off.
Be warned though, that the same instrument has the capability to erase tapes, so they should be well away!
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Old 30th Apr 2017, 3:51 pm   #4
high_vacuum_house
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Smile Re: Brenell Mk5 series 2 deck heads o/c?

If you are worried about magnetising the head, could you put a 10k resistor in series with the head on a multimeter resistance range. The current flowing would be pretty much negliable.
Christopher Capener
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Old 13th Jun 2017, 8:58 pm   #5
Hammonds
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Default Re: Brenell Mk5 series 2 deck heads o/c?

Hi Folks

All your answers make complete sense - I realise now, any current will magnetise the heads to a certain extent!

Thanks very much.

MODs please close - thanks

Dave
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Old 3rd Aug 2017, 10:14 am   #6
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Default Re: Brenell Mk5 series 2 deck heads o/c?

Hi folks

This tape deck and Brenell R2R recorder are now with Andy.

Mods - please close.

Thanks
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